Unprecedented Melting at South Pole

by Ron Kenner

Repeat satellite images taken during the past month reveal that a three-mile-wide, 25-mile long chunk of ice from Larsen B -- one of the largest threatened icebergs in the world -- has collapsed into the Weddell Sea.

Scambos said that researchers from the university-based National Snow and Ice Data Center (NSIDC) spotted the event soon after its occurrence by analyzing the repeat images from the polar-orbiting NOAA satellite.

The pictures apparently confirm earlier studies by the British Antarctic Survey that the huge shelf of ice was "nearing its stability limit," Scambos said. An image from Feb. 26 "shows that much of the ice was already gone," he explained, while the March 23 image "made it crystal clear that a significant portion of the ice shelf had broken off."

And that's only the beginning. No more immediate reduction is expected until late December when the summer begins in Antarctica, "but that may be the beginning of the end for the Larsen Ice Shelf," Scambos speculated.

One third of the huge ice shelf is nestled into protective bays, he noted, but added that if the research is correct, the remaining two- thirds of the Connecticut- sized glacier "will continue to crumble rapidly" into the Weddell Sea early next year, causing new disruptions and possibly contributing significantly to global warming.

Although the temperature dropped to -70 F. at Larsen regularly, the heat is on -- and parts of the South Pole are melting at an alarming rate, these scientists say. In addition to the Larsen B -- which serves as one of the key bellwether sites for measuring global warming -- there has been a reported general increase in the melting of floating ice in Antarctica.

"Not only are the permanent ice shelves in retreat in the Antarctica," noted Steve Alan Edwards for Ecotopics International News, "but sea ice is not as extensive as it once was."

Edwards recalled that the Greenpeace ship MV Arctic Sunrise, "as part of its 1997 tour to dramatize the effects of global warming, circumnavigated Ross Island off the Antarctic peninsula, apparently the first time this has been done. The sea lane used to be blocked by the Larsen A ice shelf, 200 meters thick, which joined the island to the continent. The ice shelf completely broke apart in a matter of a few weeks in 1995."

The Larsen B "is the northernmost ice shelf in Antartica, and therefore "on the front line of the warming trend," Scambos explained.

Authorities believe that in recent months global warming contributed to a massive die-out of Hooker seals and other sea life off the coast of New Zealand and elsewhere around the world.

Scientists in the Antarctic peninsula and elsewhere are scrambling to figure out what Larsen B means and what will be its impact on the climate. However, there appears to be a strong consensus in the scientific community about the reality of global warming.

According to author Paul Rauber, writing about global warming for the Sierra Club, "1995 was the warmest year since global records started to be kept in 1856. Despite brutal winter storms, 1996 was still among the warmest years, and 1991-1995 was the warmest five-year period in recorded history.

The greater the concentration of carbon dioxide, Rauber noted, "the hotter it gets. Before the Industrial Revolution, the atmosphere contained about 280 parts per million (carbon dioxide). Today that figure is 360 parts per million." In the U.S., he adds, "many areas of the West, Midwest, and Northeast are already three degrees warmer than they were a century ago."

"In the future," Rauber says, "we can also expect to experience more deadly heat waves likre the one that hit Chicago in the summer of 1995, killing so many people that the morgue couldn't handle all the bodies." More thasn 425 people were killed in that Midwestern heat wave.

He noted that in addition to higher air-conditioning bills in hotter weather, and serious impacts on the economy, "a hotter world means ... that vermin will spread to newly suitable habitats, bringing diseases (including malaria and cholera) to afflict newly vulnerable human populations."

All but 2.5 percent of Antarctica is covered by a huge ice sheet which at its thickest is reported to be 4,776 meters deep. Averaging more than 2,100 meters thick, Antarctica is thus the highest continent, containing glaciers that average more than one and a half miles above sea level. Antarctica contains 90 percent of all the world's ice and some 70 percent of all the world's fresh water.