The U.S. Environmental Protection Agency (EPA) has released its 18th annual report of overall U.S. greenhouse-gas emissions showing a 1.6 percent decrease in 2011 from the previous year. Recent trends can be attributed to multiple factors including reduced emissions from electricity generation, improvements in fuel efficiency in vehicles with reductions in miles traveled, and year-to-year changes in the prevailing weather.
Under this administration, EPA has taken a number of common sense steps to help reduce GHG emissions. This includes increasing fuel efficiency for cars that will reduce America’s dependence on oil by an estimated 12 billion barrels by 2025 and increasing energy efficiency through the Energy Star program that saved Americans $24 billion in utility bills in 2012.
GHGs are the primary driver of climate change, which can lead to hotter, longer heat waves that threaten the health of the sick, poor or elderly; increases in ground-level ozone pollution linked to asthma and other respiratory illnesses; as well as other threats to the health and welfare of Americans.
GHG emissions in 2011 showed a 6.9 percent drop below 2005 levels. (View a graphic illustrating total U.S. GHG emissions by year.) Total emissions of the six main greenhouse gases in 2011 were equivalent to 6,702 million metric tons of carbon dioxide. These gases include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.
“The Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011” is the latest annual report that the U.S. has submitted to the Secretariat of the United Nations Framework Convention on Climate Change since it was ratified by the U.S. in 1992. The treaty sets an overall framework for intergovernmental efforts to address the challenge posed by climate change. EPA prepares the annual report in collaboration with other federal agencies and after gathering comments from stakeholders across the country.
The inventory tracks annual greenhouse-gas emissions at the national level and presents historical emissions from 1990 to 2011. The inventory also calculates carbon-dioxide emissions that are removed from the atmosphere through the uptake of carbon by forests, vegetation, soils, and other natural processes (called carbon “sinks”).