Energy-related carbon dioxide (CO2) emissions in the United States fell 2.4% in 2011, compared to 2010 levels, the U.S. Energy Information Administration (EIA) said Sept. 10.
A weak economy, weather, changes in fuel prices and increased use of natural gas for power generation all figured into the decline, EIA said on its website.
Energy-related CO2 emissions have declined domestically for four of the past six years, EIA said.
Economic growth as measured by gross domestic product (GDP) increased by 1.8% in 2011, slower than the 2.4% growth in 2010.
Because the decline in CO2 emissions occurred in a growing economy, the carbon intensity of the economy fell. “This was mainly a result of using less energy or, in some cases, using less carbon-intensive energy, to achieve the same economic output,” EIA said.
On the weather front, warmer temperatures in the summer of 2011 resulted in a modest increase in the amount of energy needed for cooling, EIA said. The relatively mild winter also brought a significant drop in energy required for heating.
In the power sector, generation from natural gas, the least carbon intensive of the fossil fuels, increased by 3%, while generation from coal decreased by 6%. Meanwhile, power generation from renewable sources continues to rise, EIA said.