Nairobi — New scientific evidence has proved that Mount Kilimanjaro's snow is melting fast.

And there'll be severe consequences for local people who rely on the melt water runoff for irrigation and domestic use.

The report published last week by the Proceedings of the National Academy of Science also appear to prove that the rapid melting is a result of global warming.

It is not -- as some climate experts had been saying -- the result of local issues such as the cutting down of forests and greater agricultural production at the base of the mountain.

Scientists now believe that all the snow at the top of the mountain will be gone within two decades.

They say that snow at the top of Mount Kenya could also be about to disappear.

The report says that since 1912, 85 per cent of Mount Kilimanajro's glacier has disappeared and that 26 per cent has gone since 2000 alone.

The primary cause of the melting is rising global temperatures, although scientists acknowledge that changes in cloudiness and snowfall may also play a role.

They also point out that even periods of intense drought, including one which lasted 300 years, did not cause the present degree of melting.

The study is based primarily on photographs taken over the past 100 years.

They show that the 12 sq km of ice coverage in 1912 has been reduced to less than two square kilometres by 2007.

However, the scientists have also drilled down to the rock beneath the ice and extracted samples showing the pattern of freezing and melting over the past 12,000 years.

This proved that the most extensive melting had taken place in the past 40 years.

Scientists say that the melting of Mount Kilimanjaro is part of a trend of glacial retreat across Africa.

They add that melting is also occurring on Mount Kenya and in the Rwenzori mountains on the western side of Uganda.

The melting could be devastating for local people and wildlife, which depend on its runoff waters.

Britain's Met Office has predicted that glacial retreats worldwide could lead to a 20 per cent fall in global agricultural productivity.