Jeffrey Payne, National Oceanic and Atmospheric Administration
William V. Sweet, National Oceanic and Atmospheric Administration
Elizabeth Fleming, U.S. Army Corps of Engineers
Michael Craghan, U.S. Environmental Protection Agency
John Haines, U.S. Geological Survey
Juliette Finzi Hart, U.S. Geological Survey
Heidi Stiller, National Oceanic and Atmospheric Administration
Ariana Sutton-Grier, National Oceanic and Atmospheric Administration
Michael Kruk, ERT, Inc.
Matthew Dzaugis, Program Coordinator
Christopher W. Avery, Senior Manager
Allyza Lustig, Program Coordinator
Fredric Lipschultz, Senior Scientist and Regional Coordinator
<b>Fleming</b>, E., J. Payne, W. Sweet, M. Craghan, J. Haines, J.F. Hart, H. Stiller, and A. Sutton-Grier, 2018: Coastal Effects. In <i>Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II</i> [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 322–352. doi: 10.7930/NCA4.2018.CH8
As the pace and extent of coastal flooding and erosion accelerate, climate change impacts along our coasts are exacerbating preexisting social inequities, as communities face difficult questions about determining who will pay for current impacts and future adaptation and mitigation strategies and if, how, or when to relocate. In response to actual or projected climate change losses and damages, coastal communities will be among the first in the Nation to test existing climate-relevant legal frameworks and policies against these impacts and, thus, will establish precedents that will affect both coastal and non-coastal regions.
Flooding and erosion impact many populations along the coast. However, for socially and economically marginalized and low-income groups, climate change and current and future SLR could exacerbate many long-standing inequities that precede any climate-related impacts (Figure 8.5) (see also Ch. 11: Urban, KM 1; Ch. 18: Northeast, KM 3).95,96 Underrepresented and underserved communities facing additional threats from climate change span a variety of regions and contexts, ranging from the elderly in Florida97 to rural and subsistence-based fishing communities in Alaska (Ch. 26: Alaska, KM 4).98 The 2017 hurricane season provided grim imagery of the impacts to these socially and economically vulnerable coastal residents, and the long-term impacts on these communities are as yet unclear (Figure 8.6) (see also Ch. 2: Climate, Box 2.5). Given limited resources, the core of this challenge rests on questions about who is most vulnerable to the impacts, who should pay for losses incurred, who should pay for protecting coastal communities in the future, and how governments and communities set protocols and policies for keeping people safe. These types of questions bring to light the divergent views of various stakeholders regarding the role of individuals, businesses, and governments in assuming the risks and benefits of living and working near the coast (Ch. 14: Human Health, KM 2 and 3).99
Figure 8.5: Societal Options for Resource Allocation in a Changing Climate
Figure 8.5: Society has limited resources to help individuals and communities adapt to climate change. Panel (a) illustrates that there are finite resources available and that individuals and communities are starting from different levels of readiness to adapt. Panel (b) illustrates the option for society to choose an equal allocation of resources where everyone gets the same amount of help, or as illustrated in panel (c), society can choose to distribute resources equitably to give people what they need to reach the same level of adaptation. Source: adapted with permission from Craig Froehle.
Adaptation strategies, including the decision to retreat from, accommodate, or protect against a particular impact, are dependent on several factors. Economically, a property owner’s access to capital or insurance to fund these strategies contributes to adaptation choices, making poverty a driver of vulnerability in the face of climate-based impacts.100 Some property owners can afford to modify their homes to withstand current and projected flooding and erosion impacts. Others who cannot afford to do so are becoming financially tied to houses that are at greater risk of annual flooding.67 Additionally, communities are composed of renters and other individuals who do not own property, making it more difficult for them to contribute their voices to conversations about preserving neighborhoods. Culturally, coastal communities have ties to their specific land and to each other, as is the case from the bayous of Louisiana, to the beaches of New Jersey, to the sea islands of South Carolina and Georgia. These ties can impede people’s ability and willingness to move away from impacted areas. For Indigenous villages to most effectively respond to critical climate impacts, decision-makers should consider identifying a suitable place to relocate that does not infringe on the needs and territories of other populations, is large enough for the entirety of the village, and is suitable for building and accessing infrastructure (Ch. 15: Tribes, KM 3).101
Impacts of the 2017 Hurricane Season
Figure 8.6: Quintana Perez dumps water from a cooler into floodwaters in the aftermath of Hurricane Irma in …
Climate change impacts are expected to drive human migration from coastal locations, but exactly how remains uncertain.102,103,104 As demonstrated by the migration of affected individuals in the wake of Hurricane Katrina, impacts from storms can disperse refugees from coastal areas to all 50 states, with economic and social costs felt across the country.105 Sea level rise might reshape the U.S. population distribution, with 13.1 million people potentially at risk of needing to migrate due to a SLR of 6 feet (about 2 feet less than the Extreme scenario) by the year 2100.102 The Biloxi-Chitimacha-Choctaw tribe on Isle de Jean Charles in Louisiana was awarded $48 million from the U.S. Department of Housing and Urban Development to implement a resettlement plan.106,107 The tribe is one of the few communities to qualify for federal funding to move en masse. (Ch. 15: Tribes, KM 3; Ch. 19: Southeast, KM 1).
Coasts will confront a more diverse and, to a great extent, unique range of climate stressors and impacts compared with the rest of the country. Rising sea levels will force many more coastal communities to grapple with chronic high tide flooding, higher storm surges, and associated emergency response costs over the next few decades.6,7,36,75 The growing concentration of people and economic activity in coastal areas will introduce a greater degree of risk, including impacts that will ripple far beyond coastal communities themselves.70,108 Understanding these realities, coastal cities such as Boston, New York City, Miami, San Francisco, New Orleans, and Los Angeles are beginning to make investments to adapt to SLR (see the Case Study: “Key Messages in Action”) (see also Ch. 19: Southeast, KM 1). From these efforts, and others like them, examples of successful adaptation planning are being collected to provide guidance to other communities facing similar challenges (Figure 8.2) (see also Ch. 28: Adaptation).109,110,111
However, while many current plans call for risk identification, monitoring, research, and additional planning, there is still little focus on the major investments or immediate implementation actions and cost-dependent tradeoffs required to successfully adapt.110 The financial resources currently being devoted to adapt to or mitigate coastal climate change impacts are insufficient to meet the projected challenges ahead.112,113,114 Additionally, with the limited and often expensive adaptation opportunities currently under consideration, including elevating properties or constructing seawalls, climate-driven impacts may lead to a great deal of unplanned and undesired community change that is likely to disproportionately impact communities that are already marginalized. Resilience planning that considers cultural heritage and incorporates community-driven values, experiences, concerns, needs, and traditional knowledge promotes social inclusivity and equity in adaptation decisions (Ch. 15: Tribes, KM 3).115,116