By Roger Harrabin
Scientists in India have warned that the ancient glacier that feeds the holy river Ganges is likely to melt down before the end of the century.
Glaciers are vital for their contribution to water supplies
They say it could disappear even faster if climate change speeds up. They say man-made carbon dioxide (CO2) emissions are almost certainly to blame for the current level of warming.
They are worried because the glaciers are vital for their contribution to water supplies to many millions of people in the Himalayan region.
Some scientists say the effects of glacial meltdown could stretch to billions of people in one of the most densely populated areas of the planet.
A study for the UK government Department for International Development (Dfid) concluded that this figure was probably exaggerated because it is only in the mountains that the rivers are mostly dependent on glacial melt. On the plains, rivers are fed much more by the monsoons.
But head of the intergovernmental panel on climate change Dr RK Pachauri told the BBC's Newsnight programme that climate change was predicted to disrupt monsoon rains. Combined with glacial meltdown this will leave people doubly vulnerable, he said.
Local farmers are struggling to cope with water shortages
The Nepali government is calling on rich nations to reduce their CO2 emissions.
Nepal is already suffering the effects of rapid warming in the mountains.
The director of hydrology Dr Madan Shrestra told Newsnight that river flow has increased because glaciers are melting twice as fast as previously.
Some Nepali glaciers have already melted into lakes. The water is trapped behind walls of debris scoured by the glacier.
Glacial rock dams like this are highly unstable. One rock dam burst sweeping away homes and a power plant. The Nepali government want to lower the water level of hundreds of new glacial lakes. But it's expensive, and they cannot afford it.
Nepal does produce carbon dioxide emissions of its own. But the average Nepali creates five per cent of the CO2 produced by the average American.
Nepali campaigners are trying to take legal action to get redress from rich nations for the damage they've caused to the climate.
This may be a long shot. But if it fails there's another small attempt being made on the international stage.
The United Nations Educational, Scientific and Cultural Organization (Unesco) will soon consider a plea to have part of the mountain chain placed on the list of World Heritage sites in danger.
In theory that might leave all the member governments of Unesco liable if the environment there is being damaged.