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East of the Sun, West of the Moon

Saturday, September 25, 2004

Glaciers Racing To The Sea

Having just read Ocean's End yesterday's bit of news about Antarctic glaciations came as a bit of a shock to me. The book's penultimate chapter deals with the threat of global warming and the breakup of ice shelves in Antarctica. Woodard wrote the book in 1999-2000, shortly after the breakup of the Larsen-A Ice Shelf and the Wordie Ice Shelf. The gist of chapter seven was about how Antarctica is warming up, and how scientists in the 1970's predicted the first indicators of global warming would be the thawing of Polar Regions, especially the Antarctic Peninsula. His one bit of good news was that mainland Antarctic glaciers did not seem to be accelerating into the ocean with the loss of their ice shelf 'corks.' Glaciologists fear that once the ice shelves at the terminal end of glaciers are removed, the massive ice rivers coming off a section of the polar ice cap would accelerate into the ocean, greatly raising sea levels around the world and inundating major urban centers and low-lying croplands.

Larsen-B Ice Shelf collapse captured by NASA's MODIS sensor on the Terra satelliteSeems like his one ray of hope was a bit premature. Since the publication of Ocean's End, the far larger Larsen-B Ice Shelf collapsed in 2002. Now a flurry of papers are indicating that the glaciers that fed the ice shelf are accelerating into the ocean. The glaciers are losing 60% more of their mass to the ocean than is replenished by inland snowfall.Whoops, we broke Antarctica. Like it ain't enough the entire continent is baking in UV radiation after we punched a hole in the sky with rampant CFC use. Now the whole damn place is melting away.

On the whole, temperatures in the Antarctic Peninsula have increased 5°F. It might not seem like much, but 20,000 years ago a drop of 7°F triggered an ice age and blanketed much of North American and Eurasia under a mile of ice. Extreme scenarios postulate that the entire West Antarctic Ice Sheet could deteriorate and slide into the ocean, raising sea levels around the world 16 to 20 feet. New York, Venice, London, Jakarta, Manila, Amsterdam, New Orleans, Miami, Alexandria, Osaka - all lost beneath the waves. Well let's be frank. Wealthy industrial nations would probably construct massive dikes and levees around their cities, shifting the brunt of the devastation onto those least able to cope with a catastrophe. Say goodbye to Bangladesh. Adios to the Maldives. Sayonara Marshall Islands.

And here's the bad news. This isn't the kind of thing that can be fixed. Even if we abandon automobiles, jet planes and coal fired electrical plants, the damage cannot be undone. Or at least not on a timescale that is relevant of human civilization. Global warming, climate change - the damage has been done. The changes were small and imperceptible at first, but 200 years of industrialization pushed the planet inexorably into a new climate. Things are changing, and while not as fast as The Day After Tomorrow, climate change and the havoc that will ensue are inevitable.

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