Using four sets of highly cited but disparate studies that span the range of past estimates, Kopp and Denise Mauzerall, associate professor of environmental engineering and international affairs, attempted to reconcile and standardize the results into one, common global metric.
Their best estimate indicates that eliminating soot pollution from "contained combustion" sources such as diesel engines and poorly-controlled coal sources would provide the world with an additional eight years (with an uncertainty range of about one to 15 years) to reduce carbon dioxide emissions. Conversely, if these sources of carbonaceous aerosols continued at levels seen in the 1990s, more aggressive reductions in carbon dioxide emissions than previously recognized would need to occur for the world to meet the goal of avoiding "dangerous anthropogenic interference with the climate system".
"Unfortunately, most climate change mitigation scenarios used in policy contexts have focused exclusively on heat-trapping gases," Mauzerall said. "This means those eight years aren't actually eight years we can gain by cutting soot emissions; rather, our results suggest that we need to accelerate carbon dioxide emissions by about eight years relative to these scenarios if we don't also act to reduce soot emissions."
Not all soot emissions have the same effect on climate. Effects can vary depending on both where the emissions take place and what sources they come from. Black carbon that can travel to the Arctic and heat Arctic ice during the spring and summer months, for instance, has a stronger warming effect than soot confined to lower latitudes. Further, different soot sources have different ratios of light-absorbing black carbon to light-reflecting particles like organic carbon and sulfa
|Contact: Steven Schultz|
Princeton University, Engineering School