Federal Coordinating Lead Author:
David Helweg, DOI Pacific Islands Climate Adaptation Science Center
Chapter Lead:
Victoria Keener, East-West Center
Chapter Authors:
Susan Asam, ICF
Seema Balwani, National Oceanic and Atmospheric Administration
Maxine Burkett, University of Hawai‘i at Mānoa
Charles Fletcher, University of Hawai‘i at Mānoa
Thomas Giambelluca, University of Hawai‘i at Mānoa
Zena Grecni, East-West Center
Malia Nobrega-Olivera, University of Hawai‘i at Mānoa
Jeffrey Polovina, NOAA Pacific Islands Fisheries Science Center
Gordon Tribble, USGS Pacific Island Ecosystems Research Center
Review Editor:
Jo-Ann Leong, Hawai‘i Institute of Marine Biology
Technical Contributors:
Malia Akutagawa, University of Hawaiʻi at Mānoa, Hawaiʻinuiākea School of Hawaiian Knowledge, Kamakakūokalani Center for Hawaiian Studies, William S. Richardson School of Law, Ka Huli Ao Center for Excellence in Native Hawaiian Law
Rosie Alegado, University of Hawaiʻi at Mānoa, Department of Oceanography, UH Sea Grant
Tiffany Anderson, University of Hawai‘i at Mānoa, Geology and Geophysics
Patrick Barnard, U.S. Geological Survey–Santa Cruz
Rusty Brainard, NOAA Pacific Islands Fisheries Science Center
Laura Brewington, East-West Center, Pacific RISA
Jeff Burgett, Pacific Islands Climate Change Cooperative
Rashed Chowdhury, NOAA Pacific ENSO Applications Climate Center
Makena Coffman, University of Hawai‘i at Mānoa, Urban and Regional Planning
Chris Conger, Sea Engineering, Inc.
Kitty Courtney, Tetra Tech, Inc.
Stanton Enomoto, Pacific Islands Climate Change Cooperative
Patricia Fifita, University of Hawai‘i, Pacific Islands Climate Change Cooperative
Lucas Fortini, USGS Pacific Island Ecosystems Research Center
Abby Frazier, USDA Forest Service
Kathleen Stearns Friday, USDA Forest Service, Institute of Pacific Islands Forestry
Neal Fujii, State of Hawai‘i Commission on Water Resource Management
Ruth Gates, University of Hawai‘i at Mānoa, School of Ocean and Earth Science and Technology
Christian Giardina, USDA Forest Service, Institute of Pacific Islands Forestry
Scott Glenn, State of Hawai‘i Department of Health, Office of Environmental Quality Control
Matt Gonser, University of Hawai‘i Sea Grant
Jamie Gove, NOAA Pacific Islands Fisheries Science Center
Robbie Greene, CNMI Bureau of Environmental and Coastal Quality
Shellie Habel, University of Hawai‘i at Mānoa, School of Ocean and Earth Science and Technology
Justin Hospital, NOAA Pacific Islands Fisheries Science Center
Darcy Hu, National Park Service
Jim Jacobi, U.S. Geological Survey
Krista Jaspers, East-West Center, Pacific RISA
Todd Jones, NOAA Pacific Islands Fisheries Science Center
Charles Ka‘ai‘ai, Western Pacific Regional Fishery Management Council
Lauren Kapono, NOAA Papahānaumokuākea Marine National Monument
Hiʻilei Kawelo, Paepae O Heʻeia
Benton Keali‘i Pang, U.S. Fish and Wildlife Service
Karl Kim, University of Hawai‘i, National Disaster Preparedness Training Center
Jeremy Kimura, State of Hawai‘i Commission on Water Resource Management
Romina King, University of Guam and Pacific Islands Climate Adaptation Science Center
Randy Kosaki, National Oceanic and Atmospheric Administration
Michael Kruk, ERT, Inc.
Mark Lander, University of Guam, Water and Environmental Research Institute
Leah Laramee, State of Hawaiʻi Department of Land and Natural Resources
Noelani Lee, Ka Honua Momona
Sam Lemmo, State of Hawai‘i Department of Land and Natural Resources, Interagency Climate Adaptation Committee
Rhonda Loh, Hawaiʻi Volcanoes National Park
Richard MacKenzie, USDA Forest Service, Institute of Pacific Islands Forestry
John Marra, National Oceanic and Atmospheric Administration
Xavier Matsutaro, Republic of Palau, Office of Climate Change
Marie McKenzie, Pacific Islands Climate Change Cooperative
Mark Merrifield, University of Hawai‘i at Mānoa
Wendy Miles, Pacific Islands Climate Change Cooperative
Lenore Ohye, State of Hawai‘i Commission on Water Resource Management
Kirsten Oleson, University of Hawai‘i at Mānoa
Tom Oliver, University of Hawaiʻi at Mānoa, Joint Institute for Marine and Atmospheric Research
Tara Owens, University of Hawai‘i Sea Grant
Jessica Podoski, U.S. Army Corps of Engineers—Fort Shafter
Dan Polhemus, U.S. Fish and Wildlife Service
Kalani Quiocho, NOAA Papahānaumokuākea Marine National Monument
Robert Richmond, University of Hawaiʻi, Kewalo Marine Lab
Joby Rohrer, O‘ahu Army Natural Resources
Fatima Sauafea-Le‘au, National Oceanic and Atmospheric Administration—American Sāmoa
Afsheen Siddiqi, State of Hawaiʻi Department of Land and Natural Resources
Irene Sprecher, State of Hawaiʻi, Department of Land and Natural Resources
Joshua Stanbro, City and County of Honolulu Office of Climate Change, Sustainability and Resiliency
Mark Stege, The Nature Conservancy—Majuro
Curt Storlazzi, U.S. Geological Survey–Santa Cruz
William V. Sweet, National Oceanic and Atmospheric Administration
Kelley Tagarino, University of Hawai‘i Sea Grant
Jean Tanimoto, National Oceanic and Atmospheric Administration
Bill Thomas, NOAA Office for Coastal Management
Phil Thompson, University of Hawai‘i at Mānoa, Oceanography
Mililani Trask, Indigenous Consultants LLC
Barry Usagawa, Honolulu Board of Water Supply
Kees van der Geest, United Nations University, Institute for Environment and Human Security
Adam Vorsino, U.S. Fish & Wildlife Service
Richard Wallsgrove, Blue Planet Foundation
Matt Widlansky, University of Hawai‘i, Sea Level Center
Phoebe Woodworth-Jefcoats, NOAA Pacific Islands Fisheries Science Center
Stephanie Yelenik, USGS Pacific Island Ecosystems Research Center
USGCRP Coordinators:
Allyza Lustig, Program Coordinator
Fredric Lipschultz, Senior Scientist and Regional Coordinator

Hawai‘i and U.S.-Affiliated Pacific Islands

The U.S. Pacific Islands (Figure 27.1) are culturally and environmentally diverse, treasured by the 1.9 million people who call them home. The region comprises a vast ocean territory and more than 2,000 islands that vary in elevation, from high volcanic islands such as Mauna Kea on Hawaiʻi Island (13,796 feet) to much lower islands and atolls such as Majuro Atoll in the Republic of the Marshall Islands (the highest point on Majuro is estimated at 9 feet).24,25,26 Its environments span the deepest point in the ocean (Mariana Trench National Monument) to the alpine summits of Hawaiʻi Island.23 The region supports globally important marine and terrestrial biodiversity, as well as stunning cultural diversity (over 20 Indigenous languages are spoken).23

   

Figure 27.1: Pacific Islands Region Map

Figure 27.1: The U.S. Pacific Islands region includes the state of Hawaiʻi, as well as the U.S.-Affiliated Pacific Islands (USAPI): the Territories of Guam and American Sāmoa (AS), the Commonwealth of the Northern Mariana Islands (CNMI), the Republic of Palau (RP), the Federated States of Micronesia (FSM), and the Republic of the Marshall Islands (RMI). While citizens of Guam and the CNMI are U.S. citizens, those from AS are U.S. nationals. Under the Compact of Free Association (COFA), citizens from FSM, RP, and RMI can live and work in the United States without visas, and the U.S. armed forces are permitted to operate in COFA areas. On this map, shaded areas indicate the exclusive economic zone of each island, including regional marine national monuments (in green). Source: adapted from Keener et al. 2012.23

SHRINK

The U.S. Pacific Islands region is defined by its many contrasting qualities. While the area is a highly desirable tourist destination, with Hawaiʻi and the U.S.-Affiliated Pacific Islands (USAPI) drawing more than 10 million tourists in 2015,27 living in the islands carries climate-related risks, such as those from tropical cyclones, coastal flooding and erosion, and limited freshwater supplies. Because of the remote location and relative isolation of the islands, energy and food supplies are shipped in at high costs.

For example, Hawai‘i has the highest average electricity rate in the United States (more than twice the national average),28 and more than 85% of food is imported on most islands (see Ch. 17: Complex Systems and Ch. 20: U.S. Caribbean, Background and KM 5 for more information on the importance of regional supply chains).29,30,31 Though the islands are small, they are seats for key military commands, with forces stationed and deployed throughout the region providing strategic defense capabilities to the United States.

Despite the costs and risks, Pacific Islanders have deep ties to the land, ocean, and natural resources, and they place a high value on the environmental, social, and physical benefits associated with living there. Residents engage in diverse livelihoods within the regional economy, such as tourism, fishing, agriculture, military jobs, and industry, and they also enjoy the pleasant climate and recreational opportunities. Important challenges for the region include improving food and water security, managing drought impacts, protecting coastal environments and relocating coastal infrastructure, assessing climate-induced human migration, and increasing coral reef resilience to warming and acidifying oceans.

New Research Validates and Expands on Previous Assessment Findings

In previous regional climate assessments, key findings focused on describing observed trends and projected changes in climate indicator variables for specific sectors.23,32 In many cases, new observations and projections indicate that there is less time than previously thought for decision-makers to prepare for climate impacts.

   

Figure 27.2: Climate Indicators and Impacts

Figure 27.2: Monitoring regional indicator variables in the atmosphere, land, and ocean allows for tracking climate variability and change. (top) Observed changes in key climate indicators such as carbon dioxide concentration, sea surface temperatures, and species distributions in Hawai‘i and the U.S.-Affiliated Pacific Islands result in (bottom) impacts to multiple sectors and communities, including built infrastructure, natural ecosystems, and human health. Connecting changes in climate indicators to how impacts are experienced is crucial in understanding and adapting to risks across different sectors. Source: adapted from Keener et al. 2012.23

SHRINK

Regionally, air and sea surface temperatures continue to increase, sea level continues to rise, the ocean is acidifying, and extremes such as drought and flooding continue to affect the islands.33 New regional findings include (Figure 27.2)

  • a limited set of detailed statistical and dynamical downscaled temperature, rainfall, and drought projections for Hawaiʻi (unlike the 48 contiguous states, Hawaiʻi—like the Alaska and U.S. Caribbean regions—does not have access to numerous downscaled climate projections; see Key Messages 1 and 6);34,35,36

  • projected future changes to winds and waves due to climate change, which affect ecosystems, infrastructure, freshwater availability, and commerce (see Key Message 3);37,38

  • more spatially refined and physically detailed estimates showing increased sea level rise for this century (see Key Messages 3 and 6);17,39

  • models of how central Pacific tropical cyclone tracks are shifting north (see Key Message 3);40

  • identification of urbanized areas vulnerable to flooding from rising groundwater and erosion (see Key Messages 1, 3, and 6);8,41

  • detailed assessment of vulnerability to sea level rise in Hawai‘i (see Key Message 3);42

  • climate vulnerability assessments for endemic and endangered birds and plants showing shifting habitats (see Key Messages 2 and 5);43,44 and

  • projections that corals will bleach annually throughout the entire Pacific Islands region by 2045 if current warming continues (the worst bleaching event ever observed occurred during the El Niño of 2015–2016; Key Messages 4 and 6).45,46,47,48

Risks and Adaptation Options Vary with Geography

In the U.S. Pacific Islands region, the severity of the impacts of climate change differ among communities. A number of factors affect both the level of risk and a community’s approach to responding to that risk: geography (for example, high-elevation islands versus low-elevation atolls), the proximity of critical infrastructure to the coast, governance structure, cultural practices, and access to adaptation funding. As in the U.S. Caribbean (see Ch. 20: U.S. Caribbean), climate change is projected to impact the U.S. Pacific Islands through changes in ecosystem services, increased coastal hazards, and extreme events. Adaptation options in both regions are unique to their island context and more limited than in continental settings.

While uncertainty will always exist about future climate projections and impacts, communities and governments in the U.S. Pacific Islands region are planning proactively. Already, policy initiatives and adaptation programs are significant and include the accreditation of the Secretariat of the Pacific Regional Environment Programme (SPREP) to the Green Climate Fund,53 the passage of the Hawaiʻi Climate Adaptation Initiative Act,54 and the creation of separate climate change commissions for the City and County of Honolulu (established 2018) and the State of Hawaiʻi (established 2017). To increase coordination of adaptation and mitigation initiatives across the region and foster future climate leadership, island nations and the State of Hawaiʻi signed the Majuro Declaration.55 These initiatives are moving adaptation science forward, for example, by increasing freshwater supply, upgrading vulnerable infrastructure, and creating legal frameworks for state and local governments to build climate resilience into current and future plans and policies.


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