Beating a hasty, but glacial, retreat

by Liza on Apr. 25th, 2005
in The Water Cycle, Weather and Climate

comments

A survey of the glaciers on the Antarctic Peninsula shows that they are shrinking quickly. Scientists at the British Antarctic Survey think this is more evidence of global warming.

The Antarctic Peninsula is a mountain chain that stretches north from Antarctica toward South America. Its 244 glaciers all end at the sea, creating icebergs.

Over three years, the researchers looked at more than 2000 aerial and satellite photos (look at one of these images) of glaciers. Their findings? 87% of the glaciers have retreated over the last 50 years, and the icebergs are breaking off earlier each year. Lots of factors can influence the movement of glaciers and formation of icebergs, but the investigation clearly shows a pattern of retreat.

Air temperatures over Antarctica have warmed considerably, and that seems to be the biggest factor. But changing ocean currents and warming temperatures may be contributing as well.

View of Glacier Breakup off of Antarctic Peninsula in 2001

Read the BBC report on the survey. You can also see a diagram of how one of the glaciers has changed over time.

This report has a graphic that shows the retreat of the glaciers.

Your Comments, Thoughts, Questions, Ideas

Gene says:

But other parts of Antarcitca do not seem to be warming. According to this article from 2004:

The study in Nature notes that the extent of winter sea ice has been declining near the Antarctic Peninsula, where temperatures have increased by 2.5 degrees Celsius over the past 50 years.

But again, the picture is complicated. Overall winter sea ice around Antarctica has been increasing since 1979. However, Antarctica experienced a very rapid decline in winter sea ice in the early 1970s and the area covered today is not quite as large as it was before the decline in the 1970s.

But the average temperatures for most of Antarctica outside of the Antarctic Peninsula have been declining since the mid-1960s. So is this evidence that the amount of warming predicted by computer climate models is wrong? Not so fast, say even some climatologists who report on the Antarctic cooling. They insist that their data do not overturn predictions of rapid global warming. Richard Lindzen, a climatologist from MIT and a global warming skeptic, points out, "the Antarctic is not warming and there is nothing in the models that distinguish the temperature trends they predict in the Arctic from those in the Antarctic." Climate is messy.

I would repeat that last line: climate is messy.

posted on Wed, 03/29/2006 - 10:39am

Liza says:

Glaciers in Antarctica aren't the only ones retreating. In the Swiss Alps, where glaciers and skiing are a big part of the economy, resort operators are trying a novel technique to slow or stop a glacier's retreat.

They've wrapped a section of the glacier in a giant "blanket" to try and reduce the melting they've come to expect over the summer.

Time will tell how well the technique works. If it works, some resort officals expect it to become common practice. But, even if it works brilliantly, it's only a local solution. It isn't feasible, economically or ecologically, to cover up completely even a small glacier.

posted on Tue, 05/10/2005 - 12:52pm

Liza says:

The glaciers of Mount Everest are melting, too.

75% of the world's fresh water is stored in glacial ice, mostly in mountainous areas. The winter's rain and snowfall are gradually released into river networks during the summer months. So rapidly melting glaciers mean less fresh water reserves for the future.

Also, melting glaciers have swollen glacial lakes. These can burst with no warning, endangering thousands of people in neighboring areas.

posted on Wed, 05/18/2005 - 11:47am

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