Slashing emissions of these twin threats would be a “win-win-win” for climate, human health and agriculture, said NASA climate scientist Drew Shindell, who led the study appearing in the journal Science. “Even if you don’t believe climate change is a problem, these things are worth doing.”
Previous studies have noted the benefits of reducing methane and soot. But the new study looked at the specific effect of about 400 actions policymakers could take. Of those, just 14 interventions — such as eliminating wood-burning stoves, dampening emissions from diesel vehicles and capturing methane released from coal mines — would offer big benefits.
“They’re all things we know how to do and have done; we just haven’t done them worldwide,” said Shindell, who works at the NASA Goddard Institute for Space Studies in New York.
But simple changes can be difficult to implement globally, Shindell acknowledged, even when the ultimate benefits dwarf the upfront costs.
Reducing methane and soot would slow global warming dramatically — by almost a degree Fahrenheit — by the middle of the century, according to computer simulations run by the 24-member international team.
At the same time, the simulations show that better air quality would prevent lung and cardiovascular diseases, saving anywhere from 700,000 to 4.7 million lives annually. The wide range reflects uncertainties in the number of deaths caused by air pollution.
Global crop yields would also rise, by 30 to 135 metric tons annually, as rice, corn, wheat and soybean plants would have an easier time absorbing the nutrients they need from the air, according to the report.
“In the absence of a global carbon dioxide agreement, it makes sense to move ahead on global efforts to reduce these other gases,” said Joyce Penner of the University of Michigan, who has studied the climate impacts of soot but was not involved in the new research.
About 3 billion people in the developing world rely on stoves that burn wood, dung and other fuels that throw off soot. Switching to cleaner-burning stoves would help reduce short-term global warming while quickly improving local air quality. Soot particles fall out of the air in less than a week.
But getting people to switch to cleaner-burning stoves is “easier said than done,” said Elizabeth Ransom, a spokeswoman for University Research. With funding from the U.S. Agency for International Development, the group recently doled out $1.3 million in grants to three groups studying how to get people in Uganda and India to adopt cleaner-burning stoves, as some projects to introduce modern stoves “just didn’t take off.”