Weather-driven energy intensity increase led to higher energy-related emissions in 2013

U.S. energy-related carbon dioxide emissions increased in 2013 by 129 million metric tons (2.5%), the largest increase since 2010 and the fourth-largest increase since 1990. Emissions trends reflect a combination of economic factors (population multiplied by per capita output [GDP/population]), energy intensity (energy use per dollar of GDP), and carbon intensity (carbon emissions per unit of energy consumed).