This website is the digital version of the 2014 National Climate Assessment, produced in collaboration with the U.S. Global Change Research Program.

For the official version, please refer to the PDF in the downloads section. The downloadable PDF is the official version of the 2014 National Climate Assessment.

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Welcome to the National Climate Assessment

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

Explore the effects of climate change
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Southeast

Sea level rise poses widespread and continuing threats to the region’s economy and environment. Extreme heat will affect health, energy, agriculture, and more. Decreased water availability will have economic and environmental impacts.

Explore how climate change is affecting the Southeast and Caribbean.

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Introduction

The Southeast region includes the states of Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia, as well as Puerto Rico and the U.S. Virgin Islands. The Highlights section below offers a high-level overview of climate change impacts on this region, including the three Key Messages and selected topics. (see Ch. 17: Southeast)

Key Message: Sea Level Rise Threats

Sea level rise poses widespread and continuing threats to both natural and built environments and to the regional economy.

Key Message: Increasing Temperatures

Increasing temperatures and the associated increase in frequency, intensity, and duration of extreme heat events will affect public health, natural and built environments, energy, agriculture, and forestry.

Key Message: Water Availability

Decreased water availability, exacerbated by population growth and land-use change, will continue to increase competition for water and affect the region’s economy and unique ecosystems.

Southeast

The Southeast and Caribbean region is exceptionally vulnerable to sea level rise, extreme heat events, hurricanes, and decreased water availability. The geographic distribution of these impacts and vulnerabilities is uneven, since the region encompasses a wide range of environments, from the Appalachian Mountains to the coastal plains. The region is home to more than 80 million people and some of the fastest-growing metropolitan areas,4 three of which are along the coast and vulnerable to sea level rise and storm surge. The Gulf and Atlantic coasts are major producers of seafood and home to seven major ports5 that are also vulnerable. The Southeast is a major energy producer of coal, crude oil, and natural gas, and is the highest energy user of any of the National Climate Assessment regions.5

Southeast Temperature: Observed and Projected

Temperature projections compared to observed temperatures from 1901-1960 for two emissions scenarios, one assuming substantial emissions reductions (B1) and the other continued growth in emissions (A2). For each scenario, shading shows range of projections and line shows a central estimate. (Figure source: adapted from Kunkel et al. 20131).

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The Southeast warmed during the early part of last century, cooled for a few decades, and is now warming again. Temperatures across the region are expected to increase in the future. Major consequences include significant increases in the number of hot days (95°F or above) and decreases in freezing events. Higher temperatures contribute to the formation of harmful air pollutants and allergens.6 Higher temperatures are also projected to reduce livestock and crop productivity.7,8 Climate change is expected to increase harmful blooms of algae and several disease-causing agents in inland and coastal waters.9,10,11,12,13 The number of Category 4 and 5 hurricanes in the North Atlantic and the amount of rain falling in very heavy precipitation events have increased over recent decades, and further increases are projected.

Billion Dollar Weather/Climate Disasters 1980-2012

Billion Dollar Weather/Climate Disasters 1980-2012

This map summarizes the number of times over the past 30 years that each state has been affected by weather and climate events that have resulted in more than a billion dollars in damages. The Southeast has been affected by more billion-dollar disasters than any other region. The primary disaster type for coastal states such as Florida is hurricanes, while interior and northern states in the region also experience sizeable numbers of tornadoes and winter storms. (Figure source: NOAA NCDC2).

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Global sea level rose about eight inches in the last century and is projected to rise another 1 to 4 feet in this century. Large numbers of southeastern cities, roads, railways, ports, airports, oil and gas facilities, and water supplies are vulnerable to the impacts of sea level rise. Major cities like New Orleans, with roughly half of its population below sea level,14 Miami, Tampa, Charleston, and Virginia Beach are among those most at risk.15

As a result of current sea level rise, the coastline of Puerto Rico around Rincòn is being eroded at a rate of 3.3 feet per year.16 Puerto Rico has one of the highest population densities in the world, with 56% of the population living in coastal municipalities.16

Sea level rise and storm surge can have impacts far beyond the area directly affected. Sea level rise combines with other climate-related impacts and existing pressures such as land subsidence, causing significant economic and ecological implications. According to a recent study co-sponsored by a regional utility, coastal areas in Alabama, Mississippi, Louisiana, and Texas already face losses that annually average $14 billion from hurricane winds, land subsidence, and sea level rise. Losses for the 2030 timeframe could reach $23 billion assuming a nearly 3% increase in hurricane wind speed and just under 6 inches of sea level rise. About 50% of the increase in losses is related to climate change.17

Vulnerability to Sea Level Rise Vulnerability to Sea Level Rise Details/Download

Louisiana State Highway 1, heavily used for delivering critical oil and gas resources from Port Fourchon, is sinking, at the same time sea level is rising, resulting in more frequent and more severe flooding during high tides and storms.18 A 90-day shutdown of this road would cost the nation an estimated $7.8 billion.19

Freshwater supplies from rivers, streams, and groundwater sources near the coast are at risk from accelerated saltwater intrusion due to higher sea levels. Porous aquifers in some areas make them particularly vulnerable to saltwater intrusion.20,21 For example, officials in the city of Hallandale Beach, Florida, have already abandoned six of their eight drinking water wells.22

Continued urban development and increases in irrigated agriculture will increase water demand while higher temperatures will increase evaporative losses. All of these factors will combine to reduce the availability of water in the Southeast. Severe water stress is projected for many small Caribbean islands.23

Selected Adaptation Efforts

Clayton County, GA water recycling project ©CCWA

Clayton County, Georgia’s innovative water recycling project enabled it to maintain abundant water supplies, with reservoirs at or near capacity, during the 2007-2008 drought, while neighboring Lake Lanier, the water supply for Atlanta, was at record lows. The project involved a series of constructed wetlands (see photo) used as the final stage of a wastewater treatment process that recharges groundwater and supplies surface reservoirs. The county has also implemented water efficiency and leak detection programs.24

In other adaptation efforts, the North Carolina Department of Transportation is raising U.S. Highway 64 across the Albemarle-Pamlico Peninsula by four feet, which includes 18 inches to allow for higher future sea levels.25,26,27

For another example, see Adaptation for a description of the Southeast Florida Regional Compact’s plans to reduce heat-trapping gas emissions and adapt to climate change impacts.

References

  1. Alexandrov, V. A., and G. Hoogenboom, 2000: Vulnerability and adaptation assessments of agricultural crops under climate change in the Southeastern USA. Theoretical and Applied Climatology, 67, 45-63, doi:10.1007/s007040070015.

  2. AWF/AEC/Entergy, 2010: Building a Resilient Energy Gulf Coast: Executive Report. 11 pp., America’s Wetland Foundation, America’s Energy Coast, and Entergy. URL

  3. Berry, L., F. Bloetscher, H. N. Hammer, M. Koch-Rose, D. Mitsova-Boneva, J. Restrepo, T. Root, and R. Teegavarapu, 2011: Florida Water Management and Adaptation in the Face of Climate Change. 68 pp., Florida Climate Change Task Force. URL

  4. Campanella, R., 2010: Delta Urbanism: New Orleans. American Planning Association, 224 pp.

  5. Devens, T., 2012: Phone Interview.

  6. DHS, 2011: Louisiana Highway 1/Port Fourchon Study. 76 pp., U.S. Department of Homeland Security. URL

  7. Hallegraeff, G. M., 2010: Ocean climate change, phytoplankton community responses, and harmful algal blooms: A formidable predictive challenge. Journal of Phycology, 46, 220-235, doi:10.1111/j.1529-8817.2010.00815.x. URL

  8. Hammar-Klose, E., and E. Thieler, 2001: National Assessment of Coastal Vulnerability to Future Sea-Level Rise: Preliminary Results for the US Atlantic, Pacific and Gulf of Mexico Coasts. US Reports 99–593, 00-178, and 00-179. U.S. Geological Survey. URL

  9. Hatfield, J., K. Boote, P. Fay, L. Hahn, C. Izaurralde, B. A. Kimball, T. Mader, J. Morgan, D. Ort, W. Polley, A. Thompson, and D. Wolfe, 2008: Ch. 2: Agriculture. The Effects of Climate Change on Agriculture, Land Resources, and Biodiversity in the United States. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research, P. Backlund et al., Ed., U.S. Department of Agriculture, 21-74. URL

  10. Henderson, B., 2011: Rising Waters Threaten the Coast Of North Carolina. The Charlotte Observer,. URL

  11. Hewes, W., and K. Pitts, 2009: Natural Security: How Sustainable Water Strategies Are Preparing Communities for a Changing Climate. 112 pp., American Rivers, Washington, D.C. URL

  12. Ingram, K., K. Dow, L. Carter, and J. Anderson, 2013: Climate of the Southeast United States: Variability, Change, Impacts, and Vulnerability. Island Press, 341 pp. URL

  13. Kunkel, K. E., L. E. Stevens, S. E. Stevens, L. Sun, E. Janssen, D. Wuebbles, C. E. Konrad, II, C. M. Fuhrman, B. D. Keim, M. C. Kruk, A. Billet, H. Needham, M. Schafer, and J. G. Dobson, 2013: Regional Climate Trends and Scenarios for the U.S. National Climate Assessment: Part 2. Climate of the Southeast U.S. NOAA Technical Report 142-2. 103 pp., National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service, Washington D.C. URL

  14. Mackun, P., S. Wilson, T. R. Fischetti, and J. Goworowska, 2010: Population Distribution and Change: 2000 to 2010. 12 pp., U.S. Department of Commerce, Economics and Statistics Administration, U.S. Census Bureau. URL

  15. Moore, S. K., V. L. Trainer, N. J. Mantua, M. S. Parker, E. A. Laws, L. C. Backer, and L. E. Fleming, 2008: Impacts of climate variability and future climate change on harmful algal blooms and human health. Environmental Health, 7, 1-12, doi:10.1186/1476-069X-7-S2-S4. URL

  16. NOAA, 2013: Billion Dollar Weather/Climate Disasters, List of Events. National Oceanic and Atmospheric Administration. URL

  17. Obeysekera, J., M. Irizarry, J. Park, J. Barnes, and T. Dessalegne, 2011: Climate change and its implications for water resources management in south Florida. Stochastic Environmental Research and Risk Assessment, 25, 495-516, doi:10.1007/s00477-010-0418-8.

  18. Portier, C. J. et al., 2010: A Human Health Perspective on Climate Change: A Report Outlining the Research Needs on the Human Health Effects of Climate Change. 80 pp., Environmental Health Perspectives and the National Institute of Environmental Health Services, Research Triangle Park, NC. URL

  19. PRCCC, 2013: State of Puerto Rico’s Climate 2010-2013 Executive Summary. Assessing Puerto Rico’s Social-Ecological Vulnerabilities in a Changing Climate. ELECTRONIC VERSION. 27 pp., Puerto Rico Climate Change Council. Puerto Rico Coastal Zone Management Program, Department of Natural and Environmental Resources, Office of Ocean and Coastal Resource Management (NOAA-OCRM), San Juan, PR. URL

  20. SFWMD, 2009: Climate Change and Water Management in South Florida. Interdepartmental Climate Change Group report November 12, 2009. South Florida Water Management District. URL

  21. State of Louisiana, 2012: Louisiana’s Comprehensive Master Plan for a Sustainable Coast. Coastal Protection and Restoration Authority, State of Louisiana, Baton Rouge, LA. URL

  22. Strauss, B. H., R. Ziemlinski, J. L. Weiss, and J. T. Overpeck, 2012: Tidally adjusted estimates of topographic vulnerability to sea level rise and flooding for the contiguous United States. Environmental Research Letters, 7, 014033, doi:10.1088/1748-9326/7/1/014033.

  23. Tester, P. A., R. L. Feldman, A. W. Nau, S. R. Kibler, and W. R. Litaker, 2010: Ciguatera fish poisoning and sea surface temperatures in the Caribbean Sea and the West Indies. Toxicon, 56, 698-710, doi:10.1016/j.toxicon.2010.02.026.

  24. Tirado, M. C., R. Clarke, L. A. Jaykus, A. McQuatters-Gollop, and J. M. Frank, 2010: Climate change and food safety: A review. Food Research International, 43, 1745-1765, doi:10.1016/j.foodres.2010.07.003.

  25. Titus, J., 2002: Does sea level rise matter to transportation along the Atlantic coast? The Potential Impacts of Climate Change on Transportation, Summary and Discussion Papers, Federal Research Partnership Workshop, October 1-2, 2002,, U.S. Department of Transportation Center for Climate Change and Environmental Forecasting, 135-150. URL

  26. UNEP, 2008: Climate Change in the Caribbean and the Challenge of Adaptation. United Nations Environment Programme, Regional Office for Latin America and the Caribbean, 92 pp. URL

  27. Wiedner, C., J. Rücker, R. Brüggemann, and B. Nixdorf, 2007: Climate change affects timing and size of populations of an invasive cyanobacterium in temperate regions. Oecologia, 152, 473-484, doi:10.1007/s00442-007-0683-5.

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

United States Global Change Research Program logo United States Global Change Research Program participating agency logos