On the front page of The New York Times today, Elisabeth Rosenthal takes an in-depth look at a global warming problem you may not know much about: black carbon, commonly known as soot. Carbon dioxide is the main culprit in global warming, but recently scientists have found that soot may be responsible for up to 25 percent of global warming, particularly in the Arctic.
In the U.S. and Europe, soot is emitted by Diesel engines and factory smokestacks. But in India and much of the rest of the developing world, it comes from a source closer to home:
"It’s hard to believe that this is what’s melting the glaciers," said Dr. Veerabhadran Ramanathan, one of the world’s leading climate scientists, as he weaved through a warren of mud brick huts, each containing a mud cookstove pouring soot into the atmosphere.
As women in ragged saris of a thousand hues bake bread and stew lentils in the early evening over fires fueled by twigs and dung, children cough from the dense smoke that fills their homes. Black grime coats the undersides of thatched roofs. At dawn, a brown cloud stretches over the landscape like a diaphanous dirty blanket.
In Kohlua, in central India, with no cars and little electricity, emissions of carbon dioxide, the main heat-trapping gas linked to global warming, are near zero. But soot—also known as black carbon—from tens of thousands of villages like this one in developing countries is emerging as a major and previously unappreciated source of global climate change.
Soot from Asian cooking fires is carried by prevailing winds to the Arctic, where it falls on snow and ice. The black particles change the reflectivity of the ice, causing it to melt faster. In addition to its impact on the Arctic, soot is also a deadly health hazard, contributing to 1.6 million premature deaths a year, from Los Angeles to Mumbai.
But there’s good news: Because soot only stays in the atmosphere a short time—compared to decades for carbon dioxide—short-term measures to cut soot will have almost immediate benefits, slowing Arctic warming and buying valuable time to reduce CO2-caused global warming. Better yet, we already know how to stop soot: By continuing to reduce diesel emissions at home, and investing major resources in helping developing countries switch to cleaner stoves and fuels. Some cleaner-burning cookstoves cost as little as $20. Says the Times:
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 Earthjustice. [No relation to the Times reporter.] "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."
Earthjustice is working on a number of fronts to fight black carbon. In February, we joined the Australian Climate Justice Program in petitioning UNESCO’s World Heritage Committee to take action to protect some of the world’s most unique and treasured places—including Mount Everest in Nepal and Glacier National Park on the U.S.-Canadian border—from the global warming impacts of black carbon pollution. At the end of this month, Erika Rosenthal will attend the Arctic Council Ministerial meeting in Norway, where she will urge the U.S. to take leadership on this issue. You can send the same message to Secretary of State Hillary Clinton, whose State Department will represent the U.S. in Norway.