Description

 In this action, the Administrator is proposing to determine that greenhouse gas concentrations in the atmosphere endanger the public health and welfare of current and future generations within the meaning of section 231(a) of the Clean Air Act. She proposes to make this finding specifically with respect to the same six well-mixed greenhouse gases (GHGs) – carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride – that together were defined as the air pollution in the 2009 Endangerment Finding under section 202(a) of the Clean Air Act and that together constitute the primary cause of the climate change problem. The Administrator is also proposing to find that greenhouse gas emissions from certain classes of engines used in aircraft are contributing to air pollution - the mix of greenhouse gases in the atmosphere - that endangers public health and welfare under section 231(a) of the Clean Air Act. Concurrent with these proposed findings, the EPA is issuing an Advance Notice of Proposed Rulemaking to provide an overview of and seek input on a variety of issues related to setting an international CO2 standard for aircraft at the International Civil Aviation Organization (ICAO), ICAO's progress in establishing global aircraft standards that achieve meaningful reductions in CO2 emissions, and (provided the EPA promulgates final endangerment and cause and contribute findings for aircraft engine GHG emissions) the potential use of section 231 of the Clean Air Act to adopt and implement corresponding aircraft engine GHG emission standards domestically, ensuring transparency and the opportunity for public comment.