Ice Core Study Shows High Mountain Warming
By Paul Recer, Associated Press, September 14, 2000
In another indication that the Earth may be warming, an analysis of ice samples drilled from deep inside a glacier shows that the last century has been the hottest period in 1,000 years high in the Himalayan Mountains. The new finding supports other studies that show a rapid melting of mountain ice fields on three continents and a dramatic decline in water levels of some glacier-fed rivers. "We think this is alarming," says Ellen Mosley-Thompson of Ohio State University, the co-author of a study appearing Friday in the journal Science. Mosley-Thompson is a member of a team, led by Lonnie G. Thompson of Ohio State, that has analyzed ice cores from some of the most remote mountains in the world. The new cores, cylindrical specimens of ice, came from deep within a glacier more than 20,000 feet high in the Himalayas.
"The last century has been warmer than the previous nine centuries," Mosley-Thompson said, while the last decade has been the warmest period of all. Other studies, based largely on surface temperature readings, have found a global average warming of almost one degree F over the last century, but the effect may be even more dramatic in the world's mountains, she said. "These high elevation ice fields seem to be warming more strongly than what you could call the global average," Mosley-Thompson said. She said there has been a significant shrinkage of permanent ice fields in Asia, South America and Africa that provide a significant part of the flow in major rivers. Many such rivers are in areas with monsoon weather patterns, where there usually is little rain for six months of the year. Ice melt from the rivers has become an increasingly important source of water for cities and farms, Mosley-Thompson said. "For these rivers to continue to flow year-round, they have to be fed by ice in the high mountains," Mosley-Thompson said. If the ice fields continue to shrink, she said, "the question then is where will the river flow come from during the dry season." Mosley-Thompson said the mountain warming effect seems to be worldwide. "Everywhere we go, we get the same picture" of shrinking ice fields and increasing high altitude warming, she said.