The ice cap atop Tanzania's Mount Kilimanjaro portrayed by the 1912 photo (above) has thinned by about 80 percent by the year 2000

Lonnie Thompson, professor of geological sciences, reported that at least one-third of the massive ice field atop Tanzania's Mount Kilimanjaro in Africa has disappeared, or melted, in the last dozen years. About 82 percent of the ice field has been lost since it was first mapped in 1912.

"These glaciers are very much like the canaries once used in coal mines. They're an indicator of massive changes taking place . . .in the tropics."

And the Peru's Quelccaya ice cap in the Southern Andes Mountains has shrunk by at least 20 percent since 1963. More troubling however, Thompson said, 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, a researcher with Ohio State's Byrd Polar Research Center, reported the results of two decades of studies by his research team, which has surveyed tropical ice caps and retrieved and analyzed ice cores from South America, Africa, China, Tibet and other locations around the globe. He presented his findings during the annual meeting of the American Association for the Advancement of Science in San Francisco.

"These glaciers are very much like the canaries once used in coal mines," Thompson said. "They're an indicator of massive changes taking place and a response to the changes in climate in the tropics."

While Thompson's team focused on the records preserved in the ice, his colleagues from the People's Republic of China, have analyzed 30 years of records from 178 weather stations spread across the Plateau. Those records show that between 1969 and 1990, the rate of warming has increased at higher elevation sites. That is consistent with the oxygen isotope measurements from the Tibetan ice cores, Thompson said.

"We have long predicted that the first signs of changes caused by global warming would appear at the few fragile, high-altitude ice caps and glaciers within the tropics," the band extending from 30 degrees North to 30 degrees South. "These findings confirm those predictions," Thompson said.

For Kilimanjaro, four-fifths of the vast ice field that covered the top of the highest mountain in Africa has disappeared in the last 80 years. "At this rate, all of the ice will be gone between the years 2010 and 2020. "And that is probably a conservative estimate," he said.

"The loss of these frozen reservoirs threaten water resources for hydroelectric power production in the region, and for crop irrigation and municipal water supplies," he said. The ice in the high-altitude glaciers represents a "bank account" of sorts to feed their power needs. With the melting ice caps, streams have grown and the government is building new dams and hydroelectric plants.

"What they're really doing now is cashing in on a bank account that was built over thousands of years but isn't being replenished. Once it's gone, it will be difficult to reform," he said. In such cases, the countries will probably have to switch to burning fossil fuels to meet their power needs. And by doing so, they'll add more carbon dioxide and water vapor to the atmosphere -- two gases that are known to enhance the greenhouse effect and intensify global warming.

Thompson said that other researchers have documented similar ice losses. An ice cap on Mount Kenya has shrunk by 40 percent since 1963. Two glaciers atop mountains in New Guinea are disappearing and should be gone in a decade. And in Venezuela in 1972, there were six such glaciers -- now there are only two left and they will have melted in the next 10 years.

"We need to take the first steps to reduce carbon dioxide emissions," he said. "We are currently doing nothing. In fact, as a result of the energy crisis in California -- and probably in the rest of the country by this summer -- we will be investing even more in fuel-burning power plants.

"That will put more power in the grid but, at the same time it will add carbon dioxide to the atmosphere, amplifying the problem."