On Africa's Great Peaks, Glaciers Are In Retreat

The glaciers are "expected to disappear within the next two decades," they concluded. And because the 2nd century Greeks were at least partly right, that means a secondary source of Nile River waters will also disappear.

At Mount Kenya, too, "it's a dying glacier," Hastenrath said, referring to the mountain's big Lewis Glacier, once a mile-long tongue of ice draped over a saddle between peaks. "At the rate at which it goes, the end could come soon," he said.

In a meticulous new summary, the Wisconsin scientist, who first investigated Mount Kenya in 1971, shows that its ice fields have shrunk from an estimated 400 acres to less than one-fifth that area in the past century. After decades of work, he has concluded that several interrelated phenomena were responsible.

In the early years, sparser clouds and precipitation in East Africa allowed solar radiation to evaporate exposed areas of ice, which then wasn't adequately replenished, Hastenrath said. But more recently, the reduction in ice thickness has been uniform, pointing to general warmth, not limited sun exposure, as the cause. Eight of 18 glaciers have disappeared.

"Northey's gone. Gregory's about finished," said John Maina, as if mourning old friends. The 56-year-old guide knows Mount Kenya's glaciers and peaks well, having led climbers up its face since he was a teenager. As he prepared for yet another trek from Naro Moru, he recalled how it once was.

"We used to be able to ski on Lewis, but now it's all crevasses," he said. "We would climb all the way up Lewis on ice to Lenana peak, but now it's climbing on rocks. And the ice is weak. We're seeing blue ice, weak ice."

Up at 10,000 feet, where he mans a weather station in the clouds, another longtime guide, Joseph Mwangi, 45, makes his own projections. "In five years, Lewis Glacier will be gone," he said.

Mwangi worries that the water loss may unravel the unique ecosystem that surrounds him, with its high-altitude trees and bamboo groves, blue monkeys and giant forest hogs. "The lobelia trees might die," he said.

Animals are already dying in the foothills and plains below.

Glaciologists say "terminal" glaciers often discharge -- and waste -- large amounts of water in the early years, then release increasingly less as they shrink. Villagers here seem to confirm that: The Naro Moru River and other streams off Mount Kenya ran very high some years back, they say, but are now growing thin. A years-long drought magnifies the problem.

"The more the snow goes down, the lower the rivers," said Roy Mwangi, the area water officer here.

The trouble has already begun, he said. Miles downstream on the Naro Moru, where the river now vanishes in the dry season, livestock are dying of thirst. Desperate nomadic herdsmen have raided points upriver, blocking intakes for farm irrigation systems, he said.

"There's a lot of suffering on the lower side. These are armed men. I'm afraid there will be conflict," Mwangi said.

Hardship may spread even to Nairobi, Kenya's capital. Most of the country's shaky electric grid relies on hydropower, and much of that is drawn from water streaming off Mount Kenya. In a U.N. study issued in early November, scientists predicted that the glacial rivers of Mount Kenya and the rest of East Africa may dry up in 15 years.

"The repercussions on people living down the slopes will be terrible," said Grace Akumu, a Kenyan environmentalist.

Many scientists say similar repercussions could follow wherever human settlements depend on steady runoffs from healthy glaciers -- in Peru and Bolivia, India and China. It could also extend beyond that to coastal settlements, they say, as oceans rise because of the melting of land ice.

The October report by European and North American glaciologists in Geophysical Research Letters estimates that glacier melt contributed up to one-third of the one- to two-inch rise in global sea levels in the past decade. And that contribution is accelerating. Since 2001, they report, dying glaciers apparently have doubled their runoff into the world's rising seas.