Until recently, burning of coal generated the majority of the electricity in the United States; however, as of 2012 – and for the first time in history – energy production from natural gas fired power plants has equaled that of coal production. According to the graphic below, the U.S. Energy Information Agency says that energy sector CO2 emissions have dropped to 1992 levels. This dramatic decrease makes greenhouse gas production levels the lowest in 20 years.

As a result of the increased use of natural gas for power generation, many pollutants’ emissions have dropped by nearly one-third. As seen in the graphic, nitrogen oxide emissions have fallen by 31 percent and sulfur dioxide emissions are down 32 percent since 2008.