U.S. greenhouse gas emissions dropped from 2008 to 2009, the Environmental Protection Agency (EPA) noted in its latest annual greenhouse gas inventory. General aviation continues to account for less than one percent of carbon dioxide emissions from fossil fuel combustion in transportation.
AOPA explained that GA greenhouse gas emissions pale in comparison to other transportation sources in response to a 2008 advance notice of proposed rulemaking that describes sources of greenhouse gases, options for reducing emissions, and challenges involved in regulating them. The association told the EPA that imposing new requirements for GA would be difficult to justify because the GA industry is not a significant source of greenhouse gas emissions.
Previously, a 2007 Supreme Court decision had held that greenhouse gases are air pollutants covered by the Clean Air Act, and that the EPA must determine whether or not to regulate greenhouse gas emissions from new motor vehicles. The 2008 advance notice of proposed rulemaking was one response to that decision and several petitions asking the agency to regulate greenhouse gas emissions. In 2010, the EPA issued greenhouse gas regulations for light-duty vehicles and power plants, but has not regulated greenhouse gas emissions other transportation sources such as ships and aircraft.
Lower fuel and electricity consumption in the United States led to an overall 6.1-percent drop in greenhouse gas emissions in 2009 from the year before, the EPA said in its latest inventory. GA carbon dioxide emissions, from both jet fuel and avgas, decreased as well.
All of aviation, including commercial and military flying, accounts for only 8.15 percent of carbon dioxide emissions from transportation's use of fossil fuels. GA represents a fraction of that, at only 0.88percent of transportation's carbon dioxide emissions.