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Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Land Acknowledgment ii
LAND ACKNOWLEDGMENT
We wish to recognize and respect Kānaka Maoli people as the original and continuing stewards of the
land known as Hawaiʻi County. Through the ahupua‘a system, Kānaka Maoli people managed the
island waters and land for over a thousand years. Acknowledging the land is an expression of gratitude
to the territory that nurtures us and the host culture and people who have built a relationship with and
understanding of the land. Climate change is inextricably linked to the exploitation of people, land, and
nature. Land acknowledgements recognize that this exploitation is tied to colonialism as a current and
ongoing process and that governments have played a significant role in facilitating colonization on this
land. The pursuit of colonization has resulted in significant loss of traditional knowledge, cultural
practices, and native ecosystems that are essential for stewarding nature and preventing climate
change. While it is outside the scope of this document, it is essential that the restoration and
conservation of these traditional systems of knowing and ecological stewardship guide climate change
mitigation and adaptation.
Climate change is an existential threat to all life and natural systems globally and here in Hawaiʻi. The
natural cycle of greenhouse gases flowing from land and water to air (the greenhouse gas effect)
enables life as we know it to exist. However, human activities have created an enhanced greenhouse
effect that causes unprecedented warming of the Earth’s atmosphere and oceans. This warming
triggers complex, cascading effects that jeopardize natural systems on Earth. To restore balance to our
natural system, we need to reduce our greenhouse gas emissions at the local level. In order to prepare
for the current and future effects of climate change, we need to weave climate adaptation into our
efforts to build resilient communities. This Integrated Climate Action Plan (ICAP) for the Island of
Hawaiʻi establishes a greenhouse gas emissions baseline for the County, describes the impacts of
climate change on natural hazards and community systems, and identifies both climate mitigation and
adaptation actions that Hawaiʻi County can take to reduce or minimize these effects.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Acknowledgments iii
ACKNOWLEDGMENTS
The ICAP was developed and reviewed with the assistance of consultants, a Working Group and
Technical Reviewers. Bethany Morrison, County Planning, and Kendra Obermaier, County Research
and Development, led the planning effort. Amy DeBay (Focused Planning Solutions) and Kitty Courtney
(Tetra Tech, Inc.) provided technical support in developing the plan framework, risk and exposure
analysis, and Climate Cascade Mapping Tool. The Climate Action Working Group contributed to
development and review of the plan. Members of County departments reviewed the actions. Members
of the public submitted 247 comments and viewed the plan 3,000 times during the public review period.
The County would like to extend a mahalo to all the community partners, reviewers, and County staff
who contributed to the ongoing feedback and development of the ICAP.
Climate Action Plan Working Group
Graceson Ghen Hawaiʻi Energy Dr. Peter Matlock University of Hawaiʻi-Hilo
Heather Kimball County Council, District 1 Noel Morin Hawaiʻi EV
Steve Hirakami Hawaiʻi Academy of Arts & Sciences Erica Perez Coral Reef Alliance
Kilohona Hirano Kamehameha Schools Cindi Punihaole Kennedy Hawaiʻi Community College
Nicole Larson Keahole Center for Sustainability Rachel Solemsaas Hawaiʻi Community College
Dr. Robin Martin Arizona State University Jennifer Zelko Hawaiian Electric
County Staff
Planning
Zendo Kern, Director Bethany Morrison Natasha Soriano Heather Bartlett Paka Davis Janice Hata Kara Neal Sam Bergstrom
Research and Development Douglass Adams, Director Kendra Obermaier Jake Sykes Michelle Agbigay Riley Saito Issa Moffett Erika Lisco
Finance
Deana Sako, Director Diane Nakagawa Sarah Yeckley
Environmental Management
Ramzi Mansour, Director Brenda Iokepa-Moses Sanne Berrig Dora Beck
Public Works
Steve Pause, Director Malia Kekai Keone Thompson Julann Sonomora
Office of Housing Susan Kunz, Director
Water Supply
Keith Okamoto, Director Kawika Uyehara Kurt Inaba Warren Ching
Parks and Recreation
Maurice Messina. Director Michelle Hiraishi James Komata
Civil Defense
Talmadge Magno, Director Berry Periatt
Fire
Kazuo Todd, Chief Ian Chadwick
Technical Review
Dr. Makena Coffman University of Hawaiʻi at Mānoa, Department of Urban and Regional Planning; Institute for Sustainability and Resilience
Dr. Victoria Keener Arizona State University and East-West Center, Pacific Regional Integrated Sciences and Assessments (Pacific RISA)
Dr. Bradley Romine University of Hawaiʻi Sea Grant College Program; Pacific Islands Climate Adaptation Science Center
Dr. Clay Trauernicht University of Hawaiʻi at Mānoa, College of Tropical Agriculture and Human Resources
Dr. Roberta Martin Arizona State University
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Executive Summary iv
EXECUTIVE SUMMARY
The United Nations Intergovernmental Panel on Climate Change has concluded in its most recent
report that human activities have unequivocally caused global warming.1 Climate change is already
impacting the lands and waters on which we live and the health of our communities.
Purpose & Scope: The ICAP introduces the County of Hawaii’s strategic roadmap for implementing
climate action. The plan identifies actions the County government itself can take and is a first step for
the County holding itself accountable for climate action. The actions outlined in the ICAP will help the
County achieve the following vision and goals, in alignment with existing State and County priorities.
Vision: We ensure a just transition to a climate resilient island by addressing the causes and
impacts of climate change through incorporating equitable climate mitigation and adaptation priorities
into policies, programs, infrastructure, and decision making.
Goals:
1. Improve county capacity to implement climate action.
2. Reduce the County’s contribution to global greenhouse gas emissions.
3. Increase the resilience of County infrastructure, assets, and services to climate change impacts.
Climate Action Framework
To accomplish these goals, the
ICAP identifies climate mitigation
and adaptation actions to be taken
by Hawaiʻi County. Mitigation
includes actions to reduce
greenhouse gas emissions and
adaptation includes actions that
build resilience to climate change
impacts. Each action has social and
economic co-benefits beyond
climate change. A climate action
framework was developed to
describe the cascading effects of
climate change and identify
intervention points for County action
(see figure). Exposure and risk
analyses for the cascades were
conducted using a geospatial
overlay of climate hazards on maps
of County assets.
1 United Nations, Intergovernmental Panel on Climate Change (IPCC) (2023) Synthesis Report of the IPCC Sixth Assessment (AR6), Summary for Policy Makers. https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_SPM.pdf
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Executive Summary v
Five cascading areas of impact were identified. Key intervention points were determined under each
cascade. County actions were identified within these key intervention points. Individual actions that can
be taken and co-benefits of County actions were also highlighted for each cascade. The
implementation section outlines the capacity and financing improvements required to execute the ICAP
and the County’s process for monitoring and evaluation. The five cascades are:
• Climate Cascade 1 – Greenhouse Gas Emissions caused by human activities are the key
drivers of human-induced climate change. This climate cascade establishes a baseline for
greenhouse gas emissions for the Island of Hawai‘i from which to develop climate mitigation
interventions to reduce Hawai‘i County contributions to global climate change.
• Climate Cascade 2 –Air and Sea Surface Temperature are directly influenced by greenhouse
gas emissions. These climate change indicators have direct impacts on human and native
ecosystem health.
• Climate Cascade 3 – Drought and Severe Rainfall Events are among the climate hazards
resulting from increasing air and sea surface temperature and climate variability. Drought and
severe rainfall impacts to community systems are exacerbated by the compounding hazards of
wildfire, landslides, windstorms, and riverine flooding.
• Climate Cascade 4 – Sea Level Rise is a climate hazard with slowly emerging impacts on
community systems, compounded by coastal and riverine flooding and landslides.
• Climate Cascade 5 – Tropical Cyclones and Storm Surge are climate hazards with extreme
impacts on community systems.
Although Hawaiʻi Island alone will not reverse the harmful impacts of climate change, we can lead by
example and set precedent for other island-states to become more sustainable through energy
conservation and efficiency, clean transportation, zero waste initiatives, and better management of
water, land, and natural resources.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Executive Summary vi
Climate Cascade Summary
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Contents vii
CONTENTS
Land Acknowledgment ........................................................................................................................... ii
Acknowledgments ................................................................................................................................. iii
Executive Summary ............................................................................................................................... iv
Contents ................................................................................................................................................ vii
Acronyms ............................................................................................................................................... xi
Key Terms ............................................................................................................................................. xii
Planning Process .................................................................................................................................... 1
Vision, Goals, and Alignment ................................................................................................................ 1
Vision ...................................................................................................................................................................... 1
Goals....................................................................................................................................................................... 1
Alignment ................................................................................................................................................................ 1
Greenhouse Gas Reduction Targets ...................................................................................................................... 3
Climate Action Framework..................................................................................................................... 4
Climate Cascades ................................................................................................................................... 7
Climate Cascade Exposure Analysis ...................................................................................................................... 9
Hazard Mapping .............................................................................................................................................. 10
Asset Mapping ................................................................................................................................................. 11
Exposure Analysis ........................................................................................................................................... 11
Intervention Points and Actions ............................................................................................................................ 12
Climate Action Co-Benefits ................................................................................................................................... 13
Limitations and Future Data Needs ...................................................................................................................... 14
Climate Cascade I: Greenhouse Gas Emissions ............................................................................... 17
Cascade Narrative ................................................................................................................................................ 18
Greenhouse Gas Inventory .................................................................................................................................. 25
Intervention Points and Actions ............................................................................................................................ 27
1A. Energy and Electricity Use ........................................................................................................................ 27
1B. Transportation ........................................................................................................................................... 31
1C. Waste ........................................................................................................................................................ 34
1D. Land Use and Carbon Sequestration ....................................................................................................... 38
Climate Action Co-Benefits ................................................................................................................................... 41
Actions You Can Take .......................................................................................................................................... 42
Climate Cascade 2: Air and Sea Surface Temperature ..................................................................... 43
Cascade Narrative ................................................................................................................................................ 44
Cascade Exposure Analysis ................................................................................................................................. 47
Intervention Points and Actions ............................................................................................................................ 48
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Contents viii
2A. Human Health ........................................................................................................................................... 48
2B. Energy Resilience ..................................................................................................................................... 50
2C. Coral Reefs ............................................................................................................................................... 50
Climate Action Co-Benefits ................................................................................................................................... 52
Actions You Can Take .......................................................................................................................................... 53
Climate Cascade 3: Drought and Extreme Rainfall Events ............................................................... 54
Cascade Narrative ................................................................................................................................................ 55
Cascade Exposure Analysis ................................................................................................................................. 60
Intervention Points and Actions ............................................................................................................................ 64
3A. New Development ..................................................................................................................................... 64
3B. Water Resources ...................................................................................................................................... 66
3C. Parks and Recreational Areas .................................................................................................................. 67
3D. Roads and Bridges ................................................................................................................................... 68
3E. Water and Wastewater Systems ............................................................................................................... 69
3F. Existing Development ................................................................................................................................ 69
Climate Action Co-Benefits ................................................................................................................................... 71
Actions You Can Take .......................................................................................................................................... 72
Climate Cascade 4: Sea Level Rise ..................................................................................................... 73
Cascade Narrative ................................................................................................................................................ 74
Cascade Exposure Analysis ................................................................................................................................. 77
Intervention Points and Actions ............................................................................................................................ 80
4A. New Development ..................................................................................................................................... 80
4B. Cultural and Historic Resources ............................................................................................................... 82
4C. Parks and Recreational Areas .................................................................................................................. 83
4D. Water and Wastewater Systems .............................................................................................................. 83
4E. Roads and Bridges .................................................................................................................................... 84
4F. Existing Development ................................................................................................................................ 85
Climate Action Co-Benefits ................................................................................................................................... 86
Actions You Can Take .......................................................................................................................................... 87
Climate Cascade 5: Tropical Cyclones and Storm Surge ................................................................. 88
Cascade Narrative ................................................................................................................................................ 89
Cascade Exposure Analysis ................................................................................................................................. 92
Intervention Points and Actions ............................................................................................................................ 95
5A. Critical Infrastructure ................................................................................................................................. 96
5B. Social Resilience ....................................................................................................................................... 96
5C. Economic Resilience ................................................................................................................................. 97
5D. Cultural and Historic Resources ............................................................................................................... 97
5E. Hazard Tree Management ........................................................................................................................ 98
5F. Operational Capacity ................................................................................................................................. 98
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Contents ix
Climate Action Co-Benefits ................................................................................................................................. 100
Actions You Can Take ........................................................................................................................................ 101
Plan Implementation ........................................................................................................................... 102
County Processes ............................................................................................................................................... 103
Short-Term Implementation Priorities: (2023-2025) ...................................................................................... 103
Mid-Term Implementation Priorities: (2025-2030) ......................................................................................... 104
Long-Term Implementation Priorities: (2030-2040)....................................................................................... 106
Climate Action Financing .................................................................................................................................... 106
Monitoring and Evaluation .................................................................................................................................. 107
Call to Action ....................................................................................................................................... 108
Figures
Figure 1. Planning process for developing the Integrated Climate Action Plan ........................................................ 1
Figure 2. Timeline of State and County climate action commitments ....................................................................... 2
Figure 3. Hawaiʻi County greenhouse gas emission targets ..................................................................................... 3
Figure 4. Climate action framework ........................................................................................................................... 5
Figure 5. Climate cascade summary ......................................................................................................................... 8
Figure 6. Exposure analysis components for Climate Cascades 3, 4, and 5 ............................................................ 9
Figure 7. Example of cascade exposure levels ....................................................................................................... 11
Figure 8. Climate Cascade 1. Greenhouse gas emissions ..................................................................................... 17
Figure 9. Locations of County buildings for potential energy retrofits ..................................................................... 21
Figure 10. Hawaiʻi County sector overview of MTCO2e emissions for years 2005, 2015, and 2017 ..................... 25
Figure 11. Climate Cascade 2. Air & sea surface temperature ............................................................................... 43
Figure 12. Annual mean temperature (A) historical and (B) end-of century under the IPCC high-emissions
scenario (Scenario RCP 8.5) ................................................................................................................. 45
Figure 13. Climate Cascade 3: Drought and extreme rainfall ................................................................................. 54
Figure 14. Sequence and duration of drought types ............................................................................................... 56
Figure 15. Climate Cascade 3: Areas exposed by number of overlapping hazard layers (drought,
wildfire, riverine flooding, landslide susceptibility, high windstorms) ..................................................... 61
Figure 16. Climate Cascade 4: Sea level rise ......................................................................................................... 73
Figure 17. Climate Cascade 4: Areas exposed by number of overlapping hazard layers (riverine flooding,
chronic and event-based coastal flooding with sea level rise, landslide susceptibility) ....................... 78
Figure 18. Climate Cascade 5: Tropical cyclones and storm surge ........................................................................ 88
Figure 19. Climate Cascade 5: Areas exposed by number of overlapping hazard layers (hurricane wind
and storm surge, riverine flooding, chronic and event-based coastal flooding with sea level rise,
landslide susceptibility) .......................................................................................................................... 93
Figure 20. Plan Implementation Priorities ............................................................................................................. 102
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Contents x
Tables
Table 1. Cascade exposure analysis: hazards analyzed by cascade ..................................................................... 10
Table 2. Hawaiʻi County departments with primary responsibilities in the ICAP ..................................................... 12
Table 3. Climate action co-benefits considered in evaluating climate actions ........................................................ 13
Table 4. Climate Cascade 3: Number and type of County assets exposed to individual and overlapping
hazards (drought, wildfire, riverine flooding, landslide susceptibility, high windstorms) ........................... 62
Table 5. Climate Cascade 3: Number of County assets by district with high cascade exposure
(4 or 5 hazard exposures) ......................................................................................................................... 63
Table 6. Climate Cascade 4: Number and type of County assets exposed to individual and overlapping
hazards (riverine flooding, chronic and event-based coastal flooding with sea level rise,
landslide susceptibility) ............................................................................................................................. 79
Table 7. Climate Cascade 4: Number of County assets by district with high cascade exposure
(4 or 5 hazard exposures) ......................................................................................................................... 80
Table 8. Climate Cascade 5: Number and types of County assets exposed to individual and overlapping
hazards (hurricane wind and storm surge, riverine flooding, chronic and event-based coastal
flooding with sea level rise, landslide susceptibility) ................................................................................ 94
Table 9. Climate Cascade 5: Number of County assets by district with high cascade exposure
(5 or 6 hazard exposures) ........................................................................................................................ 95
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Acronyms xi
ACRONYMS
AFOLU Agriculture, Forestry, and Other Land Use
CD Hawaiʻi County Civil Defense
CO2 Carbon Dioxide
DEM Hawaiʻi County Department of Environmental Management
DFIRM Digital Flood Insurance Rate Map
DPR Hawaiʻi County Department of Parks and Recreation
DPW Hawaiʻi County Department of Public Works
DWS Hawaiʻi County Department of Water Supply
ENSO El Niño-Southern Oscillation
EPA Environmental Protection Agency
EV Electric Vehicle
FD Hawaiʻi County Fire Department
FEMA Federal Emergency Management Agency
FIRM Flood Insurance Rate Map
GDE Groundwater-Dependent Ecosystems
GHG Greenhouse Gas
ICAP Integrated Climate Action Plan
IPCC Intergovernmental Panel on Climate Change
MTA Mass Transit Agency
MTCO2e Metric Tons of Carbon Dioxide Equivalent
NASA National Aeronautics and Space Administration
NOAA National Oceanic and Atmospheric Administration
PD Hawaiʻi County Planning Department
R&D Hawaiʻi County Department of Research and Development
RCP Representative Concentration Pathway
SLR Sea Level Rise
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Key Terms xii
KEY TERMS
Carbon sequestration refers to actions that remove carbon from the atmosphere.
Cascading effects refers to the network of interactions between human activities causing climate
change and the impacts of climate change on community systems. These cascading effects are of
greater magnitude than any individual element of the network.
Climate adaptation refers to actions that adjust to actual or expected future climate with the goal of
reducing risks from the harmful effects of climate change and maximizing any potential benefit
opportunities.2
Climate cascade summarizes the cascading effects between human activities causing climate change
and the impacts of climate change on community systems.
Climate change refers to the long-term (usually at least 30 years) regional or even global average of
temperature, humidity, and rainfall patterns over seasons, years, or decades.3 Human-induced climate
change is resulting in global warming, the long-term heating of Earth’s surface.
Climate change drivers are greenhouse gases, primarily CO2, methane, and nitrous oxide, in the
atmosphere resulting from human activities over the industrial era, that are the principal drivers of many
changes observed across the atmosphere, ocean, cryosphere and biosphere.4 Greenhouse gas
emissions from building electricity, energy production, transportation, waste, and land use are
considered climate change drivers of focus in the ICAP.
Climate change hazard refers to changes in a physical process or event (hydro-meteorological or
oceanographic variables or phenomena) driven or amplified by human induced climate change that can
harm human health, livelihoods, or natural resources. Drought, extreme rainfall events, sea level rise,
and tropical cyclones and storm surge are considered climate change hazards of focus in the ICAP.
Climate change indicators are observed climate changes linked to rising levels of greenhouse gases
in our atmosphere caused by human activities.5 Increasing air and sea surface temperature and ocean
acidification are considered climate change indicators of focus in the ICAP.
Climate mitigation refers to actions that reduce the flow of greenhouse gases into the atmosphere,
either by reducing sources of these gases or enhancing the sinks that accumulate and store these
gases. Climate mitigation and “GHG reduction” are used interchangeably throughout this document:6
• GHG sources refers to processes and behaviors that emit GHG, such as burning fossil fuels for
electricity and transportation.
• GHG sinks refers to processes and behaviors that sequester and store GHG, such as forests,
oceans, and soils.
2 NASA, Global Climate Change, https://climate.nasa.gov/solutions/adaptation-mitigation/ 3NASA, Global Climate Change, https://climate.nasa.gov/global-warming-vs-climate-change/ 4 NASA, Global Climate Change, https://climate.nasa.gov/causes/ 5 EPA, Global Climate Change Program, https://www.epa.gov/climate-indicators 6 NASA, Global Climate Change, https://climate.nasa.gov/solutions/adaptation-mitigation/
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Key Terms xiii
Climate resilience is the ability to anticipate, prepare for, and respond to hazardous events, trends, or
disturbances related to climate change. Improving climate resilience involves assessing how climate
change will create new, or alter current, climate-related risks, and taking steps to better cope with these
risks.7
Climate risk occurs from the interaction of hazard, exposure, and vulnerability.8
Co-benefits refer to the potential for actions to achieve multiple positive impacts and reinforcing
outcomes.9
Community systems are the diverse and interconnected physical, social, economic, ecological,
cultural, and governance systems supporting the health and wellbeing of the people of Hawaiʻi Island.
Compounding hazards are hazards that are exacerbated by climate change indicators and hazards.
Riverine flooding, landslides, wind storms, and coastal flooding and erosion are considered
compounding hazards of focus in the ICAP.
Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period
(between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-
trapping greenhouse gas levels in Earth’s atmosphere.10
Groundwater-dependent ecosystems are ecosystems that are supported by groundwater. These
places include springs and seeps, caves and karst systems, and deep-rooted plant communities
(phreatophytes). In many cases, rivers, wetlands, and lakes are also included. Where groundwater
meets the surface, unique communities of plants and animals flourish. A wide variety of rare,
threatened, and endangered species call these places home.11 In Hawaii, groundwater-dependent
ecosystems include fish ponds, coastal springs, anchialine pools, and nearshore ecosystems.
Hazard mitigation is any sustainable action that reduces or eliminates long-term risk to people and
property from future disasters.12
Intervention points refer to specific points where a climate cascade could be disrupted by an action to
prevent cascading effects and negative impacts on community systems.
7 Center for Climate and Energy Solutions, https://www.c2es.org/content/climate-resilience-overview/#:~:text=Climate%20resilience%20is%20the%20ability,better%20cope%20with%20these%20risks. 8 International Atomic Energy Authority, https://www.iea.org/reports/climate-resilience-policy-indicator/climate-hazard-assessment 9 Mayrhofer, J. P., & Gupta, J. (2016). The science and politics of co-benefits in climate policy. Environmental Science & Policy, 57, 22-30. doi:https://doi.org/10.1016/j.envsci.2015.11.005 10 NASA, Global Climate Change, https://climate.nasa.gov/global-warming-vs-climate-change/ 11 USDA Forest Service, 2023. Groundwater-dependent ecosystems. https://www.fs.usda.gov/managing-land/natural-resources/geology/groundwater/groundwater-dependent-ecosystems#:~:text=What%20are%20Groundwater%20Dependent%20Ecosystems,and%20lakes%20are%20also%20included. 12 FEMA, Hazard Mitigation Assistance Grants, https://www.fema.gov/grants/mitigation#:~:text=%22Hazard%20mitigation%22%20is%20any%20sustainable,damage%2C%20reconstruction%20and%20repeated%20damage.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Key Terms xiv
RCP 8.5 is the future greenhouse gas emissions scenario with the highest level of emissions of the
standard scenarios in use for climate change projections. It assumes no measures will be taken to
reduce emissions from current trends.
Risk is the potential for an unwanted outcome resulting from an event, as determined by the likelihood
of the event and the associated consequences.13
Threat is a natural, technological, or human-caused occurrence, individual, entity, or action that has or
indicates the potential to harm life, information, operations, the environment, and/or property (FEMA).
Vulnerability refers to the degree to which a community is susceptible to adverse effects of climate
change, including climate variability and extremes. Vulnerability is a function of the character,
magnitude, and rate of climate variation to which a system is exposed, its sensitivity, and its adaptive
capacity (IPCC).
13 FEMA, https://emilms.fema.gov/is_0870a/groups/22.html
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Planning Process 1
PLANNING PROCESS
The Hawai‘i County Integrated Climate Action Plan (ICAP) was developed over a three year period.
Key planning activities are shown in Figure 1. The County engaged multiple stakeholders in the
planning process through the Climate Action Plan Working Group, County department working
sessions, technical reviews, and a public review period.
Figure 1. Planning process for developing the Integrated Climate Action Plan
Climate Action Plan Working Group
In the summer of 2021, Hawaiʻi County hosted three Climate Action workshops in Hilo and Kona. The
County produced a Hawaiʻi Island Climate Action simulation for the workshops. During the workshops,
the County presented the proposed Climate Action Plan scope, goals, and development process and
facilitated the simulation with the group. The County formed a Climate Action Plan Working Group with
the workshop participants. The Working Group met monthly from July 2021 – December 2021. The
group then met every 3 months from January – June 2022. The Working Group was re-convened to
review the draft plan in 2023.
The Working Group advised the County on the focus of the Plan. They also helped develop and
distribute a Climate Change Community Sentiment Survey with the County. The high-level results and
recommendations from the survey informed the identification of co-benefits for actions and the
stakeholder engagement outlined in the Implementation section. For more information on the survey
results, see Appendix C. Long-term climate action planning and implementation should include
continued partnerships like those described in the Implementation section.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Planning Process 2
County Staff
The County Climate Action Team hosted a series of interdepartmental meetings from October 2022
through January 2023 to review the outline and technical analysis of the ICAP with department
directors and deputy directors. The Team then met one-on-one with the departments that are leads for
the actions in the plan to review and amend plan actions. The actions in this document are the finalized
actions approved by the departments.
Technical Review
The County Climate Action Team reached out to academic researchers focused on climate adaptation
and mitigation in Hawaiʻi to review the ICAP. The technical reviewers provided feedback on the
scientific framework, analyses and references in the ICAP. The International Council for Local
Environmental Initiatives (ICLEI) also provided technical feedback as part of the County’s participation
in the ICLEI Integrated Climate Action Planning Cohort.
Public Review
The draft ICAP opened for comment May 1, 2023 and closed for comment June 1, 2023. The draft was
published using Konveio, an interactive website. Konveio has features that easily guide the community
through the document with summaries, videos, links, and GIS. The ICAP received 247 comments and
over 3,000 views. The County incorporated revisions addressing the public comments into the final
plan.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Vision, Goals and Alignment 1
VISION, GOALS, AND ALIGNMENT
Hawaiʻi Island has long held a reciprocal relationship between land and people. As an island community,
we can tangibly experience the cascading effects of our actions on the people and places surrounding
us. Island communities such as Hawaiʻi Island are at the forefront of climate change, as we experience
impacts such as sea level rise and coral bleaching. Our small population and island geography make
us feel more deeply the cascading effects of any impact on the health and the land of the people.
The ICAP is a first step by Hawaiʻi County to address the causes and effects of climate change. The
County has a dual role to play: reducing the County’s contribution to global climate change; and
building the resiliency of our programs, policies, and infrastructure to climate change. The actions
outlined in the ICAP will help the County achieve the following vision and goals, in alignment with
existing State and County priorities.
Vision
We ensure a just transition to a climate resilient island by addressing the causes and impacts of
climate change through incorporating equitable climate mitigation and adaptation priorities into policies,
programs, infrastructure, and decision making.
Goals
Improve County capacity to implement climate action.
Reduce the County՚s contribution to global greenhouse gas emissions.
Increase the resilience of County infrastructure, assets, and services to climate change impacts.
Alignment
Several commitments at the State and County level have set mandated and non-mandated greenhouse
gas emissions goals for select industries (Figure 2). Targets have been set for greenhouse gas
emissions, renewable energy standards, and transportation reform. However, clear and explicit goals
codified at the County level are needed to emphasize the urgency and commitment this plan requires.
To demonstrate the County’s commitment to climate action, the County should codify climate mitigation
and adaptation goals. This plan recommends that the County codify mitigation goals in alignment with
State renewable energy goals, County renewable energy for transportation goals, and the County’s
zero waste resolution. This plan recommends that the County codify adaptation goals in alignment with
the Climate Adaptation Priority Guidelines defined in the State Planning Act.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Vision, Goals and Alignment 2
Figure 2. Timeline of State and County climate action commitments
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Vision, Goals and Alignment 3
Greenhouse Gas Reduction Targets
The County greenhouse gas emission reduction targets are shown in Figure 3, in alignment with the State goals and Aloha + Challenge
dashboard. The County commits to upholding these targets and tracking the contribution of County operations to island-wide emissions.
More information on County emissions tracking and reporting is included in the Cascade 1 actions and the Plan Implementation sections.
Figure 3. Hawaiʻi County greenhouse gas emission targets
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Climate Action Framework 4
CLIMATE ACTION FRAMEWORK
The climate action framework was developed to illustrate the cascading nature of climate change.
Cascading effects result from interdependencies between natural and socioeconomic systems.14 The
term “cascading effects” has been increasingly used to describe the network of impacts across various
systems that are of greater magnitude than any individual element of network.15 The cascading effects
of climate change represent extremely complex interactions between global climate change and local
physical, ecological, social, and economic systems.
The framework captures how what we do as communities causes climate change, which in turn impacts
our same communities. Increased use of fossil fuels is causing greenhouse gases in the atmosphere to
rise. Greenhouse gases are causing global air and sea surface temperature to rise and oceans to
become more acidic. These changes in temperature and ocean pH are the key indicators of climate
change. They directly trigger climate hazards including sea level rise, drought, extreme rainfall events,
and tropical cyclones. The impacts of those climate hazards can be heightened by compounding
hazards such as landslides, wildfire, and flooding. Together, the impacts of these climate and
compounding hazards cascade across multiple social, cultural, economic, ecological, and governance
systems.16 A climate action framework was developed to describe these cascading effects of climate
change and to identify intervention points where both climate mitigation and adaptation actions can be
implemented by the County (Figure 4).
Understanding the cascading impacts of climate change on human-environmental systems is a growing
area of research.17 Better accounting of these interactions is needed to identify potential feedback
loops. The cascading effects of climate change on infrastructure and social-ecological systems related
to extreme rainfall events,18 sea level rise,19 wildfires and other disasters,20 wastewater systems,21
electrical systems,22 and fisheries and agriculture23 are some emerging topics of new research.
14 Lawrence, J., Blackett, P., & Cradock-Henry, N. A. (2020). Cascading climate change impacts and implications. Climate Risk Management, 29, 100234. doi:https://doi.org/10.1016/j.crm.2020.100234 15 Schauwecker, S., Gascón, E., Park, S., Ruiz-Villanueva, V., Schwarb, M., Sempere-Torres, D., Rohrer, M. (2019). Anticipating cascading effects of extreme precipitation with pathway schemes - Three case studies from Europe. Environment International, 127, 291-304. doi:https://doi.org/10.1016/j.envint.2019.02.072 16 Lawrence, J., Blackett, P., & Cradock-Henry, N. A. (2020). Cascading climate change impacts and implications. Climate Risk
Management, 29, 100234. doi:https://doi.org/10.1016/j.crm.2020.100234 17 Cradock-Henry, N. A., Connolly, J., Blackett, P., & Lawrence, J. (2020). Elaborating a systems methodology for cascading climate change impacts and implications. Methods X, 7. doi:10.1016/j.mex.2020.100893 18 Schauwecker, et. al, (2019). https://doi.org/10.1016/j.envint.2019.02.072 19 Yin, J., Yu, D., Lin, N., & Wilby, R. L. (2017). Evaluating the cascading impacts of sea level rise and coastal flooding on emergency response spatial accessibility in Lower Manhattan, New York City. Journal of Hydrology, 555, 648-658. doi:https://doi.org/10.1016/j.jhydrol.2017.10.067 20 Duvat, V. K. E., Volto, N., Stahl, L., Moatty, A., Defossez, S., Desarthe, J., Pillet, V. (2021). Understanding interlinkages between long-term trajectory of exposure and vulnerability, path dependency and cascading impacts of disasters in Saint-Martin (Caribbean). Global Environmental Change, 67, 102236. doi:https://doi.org/10.1016/j.gloenvcha.2021.102236 21 Hughes, J., Cowper-Heays, K., Olesson, E., Bell, R., & Stroombergen, A. (2021). Impacts and implications of climate change on wastewater systems: A New Zealand perspective. Climate Risk Management, 31, 100262. doi:https://doi.org/10.1016/j.crm.2020.100262 22 McMahan, B., & Gerlak, A. K. (2020). Climate risk assessment and cascading impacts: Risks and opportunities for an electrical utility in the U.S. Southwest. Climate Risk Management, 29, 100240. doi:https://doi.org/10.1016/j.crm.2020.100240 23 Thiault, L., Mora, C., Cinner, J. E., Cheung, W. W. L., Graham, N. A. J., Januchowski-Hartley, F. A., Claudet, J. Escaping the perfect storm of simultaneous climate change impacts on agriculture and marine fisheries. Science Advances, 5(11), eaaw9976. doi:10.1126/sciadv.aaw9976
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Climate Action Framework 5
Figure 4. Climate action framework
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Climate Action Framework 6
The Natural Hazard Cascade of 1868
Hawaiʻi Island is no stranger to cascading effects. On April 2, 1868, a 7.9-magnitude
earthquake, the largest in recorded history for Hawaiʻi Island, shook the island north of
Pahala. The quake was preceded by hundreds of smaller tremors. This earthquake
reactivated the Hilina Slump, which resulted in a tsunami that produced waves as high as 49
feet and killed 46 people. The quake also triggered numerous landslides, the largest of which
was nearly 2 miles wide and as much as 30 feet thick, causing widespread damage and
another 31 fatalities. Although not climate-related, this event exemplifies how cascading
hazard events can affect people and property.
Source: "The Great Kaʻū Earthquake of 1868." Hawaiian Volcano Observatory. April 1, 1994
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Climate Cascades 7
CLIMATE CASCADES
A climate cascade represents one component of the cascading effects and interactions of climate
change. Using the climate action framework, five climate cascades were developed to address the
three goals of the ICAP. All actions and plan implementation seek to address Goal 1, to increase the
County capacity to address climate change. Actions in Cascades 1 and 2 address Goal 2, to reduce
GHG emissions. Actions in Cascades 3, 4 and 5 address Goal 3 to increase resilience of County
infrastructure and services to climate change impacts.
• Climate Cascade 1 – Greenhouse Gas Emissions caused by human activities are the key
drivers of human-induced climate change. This climate cascade establishes a baseline for
greenhouse gas emissions for the Island of Hawai‘i from which to develop climate mitigation
interventions to reduce Hawai‘i County contributions to global climate change.
• Climate Cascade 2 –Air and Sea Surface Temperature are directly influenced by greenhouse
gas emissions. These climate change indicators have direct impacts on human and native
ecosystem health.
• Climate Cascade 3 – Drought and Severe Rainfall Events are among the climate hazards
resulting from increasing air and sea surface temperature and climate variability. Drought and
severe rainfall impacts to community systems are exacerbated by the compounding hazards of
wildfire, landslides, windstorms, and riverine flooding.
• Climate Cascade 4 – Sea Level Rise is a climate hazard with slowly emerging impacts on
community systems, compounded by coastal and riverine flooding and landslides.
• Climate Cascade 5 – Tropical Cyclones and Storm Surge are climate hazards with extreme
impacts on community systems.
A graphic and narratives were developed for each cascade based on the current state of knowledge
and experience gleaned from global, regional, and local information and data. The ICAP analyzes
exposure and risk associated with each climate cascade using a geospatial overlay of climate hazards
on County assets and a social vulnerability analysis of the population. County actions for climate
change mitigation and adaptation were identified for key intervention points within each climate
cascade. Co-benefits of climate action were identified to highlight opportunities to build climate
resilience action by action. A summary of the cascading effects is depicted in Figure 5.
Key climate change drivers, indicators, climate hazards, and compounding hazards used to develop the
climate cascades were identified from the County of Hawaiʻi Hazard Mitigation Plan 2020, the Hawaiʻi
State Climate Summary, the 4th National Climate Assessment, and other relevant literature. A closer
look at the climate hazards can be found in Appendix A. Community systems were defined as physical,
social, economic, cultural, native ecosystem, and governance assets and services. County assets and
services were identified within these community systems as the focus for action in this plan.
Climate cascades are intended as a starting point in describing the complexities of climate change
impacts in order to better anticipate feedback loops and avoid maladaptation. These cascades will be
reviewed, revised, and expanded as new research becomes available and conditions change.
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Climate Cascades 8
Figure 5. Climate cascade summary
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Climate Cascades 9
Climate Cascade Exposure Analysis
Exposure analysis is the process of identifying assets that may experience each hazard associated with
a climate cascade. Exposure analysis for Climate Cascades 3, 4, and 5 is based on the climate
hazards and compounding hazards associated with each climate cascade. For each of these climate
cascades, County assets exposed to these multiple hazards were identified using geospatial mapping
to determine:
• Areas in Hawaiʻi County where each hazard may occur (this mapping is specific to each analyzed
climate cascade)
• Locations of the County’s assets (this mapping is the same for all analyzed climate cascades)
Climate Cascade 1 does not include hazard exposure, so no analysis was conducted. Cascade 2 was
limited by data availability. Exposure analysis was not conducted but could be in the future.
The components of the exposure analysis are shown in Figure 6.
Figure 6. Exposure analysis components for Climate Cascades 3, 4, and 5
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Climate Cascades 10
Hazard Mapping
Climate Cascades 3 and 4 are characterized by five hazards each, and Climate Cascade 5 is
characterized by six hazards. The datasets used to map hazard areas for each cascade are listed in
Table 1 and described in more detail in Appendix A.
Table 1. Cascade exposure analysis: hazards analyzed by cascade
Hazard
CASCADE 3 Drought and Extreme Rainfall
CASCADE 4 Sea Level Rise
CASCADE 5 Tropical Cyclones and Storm Surge
Drought (93-year drought trends) ●
Wildfire communities at risk rating (high) ●
Riverine flooding (FEMA FIRM A/AE Zones) ● ● ●
High winds (Average wind speeds at 50m above ground: moderate (greater the 5 meters/second) and high (greater than 8.5 meters/second) severity) ●
Landslides (medium/high susceptibility) ● ● ●
Chronic coastal flooding with 3.2 feet of sea level rise (passive inundation only, SLRXA-3.2) ●
Event-based coastal flooding with 3.2 feet of sea level rise (projected future, 1% Annual Chance Coastal Flood Zone, 1%CFZ-3.2)
● ●
Event-based coastal flooding (historical; FEMA DFIRM V/VE Zone) ● ●
Hurricane – Wind (Category 4 with peak gusts greater than 125 miles per hour.) ●
Hurricane – Storm surge (Category 4) ●
Total Number of Hazards 5 5 6
By mapping all relevant hazards, this analysis was able to identify the number of hazards with the
potential to occur at any location in the County for each climate cascade. A given location might be
susceptible to multiple hazards. An example of the cascade exposure levels for a cascade with five
hazards is shown in Figure 7.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Climate Cascades 11
Figure 7. Example of cascade exposure levels
Asset Mapping
Asset data was compiled from all County departments. This included County structures, water and
wastewater lines, on-site disposal systems, roads, bridges, and parks, as well as proposed and
planned capital improvement projects. Interviews were conducted with each County department to
review existing County assets and existing departmental priorities for proposed and in progress
projects. A map of asset locations was generated from the information collected. More details on assets
and projects are available on the County Climate Cascade Exposure Tool.
Exposure Analysis
The exposure analysis overlaid the hazard area mapping on top of the asset location map. This allowed
assets to be tallied by number of potential hazards at the asset location for each climate cascade.
County assets exposed to the greatest number of hazards could be candidates for interventions. The
County Climate Cascade Exposure Tool can help County staff better understand climate-related
hazards potentially impacting County-managed assets and projects.
The Cascade Exposure Tool also contains the results of a risk analysis conducted based on the
distribution of socially vulnerable populations. The description of the risk assessment methodology and
results are provided in Appendix B.
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Climate Cascades 12
Intervention Points and Actions
Intervention points were identified for each climate cascade. These are points where the cascading
effects of climate change could be disrupted by a project or action to reduce greenhouse gas emissions
or impacts on community systems. An intervention early in the sequence that makes up a cascade is
considered more effective as it can address multiple cascading effects and thereby enhance community
resilience and save money, time, and effort.
This ICAP focuses on actions that County departments can take to improve climate resilience based on
areas of responsibility as listed in Table 2. For each cascade, actions were identified at each
intervention point based on County assets exposed and population at risk. An estimate for the cost of
each action is noted as follows:
$ - action can be accomplished within the current County budget and staff
$$ - action requires additional funding for consultants or studies
$$$ - action requires major investment for infrastructure design and implementation
Projects proposed or recently completed under the County’s capital improvement program and Multi-
Hazard Mitigation Plan were reviewed for inclusion in this plan.
Table 2. Hawaiʻi County departments with primary responsibilities in the ICAP
County Department Primary Area of ICAP Responsibility
Civil Defense Disaster response
Finance Financing for capital improvement, open spaces management
Environmental Management Solid waste and wastewater systems
Fire Department Emergency response
Mass Transit Agency Public transportation
Parks and Recreation Beach parks, senior centers, and sports centers
Planning Land use and coastal zone management
Public Works Roads, bridges, floodplain management, energy efficiency, County fleet maintenance, building and energy codes, and building permits
Research and Development Emissions data and reporting, agriculture and tourism industry support, energy transformation, and grants
Water Supply Water tanks, reservoirs, and water lines
Individual actions were also included for every cascade after the County actions and co-benefits. These
are actions that members of the community, homeowners, and businesses can take to contribute to
climate action.
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Climate Cascades 13
Climate Action Co-Benefits
Co-benefits refer to the potential for actions to achieve multiple positive impacts and reinforcing
outcomes. The concept of co-benefits implies a ‘win–win’ strategy where a single policy or action can
address two or more goals.24 The term co-benefits is also referred to as "multiple benefits" or
"synergies." Each action has co-benefits beyond impact on climate change. Table 3 describes the co-
benefits that may come with climate actions. The evaluation of co-benefits for each action is a key
activity in monitoring and evaluation (see the section on Plan Implementation).
Table 3. Climate action co-benefits considered in evaluating climate actions
Action Primary Purpose Co-Benefits
Greenhouse Gas Reduction
Actions that reduce greenhouse gas emissions through using technology that does not burn materials, especially imported fossil fuels, and through reducing the amount of energy or fuel needed.
• Improved public health through reducing local co-pollutants to improve air quality • Increased economic independence from international markets for fossil fuels • Decreased cost of living through lowering electricity and gas bills
Climate Risk Reduction
Actions that reduce cascading effects of climate change and increase the resilience of communities, infrastructure, and ecosystems to prepare and plan for, absorb, recover from, and more successfully adapt to adverse events and changing conditions.
• Reduced disruptions to government operations and the economy
• Faster recovery from disaster events
• Safer communities due to reduced loss of life and property damage
• Reduced financial impact of climate change on individuals, communities, and society as a whole
Social-Cultural Equity
Actions that prioritize historically marginalized peoples and disproportionally impacted communities in receiving support for community services at greatest risk to climate change, reduce barriers, and increase opportunities so all people can get help when they need it.
• Conserving native ecosystems that are fundamental to cultural practices • Decreasing pollution and corresponding public health risks in historically marginalized and underserved communities
• Improving access to land and water for recreation, cultural practice, and self-sufficient practices like farming
• Reducing cost of living
Environmental Protection
Actions that result in positive impacts on the environment beyond mitigating or adapting to climate change.
• Reducing air and water pollution • Removing invasive species • Restoring ecosystems • Protecting soil to reduce erosion and nutrient loss • Preserving native species and pollinating species
Economic Resilience
Actions that result in positive impacts on the economy.
• Job creation • Industry advancement • Workforce training • Reduced financial impact of climate change on businesses and residents
Plan Integration
Actions that align priorities and investment toward climate risk reduction with existing policies across County, State, and federal plans.
• General Plan
• Multi-Modal Transportation Plan
• Multi-Hazard Mitigation Plan
• Integrated Solid Waste Plan
24 Mayrhofer, J. P., & Gupta, J. (2016). The science and politics of co-benefits in climate policy. Environmental Science & Policy, 57, 22-30.
doi:https://doi.org/10.1016/j.envsci.2015.11.005
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Climate Cascades 14
Limitations and Future Data Needs
Framework: The climate action framework was developed to illustrate the cascading nature of climate
change. The framework is intended to show Hawaiʻi County’s role in reducing our contribution to global
climate change while preparing for the local effects. The cascading effects of climate change represent
extremely complex interactions between global climate change and local physical, ecological, social,
and economic systems. The framework captures how what we do as communities causes climate
change, which in turn impacts our same communities. The framework simplifies this relationship and is
intended to be improved over time as new knowledge, studies, and data emerge.
Exposure and Data Availability: The climate cascade exposure analysis presents a limited view of
the cascading effects of climate change, focusing on exposure associated with climate hazards and
compounding hazards. Geospatial analysis of exposure is constrained by data availability. Greater
investment in monitoring and analyzing climate hazards and impacts is needed to document observed
impacts of climate change on community systems, especially native ecosystems. The analysis of
overlaps among the various hazards used in the exposure analysis was limited by the following:
• Greenhouse Gas Emissions: The Greenhouse Gas Inventory was limited by data availability.
Due to limited island-specific data, Ground and marine transportation, solid waste, and AFOLU
(agriculture, forestry, and other land use) were calculated from state-level emissions based on de
facto population. Future inventories should include more data specific to the island. Further
analysis is needed to determine the contribution of industry- specific emissions.
• Air and Sea Surface Temperature Change. No geospatial analysis of climate exposure was
conducted for air and sea surface temperature change (Climate Cascade 2). Literature was
reviewed to describe cascading effects. An assessment of exposure and vulnerability of parcels
and County infrastructure to increased temperature is needed, including parcels on which the
County provides community services (activity type, vulnerable populations (i.e., keiki, kupuna),
number of people served) and facilities with high levels of technology use that may need extra
cooling infrastructure. To accomplish this, the assessment should follow a similar structure to the
analyses for Climate Cascades 3, 4, and 5. The County should gather datasets on air temperature
on Hawaiʻi Island and stack the datasets to determine the vulnerability of County assets and sites
where services are provided to determine the effects of increased air and sea surface temperature.
Notably, projected changes to air temperature are not measured just by air temperature data, but
also by surface temperature, land cover type, and potential evapotranspiration. These variables will
need to be included in the stacking process to accurately capture air temperature trends and
potential solutions, such as planting more trees in an exposed area (not something that we could
do in an area that already has vegetation). As part of this project, the County should partner with
the University of Hawaiʻi-Hilo to utilize the Hawai‘i Mesoscale Network (Mesonet) data to use data
from its mesoscale network of climate stations across the state. The County should also partner
with the Department of Land and Natural Resources to utilize the urban canopy tree viewer co-
developed with the U.S. Forest Service.
• Wildfire. Wildfire mapping differs from the other hazard mapping used in the exposure analysis as
it does not show wildfire risk over the entire island, but only the risk in populated areas.
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Climate Cascades 15
• Drought. Drought trends were based on data for the period 1920 to 20128. Incorporating the most
current decade into the trend analysis is recommended to build on that dataset moving forward.
The Hawaiʻi Mesonet is being expanded to provide advanced weather and climate monitoring with
funding from the National Science Foundation, the Hawai’i Commission on Water Resources
Management, and others. The County should actively partner with the Hawai‘i Commission on
Water Resources Management and DLNR Department of Forestry and Wildlife on drought
projections and management.
• Sea Level Rise. The Sea Level Rise Exposure Area with 3.2 feet of sea level rise (SLRXA-3.2) is
the best available projection for the end of the century available at this time. Local projections from
NOAA point to closer to 4 ft of SLR by 2100 in an Intermediate scenario. In addition, SLRXA-3.2 for
Hawaiʻi Island is based solely on passive inundation. New wave modeling with sea level rise
conducted by the University of Hawaiʻi is anticipated over the next 5 years.
• Extreme Rainfall Events. Riverine flood zones (FEMA Flood Insurance Rate Map (FIRM) A/AE
zones), mapped based on modeling historical floods, were used as a proxy for extreme rainfall
events. In a changing climate, extreme rainfall events will not be confined to these zones. Further,
riverine flood zones do not overlap with coastal flood zones (FEMA FIRM V/VE zones). This results
in an underestimation of the hazard risk in areas where a river meets the sea. Finally, the riverine
flood zones have not been mapped everywhere in the County, creating gaps in the data, especially
in Hāmākua, and therefore underestimating the number of overlapping climate hazards.
• Coastal Flooding and Erosion with Sea level Rise. For Hawaiʻi Island, coastal flooding with sea
level rise was modeled only for passive inundation, with the highest sea level rise scenario at 3.2
feet by 2100. Without considering coastal erosion and wave runup with sea level rise, the Sea
Level Rise Exposure Area with 3.2 feet of sea level rise (SLRXA-3.2) for Hawaiʻi Island
underestimates the total land area exposed by 35 to 54 percent, depending on location and sea
level rise scenario.25 Shoreline change rate studies are being conducted by the University of
Hawaiʻi for two pilot sites.
• Landslides. Geological studies are needed to better understand the conditions for cliff erosion and
failure, especially along the Hāmākua coast.
• Tropical Cyclones and Storm Surge. Tropical cyclones may make landfall anywhere on Hawaiʻi
Island or just come near enough to cause storm surge and high winds. A Category 4 tropical
cyclone, modeled to make landfall in Kona and travel northeast, was used in the cascade exposure
analysis. Overall, exposure to climate hazards in Cascade 5 should be considered island wide.
Focus on Hazards: The cascade exposure and risk analyses completed for this plan focus on climate
change related hazards and social vulnerability. A more complete analysis would need to include more
detailed data and socioeconomic and environmental indicators. Future cascades should include more
detailed analyses of critical infrastructure and hubs beyond County assets, environmental pollution, and
historical marginalization.
25 Anderson, T. R., Fletcher, C. H., Barbee, M. M., Romine, B. M., Lemmo, S., & Delevaux, J. M. S. (2018). Modeling multiple sea level rise stresses reveals up to twice the land at risk compared to strictly passive flooding methods. Scientific reports, 8(1), 14484. doi:10.1038/s41598-018-32658-x
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Climate Cascades 16
Vulnerability Analysis: This analysis was limited to the variables considered and does not fully
capture the complex, multidimensional aspects of social vulnerability, such as social networks, self-
sufficiency, and neighborhood conditions. These variables are also subjective to different contexts and
cultures. What is considered “vulnerable” to some may be a strength or may be unimportant to others.
Census data is limited by time lags, spatial scale, and missing or inaccurate information, specifically
from hard-to-reach populations such as rural communities and non-English speakers. A more complete
analysis would need to include a more comprehensive set of factors and qualitative, place-based
community engagement and research to supplement the data and better define “social vulnerability” for
communities on Hawaiʻi Island. A future analysis should also cross-reference the EPA’s Environmental
Justice Screening and Mapping Tool or other such tools to include the impact of historic marginalization
and disproportionate effects from pollution or other environmental hazards. Justice40 communities,
communities that are disadvantaged according to Justice40 Initiative criteria in the U.S. and its
territories, should be highlighted in future mapping efforts.
Invasive Species: Invasive species data was not included in the exposure analysis or greenhouse gas
inventory. Future analysis of greenhouse emissions and hazard exposure should include analyses of
the impact of invasive species. The County should partner with federal and state agencies and local
non-profits to incorporate existing data of land cover type into emissions calculations and land use
policy. Invasive species data should also be incorporated into hazard analyses. For example, invasive
trees such as albizia and eucalyptus are prone to falling and damaging infrastructure during storms.
Invasive grasses can enhance wildfire vulnerability. Invasive ungulates, such as wild goats, can cause
damage to ecosystems through deforestation, increasing vulnerability to wildfires and decreasing
carbon sequestration.
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Climate Cascade 1: Greenhouse Gas Emissions 17
CLIMATE CASCADE I:
GREENHOUSE GAS EMISSIONS
Climate Cascade 1 focuses on the primary drivers of climate change - anthropogenic greenhouse gas
emissions (GHGs) - and the community systems on Hawaiʻi Island that emit GHGs (Figure 8). This
section describes and evaluates this climate cascade and identifies intervention points for County
actions and the potential co-benefits of such actions. The County of Hawaiʻi Greenhouse Gas
Inventory, summarizing island-wide emission sources and sinks, provides a baseline for the
intervention points and informs the cascade narrative. Intervention points for County actions are
identified along with climate co-benefits.
Figure 8. Climate Cascade 1. Greenhouse gas emissions
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Climate Cascade 1: Greenhouse Gas Emissions 18
Cascade Narrative
Human activities are increasing greenhouse gas emissions globally to
levels that are changing the climate and the Earth’s ecosystem.
The natural carbon cycle includes sources that emit GHGs and sinks that sequester GHGs.
Greenhouse gases include carbon dioxide, methane, nitrous oxide, and fluorinated gases. The
“greenhouse gas effect” occurs when GHGs trap heat by impeding the release of infrared light waves
back into the atmosphere. Before 1850, global sources and sinks maintained a stable cycle of GHGs
and therefore stable temperature patterns. Since 1850, GHGs have been released at unprecedented
levels, creating today’s climate crisis. In 2021, the Intergovernmental Panel on Climate Change (IPCC)
reported that anthropogenic (human-originated) emissions are the cause of global climate change.26
In 2017, Hawaiʻi County produced 2,779,683 metric tons of GHGs.27 As of 2023, GHG sources in
Hawaiʻi County include emissions from burning of fossil fuels and biofuels for energy and transportation
and from decomposition of organic and inorganic waste. GHGs are emitted to support community
systems such as electricity, transportation, waste, and industries from agriculture to healthcare to
tourism. Simultaneously, the cycle of land development and underdevelopment has led to deforestation
and biodiversity loss, decreasing natural carbon sinks on Hawaiʻi Island. The early 20th century
expansion of plantation and cattle industries followed by the contraction of farming and ranching in the
21st century were major drivers of these impacts. Deforestation and biodiversity loss will continue
without increased investment in appropriately managing our open spaces.
As the effects of climate change emerge, so does the urgency to understand how to reduce emissions
and ensure equity while pursuing solutions. While Hawaiʻi County’s contribution to global emissions
may be small by proportion, it’s essential that we take responsibility for our contribution to global
climate change and reduce our sources of emissions alongside the rest of the world.
Increasing use of fossil fuels to generate electricity for commercial,
industrial, and residential activity emits increasing amounts of
greenhouse gases.
Hawaiʻi Island has a long history of utilizing renewable energy. In 1890, Hilo was the site of one of the
first hydropower projects in the state.28 Hawaiʻi Island also has the state’s only geothermal plant, Puna
Geothermal Ventures, founded in 1993.29 In 2022, Hawaiian Electric has made a commitment to cut its
26 IPCC (2021) Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change[Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, In press, doi:10.1017/9781009157896. 27 County of Hawaiʻi Department of Research and Development. (2021). Greenhouse Gas Emissions Inventory for 2017. County of Hawaiʻi.https://www.hawaiicounty.gov/home/showpublisheddocument/304504/637834584810900000. Note: Emissions calculations do not include emissions from volcanic eruptions, although these emissions amplify the impacts of human-caused emissions on health. 28 Hawaiian Electric. (2023). https://hawaiiainelectric.com 29 Hawaii Energy Facts & Figures (2020). Hawaii State Energy Office. https://energy.hawaii.gov/wp-content/uploads/2020/11/HSEO_FactsAndFigures-2020.pdf
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Climate Cascade 1: Greenhouse Gas Emissions 19
carbon emissions by 70 percent by 2030. Current renewable energy sources on-island include solar,
wind, hydroelectric, geothermal, and biofuels.
On and off-grid energy production and electricity use is the second-largest source of emissions on
Hawaiʻi Island, with a total of 959,900 metric tons of carbon dioxide equivalent (MTCO2e) released per
year.30 Energy production provides electricity, air conditioning, and heat that support commercial,
industrial, and residential activity. The population of Hawaiʻi County is projected to increase a little over
1 percent annually between now and 2045.31 As the population grows, additional building infrastructure
and electricity will be necessary for housing and social services such as schools, grocery stores, and
medical care. The rise in technology use places an additional burden on electricity needs, as devices
such as computers, televisions, and cellphones require immense amounts of electricity to run. Despite
potential increase in energy efficiency from digitalization, the greenhouse gas emissions and toxic
waste associated with usage and disposal of technologies outweigh the reduction in greenhouse gas
30 County of Hawaiʻi Department of Research and Development. (2021). Greenhouse Gas Emissions Inventory for 2017. County of Hawaiʻi.https://www.hawaiicounty.gov/home/showpublisheddocument/304504/637834584810900000 31 State of Hawaiʻi Department of Business, Economic Development, and Tourism. (2018). Population and Economic Projections for the State of Hawaii to 2045. https://files.hawaii.gov/dbedt/economic/data_reports/2045-long-range-forecast/2045-long-range-forecast.pdf
Solar-paneled parking lot in the West Hawaiʻi Civic Center
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Climate Cascade 1: Greenhouse Gas Emissions 20
emissions from energy efficiency.32 Increased infrastructure will augment energy demand and the
resulting carbon footprint.
On the state level, Hawaiʻi homes use 40 percent less electricity on average than the national
average.33 However, the State of Hawaiʻi has the highest energy cost of any state in the United States,
at 42.37 cents per kilowatt-hour (kWh), compared to the national average of 12.52 cents.34 These high
prices partially stem from the state’s dependence on energy importation. Foreign oil generates
60 percent of the state’s energy, and Hawaiʻi uses 12 times more energy than is produced in-state.
Pricing structures are dependent on the cost of foreign oil, even for renewable energy generation. High
prices on Hawaiʻi Island are also impacted by fuel costs, low customer density, and geographic
isolation. In 2022, Hawaiʻi Island’s electric grid was 50.1 percent dependent on foreign oil when all its
renewable power plants were running.35 However, the grid does not account for propane use, meaning
Hawaiʻi Island is more dependent on foreign fuel than reflected by the grid. Therefore, operations cost
is higher for businesses in Hawaiʻi, even when using less energy than comparable businesses on the
continent. In the face of international oil shortages or economic disruptions, the dependence on foreign
oil will continue to increase the costs of living and operating businesses on the island. Hawaiʻi residents
have already experienced increased cost of electricity as a result of the Ukraine-Russia war.
The County government can reduce its footprint by increasing the percentage of renewable fuel used to
power County buildings and infrastructure, reducing vehicle miles traveled, and establishing more
energy efficient buildings.
Inefficient energy use in existing and new buildings emits increasing
amounts of greenhouse gases.
Building energy efficiency refers to how effectively infrastructure uses energy generated. Building
design determines energy efficiency. For example, buildings that are designed with natural cooling
systems (such as windows and doors that allow for cross-ventilation or siding that better reflects
sunlight) require fewer fans or small air conditioning units. Upgrading appliances such as light bulbs,
refrigerators, and washing machines also reduces electricity usage. New building development
inevitably increases greenhouse gas emissions by adding an additional load on or off grid. New
development also includes embodied emissions from harvesting, transportation, and construction of
materials. However, buildings that are developed efficiently emit less than those that are not.
Retrofitting older buildings can also decrease electricity use and therefore greenhouse gas emissions.
This is one of the most cost-effective ways to reduce emissions, as improving energy standards costs
less than 1 cent per kWh saved.36 County facilities can be retrofitted to be more efficient using solar
panels in areas with higher solar radiance (Figure 9).
32Steffen Lange, Johanna Pohl, Tilman Santarius (2020) Digitalization and energy consumption. Does ICT reduce energy demand?, Ecological Economics, Volume 176, 106760, ISSN 0921-8009, https://doi.org/10.1016/j.ecolecon.2020.106760. 33 Hawaii State Energy Profile. U.S. Energy Information Administration. https://www.eia.gov/state/print.php?sid=HI. 1 Nov. 2022. 34 Average Price of Electricity to Ultimate Customers by End-Use Sector. U.S. Energy Information Administration. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a. 1 Mar. 2023. 35 Hawaii State Energy Profile. U.S. Energy Information Administration. https://www.eia.gov/state/print.php?sid=HI. 1 Nov. 2022. 36 Hawaii Energy Facts & Figures (2020). Hawaii State Energy Office. https://energy.hawaii.gov/wp-content/uploads/2020/11/HSEO_FactsAndFigures-2020.pdf
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Figure 9. Locations of County buildings for potential energy retrofits
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Increasing ground, air, and marine transportation for commercial,
industrial, and residential activity emits increasing greenhouse gases.
Transportation is a key facet of residential, commercial, and industrial activity. Transportation is the
largest source of emissions for Hawaiʻi County, with a total of 1,742,191 MTCO2e released per year. In
Hawaiʻi, transportation emissions are generated from ground, air, and marine transportation. Ground
transportation contributes 16.8 percent of emissions annually on Hawaiʻi Island.37 Ground
transportation includes individual and public vehicles used by residents and visitors for all purposes
from daily life to construction, trucking, and agriculture. The visitor industry adds to the use of cars on
the island. Because of the size and rural nature of our island, visitors often rent cars and drive to “hot
spot” attractions around the island.38 With increasing population and commercial activity, ground
transportation emissions increased 17.31 percent from 2015 to 2017 and are expected to continue to
increase.39 More people will be commuting and recreating, and more businesses will need to transport
goods around the island to service them.
On Hawaiʻi Island, 71.4 percent of workers rely on individual modes of transportation. In Hawaiʻi, the
cost of gas is higher than any state except Alaska and is almost double the cost of states with the
cheapest gas. The Ulupono Initiative estimates that the public costs of the vehicle economy, including
roadway and bridge maintenance and public transportation, are around $15,000 per taxpayer with an
additional $8,100 annual cost per vehicle. Therefore, 71.4 percent of workers are paying at least $8,100
per year to cover their transportation needs before taxes.40 Forty-eight percent of people on Hawaiʻi
Island are living below the ALICE (Asset Limited, Income Constrained, Employed) threshold.41 The
annual cost of vehicle ownership is 33 percent of the annual total income of an ALICE-qualified single
adult households.
Airline transportation emissions are the dominant source of transportation emissions, accounting for
54 percent of total annual emissions. Airline emissions include all flights that originate from Hawaiʻi Island.
Airline travel is an essential part of residential, commercial, and visitor industry activity on island.
Interisland commutes are a standard part of many industries, including construction. Airlines are also an
essential means of importing goods to the island. Increasing population and commercial activity
augment the need for flights and imported goods, so airline emissions are expected to increase.
37 County of Hawaiʻi Department of Research and Development (2021). Greenhouse Gas Emissions Inventory for 2017. County of Hawaiʻi.https://www.hawaiicounty.gov/home/showpublisheddocument/304504/637834584810900000 38 Hawaii Tourism Authority (2021). ”Hawaiʻi Island Destination Management Action Plan.“ https://www.hawaiitourismauthority.org/media/7040/hta-hawaii-island-action-plan.pdf 39 County of Hawaiʻi Department of Research and Development. (2021). Greenhouse Gas Emissions Inventory for 2017. County of Hawaiʻi.https://www.hawaiicounty.gov/home/showpublisheddocument/304504/637834584810900000 40 Ulupono Initiative. (2022). The Costs of the Vehicle Economy in Hawaii. https://ulupono.com/project-list/the-costs-of-the-vehicle-economy-in-hawaii/ 41 ALICE Threshold, 2007-2018. American Community Survey, 2007-2018.
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Increasing waste and wastewater production from commercial, industrial,
and residential activity emits increasing amounts of greenhouse gases.
Waste emissions account for 8.79 percent of Hawaiʻi Island emissions.42 Hawaiʻi County collected
203,872 tons of waste in its landfill in 2022. Solid waste produces emissions through the process of
decomposition, which releases nitrogen gases and methane. The process of transporting waste to
transfer stations and from transfer stations to the landfill produces additional emissions. Waste can be
diverted from the landfill or incinerator by reducing, reusing, recycling, or composting waste.
Wastewater (sewage) produces emissions during treatment processes, including nitrification and
denitrification. Managing waste is especially important for an island community, which has limited land
for waste disposal and watersheds that are easily polluted. Residential, commercial, and industrial
activity add to waste production on the island through materials used in construction, agriculture, and
the visitor industry. Without finding ways to repurpose and reduce waste, waste production will continue
to grow as population expands and economic activity increases.
Historical deforestation and degradation of native ecosystems and open
spaces reduce carbon sinks.
Hawaiʻi Island forests are the largest source of carbon sequestration in the state.43 Pre-Western-
contact, native habitat made up 85 percent of Hawaii’s landscape. Post-contact, it fell to a little more
than 40 percent of Hawaii’s landscape.44 Most deforestation in Hawaiʻi occurred in the late 1800s and
early 1900s. Recent analysis indicates that forest cover is increasing.45 As forest or shrubland is
repurposed for commercial and residential activities, ranching, and agriculture, natural carbon sinks and
vital cultural resources vanish. Additionally, land management practices, such as outplanting non-native
species, have further reduced the prevalence of native ecosystems.46
Forests are also essential pieces of the watershed. Forested lands at higher elevation catch and collect
water that then travels down to lower elevation zones, providing fresh water from mauka to makai.
Deforestation and degradation of native forests can decrease the availability of fresh water, affecting
potable water supply, agriculture, and ecosystem health. Forest composition is changing due to
invasive trees and shrubs47 which decreases groundwater recharge.48 Improved watershed
management is needed to improve groundwater recharge and protect drinking water.49 Declines in
42 County of Hawaiʻi Department of Research and Development.(2021). Greenhouse Gas Emissions Inventory for 2017. County of Hawaiʻi.https://www.hawaiicounty.gov/home/showpublisheddocument/304504/637834584810900000 43 Hawaii State Department of Health (2021). Hawaii Greenhouse Gas Emissions Report for 2017. https://health.hawaii.gov/cab/files/2021/04/2017-Inventory_Final-Report_April-2021.pdf 44 Gon, S.M.; Tom, S.L.; Woodside, U. Āina Momona, Honua Au Loli—Productive Lands, Changing World: Using the Hawaiian Footprint to Inform Biocultural Restoration and Future Sustainability in Hawaiʻi. Sustainability 2018, 10, 3420. 45 Lucas, M. (2017). Spatially quantifying and attributing 17 years of vegetation and land cover transitions across Hawai`i. MSc Thesis. University of Hawaii at Manoa 46 A. C. Medeiros, E. I. von Allmen, C. G. Chimera. (2014). "Dry Forest Restoration and Unassisted Native Tree Seedling Recruitment at Auwahi, Maui," Pacific Science, 68(1), 33-45. 47 Weller, S.G., Cabin, R.J., Lorence, D.H., Perlman, S., Wood, K., Flynn, T. and Sakai, A.K. (2011). Alien plant invasions, introduced ungulates, and alternative states in a mesic forest in Hawaii. Restoration Ecology, 19(5), pp.671-680. 48 Kagawa, A., Sack, L., Duarte, K.E. and James, S. (2009). Hawaiian native forest conserves water relative to timber plantation: species and stand traits influence water use. Ecological Applications, 19(6), pp.1429-1443. 49 Bremer, L.L., DeMaagd, N., Wada, C.A. and Burnett, K.M. (2021). Priority watershed management areas for groundwater recharge and drinking water protection: A case study from Hawaiʻi Island. Journal of Environmental Management, 286, p.111622.
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Climate Cascade 1: Greenhouse Gas Emissions 24
forest cover have also been found to increase fecal bacteria in Hawaiʻi Island soil and nearby streams,
compromising the health of the ecosystems dependent on affected watersheds.50 Urban soils on
Hawaiʻi Island are at most risk for potentially damaging fecal indicator bacteria and the staph bacteria
MRSA.51 Moreover, urban runoff carried by polluted water upstream impacts the health of coral reefs,
increasing coral bleaching and reducing coral spawning and fish nurseries.52
Reduction in fresh water and the proliferation of invasive species contribute to biodiversity loss.53 Over
90 percent of the species in Hawaiʻi are found nowhere else in the world.54 Approximately half the
species that have gone extinct in the world are island species, and over one-third of the plant species
on Hawaiʻi Island are categorized as endangered or threatened by the U.S. Fish and Wildlife Service.
Invasive species, such as coqui frogs, gorse, and albizia, reduce the ability of native ecosystems to
support biomass and sequester carbon. Native species also increase the resilience of watersheds to
extreme precipitation and warming temperatures.55 The effect of urban runoff on groundwater
discharge also feeds the growth of invasive algae species while decreasing the prevalence of native
algae species, affecting the health of coastal waters.56 On Hawaiʻi Island, there have already been
extensive efforts to combat the reduction of ʻōhiʻa and nēnē species. However, not all native plants and
animals have been able to survive the impacts of invasive species and biodiversity loss.
Native species carry immense cultural significance. ‘Ahu‘ula feather capes were traditionally made from
feathers of birds, some of which are now endangered like ‘i‘iwi.57 ‘Uala has long been a staple food.
Already, the ‘uala season in Maui has been affected by decreases in annual precipitation associated
with climate change, as the amount of precipitation changes the zones in which ‘uala can be grown.58
Traditional agriculture is a crucial piece of culture and food security in Hawaiʻi. Continued deforestation
will only decrease the prevalence of native species. Kumu Hula Pua Kanahele said, “If we cut down the
forests, we cut down ourselves.” 59
50 Strauch, A.M.; MacKenzie, R.A.; Bruland, G.L.; Tingley, R.; Giardina, C.P. (2014). Climate Change and Land Use Drivers of Fecal Bacteria in Tropical Hawaiian Rivers. J. Environ. Qual. 2014, 43, 1475 51 Tyler Gerken, Tracy N. Wiegner, Louise M. Economy. (2022). ”A comparison of soil Staphylococcus aureus and fecal indicator bacteria concentrations across land uses in a Hawaiian watershed.“ Journal of Environmental Quality, 10.1002/jeq2.20380, 51, 5, (916-929). 52 Stender, Y.; Jokiel, P.L.; Rodgers, K.S. (2014). ”Thirty Years of Coral Reef Change in Relation to Coastal Construction and Increased Sedimentation at Pelekane Bay, Hawaiʻi.“ PeerJ 2014, 2, e300. 53 Barton, K.E., Westerband, A., Ostertag, R., Stacy, E., Winter, K., Drake, D.R., Fortini, L.B., Litton, C.M., Cordell, S., Krushelnycky, P. and Kawelo, K. (2021). Hawaiʻi forest review: synthesizing the ecology, evolution, and conservation of a model system. Perspectives in Plant Ecology, Evolution and Systematics, 52, p.125631. 54 Timmons, G. and Gon III, S. (2016) The Last Stand: The Vanishing Hawaiian Forest. The Nature Conservancy of Hawaiʻi. https://www.nature.org/media/hawaii/last_stand_web_lo.pdf 55 Strauch, A.M., Giardina, C.P., MacKenzie, R.A. et al. (2017). Modeled Effects of Climate Change and Plant Invasion on Watershed Function Across a Steep Tropical Rainfall Gradient. Ecosystems 20, 583–600 https://doi.org/10.1007/s10021-016-0038-3 56 Dulai, H., C. M. Smith, D. W. Amato, V. Gibson, and L. L. Bremer. (2021). Risk to native marine macroalgae from land-use and climate change-related modifications to groundwater discharge in Hawaiʻi. Limnol. Oceanogr. Lett. 8: 141– 153. doi:10.1002/lol2.10232 57 Mallon, S., Kanawa, R. T., Collinge, R., Balram, N., Hutton, G., Carkeek, T. W., & Kapeliela, K. (2017). The ‘ahu ‘ula and mahiole of Kalani ‘ōpu ‘u: A journey of chiefly adornments. Tuhinga, 4. 58 Gon SM, Tom SL, Woodside U. ʻĀina Momona, Honua Au Loli—Productive Lands, Changing World: Using the Hawaiian Footprint to Inform Biocultural Restoration and Future Sustainability in Hawai‘i. Sustainability. 2018; 10(10):3420. https://doi.org/10.3390/su10103420 59 Timmons, G. and Gon III, S. (2003). The Last Stand: The Vanishing Hawaiian Forest. The Nature Conservancy of Hawai’i. https://www.nature.org/media/hawaii/last_stand_web_lo.pdf
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Climate Cascade 1: Greenhouse Gas Emissions 25
Greenhouse Gas Inventory
Sources of emissions for Hawaiʻi County are documented by the County of Hawaiʻi 2017 Greenhouse
Gas (GHG) Inventory. This inventory informs key intervention points; helps identify and prioritize sector-
specific carbon mitigation and reduction strategies, and aids as a benchmark to gauge progress. Data
for this report was collected from seven GHG-producing sectors made up of 42 sources, for the years
2005, 2015, and 2017 (Figure 10). These sectors and sources correspond with the State’s GHG
inventory, which was developed in accordance with the 2006 IPCC Guidelines for National GHG
Inventories.
Figure 10. Hawaiʻi County sector overview of MTCO2e emissions for years 2005, 2015, and 2017
The County of Hawaiʻi GHG Inventory is guided by the Global Protocol for Community-Scale
Greenhouse Gas Emission Inventories and estimates GHG emissions that occur in the County’s
jurisdiction encompassing the entire island of Hawaiʻi. The Global Protocol is a carbon emissions
accounting and reporting standard for cities and municipalities developed by the World Resources
Institute, C40 Cities Climate Leadership Group, and the International Council for Local Environmental
Initiatives Local Governments for Sustainability.
In 2017, overall emissions had decreased by 23 percent since 2005. The Transportation and Mobile
Sources sector remained relatively stagnant over the years and remained the largest contributor to
greenhouse gas emissions. Notably, Aviation accounted for 51 percent of total transportation
emissions, compared to 32 percent from On-Road Motor Gasoline. The second largest contributor was
Commercial Energy, but emissions from this sector decreased by approximately half between 2005 and
2017. The Residential Energy sector was the third largest contributing sector in 2005, but emissions
from residential energy steadily declined due to ~28 percent increase in renewable energy capacity. By
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2017, Solid Waste became the third largest source of emissions. Volcanic emissions are not included in
this inventory.
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Climate Cascade 1: Greenhouse Gas Emissions 27
Intervention Points and Actions
Actions are associated with four intervention points (1A – 1D) within the greenhouse gas emissions
cascade (Figure 8). Entities responsible for implementing these actions are mostly County departments
but also include the private sector and individuals. Lead County departments for this cascade are as
follows:
• Research and Development Department (R&D)
• Planning Department (DP)
• Department of Human Resources (HR)
• Department of Public Works (DPW)
• Department of Finance (DF)
• Department of Parks and Recreation (DPR)
• Mass Transit Agency (MTA)
• Department of Environmental Management (DEM)
1A. Energy and Electricity Use
Recommended actions at this intervention point fall under seven strategies, with a total of thirty-four
actions, as presented in the sections and tables below.
1A1. Develop energy benchmarking standards for Hawaiʻi County buildings
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A1.1 Aggregate all County meter data to create a baseline portfolio in Energy Star R&D $ 2023 ●
1A1.2 Establish an online platform to streamline gathering and reporting of monthly County meter data
R&D, DPW, DF $ 2023 ●
1A1.3 Create an energy benchmarking dashboard and update monthly R&D $ 2024 ●
1A1.4 Publish an annual report on County energy use and energy efficiency improvements R&D $ 2025 ●
1A1.5 Hire or contract a certified energy manager to manage Energy Star portfolio and building energy contracts DPW $ 2025 ●
1A1.6 Develop an Energy Management Plan for County owned facilities DPW $$ 2025 ●
1A1.7 Purchase an Energy Management System for County buildings DPW $$ 2025 ●
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1A2. Transition Hawaiʻi County buildings to net zero emissions
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A2.1
Screen all capital improvement projects (CIP) and maintenance projects for eligibility for energy rebates as part of the CIP project proposal checklist.
DF, DP $ 2024 ●
- Create a list of eligible rebates and specs necessary for rebate eligibility R&D $ 2023 ●
1A2.2
Conduct a cost-benefit analysis to determine the benefit of establishing an energy projects revolving fund to utilize rebates and electricity savings for future energy investments.
DF $ 2023 ●
1A2.3 Capture methane from County facilities to replace and reduce propane sources DEM $$$ 2025 ●
- Conduct a feasibility assessment
1A2.4 Apply for Energy Efficiency and Conservation Block Grants annually. R&D $ 2023 ●
1A3. Implement renewable and energy efficient purchasing policies
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A3.1 Establish an energy efficiency standard checklist for all new County equipment and building purchases DF, R&D $
- Create a cost-benefit analysis and specifications list that can be used by depts. to determine if there is a cost-appropriate energy efficient option for County equipment and building purchases 2024 ●
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1A4. Inventory greenhouse gas emissions at the municipal and County level
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A4.1 Continue to publish a municipal greenhouse gas inventory for County buildings, transportation, waste, wastewater, and land use. R&D $ 2024 ●
1A4.2 Publish a county-wide greenhouse gas inventory every 3 years. R&D $ 2024 ●
1A4.3 Develop an embodied carbon baseline for County buildings, transportation, and waste. R&D $ 2024 ●
1A5. Revise building and energy codes to incentivize energy efficiency measures for buildings,
electric vehicle (EV) use, low-cost sustainable materials, and energy efficiency standards
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A5.1 Amend Chapter 5 of the Hawaiʻi County Code to adopt the 2021 IECC energy code with modifications specific to Hawaiʻi County. DPW $ 2024 ●
1A5.2 Create a dependable permitting system by identifying and addressing inefficiencies in County permitting process. DPW $ 2023 ●
1A5.3 Incentivize developments that align with County sustainability goals and plans. DPW $ 2026 ●
- Partner with on-island developers to identify ways to offset development costs associated with green infrastructure and promote environmentally friendly, locally produced building materials
1A5.4
Amend Chapter 25 of the Hawaiʻi County Code to require all public and private parking lots to maintain a 25% parking stall minimum to be EV-charger ready by 2035.
Council, PD $ 2023 ●
1A5.5
Conduct a study to determine financial impact of waiving all permitting and review fees for development projects that have a minimum LEED certified credential or similar credential.
DPW $$ 2026 ●
1A5.6 Pilot low-emissions landscaping equipment and landscaping practices to determine effectiveness of equipment and practices. DPW $ 2025 ●
- Identify on-island partner organizations that can guide pilots
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1A6. Support residents and businesses in producing environmentally friendly on-site energy
and implementing energy efficient cooling technologies
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A6.1 Expand outreach for community rebate incentives by pursuing more public-private partnerships with Hawaiʻi Energy R&D $ 2023 ●
1A6.2 Advocate to the PUC in support of renewable energy sources and social equity in regard to rates, grid planning, and energy project siting R&D $ 2023 ●
1A6.3
Create educational workshops and an online-web series with partners to increase awareness of and access to rebates, tax credits, and energy conservation technology.
R&D $ 2023 ●
1A6.4
Release grants to encourage development and implementation of new on-site energy construction and energy efficiency measures on island
R&D $$ 2024 ●
1A6.5 Conduct a study to evaluate the environmental impact of hydrogen energy production on-island. R&D $ 2024 ●
1A7. Reduce the energy cost of the municipal water supply
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1A7.1 Replace old pumps with higher efficiency pumps for energy savings. DWS $$ 2023 ●
- Prioritize based on payback period analysis
1A7.2 Install new Hydro-turbine at Waimea Water Treatment Plant. DWS $$ 2024 ●
1A7.3 Pursue additional renewable energy projects. DWS $$ 2025 ●
1A7.4 Install power factor correction equipment at large facilities to increase power factor. DWS $$ 2024 ●
1A7.5 Conduct energy study to establish baseline and detail power and energy savings opportunities. DWS $ 2023 ●
1A7.6 Continue to optimize operations to reduce power demand and energy use. DWS $ 2023 ●
1A7.7
Continue to purchase and utilize leak detection equipment to reduce water leaks in water transmission systems. Reducing water loss will reduce DWS energy use.
DWS $ 2023 ●
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Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
- Continue partnership with Hawaiʻi Energy to help fund rebate leak
detection equipment purchases
1A7.8
Continue to conduct and improve public outreach on water conservation, including drought-resistant landscapes, water conservation practices, and reducing waters leaks. Reducing water use will reduce DWS energy use.
DWS $ 2023 ●
1B. Transportation
Recommended actions at this intervention point fall under four strategies, with a total of twenty actions,
as presented in the sections and tables below.
1B1. Continue implementation of the Multi-Modal Transportation Plan to decrease emissions
from individual commutes and decrease emissions of the public transit fleet
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1B1.1 Make riding transit easier, reliable, and compatible with other multi-modal options MTA $$
- Continue the multi-modal program to increase access to biking and walking options for residents 2023 ●
- Implement the multi-modal complete streets program for island-wide
with a focus on urban areas. 2025 ●
1B1.2 Create a transit system to serve the employment and social needs of all people MTA $$ 2023 ●
- Continue to sustain and maintain the transit network and adjust as demographics and socioeconomic conditions change. ●
1B1.3
Implement technology to provide information to riders and others, including helping to achieve clean energy goals through alternate energy bus and infrastructure purchase, doing so in a fiscally responsible manner.
MTA $$$
- Three (3) hydrogen buses go into service on Kailua-Kona routes 2023 ●
- Five (5) electric battery buses and charging equipment purchased 2024 ●
- Three (3) diesel hybrid buses purchased 2023 ●
- 28 future purchases would be a combination of diesel-electric, hybrid, electric, and/or hydrogen if approved by HDOT. 2025 ●
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Climate Cascade 1: Greenhouse Gas Emissions 32
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1B1.4
Create transit hubs and bus stops with amenities that provide rider comfort and safety and that help support community and village gathering
MTA $$$
- Plan, design, and build the Kailua-Kona hub. Consider options to provide light service from Kailua-Kona side. 2023 ●
- Design and develop a Puna hub and complete roadway improvements
to allow for Intra-Puna service. 2023 ●
1B1.5 Phase implementation in a fiscally sustainable manner MTA $
- Test hydrogen and EV fueled buses on the island to demonstrate how well they work on the island’s various climate and terrains. 2023 ●
- Add staffing to include an Assistant Mass Transit Administrator,
Inventory Clerk, and a second shift of four mechanics and working supervisor. 2023 ●
1B2. Transition the County fleet to zero emissions
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1B2.1 Create a shared-use mobility program among County depts. that use vehicles intermittently R&D, DPW, DF $ 2024 ●
1B2.2
Develop an online platform to consolidate County vehicle fuel use, vehicle miles traveled, elevation profile of vehicle routes, and vehicle maintenance data
R&D, DPW $ 2025 ●
- Integrate platform with energy management system identified in 1A1.6
1B2.3
Conduct a study to identify high-priority vehicles for fleet transformation, including vehicles that need to be replaced and highest-emitting vehicles
R&D $$$ 2025 ●
1B2.4 Publish an internal annual report and external annual summary on fleet use and fleet transition R&D $ 2023 ●
1B2.5 Create a fleet transformation plan for each dept. All, R&D, DF $$ 2025 ●
- Conduct an alternative fuel vehicle cost-benefit analysis for new vehicle purchases. The analysis should include IRA tax credits, third party financing, rebates, and methane-conversion.
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Climate Cascade 1: Greenhouse Gas Emissions 33
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
- Conduct feasibility study on retrofitting heavy-duty vehicles with zero-
emissions or renewable fuel technology. Include a cost-benefit analysis of retrofitting engines versus purchasing new vehicles
- Determine necessary, feasible steps and cost to build the capacity of the Automotive Division to work on zero emission vehicles, including: Training; Equipment Purchasing; and Public-Private partnerships with
local automotive shops and dealerships to invest in training and equipment necessary for fleet transition.
1B2.6
Place charging infrastructure in all County buildings, public parks, and baseyards for County use, including developing hydrogen fueling stations in Hilo and Kona
DPW $$$ 2027 ●
1B3. Implement carbon-free vehicle purchasing policies in Hawaiʻi County and improve
purchasing policies to reduce emissions associated with importation
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1B3.1 Establish an alternative fuel checklist for all new County vehicle purchases DF, R&D $ 2024 ●
- Utilize cost-benefit analysis (B2.5) to determine cost of alternative fuel vehicles
1B3.2
Mandate reporting of all new vehicle purchases including average mpg, emissions equivalent per gallon of fuel (or kWh), and estimated annual operation and maintenance costs
County Council, R&D, DF, DPW
$ 2024 ●
1B3.3
Revise County purchasing process to prioritize local purchasing to reduce the emissions from importation of goods and services to the County.
DF $ 2024 ●
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1B4. Increase accessibility of zero emissions vehicle infrastructure and alternative
transportation options to the public
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1B4.1
Pass an ordinance to require County-built roads to include complete street measures where most effective to promote alternative transit options and pedestrian-friendly development
County Council $ 2025 ●
1B4.2 Increase and maintain electric vehicle and hydrogen vehicle charging stations on County sites at low to no cost for users DPW $ 2028 ●
1B4.3 Create a shared-use mobility system for County-owned electric vehicles R&D, DPW $ 2026 ●
1B4.4
Partner with non-profits, schools, and State agencies to increase community-wide awareness and accessibility re: reducing transportation cost and emissions (i.e., the impact of keeping tires inflated on efficiency of cars) through education awareness program.
R&D $ 2023 ●
1B4.5 Conduct public outreach around charging stations to align new construction of County infrastructure with business and community
DPW, R&D $ 2024 ●
1C. Waste
Recommended actions at this intervention point fall under five strategies, with a total of twenty-two
actions, as presented in the sections and tables below.
1C1. Reduce the carbon footprint of the landfill.
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C1.1 Implement methane collection systems at landfill and wastewater treatment facilities so that the methane can be stored or converted for fuel
DEM, R&D $$$ 2023 ●
- Acquire grant monies to conduct an assessment to determine methane produced at wastewater and waste facilities
1C1.2 Create a strategic plan for reducing the emissions of the landfill and wastewater treatment plant DEM $$ 2024 ●
- Engage community stakeholders, businesses, and policymakers in plan creation through a taskforce
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Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C1.3
Continue to explore opportunities with third parties to divert the waste from the landfill and/or repurpose the waste for economic development and energy needs
DEM $$$ 2023 ●
1C1.4 Explore opportunities with third parties to reduce greenhouse gas emissions from the wastewater treatment plants DEM $$$ 2024 ●
1C2. Advocate for policies that promote waste diversion through source reduction and
recycling.
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C2.1
Amend Chapter 20 of the HCC to establish waste management goals that are expressed and measured in terms of environmental and community impacts (e.g. greenhouse gas emissions, toxicity, energy use) and consider life cycle impacts, in addition to tonnage-based landfill diversion and waste recovery goals
County Council, DEM $$ 2024 ●
- Create recommendations based on the lifecycle impact report
1C2.2
Amend administrative rules and procedures to include a differential tipping fee and to mandate solid waste collection fees be reviewed and equitably updated on a regular basis.
DEM $ 2023 ●
1C2.3
Amend Chapter 20 of the HCC to include a schedule of select materials that shall be separately collected, recycled, and prohibited from entering the landfill.
County Council, DEM $ 2023 ●
- Continue ongoing initiatives to implement extended producer responsibility
1C2.4 Continue to advocate for and streamline the process of state policy to increase accessibility of recycling DEM $ 2023 ●
- Advocate for mandated recycling and organic waste infrastructure be available in all public waste collection contracts
1C2.5
Develop legislation that requires owners and managers of multi-family dwellings and multi-tenant commercial building to provide recycling receptacles
County Council, DEM $ 2028 ●
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1C3. Support local businesses and community members in reusing goods and materials.
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C3.1 Hire staff to track waste collected at landfills, report findings, and connect local businesses to waste streams.
DEM, R&D $
- Procure a Landfill Diversion (LD) Database Software to collect primary data to track type, amount, and source, when possible, of materials diverted from the West Hawaiʻi Sanitary Landfill. 2024 ●
- Procure a Surplus Database Software to establish a database for
surplus materials and goods through redistribution, re-sale, or donation. Members can post listings or search for available surplus items or materials, automating the process of connecting those who have items they no longer need with those who do.
2024 ●
1C3.2 Conduct assessment of current operational methodologies to improve efficiency DEM $$ 2024 ●
1C3.3 Expand opportunities to recycle in public areas and during public events DEM $$
- Continue to install additional recycling bins in parks and other public areas 2023 ●
- Increase recycling opportunities at community events 2025 ●
1C3.4 Expand opportunities for commercial recycling DEM $$ 2024 ●
- Continue to work with HDOH Solid and Hazardous Waste Branch to modify recycling and transfer station operating permits to accommodate expanded residential recycling services.
1C3.5 Expand and improve public education and awareness programs DEM $
- Develop a business waste audit and education program to build capacity for source reduction within the local business community 2023 ●
- Develop a waste reduction education program that specifically targets
educating visitors and the hotel and lodging industry on circular economy principles 2023 ●
- Continue reuse education, outreach, and public awareness campaigns to encourage public participation and use of the reuse centers 2023 ●
- Improve signage at recycling and transfer stations to provide the public
with comprehensive information about recycling opportunities and procedures 2023 ●
- Increase participation and vendor partnerships for used motor oil program 2023 ●
1C3.6 Continue partnerships with organizations such as Goodwill Industries to develop reuse centers at existing outlets within the County DEM $ 2023 ●
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Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C3.7 Establish a building deconstruction reuse and recycling program. DEM, R&D $$ 2025 ●
- Conduct a feasibility assessment of best practices and opportunities
1C4. Support mulching operations to allow for soil enhancement County-wide.
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C4.1 Continue to explore decentralized options for mulching DEM $ 2024 ●
- Partner with others to establish mulching demonstration gardens at recycling and transfer stations or other visible locations in the community
1C4.2 Continue to apply for grants and implement pilot composting systems for homeowners. DEM $ 2023 ●
1C5. Decrease waste of County operations
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1C5.1 Mandate end-of-life requirements for County-owned renewable energy infrastructure.
County Council, R&D $ 2025 ●
- Conduct an end-of-life environmental impact assessment of County-owned renewable energy and battery storage infrastructure, including analysis of existing infrastructure, community outreach, and best
practices for disposal.
1C5.2 Continue and expand the system for sharing infrequently used items among departments through Property Management. DF $ 2023 ●
1C5.3
Continue to pilot procurement models that encourage reuse, including product-as-a-service, e-leasing, and product take-back. DF $ 2024 ●
1C5.4 Establish composting sites at County facilities and parks with proper management to prevent scavenging and unsanitary conditions.
DPW, DPR $ 2027 ●
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Climate Cascade 1: Greenhouse Gas Emissions 38
1D. Land Use and Carbon Sequestration
Recommended actions at this intervention point fall under four strategies, with a total of eighteen
actions, as presented in the sections and tables below.
1D1. Establish a system for collecting, monitoring, and evaluating the carbon sequestration
potential of Hawaiʻi Island and the impact of land use
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1D1.1 Partner with State and federal agencies to identify a carbon sequestration baseline for Hawaiʻi Island R&D, PD $ 2023 ●
1D1.2
Partner with State and federal agencies to develop a standardized platform to monitor carbon sequestration potential and land use over time
R&D, PD $ 2024 ●
- Publish a report that evaluates the impact of development and land use on Hawaiʻi Island carbon sequestration utilizing the platform. ●
1D1.3 Create policy recommendations based on carbon sequestration trends observed through monitoring system PD $ 2028 ●
1D1.4 Conduct a study to identify County-owned undeveloped or vacant lands that can be reforested R&D $ 2025 ●
1D1.5
Continue to pilot regional examples of carbon sequestering landscaping on public access and open spaces lands, County parks, and County assets
DF, DPR $$ 2023 ●
- Conduct an inventory of existing studies done on public access and open space lands to demonstrate models for evaluating carbon sequestration
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1D2. Promote reforestation and conservation of forest canopies, especially in mauka areas that
benefit watershed capacity and quality
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1D2.1 Continue to plant only native or non-invasive species as part of public access and open spaces lands management practices DF $ 2024 ●
1D2.2
Establish an ordinance to require all County owned lands to plant only native or non-invasive species, specifically plants most able to thrive in the local environment
County Council, DPR, DPW
$ 2024 ●
- Partner with state agencies, the conservation and landscaping industries, and local community members to develop a preliminary list of plants for specific sites and best management practices, such as mulching, to prevent invasive species growth.
1D2.3
Amend Chapter 2, Article 42 of the Hawaiʻi County Code to prohibit the planting of invasive species in public access and open spaces lands
County Council, DF $ 2024 ●
1D2.4 In every grubbing and grading permit, include a list of local nurseries with which developers can partner for landscaping needs DPW $ 2023 ●
- Partner with local non-profits to create a list of nurseries, such as Plant Pono certified nurseries
1D2.5
Amend Chapter 25 to require a percentage of open space to be preserved as open space as a condition of approval for any rezone or time extension to maintain forest and plant cover.
County Council, PD $ 2023 ●
1D3. Encourage farming practices that increase soil quality and ability to capture carbon
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1D3.1 Continue to provide funding to farmers through small grants, prioritizing projects that increase soil quality and improved manure management R&D $ 2023 ●
1D3.2
Explore the potential cost-benefits of creating a new category within the real property tax code with benefits for carbon neutral or carbon negative agricultural lands
DF $ 2027 ●
1D3.3 Partner with State agencies, local universities, and non-profits to provide technical assistance and educational materials on best farming R&D $ 2024 ●
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Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
practices that improve carbon sequestration potential and increase soil quality
1D3.4 Increase tool-sharing, including maintenance, to increase accessibility of local farming R&D $ 2025 ●
1D3.5
Collect baseline data on food importation and inform local producers and distributors on high demand products and incorporate this data into future County Greenhouse Gas Inventories
R&D $ 2024 ●
1D3.6 Continue partnerships with State and federal agencies to expand programs like Da Bux to increase accessibility of local food R&D $ 2023 ●
1D4. Carbon Credit Programs
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
1D4.1 Partner with the State to explore carbon markets for which the County is eligible R&D $ 2023 ●
- Establish reporting standards to measure carbon sequestration of ag and conservation land.
1D4.2
Partner with State agencies to investigate the potential of accessing national carbon credit markets for County-owned and managed properties
R&D, DF $ 2028 ●
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Climate Cascade 1: Greenhouse Gas Emissions 41
Climate Action Co-Benefits
Climate co-benefits describe the potential for actions to achieve multiple outcomes. In order to realize a
co-benefit, each action must be planned, designed, and implemented with a conscious consideration of
co-benefits.
Co-Benefit Action Number
Climate Risk Reduction
• Increased heat waves and average temperature will increase energy demand. Reducing dependence on fossil fuels for electricity will minimize the cost of increased demand on the County, residents, and businesses.
1A2, 1A3, 1A4, A5, 1A6, 1A7
• Reducing emissions via restoring native ecosystems can increase wetland barriers against sea level rise and decrease urban heat zones through cooling. 1B4.1, 1D1.4, 1D1.5, 1D2
Socio-Cultural Equity
• Incentivizing new and implementing existing energy efficiency measures for LMI communities will decrease the percentage of income spent on electricity. 1A5.2, 1A5.3, 1A5.5, 1A6, 1A7
• Increasing building energy efficiency increases access to temperature-regulated buildings for vulnerable members of the population, including kupuna, keiki, and people with chronic health conditions.
1A5.2, 1A5.3, 1A5.5, 1A6
• Increasing transit-oriented development and public transit accessibility decreases cost of transportation and commute time, allowing people to spend more time with their families. 1B1, 1B4
• Reducing waste decreases toxic runoff and water table pollution, increasing healthy watersheds that support families harvesting their own food. 1C2, IC3, IC4, IC5
• Restoring and conserving native ecosystems preserves plants that are Native Hawaiian cultural staples. 1D2.1, 1D2.2, 1D2.3, 1D2.4
• Increasing equitable resilience to climate hazards will benefit historically marginalized and frontline communities and communities that have been made vulnerable to climate change impacts. All actions
Environmental Protection
• Vegetation management focused on removal of non-native and invasive trees and vegetation and restoration of native trees and vegetation will reduce risks from both wildfire and flooding and improve management of debris flows and sediment runoff during severe rainfall events.
1D2.1, 1D2.2, 1D2.3, 1D2.4, 1D2.5
• Conservation of forest canopy and reforestation mauka decreases stream diversion and increases water tables. 1D2.1, 1D2.2, 1D2.3, 1D2.4
• Incentivizing waste reduction decreases leakage of toxic chemicals from landfilled and non-landfilled waste. 1C1, 1C2, IC3, IC4, IC5
• Incentivizing waste repurposing can build soil. 1C4, 1C5.4
• Restoring and conserving native ecosystems reduces the vulnerability of native plants to invasive species. 1D2.1, 1D2.2, 1D2.3, 1D2.4
Economic Resilience
• Increasing re-use of waste creates local jobs that support local businesses. 1C3, 1C5.2
• Reducing landfilled waste also reduces environmental externalities that are penalized by the EPA, require resources to address, and decrease the viability of land for agriculture. IC
Plan Integration
• Incorporates policies and actions in Multi-Modal Transportation Plan and Integration Solid Waste Management Plan. IB, IC
• Consistent with Hawaiʻi General Plan 1A, IB, ID
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Climate Cascade 1: Greenhouse Gas Emissions 42
Actions You Can Take
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Climate Cascade 2: Air and Sea Surface Temperature 43
CLIMATE CASCADE 2:
AIR AND SEA SURFACE TEMPERATURE
Climate Cascade 2 focuses on the primary indicators of climate change: increasing air and sea surface
temperature and lowering ocean water pH (acidification) (Figure 11). This section describes and
evaluates this climate cascade and identifies intervention points for County actions and the potential co-
benefits of such actions.
Figure 11. Climate Cascade 2. Air & sea surface temperature
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Climate Cascade 2: Air and Sea Surface Temperature 44
Cascade Narrative
Rising greenhouse gas emissions increase air and sea surface
temperature.
Increasing greenhouse gas emissions result in higher air and sea surface temperatures and greater
absorption of carbon dioxide in the ocean, which decreases ocean pH (in other words, increases
acidity). The number of hot days per year in Hawaiʻi has increased dramatically over the last decade.60
Temperature is predicted to continue rising above historical averages (Figure 12).61 Coastal
communities on the island are especially susceptible to increased temperatures, with longer stretches
of temperatures well above 80 ºF.
Higher temperatures alone can be dangerous for the health of humans and other living creatures.
Higher temperatures also change the natural cycles of our planet. For example, higher temperatures
can affect how the atmosphere retains water, leading to increased rain in some areas and drought in
others. Global warming may accelerate even more as increasing air temperature mobilizes the release
of methane from thawing Arctic permafrost.62
60 Stevens, L.E., R. Frankson, K.E. Kunkel, P.-S. Chu, and W. Sweet (2022). Hawaiʻi State Climate Summary 2022. NOAA Technical Report NESDIS 150-HI. NOAA/NESDIS, Silver Spring, MD, 5 pp. https://statesummaries.ncics.org/chapter/hi/ 61 Hawaiʻi Department of Transportation. 2021. Hawaiʻi Highways, Climate Adaptation Action Plan, Exposure Assessments, https://hidot.Hawaiʻi.gov/wp-content/uploads/2021/07/HDOT-Climate-Resilience-Action-Plan-Exposure-Assessments-April-2021.pdf 62 Froitzheim, N., Majka, J., & Zastrozhnov, D. (2021). Methane release from carbonate rock formations in the Siberian permafrost area during and after the 2020 heat wave. Proceedings of the National Academy of Sciences, 118(32), e2107632118. doi:10.1073/pnas.2107632118
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Climate Cascade 2: Air and Sea Surface Temperature 45
Figure 12. Annual mean temperature (A) historical and (B) end-of century under the IPCC high-emissions scenario (Scenario RCP 8.5)
A
B
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Climate Cascade 2: Air and Sea Surface Temperature 46
Hotter air temperature poses risks to human health.
Hot temperatures can be unsafe, especially for vulnerable populations and people exposed for
extended periods of time. Kupuna and keiki, especially keiki playing outside, are even more susceptible
to the effects of extreme heat. Prolonged exposure to extreme heat can cause heat exhaustion, heat
stroke, and death, as well as exacerbating preexisting chronic conditions such as respiratory, cerebral,
and cardiovascular diseases.63 Hot temperatures become more dangerous when combined with high
humidity, as humidity compromises the effectiveness of sweat cooling the body. This means the higher
the humidity, the hotter temperatures feel Heat indices measure the combination of humidity and
temperature. Urban areas lack the tree canopy and green spaces that absorb heat and provide shade.
Instead, infrastructure, like buildings and roads, increases the surrounding temperature, creating an
urban heat island effect.
Plants, birds, and other living beings will migrate and will likely be more
stressed with increasing air temperature.
Temperature is an essential part of how living beings regulate our behavior. The gender of honu ‘ea
[hawksbill turtles] is affected by temperature, with warmer temperatures leading to more female honu
born.64 Mamo and other damselfish species regulate their metabolism through temperature. Higher
temperatures have been shown to negatively affect their ability to metabolize and swim.65 Increased air
temperature will affect the behavioral patterns of living beings on Hawaiʻi island, often in ways we can’t
yet predict. For example, avian mosquitoes are migrating mauka with warmer air temperatures,
harming native bird populations that live at higher elevations.66
Some plant species may benefit from higher concentrations of atmospheric carbon dioxide. Increased
carbon may boost forest growth and crop yields by increasing rates of photosynthesis and decreasing
the loss of water from transpiration.67 However, other factors critical to plants’ growth, such as nutrients,
temperature, and water, may limit growth.68 For example, the seed production of koa decreases in
response to higher temperatures.69 There are many ways living creatures can adapt to increased
temperature. In alpine ecosystems across the Pacific, species have been migrating to higher elevations
in response to climate change.70 Increasing temperature exacerbates drought intensity due to higher
63 National Institutes of Environmental Health. 2022. Climate and Human Health. https://www.niehs.nih.gov/research/programs/climatechange/health_impacts/heat/index.cfm#:~:text=Prolonged%20exposure%20to%20extreme%20heat,%2C%20cerebral%2C%20and%20cardiovascular%20diseases. 64National Oceanic and Atmospheric Administration. (2022). Hawaiian Hawksbill Sea Turtle Brochure. https://media.fisheries.noaa.gov/2022-02/hawaiian-hawksbill-sea-turtle-brochure-PIRO.pdf 65 Johansen, J.L. and Jones, G.P. (2011), Increasing ocean temperature reduces the metabolic performance and swimming ability of coral reef damselfishes. Global Change Biology, 17: 2971-2979. https://doi.org/10.1111/j.1365-2486.2011.02436.x 66 L. B. Fortini, L. R. Kaiser, D. A. LaPointe, Fostering real-time climate adaptation: Analyzing past, current, and forecast temperature to understand the dynamic risk to Hawaiian honeycreepers from avian malaria. Glob. Ecol. Conserv. 23, e01069 (2020). 67 NASA. 2022. NASA Study: Rising Carbon Dioxide Levels Will Help and Hurt Crops https://www.nasa.gov/feature/goddard/2016/nasa-study-rising-carbon-dioxide-levels-will-help-and-hurt-crops 68 Cho, Renee. 2022. How will climate change affect plants? https://news.climate.columbia.edu/2022/01/27/how-climate-change-will-affect-plants/ 69 Pau, S, Cordell, S, Ostertag, R, Inman, F, Sack, L. Climatic sensitivity of species’ vegetative and reproductive phenology in a Hawaiian montane wet forest. Biotropica. 2020; 52: 825– 835. https://doi.org/10.1111/btp.12801 70 Frazier, A. G., & Brewington, L. (2020). Current Changes in Alpine Ecosystems of Pacific Islands. In M. I. Goldstein & D. A. DellaSala (Eds.), Encyclopedia of the World's Biomes (pp. 607-619). Oxford: Elsevier.
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Climate Cascade 2: Air and Sea Surface Temperature 47
evaporation which can increase tree mortality and therefore contributing to forest decline.71 Species in
Hawaiʻi are most vulnerable when they are also threatened by habitat loss and invasive species.72
Increased temperature places greater demand on energy systems.
Increasing air temperature places greater demand on energy consumption. Increased use of air
conditioners will be necessary for organizations that serve vulnerable populations, such as hospitals
and schools. Additionally, technology like data servers require immense amounts of cooling, which will
increase energy demand as temperatures and technology use rise. Disasters from climate change can
also increase energy demand, as power sources go out and need to be replaced with fossil fuel.73
Heightened energy demand further increases greenhouse gas emissions, especially without renewable
and reliable energy sources.
A warmer ocean and more acidic ocean stresses coral reef ecosystems.
Decreasing ocean pH (ocean acidification) can damage coral reefs directly and indirectly from
increasing rainfall and runoff from sewage and chemicals application, including pesticides and
fertilizers. Increasing sea surface temperature, also associated with increasing storm intensity74 can
cause similar damage. This ultimately affects fish populations, the food web in marine ecosystems, and
the people who depend on them. Hawaiʻi is impacted not only by global ocean acidification, but also
coastal acidification resulting from localized land-based pollution, such as runoff and cesspools.75
Coral bleaching may occur annually with increasing ocean temperature. Rising levels of carbon dioxide
dissolved in the ocean and the resulting increase in acidity changes the balance of minerals in the
water.76 Ocean acidification makes it more difficult for corals, some types of plankton, and other
creatures to produce calcium carbonate used to produce hard skeletons or shells, making it more
difficult for these animals to thrive and jeopardizing the health of the reef.
Cascade Exposure Analysis
Climate exposure analysis was based on a literature review. A geospatial analysis of climate exposure
and risk (as conducted for Climate Cascades 3, 4, and 5) was not conducted. Climate exposure and
risk analyses for air temperature should be conducted as described in the Limitations section.
71 Brodribb, T.J., Powers, J., Cochard, H. and Choat, B. (2020). Hanging by a thread? Forests and drought. Science, 368(6488), pp.261-266. 72 Lucas Fortini, Jonathan Price, James Jacobi, Adam Vorsino, Jeff Burgett, Kevin Brinck, Fred Amidon, Steve Miller, Sam `Ohukani`ohi`a Gon III, Gregory Koob, and Eben Paxton (2013) A Landscape-based assessment of climate change vulnerability for all native hawaiian plants. Technical Report HCSU-044. https://hilo.hawaii.edu/hcsu/documents/TR44_Fortini_plant_vulnerability_assessment.pdf 73 Perera, A.T.D., Nik, V.M., Chen, D. et al. (2020) Quantifying the impacts of climate change and extreme climate events on energy systems. Nat Energy 5, 150–159. https://doi.org/10.1038/s41560-020-0558-0 74 Walsh, K.J., McBride, J.L., Klotzbach, P.J., Balachandran, S., Camargo, S.J., Holland, G., Knutson, T.R., Kossin, J.P., Lee, T.C., Sobel, A. and Sugi, M. (2016). Tropical cyclones and climate change. Wiley Interdisciplinary Reviews: Climate Change, 7(1), pp.65-89. 75 State of Hawaiʻi (2021). State of Hawaiʻi Ocean Acidification Action Plan 2021 – 2031 https://dlnr.hawaii.gov/dar/files/2021/09/State_of_Hawaii_OA_Action_Plan.pdf 76 EPA (2022). Climate Change Indicators: Ocean Acidity. https://www.epa.gov/climate-indicators/climate-change-indicators-ocean-acidity
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Climate Cascade 2: Air and Sea Surface Temperature 48
Intervention Points and Actions
Actions are associated with three intervention points (2A – 2C) within the climate change indicators
cascade (Figure 11). Entities responsible for implementing these actions are mostly County
departments but also include the private sector and individuals. Lead County departments for this
cascade are as follows:
• Planning Department (DP)
• Department of Public Works (DPW)
• Department of Finance (DF)
• Department of Parks and Recreation (DPR)
• Department of Environmental Management (DEM)
• Research & Development (R&D)
2A. Human Health
Recommended actions at this intervention point fall under three strategies, with a total of seven actions,
as presented in the sections and tables below.
2A1. Reduce risk to community members participating in events at Parks facilities
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
2A1.1 Track the temperature and humidity of parks facilities weekly to determine trends in temperature and heat index. DPR $ 2024 ●
- Determine parks that are experiencing significant increases in temperature 2025 ●
- Conduct community meetings to determine which policies, such as hours of sport events or providing water to keiki during after-school events, need to change. 2026 ●
2A1.2 Include a requirement for forest canopy or a facility that provides shade in future parks developed. DPR $ 2028 ●
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Climate Cascade 2: Air and Sea Surface Temperature 49
2A2. Increase tree canopy in urban areas to reduce urban heat island effect
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
2A2.1
Pass an ordinance to require new County-built roads to include complete street measures where most effective to encourage planting of trees along streets to provide shade for pedestrians. [See also 1B1.1]
County Council, DPW $ 2024 ●
2A2.2 Identify and rank roads that would be most feasible and beneficial to retrofit to include complete street measures DPW $$ 2024 ●
- Conduct a vulnerability assessment for existing roads. This assessment should include vulnerability of population to heat and should identify most-highly traversed areas.
- Identify trees that are most appropriate to plant to minimize infrastructure damage from root systems or falling trees.
2A2.3
Pass an ordinance to require all development in urban zones to include urban tree cover. This requirement should be scaled based on the increasing temperature of the area
County Council, PD $ 2024 ●
2A2.4 Create a County-sponsored tree-planting program R&D $ 2026 ●
2A3. Increase awareness of effects and prevention of heat exposure
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
2A3.1 Partner with public and private entities to increase awareness of heat risks and care for people exposed to extreme heat R&D $ 2024 ●
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Climate Cascade 2: Air and Sea Surface Temperature 50
2B. Energy Resilience
Recommended actions at this intervention point include one action under one strategy, as presented in
the section and table below.
2B1. Ensure County facilities are resilient to increased temperatures
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
2B1.1 Include an energy resilience assessment and roadmap in the Energy Management Plan for County facilities. [See 1A1.5, 1A1.6, 1A1.7]
R&D, DPW $ 2025 ●
- Include an assessment of energy load from technology and vulnerability of populations that utilize facilities. Identify County facilities that could be cooling centers during heat waves or blackouts. ●
2C. Coral Reefs
Recommended actions at this intervention point include six actions under two categories, as presented
in the section and table below.
2C1. Encourage preservation of coral reefs at County beach parks
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
2C1.1 Include infographics about reef-safe activities at every County beach park DPR $ 2024 ●
2C1.2 Assist with enforcement of restriction of non-reef safe sunscreen DPR $ 2025 ●
2C1.3 Continue to partner with the Kohala Center to provide educational resources to visitors and residents at Kahaluʻu Bay DPR $ 2023 ●
2C2. Encourage conversion of cesspools
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
2C2.1
Continue to partner with State and other entities to fund cesspool conversions, research best conversion practices, and expand wastewater lines in urban areas to connect those
DEM $$$ 2023 ●
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Climate Cascade 2: Air and Sea Surface Temperature 51
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
converting from OSDS within wastewater service areas (see also 3E1.1 and 4D2.1)
2C2.2
Promote findings of State Cesspool Conversion Working Group and integrate findings into wastewater management, planning, and outreach
DEM $$ 2024 ●
2C2.3
Explore additional opportunities to fund cesspool conversions for individuals and publicize opportunities to make them easily accessible to the public
DEM, R&D $$ 2024 ●
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Climate Cascade 2: Air and Sea Surface Temperature 52
Climate Action Co-Benefits
Climate co-benefits describe the potential for actions to achieve multiple outcomes. In order to realize a
co-benefit, each action must be planned, designed, and implemented with a conscious consideration of
co-benefits.
Co-Benefit Action Number
Greenhouse Gas Reduction
• Preserving and restoring coral reef systems preserves corals as a source of carbon sequestration. 2C1.1, 2C1.2, 2C1.3
• Increasing tree canopy to reduce ambient temperature increases carbon sinks. 2A1, 2A2
Climate Risk Reduction
• Increasing tree canopy and green infrastructure in areas experiencing flooding and sea level rise will help absorb the excess water.
• Preserving and restoring reefs provides natural protection from high waves and inundation.
2A1, 2A2, 2C2
Socio-Cultural Equity
• Restoring and preserving coral reefs preserves the cultural resources associated with reefs. 2C1, 2C2
• Greening urban areas and developing climate-resilient energy systems increases the availability of cool areas for vulnerable populations, such as kupuna and keiki, to live and recreate. 2A1, 2A2, 2A3, 2B1
• Increasing equitable resilience to climate hazards will benefit historically marginalized and frontline communities and communities that have been made vulnerable to climate change impacts.
All actions
Environmental Protection
• Increasing urban forestry can create corridors for species to migrate, so they can survive reductions in their natural habitat caused by development. 2A2.1, 2A2.2, 2A2.3, 2A2.4
Economic Resilience
• Preserving and protecting coral reefs preserves the industries that rely on reefs, such as fishing. 2C1, 2C2
Plan Integration
• Consistent with Hawaiʻi State Cesspool Conversion Working Group Research Summary Report 2C2.1, 2C2.2, 2C2.3
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Climate Cascade 2: Air and Sea Surface Temperature 53
Actions You Can Take
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Climate Cascade 3: Drought and Extreme Rainfall Events 54
CLIMATE CASCADE 3:
DROUGHT AND EXTREME RAINFALL EVENTS
Climate Cascade 3 focuses on how climate change—specifically changes in temperature and climate
variability—can impact drought and extreme rainfall events, with compounding risks from wildfire,
landslides, riverine flooding, and high winds (Figure 13). This section describes and evaluates this
climate cascade and identifies intervention points for County actions and the potential co-benefits of
such actions.
Figure 13. Climate Cascade 3: Drought and extreme rainfall
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Climate Cascade 3: Drought and Extreme Rainfall Events 55
Cascade Narrative
Rising global air and sea surface temperatures are changing rainfall
patterns which may impact the frequency and intensity of future drought
and extreme rainfall events
Climate change and climate variability lead to changing drought and extreme rainfall conditions. Rainfall
trends from 1920 to 2012 show a decrease in annual rainfall for all Hawaiian Islands, with the sharpest
decline in the western part of Hawaiʻi Island.77 The worst drought of the past century on Hawaiʻi Island
occurred from 2007 to 2014. Droughts have become hotter and longer, cover larger areas, and are
increasingly exacerbated by human demands for water.78
Extreme rainfall events on Hawaiʻi Island have become more frequent.79 Extreme rainfall refers to the
intensity of a rainfall event that delivers a high quantity of rainfall over a period of time. Rainfall patterns
in Hawaiʻi are influenced by natural climate variability from the El Niño-Southern Oscillation (ENSO),
the Pacific Decadal Oscillation, and the Pacific North American teleconnection pattern.80 Extreme
rainfall events increase in La Niña years and decrease in El Niño years.81
Drought has cascading effects on agriculture, native ecosystems, and the
socioeconomy
Prolonged drought has cascading effects on native ecosystems, the economy, agriculture, and public
health. Drought can be classified into five categories depending on effects and duration:
meteorological, agricultural, hydrological, socioeconomic, and ecological (Figure 14).82 The first three
types of drought typically occur in sequence, while socioeconomic and ecological drought can occur at
any point in a drought’s progression and depends on the capacity of state and county resources to
respond and the degree to which other ecosystem threats are mitigated.83 Drought reduces stream
flow, which decreases the water available to support stream and wetland habitats, agricultural irrigation,
cultural practices, and aquifer recharge and freshwater supplies.84 Rain-fed fields and pasture lands are
the most vulnerable to drought effects in Hawaiʻi; although if a drought persists, irrigated areas also can
77 Frazier, A. G., & Giambelluca, T. W. (2017). Spatial trend analysis of Hawaiian rainfall from 1920 to 2012. International journal of climatology, 37(5), 2522-2531. doi:10.1002/joc.4862 78 Crausbay, S.; Ramirez, A.R.; Carter, S.L.; Cross, M.S.; Hall, K.R.; Bathke, D.J.; Betancourt, J.L.; Colt, S.; Cravens, A.E.; Dalton, M.S.; et al. (2017). Defining Ecological Drought for the Twenty-First Century. Bull. Am. Meteorol. Soc. 98, 2543–2550. 79 Chen, Y. R., & Chu, P. S. (2014). Trends in precipitation extremes and return levels in the Hawaiʻian Islands under a changing climate. International Journal of Climatology, 34(15), 3913-3925. doi:10.1002/joc.3950 80 Frazier, A. G., Elison Timm, O., Giambelluca, T. W., & Diaz, H. F. (2017). The influence of ENSO, PDO [Pacific Decadal Oscillation] and PNA [Pacific North American teleconnection pattern] on secular rainfall variations in Hawaiʻi. Climate dynamics, 51(5-6), 2127-2140. doi:10.1007/s00382-017-4003-4 81 Chen, Y. R., & Chu, P. S. (2014). doi:10.1002/joc.3950 82 Frazier, A.G.; Giardina, C.P.; Giambelluca, T.W.; Brewington, L.; Chen, Y.-L.; Chu, P.-S.; Berio Fortini, L.; Hall, D.; Helweg, D.A.; Keener, V.W.; et al. (2022). A Century of Drought in Hawaiʻi: Geospatial Analysis and Synthesis across Hydrological, Ecological, and Socioeconomic Scales. Sustainability, 14, 12023. https://doi.org/10.3390/su141912023 83 Crausbay, S.; Ramirez, A.R.; Carter, S.L.; Cross, M.S.; Hall, K.R.; Bathke, D.J.; Betancourt, J.L.; Colt, S.; Cravens, A.E.; Dalton, M.S.; et al. (2017). Defining Ecological Drought for the Twenty-First Century. Bull. Am. Meteorol. Soc. 98, 2543–2550. 84 Hawaiʻi County Multi-Hazard Mitigation Plan 2020. https://www.Hawaiʻicounty.gov/departments/civil-defense/multi-hazard-mitigation-plan-2020
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Climate Cascade 3: Drought and Extreme Rainfall Events 56
become vulnerable.85 The two worst droughts for the State of Hawaiʻi in the past century were 1998–
2002 and 2007–2014. Over $80 million in drought relief was provided to the agriculture sector as a
result of these droughts. 86
Figure 14. Sequence and duration of drought types
Native forests are degraded by warming and drought through increased tree mortality and accelerated
grass invasion, which together can reduce the cover of high quality forest and increase vulnerability to
fire impacts.87 Freshwater ecosystems are particularly vulnerable to drought. Stream fauna are
negatively affected by reductions in stream flow through the limited availability of freshwater habitat,
loss of hydrological connectivity, and impaired water quality.88 Reduced surface water and groundwater
inputs into nearshore environments may also have negative effects on organisms in brackish and
marine environments.
Groundwater discharge to streams has significantly decreased over the past 100 years, indicating a
decrease in groundwater storage.89 Groundwater-dependent ecosystems (GDE), such as fish ponds,
anchialine pools, and coastal springs, are culturally and ecological important ecosystems that are
impacted by drought exacerbated by unsustainable water use.90 Longer and more frequent droughts
increase the demand for potable and non-potable water for municipal and agricultural uses. Water
supply from County, private, and individual systems will be impacted by drought conditions and
increased water use to support residents, agriculture, ranching, and tourism.
85 Frazier, A.G.; Giardina, C.P.; Giambelluca, T.W.; Brewington, L.; Chen, Y.-L.; Chu, P.-S.; Berio Fortini, L.; Hall, D.; Helweg, D.A.; Keener, V.W.; et al., (2022). A Century of Drought in Hawaiʻi: Geospatial Analysis and Synthesis across Hydrological, Ecological, and Socioeconomic Scales. Sustainability 2022, 14, 12023. https://doi.org/10.3390/su141912023 86 Frazier, A.G.et al., 2022. https://doi.org/10.3390/su141912023 87 Pacific Islands Climate Science Center. (2017). Ecological Drought in the Hawaiʻian Islands: Unique tropical systems are vulnerable to drought. (Report from the Pacific Islands Climate Science Center Workshop, March 6-8, 2017). Honolulu, HI.
88 Clilverd, H.M., Tsang, Y.P., Infante, D.M., Lynch, A.J. and Strauch, A.M., 2019. Long‐term streamflow trends in Hawaiʻi and implications for native stream fauna. Hydrological Processes, 33(5), pp.699-719. 89 Hawaiʻi Water Resources Commission. 2019. Hawaiʻi Water Resources Protection Plan. https://files.Hawaiʻi.gov/dlnr/cwrm/planning/wrpp2019update/WRPP_201907.pdf 90 Gibson, V. L., Bremer, L. L., Burnett, K. M., Lui, N. K., & Smith, C. M. (2022). Biocultural values of groundwater dependent ecosystems in Kona, Hawaiʻi. Ecology and Society, 27(3). doi:10.5751/ES-13432-270318
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Climate Cascade 3: Drought and Extreme Rainfall Events 57
Improving water infrastructure and conservation by increasing water storage capacity, reducing
leakages from water systems, providing backup water systems, using stormwater to recharge
groundwater aquifers, integrating GDE needs in sustainable water yield analysis, and conducting
education and outreach activities are some of the key pre-drought management actions needed in a
changing climate.91
Severe rainfall events, compounded by flooding and landslides, increase
risks to critical infrastructure, communities, and coastal ecosystems
Heavy continuous rainfall over a period of several hours can create disaster conditions in high-sloping
areas of the island, which are prone to landslides, and in low-lying areas with poor drainage. Runoff
and flooding are some of the most disastrous impacts of severe rainfall events. As stream flows and
velocities change, erosion patterns also change, altering channel shapes and depths, possibly
increasing sedimentation behind dams, and affecting habitat and water quality. Changes in watershed
vegetation and soil moisture conditions also change runoff and recharge patterns.
Deforestation augments the impact of extreme rainfall events. When forests are removed from a
watershed, stream flows can easily double. Increased sediment prevents streambeds from carrying the
increased discharge, causing floodplains and floodplain elevations to increase.
91Abby G. Frazier, Jonathan L. Deenik, Neal D. Fujii, Greg R. Funderburk, Thomas W. Giambelluca, Christian P. Giardina, David A. Helweg, Victoria W. Keener, Alan Mair, John J. Marra, Sierra McDaniel, Lenore N. Ohye, Delwyn S. Oki, Elliott W. Parsons, Ayron M. Strauch, Clay Trauernicht (2019), Managing Effects of Drought in Hawaiʻi and U.S.-Affiliated Pacific Islands. In: Vose, James M.; Peterson, David L.; Luce, Charles H.; Patel-Weynand, Toral, eds. Effects of drought on forests and rangelands in the United States: translating science into management responses. Gen. Tech. Rep. WO-98. Washington, DC: U.S. Department of Agriculture, Forest Service, Washington Office. 95-121. Chapter 5.
Compounding effects of severe rainfall and landslides on cliff erosion and public safety
Source: Photo obtained by County after Hurricane Lane
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Climate Cascade 3: Drought and Extreme Rainfall Events 58
Many County roads, bridges, and structures are exposed to severe rainfall events and compounding
hazards, especially flooding and landslides. Impacts to roads, powerlines, and other critical facilities
result in disruption of emergency services.
Increasing numbers of severe flood events will result in increasing numbers of brown water advisories
that carry land-based sediment and contaminants, including sewage, dead animals, and pesticides, to
the shoreline, beach parks, and coastal waters, impacting both public safety and coastal ecosystems.
Wildfires compounded with heavy rainfall events, hot dry weather, and
windstorms increase risk to native ecosystems and human health
Rainfall-vegetation interactions are key predictors of fire risk.92 Heavy rainfall events prior to a drought
season magnify the growth of vegetation that serves as fuel for wildfires.93 Subsequent declining rainfall
and stream flow increase the likelihood of wildfire by drying out the vegetation that serves as fuel. As a
result, forests are more susceptible to wildfires. Invasive species further compound the impacts of
wildfire. Fire that spreads through fire-adapted invasive grasses and shrubs kills native plants that are
highly vulnerable to fire.94
Hot dry spells create the highest fire risk. Increased temperatures may intensify wildfire danger by
warming and drying out vegetation. Future drying with climate change will shift peak fire risk to higher
elevations, endangering native forests mauka.95
High windstorms spread fire, increasing the risk of wildfire. The probability of high windstorms increases
in a warmer climate, so climate change may increase the frequency of high windstorms and therefore
the frequency and intensity of fires. Faster, wind-driven fires are harder to contain, and thus are more
likely to expand into residential neighborhoods. High winds reduce the effectiveness of fuels reduction
strategies, such as mown and grazed fuel breaks, and emphasize the need for additional strategies,
especially reforestation of grasslands.
Direct impacts of wildfires may include loss of structures, crops, and grazing land. Indirect impacts
include health and safety issues, loss of nutrients from the soil, soil runoff to coral reefs, and economic
impacts on agriculture and tourism. When heavy rains occur following a wildfire, flooding and landslides
release sediment into rivers, permanently changing floodplains and damaging sensitive habitat and
riparian areas. Fire followed by a severe rainfall event could release millions of cubic yards of sediment
into streams and nearshore waters.
92 Trauernicht, C. (2019). Vegetation—rainfall interactions reveal how climate variability and climate change alter spatial patterns of wildland fire probability on Big Island, Hawaiʻi. The Science of the Total Environment, 650(Pt 1), 459-469. doi:10.1016/j.scitotenv.2018.08.347 93 Pacific Islands Climate Science Center. (2017). Ecological Drought in the Hawaiʻian Islands: Unique tropical systems are vulnerable to drought. (Report from the Pacific Islands Climate Science Center Workshop, March 6-8, 2017). Honolulu, HI. 94 Helweg, Dave; Giardina, Christian (2017). Ecological drought in the Hawaiian Islands: unique tropical systems are vulnerable to drought. University of Maryland Center for Environmental Science (UMCES) Integration & Application Network Newsletter 581. 4p. 95 Trauernicht, C. (2019). Vegetation—rainfall interactions reveal how climate variability and climate change alter spatial patterns of wildland fire probability on Big Island, Hawaiʻi. The Science of the Total Environment, 650(Pt 1), 459-469. doi:10.1016/j.scitotenv.2018.08.347
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Climate Cascade 3: Drought and Extreme Rainfall Events 59
Potential losses from wildfire include human life, structures and other improvements, and natural
resources. Given the immediate response times to reported fires, the likelihood of injuries and
casualties is minimal. Smoke and air pollution from wildfires can be a health hazard, especially for
sensitive populations including children, the elderly and those with respiratory and cardiovascular
diseases. Wildfire may also threaten the health and safety of those fighting fires. First responders are
exposed to the dangers from the initial incident and after-effects from smoke inhalation and heat stroke.
In addition, wildfire can lead to ancillary impacts such as landslides in steep ravine areas and flooding
due to silt in local watersheds and nearshore receiving areas.
Wildfire near Waimea on July 31, 2021, prompts evacuations and threatens ranches and native forests. Source: 25th Infantry Division/Handout
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Climate Cascade 3: Drought and Extreme Rainfall Events 60
Cascade Exposure Analysis
The exposure analysis for this climate cascade identified County assets exposed and socially
vulnerable communities at risk to multiple hazards. The County can use the information from these
analyses to identify areas and assets to prioritize climate action. For Climate Cascade 3, exposure and
risk were assessed from the geographic overlap of five hazards:
1. Drought
2. Wildfire
3. Riverine flooding
4. Landslide susceptibility (moderate or high)
5. High windstorms
The following are key take-aways from the exposure analysis for this climate cascade:
• Example areas with high climate cascade exposure (exposure to four or five hazards) are in South
Kohala, North Kona, and South Hilo (Figure 15).
• All types of County assets are exposed to the high cascade exposure level (exposure to four or five
hazards; Table 4).
• The low and medium exposure levels (exposure to one to three hazards; Table 4) can still pose a
risk to County assets and communities.
• North Kohala and South Kona had the highest number of County assets exposed to the high
cascade exposure level (exposure to four or five hazards; Table 5).
• Census block groups in South Hilo, Puna, and North Kona have the highest climate cascade risk
(exposure to five or six hazards) (See Appendix B).
For more information on the individual hazards see Appendix A. The climate risk analysis methodology
and maps are provided in Appendix B. To fully explore the exposure and risk analysis, please visit the
County’s Climate Cascade Exposure Tool.
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Climate Cascade 3: Drought and Extreme Rainfall Events 61
Figure 15. Climate Cascade 3: Areas exposed by number of overlapping hazard layers (drought, wildfire, riverine flooding, landslide susceptibility, high windstorms)
None Low Medium High Exposure Overlap 0 1 2 3 4 5
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Climate Cascade 3: Drought and Extreme Rainfall Events 62
Table 4. Climate Cascade 3: Number and type of County assets exposed to individual and overlapping hazards (drought, wildfire, riverine flooding, landslide susceptibility, high
windstorms)
CASCADE 3 DROUGHT AND EXTREME RAINFALL EVENTS Climate Hazards
Number of Assets
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Drought 137 4,224 27 234 9,816 14,497 1,719 62
Wildfire 130 3,357 24 118 6,157 9,253 1,691 51
Riverine Flooding 33 597 28 6 1,047 1,030 326 48
Landslide (moderate or high) 461 8,737 182 265 14,472 39,243 2,322 174
High Winds 129 3,136 107 147 4,448 9,780 160 58
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1 Hazard Exposure 363 7,188 90 261 13,669 35,810 1,965 87
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2 Hazard Exposures 177 5,150 124 214 8,917 15,602 1,859 85
3 Hazard Exposures 44 679 7 23 1,192 1,665 169 29
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4 Hazard Exposures 9 114 1 3 179 366 7 11
5 Hazard Exposures 1 14 1 0 29 66 0 1
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Climate Cascade 3: Drought and Extreme Rainfall Events 63
Table 5. Climate Cascade 3: Number of County assets by district with high cascade exposure (4 or 5 hazard exposures)
Cascade 3 Drought AND Extreme Rainfall Districts
Assets
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South Hilo 0 0 0 0 0 0 0 0
Puna 0 1 0 0 0 0 0 1
Hāmākua 0 2 0 0 0 0 0 1
North Kohala 0 0 0 0 0 0 0 0
South Kohala 7 108 2 3 198 431 0 6
North Kona 3 7 0 0 10 0 7 2
South Kona 0 4 0 0 0 1 0 1
Kaʻū 0 6 0 0 0 0 0 1
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Climate Cascade 3: Drought and Extreme Rainfall Events 64
Intervention Points and Actions
Actions are associated with six intervention points (3A – 3F) within the drought and severe rainfall
cascade (Figure 12). Actions were developed based on the County asset exposure analysis, capital
improvement program projects (proposed and completed), and the 2020 County of Hawaiʻi Multi-
Hazard Mitigation Plan update. Entities responsible for implementing these actions are mostly County
departments. Lead County departments for this cascade are as follows:
• Planning Department (DP)
• Department of Public Works (DPW)
• Fire Department (FD)
• Department of Environmental Management (DEM)
• Department of Water Supply (DWS)
3A. New Development
Recommended actions at this intervention point fall under two strategies, with a total of seven actions,
as presented in the sections and tables below.
3A1. Improve climate hazard risk knowledge
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3A1.1 Assess compounding risk of severe rainfall events and landslides on bluff failure for susceptible shorelines in Hāmākua CD $$ 2026 ●
3A1.2 Improve rainfall data collection and flood risk identification and notification by installing rain and stream gauges in Hāmākua CD $$$ 2026 ●
- Identify locations/quantity of rain and stream gauges 2024 ○
3A1.3 Update drought trends CD $$ 2026 ●
3A1.4 Use spatial and real-time assessments of fire risk and integrate these into emergency response plans and forecasts CD $ 2026 ●
3A1.5 Perform needs assessment and riverine flood studies for Puna, North Kona, and South Kohala DPW $$ 2024 ●
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3A2. Update County codes, regulatory standards, and policies to reduce risks from drought,
flooding, and fire based on best available climate projections and observed trends
Action Number Action County Lead
Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3A2.1
Update zoning (Chapter 25) and subdivision (Chapter 23) codes to incorporate new hazard mitigation requirements for drought and fire risk reduction DP $ 2024
●
3A2.2
Update floodplain management requirements (Chapter 27) to incorporate new floodplain management requirements for extreme rainfall events (see also: 3F2.2, 4A2.4, and 4F1.3)
DPW $$ 2024 ●
3A2.3 Protect riparian areas DP $$ ●
- Delineate riparian areas 2023 ○
- Develop riparian protection area setbacks and best management
practices 2024 ○
3A3. Decrease use of pesticides that create toxic runoff
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3A3.1 Eliminate the use of glyphosate for weed management on County roads and facilities DPW $ 2023 ●
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3B. Water Resources
Recommended actions at this intervention point fall under four strategies, with a total of 10 actions, as
presented in the sections and tables below.
3B1. Increase water storage capacity and groundwater recharge
Project Duration
Action Number Action County Lead Cost ($, $$, $$$) Start Year <2 yrs 2 – 5 yrs >5 yrs
3B1.1 Increase water tank capacity county-wide DWS $$$ ●
- Monitor, evaluate and identify priorities for water tank capacity improvements in areas at risk to drought 2023 ○
3B1.2 Increase groundwater recharge through watershed protection DWS $$ ●
- Develop a watershed protection plan for Kona, Kaʻū, and Kohala 2024 ○
3B1.3 Encourage private landowners to increase storage capacity in areas at risk to drought DP $ 2025 ●
3B1.4 Protect groundwater-dependent ecosystems (GDE) DWS $$ ●
- Locate wells in areas where pumping will not impact GDEs and limit pumping from wells that impact GDEs. 2025 ○
3B1.5
Update the plumbing code to include gray infrastructure, which would allow homeowners and new developments to install the latest water conservation fixtures
DPW $$ 2025 ●
3B2. Reduce water system leakages
Project Duration
Action Number Action County Lead Cost ($, $$, $$$) Start Year <2 yrs 2 – 5 yrs >5 yrs
3B2.1 Conduct annual system-wide water audit to identify sources of water loss DWS $ ●
- Develop criteria to consider drought and other climate impacts in setting
retrofit priorities as part of the annual system-wide water audit 2024 ○
- Schedule water system upgrades to reduce water system leakage 2025 ○
3B2.2 Retrofit dams/reservoirs to address embankment stability and waterproofing DWS $$$ ●
- Complete design for retrofit for Waikoloa Reservoir No. 1 2023 ○
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3B3. Identify alternative water supplies for times of drought
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3B3.1 Develop a water reuse program DEM $$ ●
- Identify opportunities for water reuse for all County systems 2024 ○
3B3.2 Update water use and development plan incorporating ecosystem needs and climate change island-wide. DWS $$$ ●
- Update water use and development plan incorporating climate change island-wide 2024 ○
- Update water master plan incorporating climate change island-wide 2023 ○
3B4. Develop water conservation program
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3B4.1
Integrate climate change into public outreach for water conservation including drought-resistant landscapes, water conservation practices, and reducing waters system losses
DWS $$ 2024 ●
3B4.2 Review/update criteria for water conservation triggers for the Waimea water system DWS $ 2024
3B4.3 Update rate structure to influence active water conservation techniques every 5 years DWS $$ ●
- Review/update rate structure based on changing use and projected future impacts of climate change on water supply 2023 ○
3C. Parks and Recreational Areas
Recommended actions at this intervention point include two actions under one strategy, as presented in
the section and table below.
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3C1. Upgrade/relocate parks and park facilities exposed to flooding, drought, and other
hazards
Action Number Action County Lead
Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3C1.1 Assess risks to park facilities as part of the design of renovation or construction projects DPR $$ ●
- Develop assessment tool to assess risks to structural conditions, landscaping, irrigation system and drainage 2025 ○
- Conduct assessment using tool at Kamakoa Nui 2026 ○
3C1.2 Develop continuous corridors that protect riparian areas and open space, provide recreational opportunities, and mitigate risk
from flood events and stormwater (see also 3A2.3)
DP $$ ●
- Map potential open space networks and trail systems 2025 ○
- Develop design standards for continuous corridors 2026 ○
3D. Roads and Bridges
Recommended actions at this intervention point include three actions under one strategy, as presented
in the section and table below.
3D1. Upgrade/relocate roads and bridges vulnerable to flooding from extreme rain events
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3D1.1 Retrofit/relocate roads and bridges in flood prone areas DPW $$$ ●
- Review flood complaint logs to identify high flood risk areas 2024 ○
- Assess flood risk to identified priorities including roads to access to Hilo hospital; roads above and below highway in Hāmākua; and Alaneo St, Haleaha Pl, Keanuiomano St, Waiaka St. 2024 ○
- Conduct multi-hazard assessment that includes climate risk to support
retrofit needs 2024 ○
- Partner with the State to retrofit/relocate State roads and bridges in flood prone areas 2024 ○
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Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3D1.2 Install drainage improvements, flood channels, and retention basins to address flood risk to communities DPW $$$ ●
- Conduct hydrology studies to address risks to development in South Kohala, North Kona, and South Kona 2024 ○
- Map floodplains for South Kohala, North Kona, and South Kona 2024 ○
- Plan for future climate impacts as a standard part of building new county facilities and infrastructure 2024 ●
3D1.3 Harden Wailuku Bridge #1 in South Hilo DPW $$$ 2025 ●
3E. Water and Wastewater Systems
Recommended actions at this intervention point include two actions under one strategy, as presented in
the section and table below.
3E1. Upgrade/relocate wastewater systems exposed to extreme rainfall events
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3E1.1 Expand wastewater lines in urban areas to connect those converting from OSDS within wastewater service areas DEM $$$ ●
- Assist DOH link County residents to federal and State funding to upgrade on-site disposal systems in wastewater service areas 2023 ○
- Conduct wastewater facility planning and resilience assessment by wastewater service area 2023 ○
3E1.2 Coordinate with the State on wastewater upgrades associated with State roads and bridges DEM $$ ●
- Assess vulnerability of wastewater system associated with Wailuku Bridge 2023 ○
3F. Existing Development
Recommended actions at this intervention point fall under two strategies, with a total of six actions, as
presented in the sections and tables below.
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3F1. Establish a fire risk reduction program
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
3F1.1 Establish fire breaks around communities and along roadways in high fire risk areas FD $$ 2024 ●
3F1.2
Continue to develop partnerships between communities and landowners to support fire risk reduction practices, improve access for firefighters, and identify where water infrastructure can support livelihoods (grazing, agriculture
FD $$ 2023 ●
3F1.3 Conduct public education on possible evacuation routes and safe zones CD $ 2024 ●
3F1.4
Improve hazard tree management in fire and flood prone areas with special focus on removing non-native and invasive species and replanting appropriate native species
DPW $$ ●
- Amend landscape rules to promote drought-resistant landscape 2024 ○
3F1.4 Participate in the Hawaiʻi Firewise Community Program to prepare Community Fire Plans CD $ 2024 ●
3F2. Improve stormwater and floodplain management
Project Duration
Action Number Action County Lead Cost ($, $$, $$$) Start Year <2 yrs 2 – 5 yrs >5 yrs
3F2.1 Maintain good standing and compliance under the NFIP DPW $$ 2023 ●
3F2.2
Update floodplain management requirements (Chapter 27) to enhance the County’s classification under the CRS program (see also: 3A2.2, 4A2.4, and 4F1.3)
DPW $$ ●
- Coordinate with State to improve BCEGS 2023 ○
3F2.3
Encourage green infrastructure in urban areas (e.g., permeable pavement or stormwater retention) for floodplain management and groundwater recharge
DP $ 2024 ●
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Climate Cascade 3: Drought and Extreme Rainfall Events 71
Climate Action Co-Benefits
Climate co-benefits describe the potential for actions to achieve multiple outcomes. In order to realize a
co-benefit, each action must be planned, designed, and implemented with a conscious consideration of
co-benefits.
Co-Benefit Action Number
Greenhouse Gas Reduction
• Limiting the spread of fires reduces the associated greenhouse gas emissions. 3A1.1, 3F1.1
• Capturing methane from wastewater systems can generate renewable energy or fuel. 3E1.1, 3E1.2
• Encouraging drought-resistant landscaping increases the area of vegetation, resulting in more carbon sequestration. 3F1.3, 3F1.4
• Reducing the risks of flooding, landslides, and fire reduces the greenhouse gas emissions associated with reconstruction of infrastructure and need for alternative routes which increase emissions during road and bridge outages
3D2.1, 3D2.2, 3D2.3
Social-Cultural Equity
• Continued participation in the FireWise program supports community-driven action to promote safety and wellbeing. 3F1.5
• Increasing equitable resilience to climate hazards will benefit historically marginalized and frontline communities and communities that have been made vulnerable to climate change impacts. All actions
• Conserving native ecosystems are fundamental to cultural practices 3B1.4
Environmental Protection
• Integrating consideration of GDEs in establishing sustainable water yields will reduce impacts to these ecosystems 3B1.4
• Vegetation management focused on removal of non-native and invasive trees and vegetation and restoration of native trees and vegetation will reduce risks from both wildfire and flooding and improve management of debris flows and sediment runoff during severe rainfall events. 3F1.1 – 3F1.4
• Fire risk reduction around communities potentially limits fire spreading into upland areas, reducing fire-driven forest loss.
• Decreasing use of pesticides can decrease toxic runoff, polluting the water supply and affecting coral and land ecosystem health. 3A3.1
Economic Resilience
• Limiting new development in fire and drought prone areas would reduce economic loss to landowners and businesses. 3A1.1
• Maintaining good standing and compliance under the NFIP and enhancing the County’s classification under the CRS program will reduce the cost of flood insurance for property owners. 3F21, 3F2.2
Plan Integration
• Incorporates policies and actions in General Plan and Hazard Mitigation Plan 3A1.1,3A1.2, 3A2.1, 3A2.2, 3D1.3, 3F1.1
• Consistent with Hawaiʻi Fire Management Organization Firewise 3F1.5
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Climate Cascade 3: Drought and Extreme Rainfall Events 72
Actions You Can Take
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Climate Cascade 4: Sea Level Rise 73
CLIMATE CASCADE 4:
SEA LEVEL RISE
Climate Cascade 4 focuses on how climate change—specifically changes in temperature and climate
variability—contributes to the slowly emerging impacts of sea level rise, with compounding hazard risk
from coastal and riverine flooding and landslides (Figure 16). This section describes and evaluates this
climate cascade and identifies intervention points for County actions and the potential co-benefits of
such actions.
Figure 16. Climate Cascade 4: Sea level rise
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Climate Cascade 4: Sea Level Rise 74
Cascade Narrative
Sea level rise is accelerating and is projected to continue to rise, even if
future GHG emissions are reduced to net zero and global warming halted.
Sea level is rising globally and the rate of sea level rise is accelerating due entirely to unabated human
activities.96 Sea level will continue to rise even if global warming is halted, as greenhouse gas
emissions have a lag effect on temperature.97 Higher global temperatures, driving melting global ice
caps and glaciers and thermal ocean expansion, are resulting in rising sea level. Relative sea level rise
is higher around Hawaiʻi Island due to subsidence of the growing island. The observed rate of sea level
rise for Hawaiʻi Island is 1.6 inches per decade, higher than Maui, O‘ahu, and Kaua‘i.98 The projected
rate of sea level rise at Hilo, Hawaiʻi, is 0.95 feet by 2040, 2.1 feet by 2060, 4.0 feet by 2080, and 6.2
feet by 2100 for an intermediate high scenario.99 The State Climate Commission and Honolulu Climate
Commission recommends the intermediate scenario for most planning.
Climate change and climate variability both play a role in shorter-term sea level variability. Sea level
rise variability is a result of variations in astronomical tides, wave setup, and migration of warm buoyant
waters through the islands brought in by winds and currents. Sea level extremes are caused by shifts of
the tropical Pacific thermocline associated with El Niño-Southern Oscillation (ENSO).100 Hawaiʻi
experienced record-high sea levels during 2017 following a strong El Niño event in 2015.101 These
record high water levels were produced by a combination of phenomena that included long-term global
sea level rise, peak annual astronomical tides (“king tides”), wave setup, and migration of warm
buoyant waters brought in by winds and currents.
96 Dangendorf, S., Hay, C., Calafat, F.M. et al. Persistent acceleration in global sea-level rise since the 1960s. Nat. Clim. Chang. 9, 705–710 (2019). https://doi.org/10.1038/s41558-019-0531-8 97 IPCC (2023) Synthesis Report of the IPCC Sixth Assessment (AR6), Summary for Policy Makers (2023) https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_SPM.pdf 98 Marra, J.J and M.C.. Kruk (2017). State of Environmental Conditions in Hawaiʻi and the U.S. Affiliated Pacific Islands under a Changing Climate, NOAA NESDIS National Centers for Environmental Information (NCEI). https://coralreefwatch.noaa.gov/satellite/publications/state_of_the_environment_2017_hawaii-usapi_noaa-nesdis-ncei_oct2017.pdf 99 Sweet, W. V., B.D. Hamlington, R.E. Kopp, C.P. Weaver, P.L. Barnard, D. Bekaert, W. Brooks, M. Craghan, G. Dusek, T. Frederikse, G. Garner, A.S. Genz, J.P. Krasting, E. Larour, D. Marcy, J.J. Marra, J. Obeysekera, M. Osler, M. Pendleton, D. Roman, L. Schmied, W. Veatch, K.D. White, and C. Zuzak,. (2022). Global and Regional Sea Level Rise Scenarios for the United States: Updated Mean Projections and Extreme Water Level Probabilities Along U.S. Coastlines. Retrieved from Silver Spring, MD: https://oceanservice.noaa.gov/hazards/sealevelrise/noaa-nos-techrpt01-global-regional-SLR-scenarios-US.pdf 100 Widlansky, M. J., Timmermann, A., & Cai, W. (2015). Future extreme sea level seesaws in the tropical Pacific. Science Advances, 1(8), e1500560. doi:doi:10.1126/sciadv.1500560 101 Long, X., Widlansky, M. J., Schloesser, F., Thompson, P. R., Annamalai, H., Merrifield, M. A., & Yoon, H. (2020). Higher Sea Levels at Hawaiʻi Caused by Strong El Niño and Weak Trade Winds. Journal of climate, 33(8), 3037-3059. doi:10.1175/jcli-d-19-0221.1
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Climate Cascade 4: Sea Level Rise 75
Coastal flooding and erosion from high tides, waves, and storm surge are
increasing, driven by rising sea level and other climate change effects.
Sea level rise increases the extent of coastal flooding and erosion from high tides102, waves, floods,
and storm surge. The number of minor flood days for Hawaiʻi Island increased from 3 days per year on
average in the 1960s to 11 days per year in the decade starting in 2005.103
ENSO is one of the principal contributors to long-term wave climate variability in Hawaiʻi.104 ENSO
events can increase or reduce the amount of wave power at the coast, affecting the probability of
coastal flooding or erosion. Wave power around the Hawaiian Islands is highly correlated with ENSO
events, increasing during El Niño and decreasing during La Niña events.
Riverine flooding and landslides compound the impacts of coastal
flooding and erosion along Hawaiʻi Island’s coastline.
Increased riverine flooding during severe rainfall events results in coastal flooding and erosion where
the river meets the sea. Severe rainfall and riverine flooding events increase risks from landslides and
cliff failure. Many of Hawaiʻi Island’s disaster declarations have been associated with severe storms,
high surf, flooding, and mudslides.105
Critical infrastructure, homes, and beach parks along the coastline are
exposed to coastal hazards exacerbated by sea level rise.
Many County roads, bridges, parks, and structures are exposed to coastal hazards exacerbated by sea
level rise. Critical infrastructure impacted by sea level rise includes hazard materials and waste storage
facilities, wastewater treatment facilities, and transportation, communication, energy, and safety and
security systems. Structures along the coastline in South Hilo, North Kona, and South Kohala have the
greatest sea level rise exposure.
Sea level rise jeopardizes shallow groundwater aquifers used for drinking
water wells and degrades water lines and wastewater systems, which
leak into groundwater aquifers and coastal ecosystems.
Many wastewater line segments, water line segments, and on-site disposal systems are exposed to
sea level rise. Saltwater intrusion from sea level rise into shallow coastal aquifers impacts potable water
supply from shallow coastal groundwater wells and underground infrastructure such as water and
wastewater infrastructure. Underground infrastructure may become corroded and contaminate
freshwater and nearshore waters.106 Sea level rise and associated inland and coastal flooding increase
102 Vitousek, Sean et al. “Doubling of Coastal Flooding Frequency Within Decades Due to Sea-Level Rise.” Scientific reports 7.1 (2017): 1399–9. Web. 103 Marra, J.J and M.C.. Kruk (2017) https://coralreefwatch.noaa.gov/satellite/publications/state_of_the_environment_2017_hawaii-usapi_noaa-nesdis-ncei_oct2017.pdf 104 Odériz, I., Silva, R., Mortlock, T. R., & Mori, N. (2020). El Niño‐Southern Oscillation Impacts on Global Wave Climate and Potential Coastal Hazards. Journal of geophysical research. Oceans, 125(12), n/a. doi:10.1029/2020JC016464 105 Hawaiʻi County. 2020. Multi-Hazard Mitigation Plan 106 Befus, K. M. et al.(2020). “Increasing Threat of Coastal Groundwater Hazards from Sea-Level Rise in California.” Nature climate change 10.10 (2020): 946–952. Web.
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Climate Cascade 4: Sea Level Rise 76
corrosion of metallic pipelines, resulting in more main breaks and higher repair and replacement
costs.107 As sea level rises, sewer lines and cesspools in coastal areas will release wastewater into the
groundwater and nearshore waters.108
Cultural resources and coastal ecosystems will be impacted by coastal
flooding and storm surge.
Cultural and historic resources located near the shoreline are at risk to coastal flooding and storm surge
exacerbated by sea level rise. National historic landmarks are cultural and historic places that hold
national significance.109 They are sites of great cultural significance sacred to the Hawaiian people.
Some sites that may be impacted include Kamakahonu and Pu'u Ali'i. Kamakahonu, the residence of
Kamehameha I, is located at the north end of Kailua Bay in Kailua-Kona on the Island of Hawaiʻi. Pu'u
Ali'i (the South Point Complex) is thought to be the site of one of the earliest settlements in the
Hawaiian Islands and is believed to be the landing place of Hawaii's first inhabitants.
Saltwater intrusion from sea level rise into shallow coastal aquifers impacts coastal ecosystems.110
Coastal ecosystems vulnerable to coastal hazards include beaches and cliffs, estuaries, fishponds, and
anchialine pools.111 Anchialine pools are unique brackish water environments that form in lava fields
near the ocean. These pools are fed by subsurface groundwater (freshwater) and tides (seawater) with
no visible connection to the ocean.112 Anchialine pools are fed by groundwater elevated above mean
sea level.113 As sea levels rise, groundwater will be pushed upward, exacerbating flooding in some
coastal areas. 114 In some cases, new pools will emerge in low-lying areas and existing pools will join
together. In other areas, a daily connection to the ocean means pools and the species that depend on
them will disappear. Large storm waves or extreme flooding events may connect pools, allowing
invasive fish to disperse. Cesspools and other coastal wastewater systems may contaminate
groundwater fed ecosystems such as anchialine pools with rising seas. Existing and future
development and land use near the shoreline will jeopardize anchialine pools as sea level rises. Hawaiʻi
is the only state with these special pools. Anchialine pools provide critical habitat for rare invertebrate
species, including shrimp, snails, and damselflies. Many of these species are endemic to the Hawaiian
Islands, meaning they exist nowhere else in the world.
107 Habel, Shellie et al. (2020). “Sea-Level Rise Induced Multi-Mechanism Flooding and Contribution to Urban Infrastructure Failure.” Scientific reports 10.1 (2020): 3796–3796. Web. 108 McKenzie, T., Habel, S., & Dulai, H. (2021). Sea-level rise drives wastewater leakage to coastal waters and storm drains. Limnology and Oceanography Letters, 6(3), 154-163. doi:https://doi.org/10.1002/lol2.10186 109 National Park Service.National Historic Sites. https://www.nps.gov/locations/Hawaiʻi/landmarks.htm, accessed January 2023 110 Befus, K. M. et al. “Increasing Threat of Coastal Groundwater Hazards from Sea-Level Rise in California.” Nature climate change 10.10 (2020): 946–952. Web. 111 Gregg, R.M., editor (2018).Hawaiian Islands Climate Vulnerability and Adaptation Synthesis. EcoAdapt, https://www.cakex.org/sites/default/files/documents/EcoAdapt_Hawaiʻian%20Islands%20Climate%20Vulnerability%20and%20Adaptation%20Synthesis%20Report_January2018.pdf 112 National Park Service. https://www.nps.gov/im/pacn/anchialine_pool.htm#:~:text=Anchialine%20pools%20are%20unique%20brackish,visible%20connection%20to%20the%20ocean. 113 Sea Level Rise Effects on Groundwater-fed Anchialine Pools https://tnc.maps.arcgis.com/apps/MapJournal/index.html?appid=4cc09bec75e94d909070610c9d4b7016 114 National Park Service, Pacific Islands Network, Anchialine Pools: Vulnerability to Climate Change in West Hawaiʻi https://media.coastalresilience.org/HI/Anchialine_Pools_FAQ.pdf
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Climate Cascade 4: Sea Level Rise 77
Cascade Exposure Analysis
The exposure analysis for this climate cascade identifies County assets exposed to multiple hazards.
The County can use the information from these analyses to identify areas and assets to prioritize for
climate action. For Climate Cascade 4, exposure and risk were assessed from the geographic overlap
of five hazards:
1. Riverine flooding
2. Event-based coastal flooding
3. Event-based coastal flooding with 3.2 feet of sea level rise (SLR)
4. Chronic coastal flooding with 3.2 feet SLR (SLRXA, passive inundation)
5. Landslide susceptibility (moderate or high)
The following are key take-aways from the exposure and risk analyses for this climate cascade:
• Example areas with high climate cascade exposure (exposure to four or five hazards) are located
in North Kona, Kaʻū, Puna, and South Hilo (Figure 17).
• All types of County assets are exposed to the high cascade exposure level (exposure to four or five
hazards; Table 6).
• The low and medium exposure levels (exposure to one to three hazards; Table 6) can still pose a
risk to County assets and communities.
• North Kona and Puna had the greatest number of County assets exposed to the high cascade
exposure level (exposure to four or five hazards; Table 7).
• Census block groups in South Hilo, Puna, and North Kona have the highest climate cascade risk
(exposure to four or five hazards) (See Appendix B).
For more information on the individual hazards see Appendix A. The climate risk analysis methodology
and maps are provided in Appendix B. To fully explore the exposure and risk analysis, please visit the
County’s Climate Cascade Exposure Tool.
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Climate Cascade 4: Sea Level Rise 78
Figure 17. Climate Cascade 4: Areas exposed by number of overlapping hazard layers (riverine flooding, chronic and event-based coastal flooding with sea level rise, landslide
susceptibility)
None Low Medium High Exposure Overlap 0 1 2 3 4 5
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Climate Cascade 4: Sea Level Rise 79
Table 6. Climate Cascade 4: Number and type of County assets exposed to individual and overlapping hazards (riverine flooding, chronic and event-based coastal flooding with sea level rise, landslide susceptibility)
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Event-Based Coastal Flooding 67 212 3 270 0 326 270 354 55
Event-Based Coastal Flooding With 3.2 Feet SLR 98 421 14 653 2 802 653 691 63
Passive Coastal Flooding With 3.2 Feet SLR 7 71 7 92 0 65 92 42 48
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None No Exposure 500 12,755 221 52,873 501 23,253 52,873 3,315 150
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2 Hazard Exposures 22 23 0 117 0 62 117 46 0
3 Hazard Exposures 49 154 5 221 0 278 221 292 20
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4 Hazard Exposures 7 60 4 72 0 49 72 45 28
5 Hazard Exposures 0 12 0 0 0 1 0 4 12
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Climate Cascade 4: Sea Level Rise 80
Table 7. Climate Cascade 4: Number of County assets by district with high cascade exposure (4 or 5 hazard exposures)
Cascade 4 Sea Level Rise County Districts
Assets Exposed to 4 and 5 Hazard Exposures
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South Hilo 7 27 4 0 32 1 47 17
Puna 0 29 0 0 3 68 0 4
Hāmākua 0 0 0 0 0 0 0 0
North Kohala 0 1 0 0 0 1 0 3
South Kohala 0 0 0 0 0 1 0 1
North Kona 0 6 0 0 15 0 2 7
South Kona 0 7 0 0 0 1 0 4
Kaʻū 0 2 0 0 0 0 0 4
Intervention Points and Actions
Climate adaptation actions are associated with five intervention points (4A – 4F) within the sea level
rise cascade (Figure 16). Actions were developed based on the County asset exposure analysis,
capital improvement program projects (proposed and completed), and the 2020 County of Hawaiʻi
Multi-Hazard Mitigation Plan update. Entities responsible for implementing these actions are mostly
County departments. Lead County departments for this cascade are as follows:
• Planning Department (DP)
• Department of Public Works (DPW)
• Department of Parks and Recreation (DPR)
• Department of Environmental Management (DEM)
4A. New Development
Recommended actions at this intervention point fall under three strategies, with a total of 13 actions, as
presented in the sections and tables below.
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Climate Cascade 4: Sea Level Rise 81
4A1. Improve climate hazard risk knowledge
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4A1.1 Monitor and map landslide events along the shoreline DP $$ 2023 ●
4A1.2 Conduct shoreline change studies DP $$ 2023 ●
4A1.3 Map shoreline regions DP $$ 2023 ●
4A1.4 Update urban growth models in the General Plan for potential influx of climate migrants from Pacific Island countries DP $ 2026 ●
4A2. Update County codes, regulatory standards, and policies requiring all coastal
development to incorporate measures to reduce risk from coastal hazards and sea level rise
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4A2.1
Revise shoreline setbacks to protect public safety from flooding and cliff failure, protect native ecosystems including GDEs, and comply with new State requirements (Rule 11)
DP $$ 2023 ●
4A2.2 Revise subdivision rules to require sea level rise mitigation in new subdivisions in flood prone areas (Chapter 23) DP $$ 2023 ●
4A2.3 Integrate sea level rise risk reduction policies and actions in General Plan update DP $ 2023 ●
4A2.4
Update floodplain management requirements (Chapter 27) to incorporate new hazard mitigation requirements for sea level rise (see also: 3A2.2, 3F2.2, and 4F1.3)
DPW $$ 2023 ●
4A2.5
Use overlay hazard zones to develop conditions for land use and design within high-risk zones and within or adjacent to urban growth areas outside of high-risk areas
DP $ ●
- Adopt the SLR Area as an overlay for planning and rules (Chapter 25) 2023 ○ ●
- Integrate hazard overlays in General Plan update 2024 ○
- Review/update hazards overlay, as needed, based on the 5-year in County Hazard Mitigation Plan update 2025 ○
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Climate Cascade 4: Sea Level Rise 82
4A3. Set aside shoreline areas as open space to benefit natural resources
and public access and reduce risk to structures from sea level rise
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4A3.1 Identify funding sources and mechanisms to acquire coastal parcels in areas exposed to coastal hazards exacerbated by sea level rise DP $ 2030 ●
4A3.2 Identify receiving areas for transfer of development rights from areas exposed to coastal hazards and sea level rise DP $$ 2024 ●
4A3.3 Identify need for expansion and provide additional shoreline access points DP $$ ●
- Maintain mapping of all County existing shoreline access points and make accessible to the public on-line 2025 ○
4B. Cultural and Historic Resources
Recommended actions at this intervention point fall under two strategies, with a total of two actions, as
presented in the sections and tables below.
4B1. Assess risks to cultural and historic resources in sea level rise prone areas
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4B1.1
Conduct a sea level rise vulnerability assessment of cultural and historic resources in coastal hazard prone areas beginning with County lands
DP $$ 2027 ●
- Form a Permitted Interaction Group under the Cultural Resources
Commission to develop protocols for assessment 2024 ○
4B2. Develop adaptation strategies for cultural and historic resources
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4B2.1
Develop place-based cultural adaptation protocols with Aha Moku council, cultural practitioners, and lineage descendants to proactively address impacts to cultural and historic resources beginning with County lands
DP $$ 2023 ●
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Climate Cascade 4: Sea Level Rise 83
4C. Parks and Recreational Areas
Recommended actions at this intervention point include one action under one strategy, as presented in
the section and table below.
4C1. Upgrade/relocate parks and park facilities exposed to sea level rise and other coastal
hazards
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4C1.1 Assess sea level rise risks to County parks with high exposure and risk to sea level rise DPR $$ ●
- Develop assessment tool that includes identification of potential adaptation strategies and multiple public benefits 2025 ○
- Use assessment tool for Kahalu‘u Beach Park (North Kona) 2026 ○
4D. Water and Wastewater Systems
Recommended actions at this intervention point fall under two strategies, with a total of four actions, as
presented in the sections and tables below.
4D1. Upgrade/relocate water infrastructure exposed to sea level rise
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4D1.1 Retrofit/relocate water infrastructure county-wide DWS $$$ ●
- Assess vulnerability of water mains subject to inundation by sea level rise and review every 5 years 2024 ○
- Coordinate with DPW and DEM on road retrofit/realignment for Hilo Bay waterfront, Kailua-Kona and other locations vulnerable to sea level rise 2024 ○
4D2. Upgrade/relocate wastewater systems exposed to sea level rise
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration <2 yrs 2 – 5 yrs >5 yrs
4D2.1 Expand wastewater lines in Hilo and Kona wastewater service areas to connect those converting from OSDS DEM $$$ ●
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Climate Cascade 4: Sea Level Rise 84
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration <2 yrs 2 – 5 yrs >5 yrs
- Assist DOH link County residents to federal and State funding to upgrade on-site disposal systems in wastewater service areas 2023 ○
- Conduct wastewater facility planning and resilience assessment by wastewater service area 2023 ○
4D2.2 Assess vulnerability of wastewater gravity mains in South Hilo DEM $$ ●
- Puʻuʻeo Bridge 2024 ○
- Hilo Bayfront 2028 ○
- Banyan Drive 2028 ○
4D2.3 Assess vulnerability of wastewater forcemains/pump stations in South Hilo DEM $$
- Pua (underway, design completed) 2023 ○
- Paukaʻa 2030 ○
- Onekahakaha 2030 ○
- Kōlea 2030 ○
- Wailoa 2030 ○
- Hale Halewai 2030 ○
4E. Roads and Bridges
Recommended actions at this intervention point include two actions under one strategy, as presented in
the section and table below.
4E1. Upgrade/relocate roads and bridges vulnerable to sea level rise and other coastal hazards
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4E1.1 Develop adaptation priorities and options for coastal roads and bridges at risk to sea level rise DPW $$ ●
- Hilo Bay waterfront 2024 ○
- Puʻuʻeo Street bridge over Wailuku River, South Hilo 2026 ○
- Ali‘i Drive, North Kona 2026 ○
4E1.2 Reassess sea level rise risks to Kalanianaʻole infrastructure improvements, South Hilo DPW $ 2024 ●
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Climate Cascade 4: Sea Level Rise 85
4F. Existing Development
Recommended actions at this intervention point include two actions under one strategy, as presented in
the section and table below.
4F1. Reduce repetitive flood loss to structures and properties
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
4F1.1
Expand and maintain home buyout program established for volcanic hazard recovery as a long-term program to incorporate properties affected by sea level rise
DP $$$ 2030 ●
4F1.2
Review and revise non-conforming use clauses in all County codes for rebuilding or repairing damaged structures to reduce repetitive flood loss
DPW $$ 2023 ●
4F1.3
Update floodplain management requirements (Chapter 27) to adopt lower threshold for substantial improvements/damages based on structure value with no lateral expansion of building footprint (see also: 3A2.2, 3F2.2, and 4A2.4)
DPW $$ 2023 ●
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Climate Cascade 4: Sea Level Rise 86
Climate Action Co-Benefits
Climate co-benefits describe the potential for actions to achieve multiple outcomes. In order to realize a
co-benefit, each action must be planned, designed, and implemented with a conscious consideration of
co-benefits.
Co-Benefit Action Number
Greenhouse Gas Reduction
• Integrating energy savings and waste management provides an opportunity mitigate greenhouse gas emissions in new development 4D2.1
• Retrofitting or relocating bridges and roads provide an opportunity to reduce greenhouse gas emissions by reducing miles travelled 4E1.1, 4E1.2
• Upgrading County wastewater systems would reduce greenhouse gas (methane) leakage 4D
Social-Cultural Equity
• Maintaining and increasing shoreline access for all and not just those who can afford beachfront property must be a consideration for sea level rise management and shoreline setback policy. 4A3.4
• Maintaining parks and recreational areas provides valuable community services. 4C1.1
• Increasing equitable resilience to climate hazards will benefit historically marginalized and frontline communities and communities that have been made vulnerable to climate change impacts.
All actions
Environmental Protection
• Improvements to County and private wastewater management systems would reduce the release of pollutants to nearshore waters as sea level rises.
4D2.1
• New shoreline setback rules would expand open space along the shoreline to support coastal ecosystems such as anchialine pools. 4A2.1
Economic Resilience
• Floodplain management rule revisions that reduce risk of coastal flooding and include consideration of increasing flood hazards with SLR will provide credits to the County’s Community Rating System reducing the cost of flood insurance and repetitive losses to properties and business.
4A2.4
Plan Integration
• Actions integrates policies and actions in General Plan and Hazard Mitigation Plan 4A2.1, 4A2.2, 4A2.3, 4A2.5
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Climate Cascade 4: Sea Level Rise 87
Actions You Can Take
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Climate Cascade 5: Tropical Cyclones and Storm Surge 88
CLIMATE CASCADE 5:
TROPICAL CYCLONES AND STORM SURGE
Climate Cascade 5 focuses on how climate change—specifically sea level rise and changes in
temperature and climate variability—can impact tropical cyclones and storm surge, with compounding
risks from high windstorms, riverine flooding, landslides and coastal flooding and erosion (Figure 18).
Preparedness and resilience are key to preparing for future storms to keep the people and assets of the
islands safe. This section describes and evaluates this climate cascade and identifies intervention
points for County actions and the potential co-benefits of such actions.
Figure 18. Climate Cascade 5: Tropical cyclones and storm surge
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Climate Cascade 5: Tropical Cyclones and Storm Surge 89
Cascade Narrative
Tropical cyclones are becoming more powerful and possibly more
frequent due to climate change.
Climate models project an increase in tropical cyclones near Hawai‘i as the zone of tropical cyclone
formation shifts poleward away from equatorial areas.115 More frequent tropical cyclones are projected
for the waters near Hawai‘i as storms are projected to follow new tracks that bring them into the region
of Hawai‘i more often.116 Major tropical cyclones have become 15 percent more likely over the past
40 years.117 A warming ocean results in less cold subsurface water to dampen tropical cyclone activity.
Increasing sea surface temperature in areas of tropical cyclone formation relevant to Hawai‘i suggests
a connection to increased tropical cyclone intensity.118 An increase in average cyclone intensity and in
the number and occurrence days of very intense category 4 and 5 storms is projected for most ocean
basins119 Sea level rise increases storm surge-related flooding along the coast.
Tropical cyclones are weather events generated in tropical latitudes characterized by very heavy rainfall
and strong and damaging winds. They can generate storm surge and extremely high waves that can
result in devasting coastal flooding regardless of whether or not they directly hit the island. Higher
temperatures are causing more extreme weather events. Sea level rise increases storm surge-related
flooding along the coast. Once a tropical cyclone reaches maximum sustained winds of 74 miles per
hour or higher, it is then classified as a hurricane, typhoon, or tropical cyclone, depending upon where
the storm originates in the world.120 In the North Atlantic, central North Pacific, and eastern North
Pacific, the term hurricane is used.
Hawaiʻi lies in the Central Pacific, which, on average, experiences four to five tropical cyclones every
year. Almost all tropical cyclones in the Pacific basin form between June 1 and November 30. While the
number of tropical cyclones in the central Pacific is highly variable from year to year, more tropical
cyclone activity is generally correlated with El Niño events. More El Niño events are expected in
response to greenhouse warming.121
In 2015, the Central Pacific saw a historic number of tropical cyclones, with 15 named storms, 8
hurricanes, and 5 major hurricanes, making 2015 the most active season at that time since reliable
115 Sharmila, S., and Walsh, K.J.E. (2018) Recent poleward shift of tropical cyclone formation linked to Hadley cell expansion. Nature Clim Change 8, 730–736. https://doi.org/10.1038/s41558-018-0227-5 116 Murakami, H., Wang, B., Li, T. et al. (2013) Projected increase in tropical cyclones near Hawaii. Nature Clim Change 3, 749–754. https://doi.org/10.1038/nclimate1890 117 Kossin, J.P., et al. (2020) Global increase in major tropical cyclone exceedance probability over the past four decades. PNAS, DOI: 10.1073/pnas.1920849117 118 Defforge, C.L., Merlis, T.M. (2017) Observed warming trend in sea surface temperature at tropical cyclone genesis, Geophys. Res. Lett., 44, 1034–1040, doi:10.1002/2016GL071045. 119 Knutson, T., et al. (2020) Tropical Cyclones and Climate Change Assessment: Part II: Projected Response to Human-made Warming, Bull. Amer. Meteor. Soc. (2020) 101 (3): E303–E322: https://doi.org/10.1175/BAMS-D-18-0194.1 120 NOAA. What is the difference between a hurricane and a typhoon? https://oceanservice.noaa.gov/facts/cyclone.html#:~:text=Once%20a%20tropical%20cyclone%20reaches,the%20term%20hurricane%20is%20used. Accessed January 2023 121 Cai, W., Borlace, S., Lengaigne, M., van Rensch, P., Collins, M., Vecchi, G., Jin, F. F. (2014). Increasing frequency of extreme El Nino events due to greenhouse warming. Nature Climate Change, 4(2), 111-116. doi:10.1038/nclimate2100
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Climate Cascade 5: Tropical Cyclones and Storm Surge 90
record-keeping began in 1970.122 The 2018 hurricane season in the eastern North Pacific broke the
2015 record in terms of frequency, intensity, and duration of hurricanes.123 The 2015 record occurred
during a strong El Niño event where increased ocean temperature fueled the hurricane season. The
2018 record was set under a weaker and later El Niño; however, surface ocean temperature was
warmer than normal where the hurricanes formed, which helped their development and made them last
longer.
As the easternmost island in the state, the island of Hawaiʻi has a slightly higher probability of tropical
cyclone landfall. Disaster declarations were issued for six tropical cyclones and severe flood events
over the last 20 years, compared to four events over the previous 40 years.124
More powerful tropical cyclones compound risks from other hazards.
“The compounding nature of the hazards produced during the Hurricane Lane event
highlights the need to improve anticipation of complex feedback mechanisms among
climate- and weather-related phenomena.”125
Hurricane Lane in 2018 put a spotlight on the risk of compounding hazards associated with tropical
cyclones.126 Hurricane Lane did not make landfall on Hawaiʻi Island yet it was the wettest tropical
cyclone ever recorded in Hawaiʻi. The island of Hawaiʻi received an average of 17 inches of rainfall with
a maximum of 57 inches over a 4-day period. Extreme and prolonged record-breaking rainfall, in part
due to the interaction of tropical cyclones with mountains, caused flooding and landslides that closed
roads across the island of Hawaiʻi.
Powerful tropical cyclones result in higher winds, greater area impacted by flooding, stronger storm
surge, and increased risk of landslides. High winds can contribute to strong surf, which in turn results in
coastal erosion. A tropical cyclone does not have to directly hit the Island of Hawaiʻi to create storm
surge that causes extensive coastal flooding. High winds result in downed trees and power lines that
block roads, impede emergency response operations, and together with flooding, create debris that
block waterways.
122 NOAA National Centers for Environmental Information, Monthly Tropical Cyclones Report for Annual 2015, published online January 2016, retrieved on Apr 1, 2023 from https://www.ncei.noaa.gov/access/monitoring/monthly-report/tropical-cyclones/201513. 123 Wood, K. M., Klotzbach, P. J., Collins, J. M., & Schreck, C. J. (2019). The Record‐Setting 2018 Eastern North Pacific Hurricane Season. Geophysical research letters, 46(16), 10072-10081. doi:10.1029/2019GL083657 124 County of Hawaiʻi (2020). Multi-Hazard Mitigation Plan. https://www.Hawaiʻicounty.gov/departments/civil-defense/multi-hazard-mitigation-plan-2020 125 Nugent, A. D., Longman, R. J., Trauernicht, C., Lucas, M. P., Diaz, H. F., & Giambelluca, T. W. (2020). Fire and Rain: The Legacy of Hurricane Lane in Hawaiʻi. Bulletin of the American Meteorological Society, 101(6), E954-E967. doi:10.1175/bams-d-19-0104.1 126 Nugent, A. D. et al., (2020) https://journals.ametsoc.org/view/journals/bams/101/6/BAMS-D-19-0104.1.xml
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Climate Cascade 5: Tropical Cyclones and Storm Surge 91
Risks to critical infrastructure from tropical cyclones and storm surge
jeopardize public safety
Many County roads, bridges, parks, and structures are exposed to multiple hazards analyzed in
Climate Cascade 5. Power outages caused by high winds and downed debris would close roads and
schools and ingress and egress for communities. Temporary structures and other structures unable to
resist sustained wind speeds may collapse, posing an immediate threat to those within or around the
structure. Long-term effects may include the removal of collapsed buildings and removal of debris from
waterways.
It's not if, but when.
A direct hit of a Category 3 or greater hurricane would result in widespread damage to private and
public property, including critical facilities and assets.127 Long-term power outages are expected, which
may result in loss of utilities such as potable water and wastewater systems. Loss of transportation
facilities such as the harbor and airport would exacerbate the magnitude of the event by taxing already
limited resources and further isolating the islands from response and recovery resources. Many
facilities and structures would require months or years to return to pre-event functionality. Tourism,
supporting industries, and the local tax base would experience long-term impacts. The County’s
emergency services will be especially stretched if a tropical cyclone occurs together with other hazards
on the island.128
127 County of Hawaiʻi (2020) Multi-Hazard Mitigation Plan. 128 Nugent, A. D., Longman, R. J., Trauernicht, C., Lucas, M. P., Diaz, H. F., & Giambelluca, T. W. (2020). Fire and Rain: The Legacy of Hurricane Lane in Hawaiʻi. Bulletin of the American Meteorological Society, 101(6), E954-E967. doi:10.1175/bams-d-19-0104.1
Hurricane Lane approaches Hawaiʻi Island August 22, 2018
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Climate Cascade 5: Tropical Cyclones and Storm Surge 92
Cascade Exposure Analysis
The exposure analysis for this climate cascade identifies County assets exposed to multiple hazards.
The County can use the information from these analyses to identify areas and assets to prioritize for
climate action. For Climate Cascade 5, exposure was assessed from the geographic overlap of six
hazards:
1. Hurricane – wind
2. Hurricane - storm surge
3. Riverine flooding
4. Event-based coastal flooding
5. Event-based coastal flooding with 3.2 feet of SLR
6. Landslide susceptibility – med/high
The following are key take-aways from the exposure analysis for this climate cascade:
• Example areas with high climate cascade exposure (exposure to five or six hazards) are located in
districts of North Kohala and North Kona (5 and 6 exposures, Figure 19).
• County roads, water and wastewater lines, and parks are most likely to be exposed to the high
climate cascade exposure (exposure to five or six hazards; Table 8)
• The low and medium exposure levels (exposure to one to four hazards; Table 8) can still pose a
risk to County assets and communities.
• North Kona and South Hilo had the greatest number of County assets exposed to the high climate
cascade exposure (exposure to five or six hazards; Table 9).
• Census block groups in South Hilo, Puna, and North Kona have the highest climate cascade risk
(exposure to four or five hazards) (See Appendix B).
For more information on the individual hazards see Appendix A. The climate risk analysis methodology
and maps are provided in Appendix B. To fully explore the exposure and risk analysis, please visit the
County’s Climate Cascade Exposure Tool.
Integrated Climate Action Plan for the Island of Hawaiʻi Greenhouse Gas Reduction and Climate Adaptation Actions to Build Local Resilience to Climate Change
Climate Cascade 5: Tropical Cyclones and Storm Surge 93
Figure 19. Climate Cascade 5: Areas exposed by number of overlapping hazard layers (hurricane wind and storm surge, riverine flooding, chronic
and event-based coastal flooding with sea level rise, landslide susceptibility)
None Low Medium High Exposure Overlap 0 1 2 3 4 5 6
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Climate Cascade 5: Tropical Cyclones and Storm Surge 94
Table 8. Climate Cascade 5: Number and types of County assets exposed to individual and overlapping hazards (hurricane wind and storm surge, riverine flooding, chronic and event-based coastal flooding with sea level rise, landslide susceptibility)
CASCADE 5 TROPICAL CYCLONES AND STORM SURGE Climate Hazards
COUNTY ASSETS
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hurricane - wind 189 4,593 114 311 12,253 16,583 1,860 63
hurricane - storm surge 58 226 6 0 387 287 344 56
riverine flooding 33 597 28 6 1,047 1,030 326 48
event-based coastal flooding 67 212 3 0 326 270 354 55
event-based coastal flooding with 3.2 feet of SLR 98 421 14 2 802 653 691 63
landslide susceptibility – med/high 461 8,737 182 265 14,472 39,243 2,322 174
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2 Hazard Exposures 78 2,003 94 104 4,063 7,465 392 41
3 Hazard Exposures 34 203 10 5 385 444 211 17
4 Hazard Exposures 62 146 3 0 274 238 286 21
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5 Hazard Exposures 0 67 0 0 46 0 52 29
6 Hazard Exposures 0 3 0 0 1 0 2 2
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Climate Cascade 5: Tropical Cyclones and Storm Surge 95 95
Table 9. Climate Cascade 5: Number of County assets by district with high cascade exposure (5 or 6 hazard exposures)
Intervention Points and Actions
Actions are associated with six intervention points (5A – 5F) within the tropical cyclone and storm surge
cascade (Figure 18). Actions were developed based on the County asset exposure analysis, capital
improvement program projects (proposed and completed), and the 2020 County of Hawaiʻi Multi-
Hazard Mitigation Plan update. Entities responsible for implementing these actions are mostly County
departments. Lead County departments for this cascade are as follows:
• Planning Department (DP)
• Department of Public Works (DPW)
• Department of Water Supply (DWS)
• Department of Finance, Department of Parks and Recreation (DPR)
• Department of Environmental Management (DEM)
• Office of Housing and Community Development (OHCD)
• Police Department (POL)
• Civil Defense (CD)
CASCADE 5
TROPICAL CYCLONES AND STORM SURGE County Districts
Assets Exposed to HIGH CASCADE EXPOSURE ( 5 and 6 Exposures) in Cascade 5
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South Hilo 36 0 0 0 23 41 13 0
Puna 12 0 0 0 0 1 2 0
North Kohala 1 0 0 0 0 0 3 0
South Kohala 0 0 0 0 0 0 1 0
North Kona 12 0 0 0 23 13 7 0
South Kona 6 0 0 0 0 0 2 0
Kaʻū 3 0 0 0 0 0 3 0
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5A. Critical Infrastructure
Recommended actions at this intervention point include seven actions under one strategy, as
presented in the section and table below.
5A1. Upgrade/harden public safety facilities to remain operational during severe storm events
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
5A1.1
Harden the County’s radio communications system through replacement of the following systems: microwave system, direct current (DC) power system, photovoltaic energy systems, and tower refurbishment
CD $$$ 2023 ●
5A1.2
Upgrade County public safety complex to eliminate flooding and failure of the entire electrical system and upgrade to be able to withstand high winds from at least a Category 1 hurricane
POL $$$ 2023 ●
5A1.3 Install backup power systems for County wastewater systems DEM $$ ●
- Conduct analysis to identify priorities based on criticality 2024 ○
5A1.4
Increase resilience of existing water producing facilities to incorporate backup power at various sites (Parker #1, Parker #2, Lālāmilo B, Lālāmilo C, Honoka‘a, Makapala, Waiaha, Kahalu‘u, Queen Lili‘uokalani Trust (QLT), Pi‘ihonua #1, Pi‘ihonua #3A and ‘Ōla‘a #3)
DWS $$$ 2023 ●
5A1.5 Assess resilience of roads to tropical cyclones (Aliʻi Drive, Kona downtown roads, North Kona) DPW $$ 2026 ●
5A1.6 Assess resilience of wastewater systems to tropical cyclones (Gravity mains in Alii Dr. and Palani Road right-of ways, North Kona) DEM $$ 2026 ●
5A1.7 Develop/routinely review multiple/alternate tsunami evacuation routes CD $ ●
- Identify priority roads based on Police response plan 2024 ○
5B. Social Resilience
Recommended actions at this intervention point include four actions under one strategy, as presented
in the section and table below.
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5B1. Enhance community resilience to withstand and recover from a disaster event
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
5B1.1
Determine feasibility of an earthquake/tropical cyclone retrofit incentive program to encourage private property owners to retrofit their properties against the impacts of earthquakes and tropical cyclones
DPW $$ 2024 ●
5B1.2 Incentivize homeowners to retrofit homes to meet current building code standards for wind and flood hazards
DPW, OHCD $$ 2024 ●
5B1.3 Encourage private property owners to purchase flood Insurance and maintain drainage facilities CD $ 2024 ●
5B1.4 Support resilience hubs in communities with high cascade hazard risk CD $$ 2024 ●
5C. Economic Resilience
Recommended actions at this intervention point include two actions under one strategy, as presented in
the section and table below.
5C1. Support incentives to enhance economic resilience to withstand a disaster event
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
5C1.1 Incentivize private sector to purchase flood insurance and maintain drainage facilities that service private properties. CD $$ 2024 ●
5C1.2
Conduct training for private sector to develop continuity of operations plans to address operations before, during and after coastal storm events.
CD $$ 2024 ●
5D. Cultural and Historic Resources
Recommended actions at this intervention point include one action under one strategy, as presented in
the section and table below.
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5D1. Develop cultural resource restoration protocols by ahupua'a
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
5D1.1 Convene a cultural resources recovery group to develop restoration priorities and approach and pre-planning for post-storm assessment DP $$ ●
- Create Cultural Commission rules allowing for permitted interaction groups to focus on this topic 2025 ○
5E. Hazard Tree Management
Recommended actions at this intervention point include three actions under one strategy, as presented
in the section and table below.
5E1. Develop a hazard tree management program to prioritize removal of trees that pose risks
to critical infrastructure from multiple hazards
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
5E1.1 Develop a procedure, evaluation rating system, and GIS database for hazard tree management DPW $$ 2024 ●
5E1.2 Remove trees that pose safety hazards during high windstorms, tropical cyclones, and extreme rainfall and flooding events DPW $$ 2026 ●
5E1.3 Maintain and revegetate public areas with appropriate native species DPW $$ 2028 ●
5F. Operational Capacity
Recommended actions at this intervention point include six actions under one strategy, as presented in
the section and table below.
5F1. Increase human resource and technological capacity for disaster response
Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
5F1.1 Develop an active recruitment, retention and training program for the Volunteer Firefighting Division and CERT team FD $$ 2024 ●
5F1.2 Develop/update integrated preparedness plan for training and qualifications for an Incident CD $$ ●
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Action Number Action County Lead Cost ($, $$, $$$) Start Year
Project Duration
<2 yrs 2 – 5 yrs >5 yrs
Command System that complies with the National Incident Management System
- Create/update qualifications task books for each position 2023 ○
- Conduct training to fill ICS positions 2024 ○
5F1.3 Develop and maintain an information management system in ArcGIS for disaster preparedness and response CD $$$
- Acquire hardware for data management and processing 2023 ○
- Increase human resource capacity in GIS 2024 ○
- Acquire unmanned aerial system (UAS) and train and license personnel to operate for data collection 2026 ○
- Develop capacity for pre-impact data capture and analysis to create decision-making tools and briefs 2025 ○
- Develop capacity for collection and analysis of critical information requirements and elements of information to create the common
operation picture and situation report
2025 ○
- Develop post-impact protocols for collecting and storing data necessary for damage assessments including potential for use of drone technology and IT solutions 2025 ○
5F1.4 Develop public information and warning policies, methods, and procedures for identified hazards CD $$ ●
Conduct a needs assessment that identifies gaps in coverage in the County’s audible warning (sirens) system based on population as well as existing systems that need to be replaced and/or updated
2024 ○
5F1.5 Improve and expand high wind shelter capacity CD $$$ ●
- Conduct best available refuge area (BARA) assessments within existing facilities 2024 ○
- Develop evacuation and sheltering protocol, policies, and procedures 2023 ○
5F1.6 Develop distribution plan for policies and procedure for logistics, management and resource support during disasters CD $$ ●
- Develop agreement with State, federal and private partners to
implement the plan 2023 ○
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Climate Action Co-Benefits
Climate co-benefits describe the potential for actions to achieve multiple outcomes. In order to realize a
co-benefit, each action must be planned, designed, and implemented with a conscious consideration of
co-benefits.
Co-Benefit Action Number
Greenhouse Gas Reduction
• Integrating renewable energy and smart energy systems into County infrastructure will reduce greenhouse gas emissions.
5A1.1 – 5A1.7 5F2.1 – 5F2.6
Social-Cultural Equity
• Upgrading and hardening public infrastructure and
safety systems with an all-hazards approach and improving evacuation routes will increase County capacity to remain operational during disaster events.
5A1.1 – 5A1.7
• Building information capacity for pre-, during, and post-disaster events will save lives and property. 5F1.3 – 5F1.4
• Supporting resilience hubs enables community-driven
actions for greater self-reliance in response to and recovery from disaster events. 5B1.4
• Creating a cultural resources recovery group with pre-
disaster protocols for restoration and preservation of cultural sites will support rapid post-disaster response. 5D1.1
• Removing tree hazards will improve public safety during severe storm events. 5E1.1 – 5E1.2
• Increasing equitable resilience to climate hazards will benefit historically marginalized and frontline
communities and communities that have been made vulnerable to climate change impacts.
All actions
Environmental Protection
• Removal of tree hazards and revegetation with native
species will improve ecosystem health, reduce sediment runoff to coastal ecosystems, and decrease debris from disaster events.
5E1.3
Economic Resilience
• A well-prepared private sector that integrates disaster preparedness planning such as continuity of operations plans, will recover quickly to a disaster
event and reduce downtime and economic losses.
5C1.1 – 5C1.2
Plan Integration
• Incorporates policies and actions in General Plan and Hazard Mitigation Plan
5A1.1 – 5A1.4, 5F1.3, 5F1.4
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Actions You Can Take
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PLAN IMPLEMENTATION
The actions in the Cascades help the County achieve goals 2 and 3 (see below). Plan Implementation
outlines how the County will accomplish goal 1, which is essential for goals 2 and 3.
Increase County capacity to implement climate action.
Reduce the County՚s contribution to global greenhouse gas emissions
Increase the resilience of County infrastructure, assets, and services to climate change impacts.
Hawaiʻi Island is already feeling the effects of climate change. While climate change touches all parts of
our lives, it is not the only challenge the island faces. In order to successfully implement the actions in
this plan, the County must integrate climate action into existing County processes, community
partnerships, funding streams, and efforts. To do this, the County must build up the capacity of
departments and community partners to include climate mitigation, risk, and adaptation into their
internal and external operations and processes. This implementation section outlines the capacity
and financing improvements required to execute the ICAP and the County’s process for
monitoring and evaluation.
Implementation priority areas reflect the systems-level needs the County will address through climate
action implementation. The priority area timelines reflect existing and anticipated capacity (Figure 20).
IMPLEMENTATION PRIORITIES
• Establish a centralized coordinating authority to oversee action implementation
• Establish regular stakeholder engagement
• Integrate climate change risk into County planning and decision-making
• Establish a County climate database
• Maintain robust stakeholder engagement
• Update the General Plan using lessons learned from climate action implementation
• Support place-based management of Hawaiʻi Island lands and waters as part of climate action efforts
Figure 20. Plan Implementation Priorities
LONG-TERM 2030 - 2040 MID-TERM 2025 - 2030 SHORT-TERM 2023 - 2025
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County Processes
The changes to processes are critical for integrating climate action into the County structures that
determine policy and infrastructure. The County can accomplish changes to these processes with
minimal contracting and financial investment. Process changes must align with and support existing
efforts, which will provide benefits beyond climate action.
Short-Term Implementation Priorities: (2023-2025)
Establish a centralized coordinating authority to oversee and manage County-wide climate
actions and mainstream interdepartmental collaboration
The Integrated Climate Action Plan is a joint effort between the Departments of Planning and Research
and Development. It is integral to plan success that a central coordinating authority be established to
consistently engage with and provide support to other departments and community partners in their
climate action implementation. The central coordinating authority must be able to:
1. Collaborate with other departments through existing County processes
2. Provide technical assistance and support to:
a. Streamline climate-related data gathering and dissemination
b. Conduct cost-benefit analyses for climate action implementation
c. Secure federal and State funding
County departments and their operations often fall into silos, limiting the amount of interdepartmental
collaboration that happens to address an interdisciplinary threat like climate change. The County must
continue interdepartmental collaboration on climate action. This will help the County proactively
minimize exposure to climate hazards and avoid long term costs.
Establish regular stakeholder engagement to increase transparency of climate action
Climate Data Dashboard and Portal: Climate change information and data must be accessible to the
public. The County will establish a centralized dashboard to show current progress on individual
strategies and actions. This dashboard will help serve as a monitoring and implementation tool for each
department to report on plan implementation targets and opportunities for collaboration. Community
stakeholders could also use the data on this site for their own climate action planning.
Place-Based Knowledge: The County must engage communities for place-based feedback and
qualitative data to guide implementation priorities and decision making. Place-based data refers to local
knowledge of place. This lived experience holds more information than captured in the Climate Change
Exposure Tool or any dataset the County may use. Place-based knowledge must guide decision-
making on climate action projects that may require changes in development or behavior within
communities. This would include incorporating regional history from lineal descendants, indigenous
practices, local values, and place-based protocols in the County’s decision-making processes.
Historically, the County has not incorporated these decision-making processes in its actions.
Establishing partnerships and ongoing relationships with communities in implementing climate action is
essential to prioritizing place-based knowledge.
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Promote Funding Opportunities: Accurate data is essential to access federal funds for mitigation and
adaptation. A centralized repository collecting climate data will streamline the County’s efforts to access
these funds.
Engagement Strategy: The County must actively engage with communities to increase transparency,
contribute resources, and share stories. To build on existing engagement, the County will:
• Attend community days and County-sponsored events to share resources and talk story
• Partner with schools and after-school programs to play the Hawaiʻi Island Climate Action Game
and develop other climate change-related materials for keiki
• Produce marketing materials around climate change that can be shared in physical spaces (like
grocery stores, parks, and churches) and virtual spaces (like social media)
• Support existing sectors in their climate action efforts
• Develop a communications strategy to inspire hope in climate communications
Mid-Term Implementation Priorities: (2025-2030)
Integrate climate change hazards and risk assessment into County planning and decision-making
processes
During the creation of the ICAP, County departments recognized that integrating climate action
principles and tools into existing processes would be more effective to 1) ensure success of actions in
the near-term by minimizing additional staffing and funding burdens on departments and 2) ensure that
climate change becomes an integral piece of how the County approaches its work long-term. Initial
processes that have been identified as opportunities for integration include:
1. Capital Improvement Project Review
a. Utilize the Climate Cascade Exposure Tool to identify hazards associated with capital
infrastructure and prioritize projects accordingly
b. Coordinate projects between departments to improve project efficiency
c. Incorporate greenhouse gas emissions reduction as a piece of capital improvement program
prioritization and implementation
d. Align capital improvement plans with multi-hazard mitigation plan
2. Purchasing and Procurement
a. Prioritize local product purchasing to reduce emissions associated with air and marine
transportation and support the local economy
b. Gather detailed specifications and resources about zero emission technology options
3. Asset Management
a. Procure County-wide software to digitally manage County assets to simplify the process of
analyzing greenhouse gas reduction opportunities and climate change hazard exposure while
streamlining efficiency of County asset management.
b. Compile existing asset management data to update the Climate Cascade Exposure Tool.
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4. Budgeting for Climate Action in Operating Budget:
a. Include suggestions for including climate action in Operating Budget during annual review.
b. Assess how climate change will impact County financing and long-term budgetary
requirements to better inform priority areas for operation budget. Key actions to assess
financial risk include:
i. Improving infrastructure project review processes
ii. Developing longer-term financial plans
iii. Describe specific co-benefits and estimate monetary value of future savings
iv. Describe how budgeted items support census block groups at highest risk and
historically marginalized communities, frontline communities, and communities that have been made vulnerable to climate change impacts.
5. Grant Management & Applications
a. Establish interdepartmental coordinating unit to co-apply for grants and manage grant
monies associated with the Inflation Reduction Act, Infrastructure Investment and Jobs Act,
and other sources of federal and state funding.
6. County Auditor
a. Request that the County auditor consider climate change risks and implementation
progress for designated climate actions on a 5-year basis to inform plan updates.
Coordinate with departments to establish a centralized internal County climate database
Mitigation: In order to measure greenhouse gas emissions, the County currently extrapolates much of
its data from State and third-party datasets. By establishing a County-managed framework for data
collection on our assets, we can more accurately measure the emissions of individual departments and
the private sector. Accurate measurements will allow the County to establish data-based metrics for
emissions mitigation and accurately measure our success in implementation. This will also direct the
conversion of the County’s buildings and fleet to zero emissions.
Adaptation: In this plan, the best available data to identify climate hazards is used. This data was used
to create a living Climate Change Exposure Tool that can be used for real-time decision-making.
However, this data will need updates and improvements in the future. Hazard events, such as a
landslide or wildfire, may also change the priority of some of the actions. Coordination between
departments and public partners will be essential in keeping this tool up to date.
Maintain robust long-term, regular stakeholder engagement
State and Federal: The limitations of the County’s physical and legal jurisdiction will make cross-
agency collaboration more imperative across the County, State, and federal levels. As demonstrated in
the Climate Action Framework, the County can impact pieces of the climate change cascade, but
certain items are outside the County’s jurisdiction. The County must grow partnerships with State and
federal agencies to tackle the impact of invasive species, cesspools, and rising sea levels. Working with
our State and federal partners for larger-scale actions is one aspect of our stakeholder engagement.
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Residents, Private Sector, Non-Profits and Other Stakeholders: Climate change will affect
everyone, but the impacts are not felt equally among all communities, and not all communities have the
same risks and vulnerabilities. Social and cultural equity and locally driven knowledge will serve as a
primary determinant in how we implement climate action in a place-appropriate manner and how
communities are empowered to take action that works for them. Climate action engagement and
implementation will focus on actions that prioritize our historically disadvantaged communities and
actions that support community services for those at the greatest risk to climate change. Key factors to
be considered in prioritizing social and cultural equity are health, affordability, accessibility, community
capacity, locally driven place-based preservation, accountability, and an equitable transition to green
jobs.
Long-Term Implementation Priorities: (2030-2040)
Update the General Plan using lessons learned from climate action implementation
The best practices identified as part of the monitoring and evaluation of the ICAP will guide the climate
change section of the General Plan. The County will also consider the impact of climate change as part
of all sections of the General Plan. The County will use lessons learned from ICAP implementation to
determine priority climate action policy areas.
Support place-based management of Hawaiʻi Island lands and waters as part of climate action
efforts
By 2030, the County and community aim to have more examples of place-based management and
more localized data. The County will support departments and communities in collecting place-based
information and developing place-based protocols. Future climate action decisions regarding
management of infrastructure, parks, and other County assets should include place-based
management with the support of localized climate data. The County should also encourage place-
based management beyond County assets through zoning and funding such as community grants.
Climate Action Financing
Identify funding opportunities
The County will increase its capacity to pursue money to finance climate actions. The federal
government has recently passed legislation, including the Inflation Reduction Act and the Infrastructure
Investment and Jobs Act, that increases the funding available to implement climate action. In order to
access these funds, the County must have dedicated staff to write and manage grants specific to
climate action. These staff members will need to work closely with the departments that will implement
the actions.
Increase the capacity of the Finance Department to manage ICAP implementation
Increasing the capacity of the Finance Department to manage climate action monies is essential. The
ICAP identifies the capital improvement program process, operations management, and procurement
as opportunities to implement internal climate action. In order to do this, the Finance Department will
need additional support to establish protocols that align with existing processes and priorities. The
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Finance Department will also need additional support to incorporate climate action into the operating
budget annually.
Monitoring and Evaluation
Establish regular monitoring, evaluating, and annual reporting on the status of actions and
targets
This plan will be monitored on an ongoing basis through the previously mentioned online dashboard
and will include a brief project description, project status, and project location when appropriate. Actions
and targets will be updated on an annual basis and reported on to make changes where necessary and
incorporate best available data. Actions under each intervention point will be tracked as: No Action,
Proposed, In Progress, or Completed.
Annual reports of the ICAP will include:
• A summary of action adjustments that were made
• Assessment of best practices for implementation
• Targets reached
• Evaluation of co-benefits of ICAP actions and documenting lessons
Climate cascade narratives and exposure analysis will be reviewed and updated every 5 years in
conjunction with the County’s Multi-Hazard Mitigation Plan update. This review will identify any changes
in projections for climate change indicators and hazards based on the best available information.
Cascading effects that have not been previously considered will be identified based on hazard
projections and documented impacts. Climate cascade narratives, risk analysis, and intervention points
will be updated based on this review. The annual evaluations will also be used to inform best practices
for actions and implementation in the 5-year plan updates.
Conduct 5-Year Plan Evaluation and Update
Annual reports and evaluations will be used to determine major document changes as the ICAP is
updated on a 5-year basis. This will allow for more accurate datasets, improved community
engagement efforts, and updated hazard and risk analyses. Once we refine implementation strategies
based on lessons learned and best practices, we can coordinate our priorities in line with updates to the
Hazard Mitigation Plan.
Timeframes and funding for many actions in the ICAP are integrated into other plans and projects, such
as capital improvement projects, hazard mitigation projects, maintenance, purchasing policies, and
policies developed in the General Plan. The ICAP identifies the actions that will contribute the most to
minimizing the impacts of each climate cascade. Other actions, including infrastructure and policies,
may become higher priority over time as the impacts of climate change evolve and community priorities
change.
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Call to Action 108
CALL TO ACTION
As we face the reality of climate change, it is time for us to take action to protect our beloved island and
planet. Hawaiʻi County is committed to the ambitious goals and concrete actions in this plan. We need
to take accountability as a County government for our own contribution to climate change and the
resilience of our infrastructure and services. We must ensure that our services will be resilient for
current and future generations in the years to come.
We have the opportunity to create a thriving, vibrant Hawaiʻi Island. We can choose how we spend our
money and our time to care for people and the place where we live. The actions in this plan represent
the ways all our departments are committed to create a future that is not only sustainable but also
thriving in the face of the worst effects of climate change.
But climate action is not just about what government can do. And it’s not just about policies, processes,
or infrastructure. Climate action is about what each of us can do to reduce our carbon footprint,
preserve our natural resources, and ensure the resilience of our community. Climate action is about
doing what we already do in our homes, our schools, our businesses, our churches, and our agriculture
in a way that intentionally mitigates and adapts to climate change.
Climate action is also about environmental justice. We cannot allow the burden of climate change to fall
disproportionately on marginalized communities. We cannot pursue reduction of greenhouse gas
emissions or climate adaptation in a way that increases the cost of living here or disproportionately
impacts low- and middle-income communities. Our solutions must be equitable and just. We must
ensure that, when we are pursuing each policy or infrastructure change, everyone has a voice in
shaping our future.
We must recognize the impact of climate change in our community and hold ourselves accountable to
act. The impacts include the potential displacement of our island brothers and sisters as climate
refugees. We are lucky that our island has high shores and a lot of land. Not all places will be easy or
possible to inhabit as the effects of climate change intensify and cascade across all parts of our lives.
We must lift up Hawaiʻi for ourselves and also for those who may seek refuge as we all feel the effects
of climate change. Let us take action now to ensure a brighter future for our island and planet.
“E lauhoe mai nā waʻa; i ke kā, i ka hoe; i ka hoe, i ke kā; pae aku i ka ʻāina.”
- Everybody paddle the canoes together; bail and paddle, paddle and bail, and the shore is reached