A glacier drops into Sermilik fjord in southeast Greenland. Photo by J. E. BOX of Time.
If all of Greenland’s ice were plopped into the ocean, sea level would rise a catastrophic 20 feet or more. Until yesterday, most experts thought global warming might make it happen in a couple of thousand years. Now they’re talking hundreds. It still sounds like a long time, but, says Michael Oppenheimer, a professor of geosciences and international affairs at Princeton, "that comes to a couple of feet per century, and that’s more than society is equipped to handle." It doesn’t, moreover, take into account the two mammoth ice sheets of Antarctica, which pack about 20 and 200 feet of potential sea-level rise, respectively, if some new process is discovered that speeds their disintegration. Given what’s being reported in Greenland, the fact that nobody knows what that process might be should be little comfort.
Here also some excerpts from the Independent which published the interview of Jim Hansen, who is the director of the Nasa Goddard Institute for Space Studies in New York, and President George Bush's top climate modeller.
A satellite study of the Greenland ice cap shows that it is melting far faster than scientists had feared - twice as much ice is going into the sea as it was five years ago. The implications for rising sea levels - and climate change - could be dramatic. This new satellite data is a remarkable advance. We are seeing for the first time the detailed behaviour of the ice streams that are draining the Greenland ice sheet. They show that Greenland seems to be losing at least 200 cubic kilometres of ice a year. It is different from even two years ago, when people still said the ice sheet was in balance.
Hundreds of cubic kilometres sounds like a lot of ice. But this is just the beginning. Once a sheet starts to disintegrate, it can reach a tipping point beyond which break-up is explosively rapid. The issue is how close we are getting to that tipping point. The summer of 2005 broke all records for melting in Greenland. So we may be on the edge.
Related links:
Rapid melt shrinks Greenland's ice cap
Greenland Glaciers Losing Ice Much Faster, Study Says
Greenland glaciers dumping ice into Atlantic at faster pace
Greenland ice swells ocean rise
Greenland glacial pace on the rise, study finds
Greenland Glaciers Dump More Ice Into Ocean
Technorati tags: Global warming, Greenland, Glacier, Weather
