This figure shows the trend in U.S. greenhouse gas emissions between 1990 and 2012. Emissions increased by 4.7 percent between 1990 and 2012.
Greenhouse gas emissions have been declining since 2007 for a few reasons:
- A greater share of electricity is being generated with natural gas and renewable energy. This has offset coal-fired electricity generation, which emits about two times the amount of carbon dioxide (a greenhouse gas) as natural gas-fired electricity generation per unit of electric energy. Energy efficiency has also contributed by keeping electricity demand growth very low.
- Economic activity decreased during the Great Recession, which ran from December 2007 until June 2009. Additionally, the structure of the U.S. economy continues its long-term shift from a manufacturing-based to a service-based economy, which is less energy-intensive.
- Consumption of fossil fuels in the transportation sector has decreased due to lower economic activity, more fuel-efficient vehicles on the road, greater use of biofuels and other social shifts that reduce total vehicle miles traveled, including an aging population, technology (telework), growing cities and greater use of public transportation.
Emissions have decreased 10 percent from 2005 to 2012.
Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2012 (EPA 2014)