Meela, who lives in Marangu village at the base of the mountain, had used Kilimanjaro's Gredner glacier as a landmark for a climb just six years before.

"But now it was completely gone," he said.

Worse may be to come. The little ice remaining atop majestic Kilimanjaro, Mount Kenya and the Rwenzori Mountains in western Uganda may vanish in the next 20 to 50 years, scientists say.

Why these glaciers on Africa's highest peaks are melting, and how they can be saved, are questions casting shadows on a UN climate change summit underway in the Kenyan capital of Nairobi.

The consensus among scientists is that the loss of these natural treasures can be overwhelmingly pinned on Man -- on "greenhouse gas" pollution from fossil fuels that traps the Sun's heat, causing atmospheric temperatures to rise.

But they also admit to unknowns, given the sketchy evidence of local meteorological records. Other theories blame a warming effect from natural sources, local deforestation and a cyclical disruption of rainfall patterns in this part of East Africa.

"A lot of people want to say 'Oh, it's got to be global warming'," said Ellen Mosley-Thompson, a glaciologist at Ohio State University in the United States who has studied ice core samples over an 11,700-year lifespan.

"But it's irresponsible to point to just one thing," she told AFP in an interview. "It's too complex."

Stefan Hastenrath, a professor of atmospheric studies at University of Wisconsin and expert on African glaciers, says little can be done to preserve Africa's icy peaks, which he says have been melting on Kilimanjaro since 1880.

Hastenrath said reports from that time, when the Industrial Revolution was still at its early stages, show a dramatic decrease in lake levels and an increase in westerly winds, indicating a drier climate developing in east Africa.

"That's not really our fault," he told AFP.

In contrast, a study published in May in the journal Geophysical Research Letters blamed warmer temperatures, beginning in the 1960s and mirroring an increase in global carbon pollution, for accelerating the ice melting atop Uganda's Rwenzori Mountains.

Greenhouse gas emissions are the key agenda item at the conference in Nairobi of the UN Framework Convention on Climate Change (UNFCCC), parent of the Kyoto Protocol aimed at tackling this pollution. The talks run until November 17.

Conservationists say deforestation must also bear responsibility.

The Green Belt Movement, founded by Kenyan Nobel Peace laureate Wangari Maathai, has launched a two-million-dollar tree-planting project to rehabilitate forests on the flanks of Mount Kenya, Africa's second highest summit, partly to stop the melting.

Cutting trees reduces moisture in the atmosphere, which thus reduces the cover afforded by haze and cloud. As a result the glaciers are at the mercy of dry winds and powerful equatorial sunlight, according to Fredrick Njau, a Green Belt spokesman.

The glaciers not only provide stunning views. They are a vital water source, too.

A UN report released on Sunday says their loss would contribute to water insecurity, a problem that some 480 million Africans may face by 2025.

With time running out, one proposal has suggested blanketing the summit of Kilimanjaro in a giant white sheet to slow thawing until action can be done to address the problem.

But many say such thinking is a waste of time and money.

"The saddest thing is that pretty soon the only ice left from Kilimanjaro will be in the freezers at Ohio State University," said Mosley-Thompson.