Mid-Atlantic

 -- An overview prepared by Susan Subak, Ph.D., Natural Resources Defense Council--
 

Climate and changes in it – regardless of their cause – matter to people, communities and businesses. Global warming is likely to bring many changes to the nation. The United States as a whole is in a strong economic position to adapt to many of these changes, but adaptation is often expensive, not always possible or successful, and during transitions ecosystems, communities, and individuals could suffer. Moreover, national impact summaries disguise local dislocations and disruptions to the ways we live, work and recreate. Climate change adds a serious stress to our already threatened resources and treasured places. Overall impact statements also mask significant opportunities. To minimize the negative changes and make the most of the positive changes we need to take a close look at how climate change will affect each region. How will the Mid-Atlantic region experience the effects of global warming? And how can we respond?

Summary
The Mid-Atlantic region, with its extensive coastline, is likely to suffer from the impacts of increased flooding and sea-level rise expected under scenarios of climate change. Changes in temperature and rainfall could take a toll on the region’s important deciduous forests and migratory bird habitats and contribute to summer heat stress and other health risks.  These are among the conclusions of the Mid-Atlantic Regional Assessment, which was led by a team of experts from Pennsylvania State University with support from the U.S. EPA. The regional assessment, which included input from stakeholders, is part of the first congressionally mandated assessment of the potential consequences of climate change and variability throughout the United States.  The National Assessment includes all regions in the United States and five sectors including coastal areas, forests, water resources, agriculture, and human health. Given the uncertainties in projecting climate change, the researchers used two different climate scenarios in their analysis to assess the region’s vulnerability to various climate changes. They considered scenarios for the region of higher average temperatures of 2-3° F by 2030 and 4° or 10° F by the end of the century. The group also considered scenarios with both higher and lower precipitation levels and, in both cases, more intense rainfall and flooding. 

Recent weather events, though not necessarily due to global warming, underscore the devastation that can follow when communities lie in the path of a powerful storm.  Storm damages are expected to worsen in the future because sea-level rise means higher storm surge levels. Losses from Hurricane Floyd in 1999 in the Mid-Atlantic and Southeast regions included more than 77 deaths and $6 billion in damages. Contamination from animal wastes following the storm was unprecedented in scale and has long-lasting implications for fisheries and the region’s coastal ecosystem.  Recommended actions for protecting against future impacts from sea-level rise and increased flooding include improving watershed management and removing incentives that encourage agricultural investment and human settlements in areas vulnerable to erosion and flooding. 

Key Findings
The National Assessment identifies a number of important impact categories that are addressed in greater detail in the recently released regional assessment report. Potential impacts of global warming on coastal areas, forests and human health are summarized below. 

Coastal Zones
More than half of the region’s population lives near the coast, and communities and recreational areas along the region’s lengthy coastline are already vulnerable to coastal flooding, erosion and storms.  Sea-level rise due to global warming would raise storm surge levels and increase the risk of salt-water intrusion into coastal groundwater resources and estuaries.  For example, a scenario of a 24-inch rise in sea level along Delaware’s coast could mean inundation of about 22,000 acres of land in the state if no protective measures are taken. If sea level rises faster than wetlands can migrate inland, they would be inundated and eventually lost. Seawalls and other structures can impede wetland migration. Much of the region’s coastal areas, particularly in the Chesapeake and Delaware Bays, are host to one of the largest concentrations of migratory birds in the western hemisphere.  Stress on wetlands will mean less habitat for these shorebirds.  Higher water temperatures and lower stream-flows would put further stress on the region’s fish and shellfish populations, which are already suffering from low summer oxygen levels due to water pollution and higher temperatures. These findings underscore the importance of preserving coastal wetlands, which also provide important buffers in the event of flooding and help to cycle organic and other pollutants. 

Forest Habitats and Productivity
More th11an half of the region’s land area is covered by deciduous forest, and the assessment concluded that major changes in the mix of tree species are possible.  Most likely, the maple-beech-birch forests that dominate the region would decline and the oak-hickory forests and, to a lesser extent, southern pine and mixed oak-pine forests would become more dominant.  Although overall forest productivity might increase, a relatively rapid shift in dominant forest types might foster invasive species and reduce diversity. This would make for an uncertain future for some of the region’s many small hardwood processors.  Fragmented, younger tree stands could also mean a decline in the role of forests in preventing erosion and siltation. The population of some perching bird species, which are important insect predators and popular with birders -- such as the wood warbler-- is expected to decline.  Although other bird species may become more abundant, the overall trend is expected to be a loss of biodiversity. 

Human Health
The heavily populated Mid-Atlantic region already suffers relatively more heat-related mortality than other parts of the country.  Global warming could increase risks especially for children, the elderly, ailing individuals, and people lacking access to air conditioning, safe water supplies or adequate health care.  The assessment cites a study that suggests that, even allowing for a lower death rate in warmer winters, higher temperatures could mean an additional 400-500 deaths in Philadelphia each year.  Higher rainfall and floods increase the risks of waterborne diseases like Cryptosporidiosis, which is caused in part by water contaminated with cattle wastes. Cryptosporidiosis has already emerged in the region. 

Adapting to the impacts of global warming
 

Climate scientists agree that further climate change may be inevitable and will therefore require adaptation, although most scientists also think that the pace of climate change can be slowed by substantially reducing greenhouse gas emissions. This would give governments, businesses, and ecosystems around the world more time to respond and adapt to climate change as well as reducing the overall severity of climate change-related impacts, thereby buying "insurance" for an uncertain future.  Another way to buy insurance now is to incorporate climate change into all long-term decisions about natural resources, thereby providing greater resilience.

The assessment outlines some strategies aimed at improving the resilience of the region to global warming.  It underscores the importance of preserving existing forests, wetlands, and coastal areas, and of cutting the volume of pollutants that flow into the region’s watersheds and coastal areas from agricultural production and human settlements. Many communities have already committed to develop and implement watershed protection plans that would improve water quality and reduce damages from floods and droughts.  Many of these plans are not yet implemented, but the risks of global warming underlines the importance of completing these programs. 

More specific actions listed in the assessment include: 

• Improve water pricing in order to promote more efficient water use;
• Implement regulations to improve water quality, such as the Enhanced Surface Water Protection Rule;
• Consider a range of plans for coping with sea-level rise and associated coastal hazards locally, including beach replenishment, improved zoning, and “strategic retreat.”  “Strategic retreat” allows some low-lying areas to be inundated while gradually retreating from the encroaching sea. This could be accompanied by a policy of rolling easements that would maintain public access to tidal lands as shorelines retreat.

Additional information
For more detailed information on the potential impacts of global warming on the mid-Atlantic Region, several experts are available to answer your questions:

Dr. Ann Fisher: Team Leader for the Mid-Atlantic Regional Assessment. 
Pennsylvania State University, 107 Armsby Building, University Park, PA 16802. 
 Tel.: (814) 865-3143  Email: fisherann@psu.edu.

Dr. James Shortle: Mid-Atlantic Regional Assessment Team.
Pennsylvania State University, Armsby Bldg., University Park, PA  16802. 
 Tel.: (814) 865-7657  Email: jshortle@psu.edu.

Dr. Susan Subak: Author, IPCC’s Second Assessment Report, Climate Change Impacts on 
Coastal Zones. NRDC, 1200 New York Ave., N.W., Wash. DC 20005. 
 Tel.: (202) 289-2417  Email: s.subak@uea.ac.uk.

Dr. Brent Yarnal: Editor, Climate Research. Department of Geography, The Pennsylvania State 
University, University Park, PA 16802. 
 Tel.: (814) 863-4894  Email: alibar@essc.psu.edu.

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