 High in the Himalayas, the isolated mountain kingdom of Bhutan has done more to protect its environment than almost any other country. Forests cover nearly three quarters of its land, and help to absorb the greenhouse gases others emit. Its strict conservation policies help to guard one of the world's top 10 biodiversity hotspots, often to the chagrin of its own farmers. Yet Bhutan could pay a high price for the sins of others - global warming is a major threat to its fragile ecosystem and the livelihoods of its people. "Our farmers are paying a high price for our strict conservation policies," Agriculture Minister Sangay Ngedup told Reuters in an interview. "We are sacrificing a lot, but the world is not making a positive contribution to us." "The effect of climate change and global warming is going to cause havoc to our ecosystem here." The most dramatic threat is posed by what scientists call Glacial Lake Outburst Floods. As the Himalaya's glaciers recede, these lakes are forming and filling with melt water all along the mountain range, dammed by the rocks of glacial moraine. In 1994, one of those lakes burst its banks in Bhutan, and unleashed a torrent of floodwater which claimed 17 lives in the central Punakha valley, sweeping away homes, bridges and crops. Some of Bhutan's glaciers are believed to be retreating at 20 to 30 metres a year. And as that glacial melt accelerates, 24 of Bhutan's 2,674 glacial lakes are in danger of bursting. Some studies predict the wall separating two lakes in central Bhutan could burst as early as 2010, unleashing 53 million cubic metres of water, twice the volume of the 1994 outburst. "You get what is almost a mountain tsunami, which can wipe out anything in its path," said Nicholas Rosellini, resident representative of the United Nations Development Programme. The government, with the UN's help, is beginning the delicate task of trying to lower water levels in some of the high risk lakes, by making holes in the moraine dams without causing the whole structure to burst. Some people in remote places have been given radios to act as a rudimentary early warning system, and studies are being conducted to map the most vulnerable lakes and populations. But much remains to be done. The retreat of Bhutan's glaciers presents an even more formidable and fundamental challenge to a nation of around 600,000 people, nearly 80 percent of whom live by farming. Bhutan's rivers sustain not only the country's farmers, but also the country's main industry and export earner - hydro-electric power, mostly sold to neighbouring India. For a few years, Bhutan's farmers and its hydro power plants might have more summer melt water than they can use. One day, though, the glaciers may be gone, and the "white gold" upon which the economy depends may dry up. The threat led the government's National Environment Commission to a stark conclusion. "Not only human lives and livelihoods are at risk, but the very backbone of the nation's economy is at the mercy of climate change hazards," it wrote in a recent report. Scientists admit they have little solid data on how Bhutan's climate is already changing, but say weather patterns are becoming increasingly unpredictable. There was no snow during the winter of 1998 and, even more rarely, snow in mid-summer in the mountainous north in 1999. In August 2000 flash floods caused by torrential rains claimed dozens of lives. Droughts and landslides are likely to be increasingly commonplace concerns for Bhutan's mountain folk. Malaria, dengue and water-borne diseases like diarrhoea are also marching higher into the Himalayan foothills as temperatures rise. "In places where there was no malaria, malaria is appearing - in higher altitudes," said Dr Ugen Dophu, director of the Department of Public Health. "There is also a risk of epidemic outbreaks." Former King Jigme Singye Wangchuck made protection of Bhutan's rich environment a cornerstone of the country's philosophy of Gross National Happiness, the idea that lifestyle and values were as important as material gains. A quarter of the country's 38,400 square km is set aside as national parks or wildlife sanctuaries, and parliament has passed a law that forest cover should never fall below 60 percent. Yet environmental protection does not come cheap, says minister Ngedup. Farmers would love to convert some of the forest to arable land, while many lose livestock and crops to depredation by wild boar, tigers, leopards, bears and barking deer. Bhutan's government is drawing up a national plan to address the problems of climate change, with taskforces looking at the effects on agriculture, forests and biodiversity, health, water resources and energy, and the risk of natural disasters. But even the best planning in the world will not be enough if the predictions of the global Intergovernmental Panel on Climate Change come true. "Even a slight increase of 1.5 degrees Celsius could have a devastating impact on our ecosystem," said Ngedup. "It would change the whole way of life for humans, as well as animal species and plants."