Climate change has accelerated the retreat of glaciers at rates not seen for thousands of years, glaciologist Lonnie Thompson told reporters at the American Association for the Advancement of Sciences' annual meeting.

Thompson, a world-acclaimed paleoclimatologist and professor of earth science at Ohio State University, revealed that the Qori Kalis glacier high in the Andes would soon disappear at current rates.

The glacier, part of the Quelccaya Ice Cap, the largest body of ice in the tropics, had vanished at a speed of 60 meters (200 feet) per year over the past 10 years. In the preceding decade it had retreated at a rate of six meters (20 feet) per year.

"If you look at what's happening, they're not just retreating, they're accelerating," Thompson said.

Thompson has visited the Quelccaya ice cap 27 times since 1974, conducting various studies on the region's glaciers.

He said the regular discovery since 2002 of ancient plant beds which have been buried for thousands of years, were evidence that the current rate of glacial retreat was faster than at any other time in the past 50 centuries.

"These glaciers are going to be gone," Thompson said. "If you are living at the base of one of these mountains it doesn't matter why they're disappearing, only that they are.

"Millions of people are going to have to adapt to these changes, many of which will occur in some of the poorest regions of the globe."

Thompson cited the example of a newly formed lake below the Oori Kalis glacier that had been created by melting ice.

"In 1991 it didn't exist," he said. Last year, a huge chunk of ice fell from the glacier into the lake and triggered a wave which crashed into the valley below, flooding villages.

Similar problems could be expected in other mountain regions, Thompson said.

"You see this unfolding in the Himalayas where you have the retreat of glaciers and the formation of high-altitude lakes. The people in the valleys below face a new geological hazard."

In African mountain ranges, Thompson said a similar pattern was emerging. In 2001 he had predicted the snows of Kilimanjaro in Tanzania would disappear within 15 years -- but now believes that may happen sooner.

"Kilimanjaro is behaving just like Mount Kenya and the Rwenzori as well as the Andes and the Himalayas," Thompson said. "This widespread retreat of mountain glaciers may be our clearest evidence of global warming," he added.

Meanwhile in Greenland, the Jakobshavn glacier has doubled the speed it is sending ice out to the ocean, Thompson said.

"We're talking about huge amounts of ice and water going into the ocean in this one single case," he said.

Some 10,000 scientists from 60 countries are attending the five-day AAAS forum that aims to raise awareness among researchers, politicians and the public at large about crucial scientific and social issues.

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