Press Release: Increases in Global Temperature Could Accelerate Historical Rate of Sea-Level Rise

For Immediate Release:
February 29, 2000

Contact: Kelly Sullivan, 202-289-5900

Increases in Global Temperature Could Accelerate Historical Rate of Sea-Level Rise

U.S. Coastal Development, Wetland Resources, and Recreation Affected

WASHINGTON, D.C. — A new report released today by the Pew Center on Global Climate Change states that climate change will lead to a rise in sea levels through the warming of oceans and melting of ice. Rising seas will affect coastal development, wetland resources and recreation along the U.S. coastline. The impacts will be greatest in coastal areas that already face a wide range of natural and human-induced stresses, including erosion, storms, and pressures from development and recreational uses. If the effects of sea-level rise are better assimilated into coastal planning decisions, many impacts of sea-level rise could be reduced and the costs of adapting minimized.

The report, Sea-Level Rise & Global Climate Change: A Review of Impacts to U.S. Coasts, finds that the vulnerability of a coastal area to sea-level rise varies according to the physical characteristics of the coastline, the population size, and amount of development, and the responsiveness of land-use and infrastructure planning at the local level.

"The potential impacts to our coastal areas are another reason for our policy makers to address the challenge of climate change," said Eileen Claussen, President of the Pew Center on Global Climate Change. "Responses to sea-level rise at the national, state and local level must reflect an understanding of the complex interactions of human and ecological systems in coastal areas."

The report concludes that sea levels have already risen between 10 and 25 cm (4 and 10 inches) over the last century and climate change will accelerate these rates, with sea levels projected to rise by 50 cm (20 in) by 2100. Low-lying areas in the Gulf Coast, the South, and the mid-Atlantic regions are especially at risk. In addition, the rapid increase in coastal development over the last few decades has brought with it a greater likelihood of increased property damage in coastal areas and the need for more widespread, and more costly, protection of that property.

The major physical impacts of a rise in sea level include erosion of beaches, inundation of deltas as well as flooding and loss of many marshes and wetlands. Estimates of land in the United States inundated by a 50 cm (20 in) rise in sea level are about 24,000 km2 (9,000 mi2), divided almost equally between upland areas and wetlands. In addition, increased salinity will likely become a problem in coastal aquifers and estuarine systems as a result of saltwater intrusion. These changes, in turn, affect human uses of the coast, such as tourism, settlement, shipping, commercial and recreational fishing, agriculture and wildlife viewing.

Although there is some uncertainty about the effect of climate change on storms and hurricanes, rising sea level could result in more risks from coastal storms. Also, increases in the intensity or frequency or changes in the paths of these storms could increase storm damage in coastal areas. Damage to and loss of coastal areas would compromise the economic and ecological amenities provided by coastal wetlands and marshes, including flood control, critical ecological habitat, and water purification. Major coastal cities such as New Orleans, Miami, New York, and Washington, DC, will have to upgrade flood defenses and drainage systems or risk adverse consequences.

"Damages and economic losses could be reduced if local decision-makers understand the potential impacts of sea-level rise and use this information for planning," Claussen said.

There are three options for responding to coastal threats: planned retreat, accommodation, and protection. Impact and adaptation assessments, which evaluate the costs of these options and the damages to unprotected resources, indicate that property losses or the costs to protect property dominate the existing impact estimates for the United States. Estimates of the impacts of a 50 cm (20 in) sea-level rise by 2100 on coastal property range from about $20 billion to about $150 billion. In addition, although current assessments do not include the monetary costs of impacts to wetlands, the implications of this loss could also be significant

The report is the fourth in a series of reports examining the potential impacts of climate change on the U.S. environment and society. The report's principal authors are James E. Neumann of the Industrial Economics, Inc., Gary Yohe of Wesleyan University, and Robert Nicholls of Middlesex University.

A complete copy of the report is available on the Pew Center's web site,

The Pew Center was established in May 1998 by the Pew Charitable Trusts, one of the nation's largest philanthropies and an influential voice in efforts to improve the quality of the U.S. environment. The Pew Center is conducting studies, launching public education efforts, promoting climate change solutions globally and working with businesses to develop marketplace solutions to reduce greenhouse gases. The Pew Center is led by Eileen Claussen, the former U.S. Assistant Secretary of State for Oceans and International Environmental and Scientific Affairs.

The Pew Center includes the Business Environmental Leadership Council, which is composed of 21 major, largely Fortune 500 corporations working with the Center to address issues related to climate change. The companies do not contribute financially to the Pew Center, which is solely supported by contributions from charitable foundations.