Jeffrey Payne
William V. Sweet
Michael Craghan
John W. Haines
Juliette Finzi Hart
Heidi Stiller
Ariana Sutton-Grier
David Reidmiller
C. W. Avery
D. R. Easterling
K. E. Kunkel
K. L. M. Lewis
T. K. Maycock
B. C. Stewart
Elizabeth Fleming
2018
<div class="card card-body bg-light"><p class="mb-0">The Coasts chapter of the Third National Climate Assessment, published in 2014, focused on coastal lifelines at<span> </span>risk, economic disruption, uneven social vulnerability, and vulnerable ecosystems. This Coastal Effects chapter of the Fourth National Climate Assessment updates those themes, with a focus on integrating the socioeconomic and environmental impacts and consequences of a changing climate. Specifically, the chapter builds on the threat of rising sea levels exacerbating tidal and storm surge flooding, the state of coastal ecosystems, and the treatment of social vulnerability by introducing the implications for social equity.</p></div><p>U.S. coasts are dynamic environments and economically vibrant places to live and work. As of 2013, coastal shoreline counties were home to 133.2 million people, or 42% of the population.<sup id="fnref:64c724bf-dcc0-403d-b14b-61ada21e5945"></sup><span> </span>The coasts are economic engines that support jobs in defense, fishing, transportation, and tourism industries; contribute substantially to the U.S. gross domestic product;<sup id="fnref:64c724bf-dcc0-403d-b14b-61ada21e5945"></sup><span> </span>and serve as hubs of commerce, with seaports connecting the country with global trading partners.<sup id="fnref:adfa0d92-5694-40eb-a201-32f7b499ab1d"></sup><span> </span>Coasts are home to diverse<span> </span>ecosystems<span> </span>such as beaches, intertidal zones, reefs, seagrasses, salt marshes, estuaries, and deltas<sup id="fnref:709431bd-5f49-49b1-b70a-8fcb69de7330"></sup><span> </span>that support a range of important services including fisheries, recreation, and coastal storm protection. U.S. coasts span three oceans, as well as the Gulf of Mexico, the Great Lakes, and Pacific and Caribbean islands.</p><p>The social, economic, and environmental systems along the coasts are being affected by<span> </span>climate change. Threats from sea level rise (SLR) are exacerbated by dynamic processes such as high tide and storm surge flooding<span> </span><i>(Ch. 19: Southeast, KM 2)</i>,<span> </span>erosion<span> </span><i>(Ch. 26: Alaska, KM 2)</i>,<sup id="fnref:c328c6d9-f1ea-4083-8dd7-d38ae4bb06af"></sup><span> </span>waves and their effects,<sup id="fnref:e16534d0-638a-4fdc-88fb-426611965c54"></sup><span> </span>saltwater intrusion into coastal aquifers and elevated groundwater tables<span> </span><i>(Ch. 27: Hawaiʻi & Pacific Islands, KM 1;<span> </span>Ch. 3: Water, KM 1)</i>,<sup id="fnref:0b68570e-5da4-41ed-a8c1-056e7c7d3f51"></sup><span> </span>local rainfall<span> </span><i>(Ch. 3: Water, KM 1)</i>,<sup id="fnref:faea1d4f-493d-4545-bea1-1703ad92ac95"></sup><span> </span>river runoff<span> </span><i>(Ch. 3: Water, KM 1)</i>,<sup id="fnref:2ec30e37-5594-44e2-acd4-a7a8b3964027"></sup><span> </span>increasing water and surface air temperatures<span> </span><i>(Ch. 9: Oceans, KM 3)</i>,<sup id="fnref:2e04e4ff-6097-4e89-9235-fe7856aeb350"></sup><span> </span>and<span> </span>ocean acidification<span> </span><i>(see<span> </span>Ch. 2: Climate, KM 3<span> </span>and<span> </span>Ch. 9: Oceans, KM 1,<span> </span>2, and<span> </span>3 for more information on ocean acidification, hypoxia, and ocean warming)</i>.<sup id="fnref:6327a193-36ee-4405-a209-49b40dc289cf"></sup><sup id="fnref:619c8604-d3f9-49e3-b138-abdc502f0887"></sup></p><p>Although storms, floods, and erosion have always been hazards, in combination with rising sea levels they now threaten approximately $1 trillion in national wealth held in coastal real estate<sup id="fnref:88b92afe-e788-4716-9a3d-1872257ddffb"></sup><span> </span>and the continued viability of coastal communities that depend on coastal water, land, and other resources for economic health and cultural integrity<span> </span><i>(Ch. 15: Tribes, KM 1<span> </span>and<span> </span>2)</i>.</p>
application/pdf
10.7930/NCA4.2018.CH8
en
U.S. Global Change Research Program
Coastal effects
reports