David Helweg
Susan Asam
Seema Balwani
Maxine Burkett
Charles Fletcher
Thomas Giambelluca
Zena Grecni
Malia Nobrega-Olivera
Jeffrey Polovina
Gordon Tribble
David Reidmiller
C. W. Avery
D. R. Easterling
K. E. Kunkel
K. L. M. Lewis
T. K. Maycock
B. C. Stewart
Victoria Keener
2018
<div class="offset-lg-1 col-lg-7"><p>The U.S. Pacific Islands are culturally and environmentally diverse, treasured by the 1.9 million people who call them home. Pacific islands are particularly vulnerable to<span> </span><a class="glossarizer_replaced" title="" data-toggle="tooltip" data-hasqtip="49" data-mce-tabindex="0">climate change</a><span> </span>impacts due to their exposure and isolation, small size, low elevation (in the case of atolls), and concentration of infrastructure and economy along the coasts.</p><p>A prevalent cause of year-to-year changes in climate patterns around the globe<sup id="fnref:1a46c6a2-4b5f-408d-b3d0-21ebdd4f960b"></sup><span> </span>and in the Pacific Islands region<sup id="fnref:58830638-c7c0-454b-8e73-3fabe28703b3"></sup><span> </span>is the<span> </span><a class="glossarizer_replaced" title="A natural variability in ocean water surface pressure that causes periodic changes in ocean surface temperatures in the tropical Pacific ocean. El Niño Southern Oscillation (ENSO) has two phases: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the western Pacific. Each phase generally lasts for 6 to 18 months. ENSO events occur irregularly, roughly every 3 to 7 years. The extremes of this climate pattern's oscillations cause extreme weather (such as floods and droughts) in many regions of the world." data-toggle="tooltip" data-mce-tabindex="0">El Niño</a>–Southern Oscillation (ENSO). The El Niño and La Niña phases of ENSO can dramatically affect precipitation, air and ocean temperature, sea surface height, storminess, wave size, and trade winds. It is unknown exactly how the timing and intensity of ENSO will continue to change in the coming decades, but recent climate model results suggest a doubling in frequency of both El Niño and La Niña extremes in this century as compared to the 20th century under scenarios with more warming, including the higher scenario (RCP8.5).<sup id="fnref:e5f02380-28e9-4238-994f-09a2efba32ae"></sup><sup id="fnref:6e320831-727b-482d-982a-45732be3790f"></sup></p><p>On islands, all natural sources of freshwater come from rainfall received within their limited land areas. Severe droughts are common, making water shortage one of the most important climate-related risks in the region.<sup id="fnref:8bc3a3d4-e52d-45d1-adc0-89a5691309ff"></sup><span> </span>As temperature continues to rise and cloud cover decreases in some areas, evaporation is expected to increase, causing both reduced water supply and higher water demand. Streamflow in Hawai‘i has declined over approximately the past 100 years, consistent with observed decreases in rainfall.<sup id="fnref:8e3247e0-fd15-4c29-8ed4-4aafd9c8660f"></sup></p><p>The impacts of sea level rise in the Pacific include coastal erosion,<sup id="fnref:4dba7d38-c7c4-4720-9bd0-528ed4ef7e01"></sup><span> </span>episodic flooding,<sup id="fnref:7717dd13-7f6b-4b7c-ab84-571d50f7b8da"></sup><span> </span>permanent inundation,<sup id="fnref:d257e4a8-9a04-460e-92e2-3528093581c9"></sup><span> </span>heightened exposure to marine hazards,<sup id="fnref:f4859f1b-a4d7-4e21-a05b-70204fd6df59"></sup><span> </span>and saltwater intrusion to surface water and groundwater systems.<sup id="fnref:88dcd306-5ae7-48df-8411-658f9c5d97bc"></sup><span> </span>Sea level rise will disproportionately affect the tropical Pacific<sup id="fnref:99cff8ea-3607-415a-be6b-c4c8d76f888f"></sup><span> </span>and potentially exceed the global average.<sup id="fnref:7c979a1d-a012-4e44-8824-fa4a44c3736a"></sup><sup id="fnref:c66bf5a9-a6d7-4043-ad99-db0ae6ae562c"></sup></p><p><a class="glossarizer_replaced" title="A non-native organism whose introduction within a particular ecosystem causes or is likely to cause economic or environmental harm, or harm to human, animal, or plant health." data-toggle="tooltip" data-mce-tabindex="0">Invasive species</a>, landscape change, habitat alteration, and reduced resilience have resulted in extinctions and diminished ecosystem function. Inundation of atolls in the coming decades is projected to impact existing on-island ecosystems.<sup id="fnref:8fd88741-58fd-4753-ae35-af3a2ed38915"></sup><span> </span>Wildlife that relies on coastal habitats will likely also be severely impacted. In Hawaiʻi, coral reefs contribute an estimated $477 million to the local economy every year.<sup id="fnref:0b2f232e-6eee-4a9b-860f-9a2b2a2c61b5"></sup><span> </span>Under projected warming of approximately 0.5°F per decade, all nearshore coral reefs in the Hawai‘i and Pacific Islands region will experience annual bleaching before 2050. An<span> </span><a class="glossarizer_replaced" title="All the living things in a particular area as well as components of the physical environment with which they interact, such as air, soil, water, and sunlight." data-toggle="tooltip" data-mce-tabindex="0">ecosystem</a>-based approach to international management of open ocean fisheries in the Pacific that incorporates climate-informed catch limits is expected to produce more realistic future harvest levels and enhance ecosystem resilience.<sup id="fnref:6cf389bc-8e3b-4613-91ee-45cf028a4f42"></sup></p><p>Indigenous communities of the Pacific derive their sense of identity from the islands. Emerging issues for Indigenous communities of the Pacific include the<span> </span><a class="glossarizer_replaced" title="A capability to anticipate, prepare for, respond to, and recover from significant multi-hazard threats with minimum damage to social well-being, the economy, and the environment." data-toggle="tooltip" data-mce-tabindex="0">resilience</a><span> </span>of marine-managed areas and climate-induced human migration from their traditional lands. The rich body of traditional knowledge is place-based and localized<sup id="fnref:5db43854-3226-408c-a5ef-aa7898146f1f"></sup><span> </span>and is useful in<span> </span><a class="glossarizer_replaced" title="Adjustment in natural or human systems to a new or changing environment that exploits beneficial opportunities or moderates negative effects." data-toggle="tooltip" data-mce-tabindex="0">adaptation</a><span> </span>planning because it builds on intergenerational sharing of observations.<sup id="fnref:b6b97866-7f94-48b4-8d8a-25d4893bbf23"></sup><span> </span>Documenting the kinds of governance structures or decision-making hierarchies created for management of these lands and waters is also important as a learning tool that can be shared with other island communities.</p><p>Across the region, groups are coming together to minimize damage and disruption from coastal flooding and inundation as well as other climate-related impacts. Social cohesion is already strong in many communities, making it possible to work together to take action. Early intervention can lower economic, environmental, social, and cultural costs and reduce or prevent conflict and displacement from ancestral land and resources.</p></div><div class="figure-social-icons"><br data-mce-bogus="1"></div>
application/pdf
10.7930/NCA4.2018.CH27
en
U.S. Global Change Research Program
Hawai‘i and U.S.-Affiliated Pacific Islands
reports