U.S. net emissions declined 12 percent from 2005 to 2017 due to a range of market- and policy-related factors. Electric power sector emissions fell 27 percent as a result of a shift from coal to natural gas, increased use of renewable energy, and a leveling of electricity demand. Improved vehicle efficiency helped reduce transportation-related emissions by nearly 6 percent, although transportation emissions have been increasing since 2012.
C2ES analysis projects that by 2025, U.S. emissions could be 14 percent to 18 percent below 2005 levels, far short of what is needed to address climate change.