[LINK] o/t: Soot

stephen at melbpc.org.au stephen at melbpc.org.au
Fri Apr 17 03:28:52 AEST 2009

Third-World Stove Soot Is Target in Climate Fight

KOHLUA, India — "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.

(NYTimes: By Degrees: 'Black Carbon'  This is the first in a series of 
articles about stopgap measures that could limit global warming. Future 
articles will address appliance-efficiency standards, reducing global-
warming gases other than carbon dioxide and other efforts. Share your 
thoughts. Post/Read Comments)

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 are near zero. 

But, soot — also known as black carbon — from tens of thousands of 
villages like this one is emerging as a major and previously 
unappreciated source of global climate change. 

While carbon dioxide may be the No. 1 contributor to rising global 
temperatures, scientists say, black carbon has emerged as an important 
No. 2,  with recent studies estimating that it is responsible for 18 
percent of the planet’s warming, compared with 40 percent for carbon 

Decreasing black carbon emissions would be a relatively cheap way to 
significantly rein in global warming — especially in the short term, 
climate experts say. 

Replacing primitive cooking stoves with modern versions that emit far 
less soot could provide a much-needed stopgap, while nations struggle 
with the more difficult task of enacting programs and developing 
technologies to curb carbon dioxide emissions from fossil fuels.

In fact, reducing black carbon is one of a number of relatively quick and 
simple climate fixes using existing technologies — often called “low 
hanging fruit” — that scientists say should be plucked immediately to 
avert the worst projected consequences of global warming. 

“It is clear to any person who cares about climate change that this will 
have a huge impact on the global environment,” said Dr. Ramanathan, a 
professor of climate science at the Scripps Institute of Oceanography, 
who is working with the Energy and Resources Institute in New Delhi on a 
project to help poor families acquire new stoves. 

“In terms of climate change we’re driving fast toward a cliff, and this 
could buy us time,” said Dr. Ramanathan, who left India 40 years ago but 
returned to his native land for the project. 

Better still, decreasing soot could have a rapid effect. Unlike carbon 
dioxide, which lingers in the atmosphere for years, soot stays there for 
a few weeks. Converting to low-soot cookstoves would remove the warming 
effects of black carbon quickly, while shutting a coal plant takes years 
to substantially reduce global CO2 concentrations.

But the awareness of black carbon’s role in climate change has come so 
recently that it was not even mentioned as a warming agent in the 2007 
summary report by the Intergovernmental Panel on Climate Change that 
pronounced the evidence for global warming to be “unequivocal.” 

Mark Z. Jacobson, professor of environmental engineering at Stanford, 
said that the fact that black carbon was not included in international 
climate efforts was “bizarre,” but “partly reflects how new the idea is.” 

The United Nations is trying to figure out how to include black carbon in 
climate change programs, as is the federal government.

In Asia and Africa, cookstoves produce the bulk of black carbon, although 
it also emanates from diesel engines and coal plants there. 

In the United States and Europe, black carbon emissions have already been 
reduced significantly by filters and scrubbers.

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. 

They earn about $2 a day and, for the most part, have not heard about 
climate change. But they have noticed frequent droughts in recent years 
that scientists say may be linked to global warming. Crops ripen earlier 
and rot more frequently than they did 10 years ago. The villagers are 
aware, too, that black carbon can corrode. In Agra, cookstoves and diesel 
engines are forbidden in the area around the Taj Majal, because soot 
damages the precious facade. 

Still, replacing hundreds of millions of cookstoves — the source of heat, 
food and sterile water — is not a simple matter. “I’m sure they’d look 
nice, but I’d have to see them, to try them,” said Chetram Jatrav, as she 
squatted by her cookstove making tea and a flatbread called roti. Her 
three children were coughing.

She would like a stove that “made less smoke and used less fuel” but 
cannot afford one, she said, pushing a dung cake bought for one rupee 
into the fire. She had just bought her first rolling pin so her flatbread 
could come out “nice and round,” as her children had seen in elementary 
school. Equally important, the open fires of cookstoves give some of the 
traditional foods their taste. Urging these villagers to make roti in a 
solar cooker meets the same mix of rational and irrational resistance as 
telling an Italian that risotto tastes just fine if cooked in the 

In March, the cookstove project, called Surya, began “market testing” six 
alternative cookers in villages, in part to quantify their benefits. 
Already, the researchers fret that the new stoves look like scientific 
instruments and are fragile; one broke when a villager pushed twigs in 
too hard. 

But if black carbon is ever to be addressed on a large scale, acceptance 
of the new stoves is crucial. “I’m not going to go to the villagers and 
say CO2 is rising, and in 50 years you might have floods,” said Dr. 
Ibrahim Rehman, Dr. Ramanathan’s collaborator at the Energy and Resources 
Institute. “I’ll tell her about the lungs and her kids and I know it will 
help with climate change as well.” 

A version of this article appeared in print on April 16, 2009, on page A1 
of the New York edition.



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