Ice Sheets Melting at a Worrisome Rate
by: Dennis O'Brien 24 March 2006
BALTIMORE Polar ice sheets are melting faster than authorities realize and could eventually submerge coastal communities worldwide, according to two studies released today.
Researchers from the University of Arizona and the National Center for Atmospheric Research noted that sea levels rose 20 feet during a warming period 129,000 years ago and said the waters could rise just as high sometime after 2100 if global temperatures continue to climb.
Scientists have warned for decades that carbon dioxide and other greenhouse gases from power plants and vehicle exhaust are warming the planet and raising the seas. They say the best way to minimize the damage is to significantly reduce smokestack and tailpipe emissions.
Although some researchers dispute specific aspects of global warming, more than 2,000 scientists from 100 countries who served on the Intergovernmental Panel on Climate Change concluded in 1995 and 2001 that global warming was real and that carbon dioxide produced by humans was largely to blame.
The two studies published today in the journal Science argue that the impact of melting from Antarctica's ice sheets has been underestimated.
The studies, funded by the National Science Foundation, are among several recent reports that used satellite imagery, ice cores and geological records to measure the effects of warming on glaciers and ice sheets.
A study last month by NASA showed substantial melting of Greenland's glaciers, and a University of Colorado study published earlier this month found substantial melting in Antarctica.
The Goddard Institute for Space Studies in New York released a report in January showing that 2005 was the warmest year on record. A NASA study released in September showed less sea ice floating in the Arctic Ocean than at any time in the last century.
The Bush administration, which has often been criticized for not taking steps to combat warming, declined to discuss the latest studies.
No one is sure of the extent of the melting or the timing of its effects.
But the researchers say that with the warming climate, melting ice sheets in Greenland, the Arctic and Antarctica could inundate coastal areas around the world.
Maps released with the studies show extensive coastal areas in Florida, New Orleans and Cape Cod, Mass., that the researchers say might one day be submerged.
"As [Hurricane] Katrina pointed out, we only need a meter of sea level rise to make much of New Orleans unlivable. The same goes for a number of coastal areas," said Jonathan T. Overpeck, a geosciences professor at the University of Arizona and lead author of one study.
Ice cores and ancient sediments show a 20-foot rise in sea levels during the warm stretch 129,000 years ago, known as the Last Interglaciation.
The seas rose because of melting ice in Greenland and in the Arctic, as well as the melting of two Antarctic ice sheets.
The impact of the Antarctic ice sheets has been underrated, the researchers say.
"I was really surprised at the amount of sea level rise and how little warming you need to get to it," Overpeck said.