By Devin Powell
Carbon dioxide may be public enemy number one in the fight against global warming. But taking aim at methane and soot has a better chance of keeping the planet cooler in the short run, a new study finds.
Cutting the amounts of these two pollutants that are poured into the sky would diminish warming by half a degree Celsius by 2050, researchers report in the Jan. 13 Science. That could buy a little time for the world — slowing sea level rise, glacial melting and other problems caused by rising temperatures. Targeting these agents of climate change would also improve air quality, potentially preventing up to 4.7 million premature deaths every year, the researchers calculate.
“These are really the low-hanging fruit both for mitigating climate change and improving air quality,” says study leader Drew Shindell, a climate scientist at the NASA Goddard Institute for Space Studies in New York City.
Shindell and his colleagues put 400 known pollution controls to test, selecting 14 interventions that had the greatest impact on warming in a computer simulation. These measures work quickly because methane and soot don’t hang around in the atmosphere for very long — about 12 years for methane and weeks for soot. Cut emissions, and levels of methane and soot drop rapidly. Carbon dioxide, on the other hand, can linger high above for centuries.