United States Green House Gas Emissions Fell 1.5% in 2006

The total U.S. greenhouse gas emissions in 2006 were 1.5 percent below the 2005 total. This is the first annual drop since 2001 and only the third since 1990. U.S. carbon dioxide emissions in 2006 were 110.6 million metric tons (MMT) below their 2005 level of 6,045.0 MMT, due to favorable weather conditions; higher energy prices; a decline in the carbon intensity of electric power generation that resulted from increased use of natural gas, the least carbonintensive fossil fuel; and greater reliance on nonfossil energy sources.

A growing economy in harmony with CO2 reduction 
Unlike past reductions in carbon dixoide emmission, the U.S. economy grew substantially during the period. From 2005 to 2006, the greenhouse gas intensity of the U.S. economy—measured as metric tons carbon dioxide equivalent (MTCO2e) emitted per million dollars of gross domestic product (GDP)—fell by 4.2 percent, the largest annual decrease since the 1990 base year

Relatively robust economic growth in 2006, at 2.9 percent, coupled with a 1.5-percent drop in total greenhouse gas emissions, led to the decrease in greenhouse gas intensity.

Emmision Reduction Factors
The important factors that contributed to a drop in carbon dioxide emissions in 2006 included: total energy consumption in 2006 that was 0.5 percent below the 2005 total—due in part to favorable weather conditions (both heating and cooling degree-days were below 2005 levels) and in part to higher energy prices that helped to dampen energy demand.

A decline in the carbon intensity of electric power generation that resulted from increased use of natural gas, the least carbon-intensive fossil fuel, and greater reliance on non-fossil energy sources also contributed to the decrease.

From 2005 to 2006, electricity demand was essentially flat and the carbon intensity of the electricity supply fell, leading to a drop in electric power sector emissions. From 2000 to 2006, the overall efficiency of U.S. electricity generation has increased.

Carbon Sequestration
In addition; In 2005, the latest year for which data are available, U.S. land use, land-use change, and forestry activities resulted in total carbon sequestration of 828.5 MMTCO2e, equal to 11.5 percent of U.S. greenhouse gas emissions in 2005.