Energy efficiency drove U.S. emissions decline, not natural gas, study says
Conventional wisdom says switching to natural gas is why CO2 fell last year, but a recent analysis found a different explanation.
Aggressive energy efficiency efforts by households, companies and motorists led to the decline in carbon dioxide emissions from energy use in the United States, according to a recent report. The controversial finding contradicts recent studies that say the power sector's shift away from coal to cheap natural gas caused the bulk of reductions.
U.S. emissions last year fell by 205 million metric tons, or 4 percent, from 2011 levels. CO2 Scorecard Group, a small environmental research organization, says that nearly half the decline came from energy-saving measures such as retrofits and smarter appliances in homes and offices, as well as from Americans driving fewer miles, and using more fuel-efficient vehicles.
Natural gas is responsible for only about one-quarter of last year's emissions drop, CO2 Scorecard Group asserts.
"Everybody started to believe that shale gas is driving all these CO2 reductions," said CO2 Scorecard chief executive Shakeb Afsah, an environmental economist and co-author of the study. After investigating, he said he and colleagues found that "the numbers just don't add up."
Indeed, the report challenges a common belief that America's dramatic natural gas boom—made possible by the hydraulic fracturing, or fracking, of shale gas wells—is the main factor in the decline of energy-related emissions. And it goes against other recent studies, including those by the International Energy Agency, the Breakthrough Institute and former Pennsylvania environment secretary John Hanger, that made that argument.