; (B) methane; (C) nitrous oxide; (D) hydrofluorocarbons; (E) perfluorocarbons; (F) sulfur hexafluoride; or (G) any other anthropogenically emitted gas that is determined by the Administrator, after notice and comment, to contribute to global warming to a non-negligible degree. (2) United States net greenhouse gas emissions The term United States net greenhouse gas emissions means net greenhouse gas emissions, as calculated by the Administrator on an annual basis and reported to the United Nations Framework Convention on Climate Change Secretariat.