The Environmental Protection Agency has published the National U.S. Greenhouse Gas Inventory Report. The most recent decline in the rate of emissions cited in the report – 6.1% in 2009 – is much faster than the rate of cumulative increase (.4%/year) over the previous 19 years (total 7.3%). The cause for this recent steep decline isn’t attributed to any strong policy change or the growing awareness of the issue of climate change, rather it is considered to be the result of a weak economy and an increase in the cost of coal.

Short excerpt: ‘Recent Trends in U.S. Greenhouse Gas Emissions and Sinks’

‘In 2009, total U.S. greenhouse gas emissions were 6,633.2 Tg or million metric tons CO 2 Eq. While total U.S. emissions have increased by 7.3 percent from 1990 to 2009, emissions decreased from 2008 to 2009 by 6.1 percent (427.9 Tg CO 2 Eq.). This decrease was primarily due to (1) a decrease in economic output resulting in a decrease in energy consumption across all sectors; and (2) a decrease in the carbon intensity of fuels used to generate electricity due to fuel switching as the price of coal increased, and the price of natural gas decreased significantly. Since 1990, U.S. emissions have increased at an average annual rate of 0.4 percent.’