June 12, 2001. Copyright 2001. Graphic News. All rights reserved.

Meltdown for tropical glaciers and ice caps

LONDON, June 12, Graphic News: The glaciers of Mount Kilimanjaro in east Africa and the Andes of Peru are melting so fast that they could disappear within 10 to 20 years, says Lonnie Thompson, professor of geological sciences at Ohio State University. He also warns that ice fields in the Arctic, South America, Africa, China, Tibet and other locations around the globe are both shrinking in area and thinning in depth.

Following two decades of research Thompson says the Quelccaya glacier in Peru has retreated 32 times faster in the past two years than in the 20 years from 1963 to 1983. More troubling, however, is the observation that the rate of retreat for one of the main glaciers flowing out from the ice cap, Qori Kalis, has been 32 times greater in the last three years than it was in the period between 1963 and 1978.

Thompson and his colleagues began mapping the Quelccaya ice cap in 1976, collecting ice samples and using satellite images and ground surveys. The Qori Kalis glacier was then retreating by 16 feet (4.9 metres) per year. Every time the scientists returned, Qori Kalis was melting faster. Between 1998 and 2000, it was retreating at a rate of more than a foot (42 cm) per day -- 510 feet (155 metres) per year -- 32 times faster than in 1978. The four-inch-thick (10cm-thick) ice cores are now stored in freezers at Ohio State. In the future, says Thompson, that may be the only place to see whatÕs left of the Quelccaya ice cap.

Four-fifths of the vast ice field that covered the top of AfricaÕs highest mountain -- Mount Kilimanjaro -- have disappeared since it was first mapped in 1912. The icecap of Mount Kenya has shrunk by 40 percent since 1963. In 1972, in Venezuela, there were six glaciers; now there are only two. They too will melt within a decade.

ÒAs a result of global warming, many tropical glaciers around the globe may disappear completely by 2020,Ó says Professor Thompson. ÒApart from the dramatic impact on local communities it is also a potent sign that the Earth is undergoing enormous changes.Ó

The phenomenon isnÕt confined to the tropics. Glaciers in Europe, Russia, New Zealand, the United States, and elsewhere are also melting. AlaskaÕs massive Bering and Columbia Glaciers, for example, have receded by more than six miles (10 kilometers) during the past century. A study by geologists at the University of Colorado at Boulder also predicts that Glacier National Park in Montana will lose all of its glaciers by 2070. 

For many scientists, the widespread meltdown is a clear sign that humans are affecting global climate, primarily by raising the levels of carbon dioxide and other greenhouse gases in the atmosphere. The latest report from the Intergovernmental Panel on Climate Change, prepared by hundreds of scientists and approved by government delegates from more than 100 nations, states: ÒThere is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.Ó The report, released in January, says that the planetÕs average surface temperature increased by about 0.6¡C during the 20th century, and is projected to increase another 1.4¡C to 5.8¡C by 2100. That rate of warming is Òwithout precedent during at least the last 10,000 years,Ó says the IPCC. 

ThatÕs not to say that glaciers havenÕt melted in the past, whatÕs different now is the speed at which they are retreating, says Thompson. Even the glaciers in the Himalaya appear to be melting faster than they can be replenished. 

Only Scandinavia and the heart of Antarctica are bucking the melting trend. Glaciers in Norway and Sweden are advancing after a shifts in the jet stream increased snowfall sufficiently to offset temperature rises. 
/ENDS

Sources: Intergovernmental Panel on Climate Change, USGS, Reuters, Associated Press