The Hot Zone

Sooty skies

Posted by Alison Hawkes on July 29, 2010
Category : The man made climate

If the world could make one major change that would stave off climate change, what would it be?

Stanford University engineering scientist Mark Jacobson has the answer: get rid of black soot. The dense carbon particles are the result of incomplete combustion of a hydrocarbon from engines, forest fires, and power plants. Ever seen discolored walls above the baseboard of an electric heating unit? That’s black soot.

Black soot is the result of incomplete combustion of a hydrocarbon

Black soot is responsible for somewhere between 25 percent and 50 percent of observed global warming, recent studies have shown. That’s because being dark it absorbs a lot of sunlight and converts it to infrared (heat) radiation, emitting it back to the surrounding air. When it settles onto snow or ice, the soot effectively warms those surfaces too, contributing to melt. To give a comparison, black soot warms the air up to 2 million times more than the same amount of CO2.

Jacobson compared the effects of curbing back soot to reductions in CO2, methane, and several dozen other molecules. Using computer simulations, he found that controlling soot would reduce temperatures faster than controlling CO2 over the next 25 years, by up to 23 percent.

After that, CO2 is still the major bogeyman in the atmosphere. But with immediate relief from soot, some of the tipping points could be delayed. Jacobson published his findings in the latest Journal of Geophysical Research.

Although CO2 emissions are the primary cause of climate warming over the past century, and ultimately need to be curtailed, black soot removal provides immediate relief. That’s because the carbon-heavy molecules settle out of the atmosphere more quickly — in just a few weeks — so stopping their production now means tangible, immediate reversal of warming.

The good news is that we have the technology to curb back soot. Scrubbers on power plants do the trick, as do clean burning ovens for the world’s poor, and electrified transportation.

-Alison Hawkes


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