Newspaper article The Christian Science Monitor

Breakaway Iceberg Should Not Sound Global Warming Alarms

Newspaper article The Christian Science Monitor

Breakaway Iceberg Should Not Sound Global Warming Alarms

Article excerpt

WHEN Antarctica's ice sheets and coastal glaciers break off, sending huge blocks of ice drifting into the ocean, often the only ones to notice are penguins and shipowners.

But when the Larsen Ice Shelf calved recently, it gave birth to a veritable Babe the Blue Ox of icebergs -- roughly the size of Rhode Island and some 600 feet thick. And while explanations vary as to the cause of the split, the event is giving researchers a good look at the mechanics of "deglaciation," one predicted result of long-term global warming theories.

Researchers seem to agree on two things: that temperatures on the Antarctic Peninsula, which shelters the Larsen Ice Shelf, have been rising; and that calving is part of the natural cycle of ice sheets.

"There is no doubt that the climate on the Antarctic Peninsula has warmed significantly over the last few decades," says David Vaughan, a glaciologist with the British Antarctic Survey. Researchers note the average annual air temperature there has risen 2.5 degrees Celsius since the 1940s.

"The temperature increase is quite striking," agrees Charles Bentley, director of the Geophysical and Polar Research Center at the University of Wisconsin at Madison.

But trying to tie the increase to human-induced climate change is a shaky endeavor. "Global climate models do not have the geographic resolution, especially in regions with such uncertain boundary conditions," he says of the peninsula's geography. It faces open ocean on one side, ice on the other, has mountains running its length, and is among the northernmost reaches of the continent. These factors make the region highly sensitive to climate fluctuations. Moreover, he adds, researchers in other regions of the continent have been reporting suspected cooling trends.

Indeed, three major climate models -- from researchers at Princeton University, the National Aeronautics and Space Administration, and the National Center for Atmospheric Research in Boulder, Colo. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.