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Please see EPA's Climate Change site for current information on climate change and global warming. EPA no longer updates EPA's Global Warming Site, but is maintaining this archive for historical purposes. Thank you for visiting the archive of EPA's Global Warming Site.
Chesapeake Bay
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Blackwater National Wildlife RefugeBlackwater National Wildlife Refuge, on the eastern shore of Chesapeake Bay near Cambridge, Maryland, has the largest concentration of nesting bald eagles on the east coast north of Florida. The wetlands of the wildlife refuge are vital for migratory waterfowl and shorebirds, and also are important for flood control and maintaining water quality.
Blackwater is one of Chesapeake Bay's most popular sites for birders, attracting thousands of visitors annually.
Since 1938, one-third of the marsh at Blackwater has disappeared due to a combination of sea level rise and overgrazing by nutria, large non-native beaver-like rodents that dig canals through the marsh and eat the vegetation. More than 5,000 acres of marsh have been lost, and most of the remaining wetlands are projected to disappear within 30 years.
As the sea rises, inundation by seawater of lowland habitats surrounding the marshes could result in the disappearance of habitat for migratory birds and other species, such as the endangered Delmarva fox squirrel. Similar impacts could occur at Back Bay National Wildlife Refuge, south of Virginia Beach, which contains extensive marshlands.
Waterfowl and Other BirdsChesapeake Bay is used by nearly 1 million ducks, geese, and swans in the winter months, and by thousands more during migration seasons. The bay also provides important habitat for a variety of other resident and migratory birds, including the osprey, bald eagle, six colonially nesting waders (such as the great blue heron and snowy egret), and dozens of shorebird species. Chesapeake Bay's abundant bird life and its proximity to major urban centers make it a very popular destination for birders. But in the future, global warming could make the bay a much less attractive place for some species of waterfowl and other birds.
Wintering populations of many ducks have declined in recent decades, some quite dramatically. Overwintering Northern pintails, for example, declined from an average of about 40,400 birds from 1950-1959 to only 2,600 birds in 1985-1999. Other species, such as the Canada goose, snow goose, and Brant, have become more abundant.
Researchers believe that the population changes are related to impacts on food resources in and around Chesapeake Bay. In particular, degradation of bay water quality caused by heavy nutrient and sediment runoff has reduced submerged aquatic vegetation, a prime waterfowl food, throughout much of the bay. Geese and swans respond by switching to other foods, such as waste corn in agricultural fields. But species that rely on submerged aquatic vegetation, such as the Northern pintail, redhead, and American widgeon, have practically disappeared from the bay.
Global warming could exacerbate these problems if increases in precipitation lead to greater nutrient and sediment runoff, and if water temperatures become warmer. Sea level rise and coastal development could eliminate many of the marshes and other shallow water habitats that ducks use in winter — reducing the wildlife that attract many people to the area.
What People Can Do
We all add greenhouse gases to the atmosphere whenever we use energy from fossil fuels. Residential energy use accounted for 19 percent of overall CO2 emissions from the combustion of fossil fuels in 1997, and motor vehicle use accounted for approximately 20 percent. Here are a few actions that people can take to reduce their emissions.
- Use mass transit, carpool with friends, or ride a bike whenever possible.
- When it's time to replace the family vehicle, consider one that gets more miles per gallon than your present vehicle.
- If you have a small boat for fishing and recreation, run it with "human power" when possible.
- When it's time to replace an appliance, look for the Energy Star® label identifying energy-efficient models.
- When buying or building a new house, an Energy Star model gives greater quality and comfort as well as lower monthly costs. For more information, go to the Energy Star Homes web site.
- Buy products that feature reusable, recyclable, or reduced packaging to save the energy required to manufacture new containers and reduce greenhouse gas emissions from landfills.
- Encourage your company to join EPA programs such as Energy Star BuildingsSM and Waste Wi$e recycling programs, and to buy office equipment with the Energy Star label.
- Plant trees, which absorb carbon dioxide from the air.
- Educate others. Let friends and family know about these practical, energy-saving steps they can take to save money while protecting the environment.
- Encourage scientific research and public discussion on global warming and solutions such as energy efficiency and alternative energy.
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In addition, global warming is expected to affect the prairie pothole region of the north-central United States and south-central Canada, where 50-80 percent of North America's ducks and other waterfowl nest. The shallow prairie wetlands are vulnerable to drought, and computer models indicate that global warming is likely to bring stronger and more frequent droughts to the prairie pothole region.
Many ducks that overwinter in Chesapeake Bay nest in the prairie pothole region, including mallards, Northern pintails, American widgeons, canvasbacks, redheads, lesser scaups, common goldeneyes, ruddy ducks, and buffleheads. Virtually all of the canvasbacks that winter in Chesapeake Bay nest in the prairie pothole region.
Chesapeake and Delaware Bays harbor the largest concentrations of migratory shorebirds in the western hemisphere. The loss of bay islands, marshes, and beaches will eliminate important shorebird habitats and will directly affect shorebird populations.
Changes in climate may affect inland birds as well. According to one research study, global warming could cause the Baltimore oriole to shift its range northward out of Maryland. There might be no more Baltimore orioles in Baltimore by the year 2100.
Searching for SolutionsTo address the threat of global warming, Maryland, Virginia, and the other mid-Atlantic states could improve the health and resiliency of natural ecosystems, prepare for a changing climate and rising sea level, and/or work to limit future global warming by reducing greenhouse gas emissions.
The Chesapeake Bay Program, a federal-state effort launched in 1983, responds to the problems of nutrient enrichment, population growth, coastal development, habitat loss and degradation, and toxic substances. In addition, the program's Scientific and Technical Advisory Committee launched Chesapeake Futures, a team of experts looking at issues related to the bay of 2030. By working to improve the health of the ecosystem, the Chesapeake Bay Program may help make the bay and its wildlife more resilient to the future impacts of climate change.
In addition, the Federal Agencies Chesapeake Ecosystem Unified Plan (FACEUP) was established in 1998 to help protect the Chesapeake Bay region. FACEUP added 50 new commitments, such as increased support to the states for research on Pfiesteria.
Island and beach restoration programs also can help mitigate the effects of climate change and sea level rise. The Poplar Island restoration project, led by the U.S. Army Corps of Engineers, is designed to reconstruct the island to its approximate size in 1847 (1,100 acres) using uncontaminated dredged material from Baltimore Harbor and the Channels Federal Navigation project. The restoration will create new habitat for wildlife, including marshes, uplands, small ponds, and wooded areas. The first phase of the 20-year project, which included constructing 640 acres of dikes and a breakwater, was completed in 1999.
Slowing Climate ChangeToday, action is occurring at every level to reduce, avoid, and better understand the risks associated with global warming. Many cities and states across the country have prepared greenhouse gas inventories, and many are pursuing programs and policies that will result in reductions of greenhouse gas emissions.
At the national level, the federal government is working in partnership with businesses, states, and localities to address global warming while also strengthening the economy. In addition, the U.S. Global Change Research Program coordinates the world's most extensive research effort on climate change.
For More Information
- The U.S. Environmental Protection Agency's global warming site includes detailed information on climate change, impacts, and actions.
- The Chesapeake Bay Program's web site
 offers a wealth of information on the current and future status of Chesapeake Bay.
- The Poplar Island Restoration Project web site provides an overview and updates on progress in restoring the island.
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