High in the Himalayas, above this peaceful valley where farmers till a patchwork of emerald-green fields, an icy lake fed by melting glaciers waits to become a "tsunami from the sky."
The lake is swollen dangerously past normal levels, thanks to the global warming that is causing the glaciers to retreat at record speed. But no one knows when the lake can take no more, sending torrents of water crashing into the valley below.
Such floods from above have hit Punakha before, most recently in 1994, a calamity that killed about two dozen people and wiped out livelihoods and homes without warning. But scientists say a new flood could unleash more than twice as much water and be far more catastrophic.
Punakha's residents are not alone in this picturesque Buddhist kingdom in having the threat of death and destruction hanging over their heads like an environmental sword of Damocles. Because of Earth's rising temperatures, at least 25 glacial lakes in Bhutan are at risk of overflowing and dumping their contents into the narrow valleys where much of the country's population lives.
Like many poor countries, Bhutan is paying for the environmental damage wrought by the developed world and the expanding economies of nations such as China and India, whose fossil-fuel consumption and greenhouse gas emissions are pushing global temperatures upward.
The irony here is that Bhutan probably has done more to safeguard its environment than almost any other country.
A land of breathtaking vistas, little pollution and great biodiversity, Bhutan regards conservation as one of its most important public policy goals.
Sustainable development is the official mantra. By law, the country's forest cover must never drop below 60 per cent. Snow leopards, Himalayan black bears, barking deer and red pandas roam unmolested in the national parks and wildlife reserves that account for one-quarter of Bhutan's territory. A sanctuary in the east is famous as the only one in the world set aside for the yeti - or "migoi," the mythical Abominable Snowman.
"This country is committed to being conducive to environmental sustainability, but the impact of climate change is coming anyway," said Doley Tshering of the UN Development Program office in Thimphu.
Some shifting weather patterns already are being felt. "The winters are not so cold. The hot season is arriving much earlier," Tshering said. "Even fruit trees that would not fruit in Thimphu are now starting to fruit."
Less benign are diseases such as malaria and dengue fever, common in the lower-lying, warmer south, which now are appearing at higher altitudes.
Officials are also worried that any changes to Bhutan's monsoon season could deal a major blow to agriculture, the main source of income for about 70 per cent of the country's population of fewer than 700,000 citizens.
But the most dramatic effect of global warming on Bhutan can be seen in its glaciers - or, perhaps more accurately, not seen.
On satellite images taken in 2000 and 2001, some of the smaller ice sheets along Bhutan's 200-mile stretch of the Himalayas no longer could be found, according to a report last year by the International Centre for Integrated Mountain Development and the UN Environment Program.
Experts estimate that Bhutan's glaciers are retreating by as much as 100 feet annually. The loss has grave consequences for the country's long-term development, because Bhutan relies heavily on selling hydroelectric power, which accounts for about one-third of national revenue.
"In the short run, we'll have increased summer flows, but after 40 years, it'll dry up," said Thinley Namgyel, a senior officer at Bhutan's National Environment Commission.
Of more immediate concern is the risk of floods from glacial lakes. In 1994, the Luggye lake burst and sent water hurtling down into Punakha. Now, a neighbouring lake, the Thorthormi, poses a greater peril.
Fed by a separate glacier, the Thorthormi has bulked up to alarming size and is in danger of swamping a third body of water, the Raphstreng. In a nightmare scenario, the two lakes could merge, punch through the natural but unstable moraine dams holding them back and go cascading into the valley, picking up debris as they thunder downhill.
A 2002 study estimated that such a rupture could send 14 billion gallons of water barrelling toward Punakha, though not all of it would reach the valley.
To try to prevent such a catastrophic flood, the government is set to embark on a four-year, $7-million project to relieve some of the pressure on the Thorthormi. The effort is fraught with difficulty. The lake is reachable only after 10 days' hiking and only through 16,000-foot-high mountain passes from all directions.
Hauling major equipment there, let alone getting it to work in the thin, frigid air, is so tricky that digging the channels to siphon off water from the lake will have to be done mostly by hand. Weather conditions allow for work barely six months of the year.
Not that there is much choice. "Either drain it or get people out of the way," Namgyel said.
Especially grievous to many people in this devoutly Buddhist country was the effect on Punakha's 17th-century "dzong," the monastery-cum-fortress that once served as Bhutan's seat of government. The complex was surrounded by the tumbling waters, the force of which severely damaged one of the "dzong's" oldest temples.
Kezang, a grizzled senior monk, put his faith in divine protection. "I wasn't particularly worried because of the blessing and the power of this place," he said, smiling.
Scientists are not so sanguine. A flood of larger proportions emanating from above Punakha would be far more devastating now that new infrastructure, new hydroelectric projects and even a new town lie in its path.
Despite Bhutan's record as one of the world's most environmentally vigilant nations, it has no choice but to plan for problems incurred by the actions of others, experts say.
"There is a sense of helplessness," said Tshering. "But at the same time, you can't sit back and do nothing about it."
Los Angeles Times
