The U.S. Environmental Protection Agency (EPA) released its 19th annual report of overall U.S. greenhouse gas (GHG) emissions today, showing a 3.4 percent decrease in 2012 from 2011. The Inventory of U.S. Greenhouse Gas Emissions and Sinks, which is submitted annually to the Secretariat of the United Nations Framework Convention on Climate Change, presents a national-level overview of annual greenhouse gas emissions since 1990.
The major contributors to the decrease in emissions from 2011-2012 were the decrease in energy consumption across all sectors in the U.S. economy, and the decrease in carbon intensity for electricity generation due to fuel switching from coal to natural gas. Other factors included a decrease in transportation sector emissions attributed to an increase in fuel efficiency across different transportation modes and limited new demand for passenger transportation.
Greenhouse gases are the primary driver of climate change, leading to increased heat-related illnesses and deaths; worsening the air pollution that can cause asthma attacks and other respiratory problems; and expanding the ranges of disease-spreading insects. Climate change is also affecting the frequency and intensity of heat waves, droughts, and other extreme weather events.
Under President Obama's Climate Action Plan, EPA is taking steps to address carbon pollution from the power and transportation sectors, and to improve energy efficiency in homes, businesses and factories. This includes increasing fuel efficiency for cars and light trucks for model years 2012-2025 that, over the lifetime of these vehicles, will save Americans more than $1.7 trillion. In addition, we are increasing energy efficiency through the Energy Star program that saved Americans more than $26 billion in utility bills in 2012.
According to the report, GHG emissions in 2012 showed a 10 percent drop below 2005 levels. Total emissions of the six main greenhouse gases in 2012 were equivalent to 6,526 million metric tons of carbon dioxide. These gases include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.
EPA prepares the annual report in collaboration with other federal agencies and after gathering comments from stakeholders across the country. In addition to tracking U.S. GHG emissions, the inventory also calculates carbon dioxide emissions that are removed from the atmosphere through the uptake of carbon in forests, vegetation, soils, and other natural processes (called carbon "sinks").
