Like tiny heat-absorbing black sweaters, soot particles warm the air and melt the ice by absorbing the sun’s heat when they settle on glaciers. One recent study estimated that black carbon might account for as much as half of Arctic warming. While the particles tend to settle over time and do not have the global reach of greenhouse gases, they do travel, scientists now realize. Soot from India has been found in the Maldive Islands and on the Tibetan Plateau; from the United States, it travels to the Arctic. The environmental and geopolitical implications of soot emissions are enormous. Himalayan glaciers are expected to lose 75 percent of their ice by 2020, according to Prof. Syed Iqbal Hasnain, a glacier specialist from the Indian state of Sikkim.

These glaciers are the source of most of the major rivers in Asia. The short-term result of glacial melt is severe flooding in mountain communities. The number of floods from glacial lakes is already rising sharply, Professor Hasnain said. Once the glaciers shrink, Asia’s big rivers will run low or dry for part of the year, and desperate battles over water are certain to ensue in a region already rife with conflict.

Doctors have long railed against black carbon for its devastating health effects in poor countries. The combination of health and environmental benefits means that reducing soot provides a “very big bang for your buck,” said Erika Rosenthal, a senior lawyer at Earth Justice, a Washington organization. “Now it’s in everybody’s self-interest to deal with things like cookstoves — not just because hundreds of thousands of women and children far away are dying prematurely.”

In the United States, black carbon emissions are indirectly monitored and minimized through federal and state programs that limit small particulate emissions, a category of particles damaging to human health that includes black carbon. But in March, a bill was introduced in Congress that would require the Environmental Protection Agency to specifically regulate black carbon and direct aid to black carbon reduction projects abroad, including introducing cookstoves in 20 million homes. The new stoves cost about $20 and use solar power or are more efficient. Soot is reduced by more than 90 percent. The solar stoves do not use wood or dung. Other new stoves simply burn fuel more cleanly, generally by pulverizing the fuel first and adding a small fan that improves combustion.

That remote rural villages like Kohlua could play an integral role in tackling the warming crisis is hard to imagine. There are no cars — the village chief’s ancient white Jeep sits highly polished but unused in front of his house, a museum piece. There is no running water and only intermittent electricity, which powers a few light bulbs.

The 1,500 residents here grow wheat, mustard and potatoes and work as day laborers in Agra, home of the Taj Majal, about two hours away by bus.