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What's Hidden Under Greenland's Ice?
Roland Piquepaille writes "Ice has covered Greenland for millions of years. So what's hidden under this ice cap? Mountains and valleys? Rivers and lakes? Of course, we might know it sooner than we would have liked if the ice covering Greenland continues to melt. But researchers from Ohio State University have decided that they wanted to know it next year and have developed a radar to reveal views of land beneath polar ice. Their first tests of this new radar, which helps them to catch 3-D images of the ground under the ice, took place in May 2006. The next images will be shot in April 2007. Here are some images of the new GISMO device and what it can do."
Sorry, but this was predicted by the models.
What happens is that warming causes ice near the edges to melt. This dumps cold freshwater into the water nearby, disrupting warmer ocean currents. It also increases humidity. Due to the disrupted ocean currents, the prevailing winds go inland, taking the humid air with it. This gets dumped as snow in the middle, causing the central ice dome to increase. A similar effect occurs in Antartica, where the central ice dome is about 4ks thick.
As shown in the link you provided, _below_ 1500m, the average change was a shrinking of 2cm (+- 0.9cm). Yes, the overall effect was to increase the thickness of the ice dome, but the dome is definitely getting more pronounced.
What the models predict next, however, is that as the slope of the dome gets more steeper, it gets unstable. You then get large stress fractures occurring, and huge slabs - say, about the size of New York State - break off and slide down to the ocean. Fun stuff.
Also, there's ice and there's ice. Old ice is very dense - it's been compressed over thousands or even millions of years, and contains more water by volume than the newer ice being laid down above. The main contributor to this is that the new ice has a lot of gas dissolved into it, or caught in bubbles. What this means is you can melt a million cubic meters of old glacial ice to get a bit less than a million cubic meters of water. However, the same volume of water (a bit less than a million cubic meters) falls as about 3 million cubic meters of snow inland, which gets packed down to about 1.5 million cubic meters of new ice. So, yes, the _volume_ of ice over Greenland is increasing, but the quantity of water in that ice is decreasing.
Here's an paper from the same March 2006 issue of Science that describes the process.
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You can read the paper here. It was published in Science on August 10, 2006. Abstract:
Just a Guess.. but maybe there is.. uh... green land under Greenlands ice caps?
Heh. Actually, we've known for a few decades that most of the interior is below sea level. Greenland is a big, backwards "C", with a ring of mountains around the edges and lower land inside. But when the ice melts, the land will slowly start rising, as has happened in Scandinavia, and there might be some dry land there in a couple thousand years.
And you should look up the history of the name "Greenland". It's a good example of what can be done with a dishonest marketing campaign. The Vikings that fell for it and settled there ended up all dying some time later, leaving behind only a few interesting archaeological sites. The smarter ones settled further south, despite the name "Iceland", so their descendants are still alive today.
This study will be interesting because it will give us details of the terrain under the ice. What we have now is the general contours showing that Greenland is a large bowl.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.