"This country is committed to being conducive to environmental sustainability and not to be harmful to the world, but the impact of climate change is coming anyway," said Doley Tshering of the United Nations Development Program office in Thimphu, the capital. "You know you haven't created the problem, [yet] you know you're probably having the worst of it."
Some shifting weather patterns are already 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, that people just planted as ornamental flowers, are now starting to fruit."
Less benign are diseases such as malaria and dengue fever, common in the lower-lying, warmer south, now are appearing at higher altitudes.
Officials say they 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 percent of the country's population of fewer than 700,000 citizens. Estimates of the population vary - other agencies have put the figure as high as 2.3 million.
But possibly the most drastic 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 Center for Integrated Mountain Development and the U.N. 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 fast-filling glacial lakes.
In 1994, the Luggye lake burst and sent water hurtling down into Punakha. Now, a neighboring lake, the Thorthormi, poses an even 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.
