Energy-related carbon dioxide (CO2) emissions decreased by 89 million metric tons (MMmt), from 5,259 MMmt in 2015 to 5,170 MMmt in 2016. Although real gross domestic product (GDP) increased 1.5% over that period, other factors contributing to energy-related CO2 emissions more than offset the growth in GDP, leading to a 1.7% decline in energy-related CO2. These factors include the following: •A decline in the carbon intensity of the energy supply (CO2/British thermal units [Btu]) of 1.7%
•A 1.4% decline in energy intensity (Btu/GDP)
Combining these two factors, the overall carbon intensity of the economy (CO2/GDP) declined by 3.1%. Emissions have declined in 6 out of the past 10 years, and energy‐related CO2 emissions in 2016 were 823 MMmt (14%) below 2005 levels.