As a strong absorber of solar radiation, black carbon is believed to also contribute to the surface warming of the polar and alpine glaciers.
But black carbon stays in the atmosphere for only a few days or weeks, depending on the size of the particles, before the particles are flushed out through rain, snow or other forms of precipitation. This is an extremely short period of time compared to carbon dioxide, which is believed to remain in the atmosphere for decades.
Because of black carbon's short residency in the atmosphere, reducing black carbon emissions is considered a short-term strategy for mitigating global climate change.
Testifying to the House Oversight and Government Reform Committee in 2007, Ramanathan said of cutting black carbon emissions that "at best, it is a short-term measure to probably buy a decade or two, time for implementing CO2 emission reduction strategies."
Not 'rocket science,' but selling them is difficult
Reducing emissions from cookstoves is not a new problem. Engineers and nongovernmental organizations have tried for at least three decades address the problem.
Ashok Gadgil, a senior scientist at Lawrence Berkeley National Laboratory, said previous cookstove initiatives failed for a variety of reasons. "They are all doable," he said, "it's not rocket science."
When the first series of cookstove projects came online in the 1970s and '80s, engineers throughout the developed world designed several excellent stoves in their laboratories and distributed them around the world. But, in Gadgil's opinion, most cookstoves at that time failed to catch on because, while their testing in idealized laboratory settings might have been top-notch, field testing was practically nonexistent.
Stove engineers learned an important lesson: One stove does not fit all.
A stove Gadgil later helped design for the U.S. Agency for International Development resulted in the Berkeley-Darfur Stove. Each one promises to cut wood consumption by half to two-thirds, preventing up to 2 tons of carbon dioxide emissions each year and reducing the number of dangerous wood-collecting trips Sudanese women must make.
The Berkeley-Darfur Stove design was based on a stove used in India. However, before it was deemed suitable for distribution in Darfur, it underwent 14 modifications after several field tests, said Andrée Sosler, executive director of the Darfur Stoves Project. It distributes the stoves in partnership with Oxfam America and the Sustainable Action Group, a Sudanese organization.
Cookstove design depends on what food items are being cooked, what types of wood or other fuel is available and general customer acceptance.
Fighting thousands of years of tradition
Not every stove works in every country or even in different regions of the same country. A stove can be a deeply personal item in many homes, poor or not, and one that does not meet expectations is not useful.
If a cook cannot prepare traditional foods or use traditional pots, then a new stove it is not worth the engineering put into it, experts said. Recently, Sosler and Gadgil agree, this barrier has become widely recognized.
Still, Sosler said, "a lot of people like their own invention."
In an effort to address deforestation, Lawrence Berkeley Lab and the nonprofit World Vision are looking to modify the Berkeley-Darfur stove for Ethiopian use, because of the country's devastated forest resources.
As an important sink for climate-affecting greenhouse gases, forests remain at the mercy of people for whom the life of a tree may stand between them and feeding their families.