WASHINGTON — After a scientific review ordered in 2007 by the U.S. Supreme Court, the U.S. Environmental Protection Agency (EPA) has issued a proposed finding that greenhouse gases contribute to air pollution that may endanger public health or welfare. The proposed finding, which now moves to a public comment period, identified six greenhouse gases that pose a potential threat.

The proposed endangerment finding states, “In both magnitude and probability, climate change is an enormous problem. The greenhouse gases that are responsible for it endanger public health and welfare within the meaning of the Clean Air Act.”

EPA’s proposed endangerment finding is based on scientific analysis of six gases — carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. According to the EPA, the science clearly shows that concentrations of these gases are at unprecedented levels as a result of human emissions, and these high levels are very likely the cause of the increase in average temperatures and other changes in our climate.

The proposed endangerment finding now enters the public comment period, which is the next step in the deliberative process EPA must undertake before issuing final findings. This proposed finding does not include any proposed regulations. Before taking any steps to reduce greenhouse gases, EPA must conduct its regulatory process and consider stakeholder input.

For more information, including instructions on how to submit written comments and details on upcoming public hearings, visit http://epa.gov/climatechange/endangerment.html.

Publication date: 04/27/2009