Environment - June 25
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Greenland's Ice Sheet Is Slip-Sliding Away
Robert Lee Hotz, LA Times
The massive glaciers are deteriorating twice as fast as they were five years ago. If the ice thaws entirely, sea level would rise 21 feet.
The Greenland ice sheet - two miles thick and broad enough to blanket an area the size of Mexico - shapes the world's weather, matched in influence by only Antarctica in the Southern Hemisphere.
It glows like milky mother-of-pearl. The sheen of ice blends with drifts of cloud as if snowbanks are taking flight.
In its heartland, snow that fell a quarter of a million years ago is still preserved. Temperatures dip as low as 86 degrees below zero. Ground winds can top 200 mph. Along the ice edge, meltwater rivers thread into fraying brown ropes of glacial outwash, where migrating herds of caribou and musk ox graze.
The ice is so massive that its weight presses the bedrock of Greenland below sea level, so all-concealing that not until recently did scientists discover that Greenland actually might be three islands.
Should all of the ice sheet ever thaw, the meltwater could raise sea level 21 feet and swamp the world's coastal cities, home to a billion people. It would cause higher tides, generate more powerful storm surges and, by altering ocean currents, drastically disrupt the global climate.
Climate experts have started to worry that the ice cap is disappearing in ways that computer models had not predicted.
By all accounts, the glaciers of Greenland are melting twice as fast as they were five years ago, even as the ice sheets of Antarctica - the world's largest reservoir of fresh water - also are shrinking, researchers at NASA's Jet Propulsion Laboratory and the University of Kansas reported in February.
...Across the ice cap, however, the area of seasonal melting was broader last year than in 27 years of record-keeping, University of Colorado climate scientists reported. In early May, temperatures on the ice cap some days were almost 20 degrees above normal, hovering just below freezing.
From cores of ancient Greenland ice extracted by the National Science Foundation, researchers have identified at least 20 sudden climate changes in the last 110,000 years, in which average temperatures fluctuated as much as 15 degrees in a single decade.
The increasingly erratic behavior of the Greenland ice has scientists wondering whether the climate, after thousands of years of relative stability, may again start oscillating.
(25 June 2006)
Study finds strong warming tie to hurricanes
Half of Atlantic temperature increase in 2005 linked to global rise
Global warming accounted for about half of the extra hurricane-fueling warmth in Atlantic waters off the United States in 2005, while natural cycles were smaller factors, according to a study released Thursday by the National Center for Atmospheric Research.
"The global warming influence provides a new background level that increases the risk of future enhancements in hurricane activity," co-author Kevin Trenberth wrote in the study.
A statement issued by the center said that the study "contradicts recent claims that natural cycles are responsible for the upturn in Atlantic hurricane activity since 1995. It also adds support to the premise that hurricane seasons will become more active as global temperatures rise."
(22 June 2006)
Press release from NCAR.
Humans 'destroying coastal life'
Human activity has had a devastating effect on coasts since Roman times, research suggests.
More than 90% of coastal life has declined and there is widespread degradation of water quality.
Scientists studied 12 estuarine and coastal regions in Europe, North America and Australia from the onset of human settlement until today.
Their findings, reported in Science, suggest that 20th Century conservation efforts have had only limited success.
A team from nine research centres in the US, Canada, Australia and Panama used archaeological, historical and ecological records to study the human footprint on coasts and estuaries over the past 2,500 years.
The group found that depletion of natural resources began during Roman times, then accelerated in Medieval times and in the wake of European settlement in North America and Australia.
(24 June 2006)
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