The Energy Information Administration reported this week that US carbon dioxide emissions from energy use were down 7 percent in 2009.
The reduction, the largest since the EIA began record-keeping in 1949, was due to both the effects of the Great Recession and longer-term trends in the economy.
The EIA figure includes emissions from power plants, emissions from industrial, commercial and residential sectors, and from transportation. Total CO2 emissions related to energy were 5,405 million metric tons in 2009, down from 5,810 million in 2008.
Changing economy, cheaper gas, pricier oil
America’s shift away from energy-intensive manufacturing to a service-oriented economy has worked to push down CO2 emissions three out of the last four years, reflecting a long-term trend, according to the report.
Since 2000, emissions have fallen in absolute terms even as the economy has expanded, albeit at a slower pace than in the 1990s. “Even with the reduction in economic growth since 2000, emissions would nonetheless have grown by 0.6 to 0.7 percent annually had the proportional relationship between economic and emissions growth remained the same as during the 1990s,” the report stated.
Another factor is the narrowing of the price gap between natural gas and coal, which means utilities buy more power from natural gas power plants, which emit half the CO2 of coal plants. Renewable energy generation also grew 2 percent in 2009.
A rise in the price of oil also contributed to the decrease, as did an increase in overall vehicle fuel economy, from 27 mpg to 28.5.
EIA warned emissions could rise rapidly if coal use rebounds.
“However, longer-term trends continue to suggest decline in both the amount of energy used per unit of economic output and the carbon intensity of our energy supply, which both work to restrain emissions.”