The Air Is Sooty. We Should Clean It Up.


I’m no chemist. In fact, I get a little jittery around (and refuse to make eye contact with) the Periodic Table on my son’s closet door. But, given the subject matter here, I must do my best to understand the basic causes surrounding greenhouse gas emissions and their impact on global warming. At times, the concepts seem simple to me (I “get” the greenhouse metaphor) and other times my eyes tragically glaze over when well-meaning scientists try to explain exactly what’s happening here that’s threatening the lives and future of my children. But mental gymnastics aside (sorry folks, some of it is hardcore science), I just read something that I can get my wee right brain around: the air is sooty and we should clean it up.

“A massive simulation of soot’s climate effects finds that basic pollution controls could put a brake on global warming, erasing in a decade most of the last century’s temperature change,” says a Wired Science post. What they’re getting at is that greenhouse gas emissions aside, which are a huge problem and require long-term solutions (“new energy technology and profound changes in lifestyle”), our habit of pumping good ol’ soot into the atmosphere (wood and dung burning, diesel exhaust, small boilers, residential coal use) is something that 1) is a huge part of the problem of global temperature change, and 2) we should be able to get a handle on for immediate impact using simple tools that already exist, like exhaust filters and clean-burning stoves.

The article is based in part on the work of Stanford University climate scientist Mark Jacobson, who conducted the simulation. He found that soot, or black carbon, plays a critical role in global warming, a fact apparently uncovered by prior studies, as well, including work done by NASA back in 2003. But Jacobson’s work takes the simulation a step further, looking into the immediate effects of decreasing the emissions of said soot. The good news, he reports, is that soot has a lifetime in the atmosphere of just a few weeks, while carbon dioxide, for example, has a lifetime of 30 to 50 years. So getting our black carbon problem under control could have a quick and significant effect on global temperatures.

“If you totally stop CO2 emissions today, the Arctic will still be totally melted,” says Jacobson. If we pull in the reins on soot, “the reductions start to occur pretty much right away. Within months, you’ll start seeing temperature differences.”

Explains the article’s author, Brandon Keim: “Soot comes from the incomplete combustion of fossil fuels, and also from the burning of wood or dung for fuel. Crop residue and forest-burning are another major source.”

The 2003 NASA simulation said soot was responsible for one quarter of all global warming in the 20th century. And soot has been identified a key contributor to crises ranging from to glacier melts to abnormal monsoon activity. The United Nations, says Keim, “puts the soot-related death toll at 1.5 million people annually.”

If stopped tomorrow, the disappearance of soot would could drop average world temps by about a degree Fahrenheit. “That’s about half the net warming – total global warming, minus cooling from sun-reflecting aerosols – experienced since the beginning of the industrial age,” says Keim. “The effect would be even larger in the Arctic, where sea ice and tundra could rapidly refreeze.”

The big picture impact of a wide-scale soot reduction effort could buy time and delay “tipping points” in climate change as greenhouse gases continue to take their toll. While the last year’s draft climate treaty generated in Copenhagen last year doesn’t say anything “soot-specific,” the United Nations Environmental Program (UNEP) will be discussing soot problems next year. Meanwhile, here in the States, the EPA will soon begin its own black carbon study. In the meantime, it’s nice to know that there may be some immediate answers out there if we just listen up and put a lid – or a filter – on it.

Image: stoixeia

Scott Adelson

Scott Adelson is EcoSalon's Senior Editor of HyperKulture, a monthly column that explores opening cultural doors to initiate personal change. He is also the author of InPRINT, which reviews and discusses books, new and old. You can reach him at