Posted on 02/16/2006 9:27:29 PM PST by quantim
Sea levels are rising quicker than previously thought because the amount of water Greenland's glaciers are dumping into the Atlantic Ocean has almost doubled in five years, according to research to be published today.
Scientists who carried out the first comprehensive analysis of changing speeds of the glaciers on the world's largest island were shocked to discover that many have doubled in speed within the past decade.
Warmer temperatures are "lubricating" the glaciers and have driven a 150 per cent increase in the amount of ice they are delivering to the ocean between 1996 and last year. The latitude at which this is happening is moving north.
The researchers fear that as a result current estimates that sea levels will rise by up to 90cms during the 21st century could underestimate the problem.
While there have been previous isolated reports of particular glaciers speeding up, the research presented yesterday at the American Association for the Advancement of Science conference in St Louis is the first detailed study showing the effect is widespread across Greenland.
Eric Rignot, of Nasa's Jet Propulsion Laboratory at the California Institute of Technology in Pasadena, the leading author of the study, said: "Climate change can work in different ways, but generally speaking, if you warm up the ice sheet, the glacier will flow faster.
"The southern half of Greenland is reacting to what we think is climate warming. The northern half is waiting but I don't think it is going to take long. If more glaciers accelerate farther north, especially along the west coast, the mass loss from Greenland will continue to increase well above predictions."
The Intergovernmental Panel on Climate Change has estimated that global sea levels will increase by 10-90cms over the next century. Last century they rose by 10-20cm. Previously models of the melting of the Greenland ice sheet have been based mainly on airborne laser altimetry and have suggested that while the interior is reasonably stable, the periphery was thinning, especially in areas where glaciers meet the sea.
Dr Rignot and colleagues set out to obtain accurate measurements to help to build a clearer picture of Greenland's current and future contribution to rising sea levels. They collected satellite data on the speeds of 27 glaciers and made estimates for two others.
The velocities of several large glaciers had doubled in recent years to 12km per year, making them among the fastest flowing in the world.
The scientists found that warmer air temperatures have increased the overall shrinkage of the Greenland ice sheet from 91 cubic km per year in 1996 to 138 cubic km per year in 2000 and to 224 cubic km per year in 2005.
About two-thirds of this was caused by the dumping of ice in the Atlantic by glaciers and so the ice loss attributable to glacier flow grew by 150 per cent from 60 cubic km a decade ago to 150 cubic km last year.
On this basis Dr Rignot, whose work is published in Science, concluded that Greenland's contribution to rising global sea levels increased from around 0.23mm per year in 1996 to around 0.57mm per year in 2005.
The Greenland ice sheet is 1.7 million sq km - a little smaller than Mexico - and three kilometres thick. If it melted completely sea levels would rise by seven metres
and the more cold water that gets dumbed into the atlantic will mess up the warm gulf current, and make europe very cold!!!
IBBF! (In Before Bush's Fault)
The sad thing about this is that this topic is so politicized that you don't take any of these studies at face value. And they've cried wolf so many times...
Kind of counter-intuitive, don't you think?
They're partially right. Cold water does lead to shrinkage.
Nothing like a dip in Lake Michigan any time of year for one to caibrate the perception of manhood.
Now let me get this straight, in Alaska "global warming" is causing the glaciers to retreat, but in Greenland "global warming" causes glaciers to advance?
How is that counterintuitive? Warm air=more melting.
This is in Antarctica, I believe. Increased snowfall has built upon the part of the glaciers there.
It seems to me the glaciers should be retreating away and not advancing toward the ocean if they are melting,and the ocean level rising is probably only in the computer projections of algore and every other ex-hippy enviro-wacko who wants to stop the USA from producing anything. man-made global warming is no doubt the biggest hoax ever pulled in history
That's what brought out Chicken Little. That is to suggest the heat is underneath, rather than above. Pure nonsense as you point out.
This one is obviously fake because the over all ice is actually growing. But if a factual report does come out one day will we be able to spot it through all the bull that we have been fed?
Pass the baloney.
Not according to this benchmark, struck in 1841:
" But if a factual report does come out one day will we be able to spot it through all the bull that we have been fed?"
Probably not until the effect is something we can see or feel ourselves.
Ted Kennedy used that excuse once.
This could be a good school class project. Every day take them down to the beach and watch the water level rise. (Psst. Don't tell them about the tide)
which isn't a logical contradiction to any global warming scenario either.
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