Professor Documents Glacial Retreat, Warns of Global Warming's Impact

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When Lonnie Thompson started collecting ice samples from the world's glaciers in the 1970s, people were abuzz about a coming ice age. Since then, global warming has become more than an academic concept for the Ohio State University professor. He's watched it.

COLUMBUS, Ohio — When Lonnie Thompson started collecting ice samples from the world's glaciers in the 1970s, people were abuzz about a coming ice age.


Since then, global warming has become more than an academic concept for the Ohio State University professor. He's watched it.


"It's amazing how quickly the change has come," Thompson told The Associated Press on Tuesday.


Some of his ice samples, kept in a Columbus freezer, within the next decade could become all that's left of glaciers that help prevent flooding and provide a steady water supply and hydroelectric power during the dry season for many mountain and riverside communities worldwide.


"There are (South American) villages that the only source of water are the glaciers," he said. Glaciers also form the headwaters of many great rivers -- the Amazon, the Ganges, the Yangtze.


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"If you have a disruption in a climate system you will displace people, and those people will have to go somewhere," Thompson said. "As our numbers increase, we become more vulnerable to abrupt changes."


Global temperatures rose about 1 degree Fahrenheit in the 20th century, and a U.N.-sponsored network of climate experts says they will keep rising so long as carbon dioxide from burning fossil fuels and other gases keep building up in the atmosphere, trapping heat like a greenhouse.


Five years ago, Thompson predicted the ice cap of Mount Kilimanjaro in Tanzania would disappear by 2015. In January he returns to check if the prediction is on track, or if the ice is melting even faster. His team also measures groundwater sources around the mountain to determine what affect the missing ice will have.


Thompson just returned from a summer expedition to the Andes in Peru, where the largest ice sheet in the tropics, Quelccaya, is retreating as fast as 1 foot (33 centimeters) a day.


His team again collected preserved plants up to 6,500 years old. He's been collecting the mosses and grasses from a former wetland -- a bit musty and brown but with leaves and DNA intact -- since a walk around a lake formed by the rapidly melting glacier in 2002. The ice, right next to the plants when he collected them, now can barely be seen in the distance.


Two botanists from the University of Texas this summer confirmed that the plants were found where they grew. The ice had not moved them, showing just how long it's been since the ground has been bare.


"That gives us a perspective on the retreat that we've been monitoring," Thompson said.


Thompson didn't set out in his career to sound warnings about the planet's future. He drills cores from vast ice fields, where layers of snow can be counted like tree rings and trap each year's air chemistry, pollen from nearby plants, ash from volcanic eruptions and other snapshots of a climate. He hoped to correlate climate changes with the rise and fall of civilizations.


"The whole issue of recent climate change is a small part of what we actually do here," he said, but an important part.


Global warming has already changed ways of life. Spruce trees are dying in Alaska because the winters aren't cold enough to kill bark beetle eggs, people who depend on fishing in Greenland can't get their sleds over ever more slushy and dangerous ice fields, and scientists this summer debated whether warming oceans are fueling the increasing number of deadly storms such as Hurricane Katrina.


"We need to be concerned about these changes," Thompson said. "The thing that is discouraging is that there are so many vested interests who for their own short-term gain will negate what anyone can observe for themselves."


Thompson said he doesn't mean to be political, amid increasing pressure over U.S. President George W. Bush's refusal to sign the Kyoto treaty on global warming.


"If people ask, I'm going to talk about what we see and what we measure," he said. If the glaciers around the world start growing again, "we'd be the first to report that."


Source: Associated Press