U.S. energy-related carbon dioxide emissions in 2015 are 12% below their 2005 levels
After increasing in 2013 and in 2014, energy-related carbon dioxide (CO2) emissions fell in 2015. In 2015, U.S. energy-related carbon dioxide emissions were 12% below the 2005 levels, mostly because of changes in the electric power sector. . . Many of the changes in energy-related CO2 emissions in recent history have occurred in the electric power sector because of the decreased use of coal and the increased use of natural gas for electricity generation.