U.S. Carbon Dioxide Emissions in 2009: A Retrospective Review
"The U.S. Energy Information Administration (EIA) recently expanded its reporting of energy-related carbon dioxide emissions starting in the fall of 2009. This analysis examines the level and drivers of energy-related carbon dioxide emissions in 2009.

What happened to carbon dioxide emissions from energy use in 2009?

In 2009, energy-related carbon dioxide emissions in the United States saw their largest absolute and percentage decline (405 million metric tons or 7.0 percent) since the start of EIA’s comprehensive record of annual energy data that begins in 1949, more than 60 years ago. While emissions have declined in three out of the last four years, 2009 was exceptional. As discussed below, emissions developments in 2009 reflect a combination of factors, including some particular to the economic downturn, other special circumstances during the year, and other factors that may reflect persistent trends in our economy and our energy use..."