WASHINGTON (AP) The United States cut its energy-related carbon dioxide pollution by 3.8 percent last year, the second biggest drop since 1990, the Department of Energy said Monday.
The only recent year with a bigger percentage drop was in 2009, when America was in a large recession. American cars and factories spewed 5.83 billion tons of carbon dioxide in 2012, down from 6.06 billion in 2011. It is the lowest level for U.S. emissions since 1994. Carbon dioxide is the chief man-made global warming gas.
Energy Department economist Perry Lindstrom said carbon pollution reduction is due to warm winter weather, more efficient cars because of new mileage requirements and an ongoing shift from coal-power to natural gas to produce electricity.
The coal shift is a big factor as is a sluggish economic recovery, said Jay Apt, director of the Carnegie Mellon Electricity Industry Center. He said in 1994 coal provided 52 percent of the U.S. power and now it is down to 37 percent. Burning coal produces far more carbon dioxide than burning natural gas.
Some past cuts in carbon pollution were mostly due to economic factors, such as the 7.1 percent drop in 2009, Lindstrom said. But this drop happened while the U.S. economy was growing 2.8 percent, as reflected by the gross domestic product, and its energy use was dropping by more than 2 percent.
