EPA Publishes Annual National Greenhouse Gas Inventory

The U.S. Environmental Protection Agency has released the national greenhouse gas inventory, which finds that overall emissions during 2006 decreased by 1.1 percent from the previous year. The report, Inventory of U.S. Greenhouse Gas Emissionsand Sinks: 1990-2006, is the latest in an annual set of reports that the U.S submits to the Secretariat of the United Nations Framework Convention on Climate Change, which sets an overall framework for intergovernmental efforts to tackle the challenge posed by climatechange. Each year since 1993, EPA’s experts have built a comprehensive inventory of U.S. greenhouse gas emissions. Our understanding of emission sources is paramount to combating climate change.

Total emissions of the six main greenhouse gases in 2006 were equivalent to 7,054.2 million metric tons of carbon dioxide. These gases include:

1) carbon dioxide,
2) methane,
3) nitrous oxide,
4) hydrofluorocarbons,
5) perfluorocarbons and
6) sulfur hexafluoride.

The report indicates thatoverall emissions have grown by 14.7 percent from 1990 to 2006, while the U.S. economy has grown by 59 percent over the same period.The decrease in emissions in 2006 was due primarily to a decrease in carbon dioxide emissions associated with fuel and electricity consumption. The following factors were primary contributors to this decrease:

compared to 2005, 2006 had warmer winter conditions, which decreased consumption of heating fuels, as well as cooler summer conditions, which reduced demand for electricity;

restraint on fuel consumption caused by rising fuel prices, primarily in the transportation sector; and

increased use of natural gas and renewables in the electric power sector.

EPA prepares the annual report in collaboration with experts from multiple federal agencies and after gathering comments from a broadrange of stakeholders across the country.The inventory tracks annual greenhouse gas emissions at the nationallevel and presents historical emissions from 1990 to 2006. The inventory also calculates carbon dioxide emissions that are removed from theatmosphere by “sinks,” e.g., through the uptake of carbon by forests,vegetation and soils.Information on the greenhouse gas inventory report