January 17, 2007

Greenland Melting

Warming Island, Greenland, in 2006Another very good article on how global warming is affecting the earth. This New York Times article is about the melting ice sheet in Greenland. The photo to the right shows a recent image of "Warming Island." Further below is a photo from 1986 that shows "Warming Island" when it was thought to be a peninsula of mainland Greenland.

Be sure to let all your wingnut friends that they'll be having beachfront property much sooner than they thought. Some quotes:

Mr. Schmitt, a 60-year-old explorer from Berkeley, Calif., had just landed on a newly revealed island 400 miles north of the Arctic Circle in eastern Greenland. It was a moment of triumph: he had discovered the island on an ocean voyage in September 2005. Now, a year later, he and a small expedition team had returned to spend a week climbing peaks, crossing treacherous glaciers and documenting animal and plant life.

...

Maps of the region show a mountainous peninsula covered with glaciers. The island’s distinct shape — like a hand with three bony fingers pointing north — looks like the end of the peninsula.

Now, where the maps showed only ice, a band of fast-flowing seawater ran between a newly exposed shoreline and the aquamarine-blue walls of a retreating ice shelf. The water was littered with dozens of icebergs, some as large as half an acre; every hour or so, several more tons of ice fractured off the shelf with a thunderous crack and an earth-shaking rumble.

All over Greenland and the Arctic, rising temperatures are not simply melting ice; they are changing the very geography of coastlines. Nunataks — “lonely mountains” in Inuit — that were encased in the margins of Greenland’s ice sheet are being freed of their age-old bonds, exposing a new chain of islands, and a new opportunity for Arctic explorers to write their names on the landscape.

“We are already in a new era of geography,” said the Arctic explorer Will Steger. “This phenomenon — of an island all of a sudden appearing out of nowhere and the ice melting around it — is a real common phenomenon now.”

In August, Mr. Steger discovered his own new island off the coast of the Norwegian island of Svalbard, high in the polar basin. Glaciers that had surrounded it when his ship passed through only two years earlier were gone this year, leaving only a small island alone in the open ocean.

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The sudden appearance of the islands is a symptom of an ice sheet going into retreat, scientists say. Greenland is covered by 630,000 cubic miles of ice, enough water to raise global sea levels by 23 feet.

Warming Island Greenland in 1986Carl Egede Boggild, a professor of snow - and - ice physics at the University Center of Svalbard, said Greenland could be losing more than 80 cubic miles of ice per year. “That corresponds to three times the volume of all the glaciers in the Alps,” Dr. Boggild said. “If you lose that much volume you’d definitely see new islands appear.”

He discovered an island himself a year ago while flying over northwestern Greenland. “Suddenly I saw an island with glacial ice on it,” he said. “I looked at the map and it should have been a nunatak, but the present ice margin was about 10 kilometers away. So I can say that within the last five years the ice margin had retreated at least 10 kilometers.”

The abrupt acceleration of melting in Greenland has taken climate scientists by surprise. Tidewater glaciers, which discharge ice into the oceans as they break up in the process called calving, have doubled and tripled in speed all over Greenland. Ice shelves are breaking up, and summertime “glacial earthquakes” have been detected within the ice sheet.

“The general thinking until very recently was that ice sheets don’t react very quickly to climate,” said Martin Truffer, a glaciologist at the University of Alaska at Fairbanks. “But that thinking is changing right now, because we’re seeing things that people have thought are impossible.”

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There is no consensus on how much Greenland’s ice will melt in the near future, Dr. Alley said, and no computer model that can accurately predict the future of the ice sheet. Yet given the acceleration of tidewater-glacier melting, a sea-level rise of a foot or two in the coming decades is entirely possible, he said. That bodes ill for island nations and those who live near the coast.

“Even a foot rise is a pretty horrible scenario,” said Stephen P. Leatherman, director of the Laboratory for Coastal Research at Florida International University in Miami.

On low-lying and gently sloping land like coastal river deltas, a sea-level rise of just one foot would send water thousands of feet inland. Hundreds of millions of people worldwide make their homes in such deltas; virtually all of coastal Bangladesh lies in the delta of the Ganges River. Over the long term, much larger sea-level rises would render the world’s coastlines unrecognizable, creating a whole new series of islands.

“Here in Miami,” Dr. Leatherman said, “we’re going to have an ocean on both sides of us.”

...

Global warming has profoundly altered the nature of polar exploration, said Mr. Schmitt, who in 40 years has logged more than 100 Arctic expeditions. Routes once pioneered on a dogsled are routinely paddled in a kayak now; many features, like the Ward Hunt Ice Shelf in Greenland’s northwest, have disappeared for good.

2 comments:

Bin Gregory said...

I was an ecology major as an undergrad and so global warming is something I've always believed in. But seeing it play out this fast, this dramatically... it gives me goosebumps. You know, maybe you and I ought to reconsider life on these islands... ;-)

JDsg said...

LOL. Well, at least your island has some higher mountains; I'm not sure all of us can fit onto Mount Faber. ;) Have you ever read Kim Stanley Robinson's Mars trilogy? A major event in the plot is the melting of Antarctic ice sheets (by erupting volcanoes underneath the sheets, not by global warming), which causes a massive drowning of coastal areas.

But, yeah, I understand what you're saying and that's one of the things that just drives me crazy about one of my sisters, that she can just blithely ignore the evidence and blame it all on "liberals." And while her background is in nursing, she at least understands the rudiments of how science works (or at least I thought).