Sunday, April 5, 2009

Black carbon linked to half of Arctic warming

NASA image courtesy Dorothy Koch and James Hansen, NASA GISS 

Black carbon is responsible for 50 percent of the total temperature increases in the Arctic from 1890 to 2007 according to a study published in Nature Geoscience. Since 1890 the temperature in the Arctic has risen 1.9 degrees Celsius, linking black carbon to nearly an entire degree rise in Celsius or almost two degrees Fahrenheit.

Black carbon, a particulate air pollutant, is formed by-way of the incomplete combustion of fossil fuels, biofuels, and biomass. In places like Asia black carbon is usually produced by burning wood, coal, or cow dung for cooking or heating. In America and Europe, the use of diesel contributes heavily to black carbon. In total the destruction of forests and savannah by burning is the largest contributor of black carbon.

Black carbon is a double-whammy in terms of climate change: when in the atmosphere dark carbon particulates absorb sunlight and emit it as heat and after falling back to the earth black carbon can darken snow and ice, reducing their ability to reflect sunlight, thereby accelerating melting.

The study conducted by Drew Shindell of the NASA Goddard Institute for Space and Greg Faluvegi of Columbia University also found that the Arctic is most sensitive to black carbon produced within the middle latitudes of the Northern Hemispheres. A previous study had shown that 25 to 35 percent of the world's black carbon emissions come from China and India alone: two nations whose latitude lies at least partly in the sensitive zone.

“Climate conditions in the Arctic are rapidly deteriorating,” said Rafe Pomerance, president of Clean Air - Cool Planet. “This study reinforces the opportunity to control short-lived forcers of global warming including black carbon, methane and tropospheric ozone in order to slow the rate of warming in the Arctic. We cannot afford to allow the shrinkage of the Greenland ice sheet to accelerate.”

Black carbon linked to half of Arctic warming

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