Coastal Areas Threatened by Climate Change

By Cat Lazaroff

WASHINGTON, DC, January 22, 2001 (ENS) - Climate changes in this century may cause coastal erosion, coral reef die offs, and other serious impacts on U.S. coastal and marine resources, concludes a new report from the National Oceanic and Atmospheric Administration's National Ocean Service. The report was released Friday, the last full day of the outgoing Clinton administration.

"While there are still important uncertainties associated with the assessment, it is clear that critical coastal ecosystems - like corals, wetlands and estuaries - are becoming increasingly stressed by human activities," said Margaret Davidson, acting assistant administrator for NOAA's National Ocean Service. "The climate related stresses described in the report will certainly add to their vulnerability."

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Like most areas in Chesapeake Bay, Wye Island suffers from the scourge of erosion as waves beat against the shoreline (Photo courtesy NOAA)
The report, "The Potential Impacts of Climate Change on Coastal and Marine Resources," indicates that climate change will add to the stresses already impacting coastal and marine resources, as a result of increasing coastal populations, development pressure and habitat loss, over fishing, nutrient enrichment, pollution and invasive species.

The report, prepared as part of the U.S. Global Change Research Program's National Assessment of the Potential Consequences of Climate Variability and Change, compiles scientific studies by representatives of government, the private sector and academia, to evaluate the implications of both existing climate variability and future climate change on U.S. coastal and marine resources.

"Looking at the findings of this important report, scientists believe it is critical that we integrate human activities with climate changes, in order to minimize future impacts on coastal and marine resources," said NOAA Administrator D. James Baker. "It is very important for those Americans, who are or will likely be effected by climate impacts, to be aware of the risks and potential consequences that future change will pose to their communities and their livelihoods."

The report highlights key issues of climate change - shoreline erosion and human communities, threats to estuarine health, coastal wetland survival, coral reef die offs, and stresses on marine fisheries. It also addresses that coral reefs are already under severe stress from human activities and high ocean temperatures associated with severe weather events caused by El Niņo weather patterns.

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Rising sea levels could increase inland flooding (Photo courtesy U.S. Environmental Protection Agency)
According to the report, corals have experienced unprecedented increases in the extent of bleaching, emergent coral diseases, and widespread die offs in recent years. The impact of increasing atmospheric carbon dioxide on ocean chemistry is likely to severely inhibit the ability of coral reefs to grow and persist in the future, further threatening these already vulnerable ecosystems, the researchers conclude.

Sea level will continue to rise, and the developed nature of many coastlines will make both human settlements and ecosystems more vulnerable to flooding and inundation, the NOAA researchers said. Barrier islands are particularly vulnerable to the combined effects of sea level rise and uncontrolled development that hinders or prevents migration.

Ultimately, choices will have to be made between the protection of human settlements and the protection of coastal ecosystems such as beaches, barrier islands and coastal wetlands, the researchers warned.

Increases in precipitation and runoff are likely to intensify stresses on estuaries in some regions, by increasing the flow of nutrients and contaminants into coastal ecosystems. In contrast, the flow of sediments from rivers and streams could decrease, reducing the amount of soil and sand available to maintain wetlands, beaches and shorelines.

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A dead fish floats on the surface after an oil spill in Swanson Creek, Maryland in April 2000 (Photo by Mary Hollinger, courtesy NOAA)
Changes in ocean temperatures, currents and productivity will affect the distribution, abundance and productivity of marine populations, with unpredictable consequences to marine ecosystems and fisheries, the report notes.

Increasing carbon dioxide levels could trigger abrupt changes in ocean circulation driven by differences in the density of sea water, which is controlled by the effects of temperature and salinity. This can result in massive consequences for the oceans and for global climate, the report found.

Extreme and ongoing declines in the thickness and extent of Arctic sea ice will have enormous consequences for Arctic ecosystems, the researchers said.

With the U.S. coastline stretching over 95,000 miles, and the nation's economy dependent on the goods and services that it provides, the adaptation of the marine environment to climate change could have major environmental and economic consequences in the U.S.

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A spring storm brewing near the mouth of the Patuxent River in Maryland (Photo courtesy NOAA)
"Most coastal resource management programs are not yet taking climate change into account in their goals and plans," said Donald Boesch, Ph.D., the other co-chair of the assessment and president of the University of Maryland Center for Environmental Science. "With the scientific consensus that there is now clear evidence of a changing climate, these programs should clearly begin to take into account the environmental changes that are possible over the next several decades."

More information on the National Assessment of the Potential Consequences of Climate Variability and Change is available at: http://www.nacc.usgcrp.gov