Posted on 02/16/2006 4:54:22 PM PST by blam
Greenland ice swells ocean rise
By Paul Rincon
BBC News science reporter, St Louis
Kangerdlussuaq Glacier "drains" about 4% of the ice sheet
Greenland's glaciers are sliding towards the sea much faster than previously believed, scientists have told a conference in St Louis, US.
It was thought the entire Greenland ice sheet could melt in about 1,000 years, but the latest evidence suggests that could happen much sooner.
It implies that sea levels will rise a great deal faster as well.
Details of the study, by Nasa and University of Kansas researchers, are also reported in the journal Science.
The comprehensive analysis found that the amount of ice dumped into the Atlantic Ocean has doubled in the last five years.
If the Greenland ice sheet melted completely, it would raise global sea levels by about 7m.
Greenland's contribution to global sea level rise today is two to three times greater than it was in 1996.
Sleeping giant
"We are concerned because we know that sea levels have been able to rise much faster in the past - 10 times faster. This is a big gorilla. If sea level rise is multiplied by 10 or more, I'm not sure we can deal with that," co-author Eric Rignot, from the US space agency's (Nasa) Jet Propulsion Laboratory in California, told the BBC News website.
Previous estimates suggested it would take many hundreds of years for the Greenland ice sheet to melt completely. The new data will cut this timescale, but by how much is uncertain.
It takes a long time to build and melt an ice sheet, but glaciers can react quickly to temperature changes
Dr Eric Rignot, Nasa "It depends on how fast the glaciers can go and how sustainable the acceleration can be," said Dr Rignot.
He added: "It takes a long time to build and melt an ice sheet, but glaciers can react quickly to temperature changes."
In 1996, Greenland was losing about 100 cubic km per year in mass from its ice sheet. In 2005, this had increased to about 220 cubic km. By comparison, the city of Los Angeles uses about one cubic km of water per year.
Rising surface air-temperatures seem to be behind the increases in glacier speed in the southern half of Greenland since 1996; but the northward spread of warmer temperatures may be responsible for a rapid increase in glacier speed further north after 2000.
Satellite monitoring
Over the past 20 years, the air temperature in south-east Greenland has risen by 3C.
Warmer temperatures cause more surface melt water to reach the base of the ice sheet where it meets the rock. This is thought to serve as a lubricant, easing the glaciers' march to the sea.
Helheim Glacier loses the equivalent of about half a football field a day
The study's results come from satellites that monitor glacier movement from space.
Rignot and colleague Pannir Kanagaratnam, from the University of Kansas, built up a glacier speed map from the data for 2000 and then used measurements from 1996-2005 to determine how glacier velocity had changed in the last decade.
The researchers plan to continue their monitoring of the Greenland glaciers using satellite data.
The Greenland ice sheet covers 1.7 million sq km and is up to 3km thick.
The scientists described their results at the annual meeting of the American Association for the Advancement of Science.
At the present rate of rise the ocean would rise 7 meters in about 1000 years. I must be reborn to come back and watch it.
And if the geothermal heating below the ice sheets slows down it may never get there.
They really are informative.
BTW, the other night we picked up on another interesting element in population movement. It seems that when things cool down in the North, and the area of permafrost increases, the Sa'ami and other reindeer herd followers move South into the new areas opened up to them by the bad weather.
When things warm up, the reindeer move North and so do the people. However, additions to the gene pool may be left behind.
Folks living in the warmer regions to the South do not follow the reindeer and do not leave a genetic impact on the Polar people. It's all a one-way flow.
Lest anyone get the idea that reindeer herding is not big time, at present about 1/4 of Earth's land surface is given over to reindeer herds.
Mike, what are you trying to say?
Yup. Those are pernamently bookmarked. I became a believer after reading Mike Baillie's book Exodus To Arthur, he's done some excellent dendrochronology work worldwide.
"Folks living in the warmer regions to the South do not follow the reindeer and do not leave a genetic impact on the Polar people. It's all a one-way flow."
Interesting. There's a lot of DNA here and there that doesn't make sense. Maybe an explanation.
I read a few years ago where some folks found an airplane they'd been searching for since the 50's, I think it was. They were looking up near the top of a mountain, because they were sure that's where it crashed, but the plane was discovered halfway down the mountain because it had landed on a glacier, then was covered with snow, and as the glacier moved, it took the plane with it. I guess eventually with the heaving of the ice, and the lower altitude and warmer temp there, the plane was spotted near the surface of the ice.
The same condition is found in fairly high frequencies among all the polar peoples, whether Sa'ami, Eskimo or Chechi. Presumably the human custom of trading daughters to the neighboring tribe works to move such genes along lines of latitude.
The heme lost by the body results in a flow of photo-reactive iron compounds into urine. I had a relatively distant cousin who used to say "I can pee purple at Noon", and he could. It's within just the last couple of years I found out what that was about ~ it even identifies the version of the anomalous gene he had!
Type II diabetes probably has a similar relationship. I was just thinking about the news that more Type II is "diagnosed" in March and April than at any other time of the year. Let's say your system is on a fundamental time-clock that responds to the absence of fresh fruits, vegetables, grain, even grass in the Early Spring in the Arctic. One way of responding to the absence of those sources of carbohydrates would be to kick your metabolism over to having your liver produce extra sugar (for use by the brain) out of body fat.
By eating carbs in mid-Winter and early-Spring you might well be loading so much sugar in your system that you start destroying your kidneys and messing up your insulin production.
Having a genetic predisposition for this to happen in more pleasant environments further South would not make sense.
LOL. I posted that. It caught my eye because my doctor has told me that I need to watch my diet and exercise more because I was a 'good' candidate for type-2.
I don't understand. What allows them to disgorge the iron?
Since glacial ice behaves like a plastic the ice only flows in response to gravitational forces. It has to be thicker (heavier) to flow faster. That means that the ice is not disappearing.
I've been hiking in the Rockies for near on a quarter century. I have an old scar on my leg where I went through the ice on the edge of a glacier in the Indian Peaks and gashed it on the boulders underneath. A went back a couple of years ago, and the glacier I was hiking on is entirely gone. Even much further north, in Glacier National Park, there are hardly any glaciers left.
Now this is only a short period of time - 25 years - and a relatively small geographical area - the continental US. But there's absolutely no doubt the glaciers are disappearing, very fast.
I read somewhere that excavations at these sites showed they lived entirely on sea mammals, not fish, which you and I would expect.
I remember a program on TV several years ago that said the Great Fire of Chicago was actually caused by several meteorite hits. Apparently that summer had been dry, and the Midwest was a tinderbox. There was one small town that was wiped out from a fire begun by a meteorite hit. People from the town fled to the nearest river, but I think it was over 1000 who died that night in that one place.
That sounds familiar.
Your Understanding is correct. Eric the Red was trying to trick people to settle there from Iceland.
Sea levels are rising, mainly due to thermal expansion. Accurate satellite measurements of mean sea surface level confirm this. I can provide figures if you would care to see them.
...start drinking more water.
Funny. But you know there's going to be a follow up report on how to stop Greenland from melting in 500 years. And I'll betcha the 2008 Dem. candidate has a very vague yet sincere solution.
One problem: meteorites are not hot enough to start fires.
Related to what we were discussing yesterday.
Here's another take on the same story:
Greenland Ice Loss Doubles in Past Decade, Raising Sea Level Faster
OK, the Peshtigo fire is the one we heard about. Hmmm. Considering the dry conditions, could lightning strikes, which could have occurred coincidental to the meteorites, have caused the fires? If there were conditions over the whole area conducive to lightning, which can come without rain, it would explain the multiple sources of fire especially given the dryness of the are at the time.
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