For the second year in a row, energy-related carbon dioxide (CO2) emissions in the United States have increased, according to the latest official figures. However, unlike 2013, when emissions and gross domestic product (GDP) grew at similar rates (2.5% and 2.2%, respectively), 2014's CO2 emissions growth rate of 0.7% was much smaller than the 2014 GDP growth rate of 2.4%.