The ice atop Mount Kilimanjaro in Tanzania has continued to retreat rapidly, declining 26 percent since 2000, scientists say in a new report.

Yet the authors of the study, to be published Tuesday in the Proceedings of the National Academy of Sciences, reached no consensus on whether the melting could be attributed mainly to humanity’s role in warming the global climate.

Stephen Morrison/European Pressphoto Agency

Mount Kilimanjaro's top, shown in June, has lost 26 percent of its ice since 2000, a study says.

Eighty-five percent of the ice cover that was present in 1912 has vanished, the scientists said.

To measure the recent pace of the retreat, researchers relied on data from aerial photographs taken of Kilimanjaro over time and from stakes and instruments installed on the mountaintop in 2000, said Douglas R. Hardy, a geologist at the University of Massachusetts and one of the study’s authors.

The photographs measure horizontal shrinkage of the ice, and the stakes indicate the reduction in depth. Both are decreasing at the same rate, Dr. Hardy said.

Researchers studying the mountaintop, including those involved in this study, differ in their conclusions on how much of the melting could result from human activity or other climatological influences.

The lead author of the study, Lonnie G. Thompson, a glaciologist at Ohio State University, has concluded that the melting of recent years is unique.

In 2000 he extracted deep cylinders of ice from Kilimanjaro’s glaciers and found that the higher layers were full of elongated bubbles — signs that melting and refreezing had occurred in recent years.

There was no presence of the bubbles in the deeper layers of the cores, Dr. Thompson said.

If his dating of the ice core layers is accurate, surface melting like that seen in recent years has not occurred over the last 11,700 years.

But Georg Kaser, a glaciologist at the Institute for Geography of the University of Innsbruck in Austria, said that the ice measured was only a few hundred years old and that it had come and gone over centuries.

What is more, he suggested that the recent melting had more to do with a decline in moisture levels than with a warming atmosphere.

“Our understanding is that it is due to the slow drying out of ice,” Dr. Kaser said. “It’s about moisture fluctuation.”

But Dr. Thompson emphasized that the melting of ice atop Mount Kilimanjaro was paralleled by retreats in ice fields elsewhere in Africa as well as in South America, Indonesia and the Himalayas.

“It’s when you put those together that the evidence becomes very compelling,” he said.

Cabinet to Meet on Mt. Everest

KATMANDU, Nepal (AP) — Nepal’s cabinet will hold a meeting on Mount Everest to highlight the threat from global warming, which is causing glaciers to melt in the Himalayas, an official said Monday.

The cabinet will meet at the Everest base camp this month, just before an international climate change conference in December in Copenhagen, said Deepak Bohara, the forest and soil conservation minister.

Prime Minister Madhav Kumar Nepal and other cabinet members will fly by plane to the 17,400-foot camp, the starting point for mountaineers trying to climb the world’s highest mountain.

Last month, the cabinet of Maldives donned scuba gear and held an underwater meeting to highlight the threat of global warming to that nation, the world’s lowest.

www.nytimes.com/2009/11/03/world/africa/03melt.html