The U.S. Environmental Protection Agency released this April 2010 report. The EPA states,
"The U.S. Environmental Protection Agency (EPA) has released the15th annual U.S. greenhouse gas inventory report, which shows a drop in overall emissions of 2.9 percent from 2007 to 2008. The downward trend is attributed to a decrease in carbon dioxide emissions associated with fuel and electricity consumption.
Total emissions of the six main greenhouse gases in 2008 were equivalent to 6,957 million metric tons of carbon dioxide. The gases include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. Though overall emissions dropped in 2008, emissions are still 13.5 percent higher than they were in 1990.
The Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2008 is the latest annual report that the United States has submitted to the Secretariat of the United Nations Framework Convention on Climate Change. The convention sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. EPA prepares the annual report with experts from multiple federal agencies and after gathering comments from a broad range of stakeholders across the country.
The inventory tracks annual greenhouse gas emissions at the national level and presents historical emissions from 1990 to 2008. The inventory also calculates carbon dioxide emissions that are removed from the atmosphere by “sinks,” which occurs through the uptake of carbon by forests, vegetation and soils."