The U.S. Environmental Protection Agency (EPA) advanced plans to limit carbon emissions from aircraft, as it finalised a determination that greenhouse gas (GHG) emissions from certain types of aircraft engines contribute to the pollution that causes climate change and endangers Americans’ health and the environment.

However, the U.S. agency is not issuing emissions standards for aircraft engines in this action. But the final endangerment and contribution findings for aircraft engine GHG emissions are an important step that EPA must take prior to adopting domestic GHG engine standards.

The EPA said it anticipates that the International Civil Aviation Organization (ICAO) will formally adopt its environmental committee’s February 2016 agreement on international aircraft CO2 standards in March 2017.

The EPA said it anticipates moving forward on standards that would be at least as stringent as ICAO’s standards.

The EPA’s findings support the goals of U.S. President Barack Obama’s Climate Action Plan to reduce emissions from large sources of carbon pollution. U.S. aircraft emit roughly 12% of GHG emissions from the U.S. transportation sector and 29% of GHG emissions from all aircraft globally.

Under the Clean Air Act, the EPA consults with the Federal Aviation Administration as it develops aircraft engine emissions standards. By law, any standards the EPA sets must not cause a significant increase in noise or adversely affect safety.

The EPA’s findings are that carbon dioxide (CO2), methane, nitrous oxide, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), all contribute to GHG pollution and represent the largest driver of human-caused climate change. These particular GHGs come primarily from engines used on large commercial jets.

The EPA’s findings do not apply to small piston-engine planes (the type of plane often used for recreational purposes) or to military aircraft.

“Addressing pollution from aircraft is an important element of U.S. efforts to address climate change. Aircraft are the third largest contributor to GHG emissions in the U.S. transportation sector, and these emissions are expected to increase in the future,” said Janet McCabe, EPA’s acting assistant administrator for air and radiation.

“EPA has already set effective GHG standards for cars and trucks and any future aircraft engine standards will also provide important climate and public health benefits.”