; and (2) not less than every 5 years thereafter— (A) review such regulations, taking into account the reports under section 302; and (B) revise such regulation as necessary to implement such emission reduction targets. (b) Rulemaking on recommendations of national academies If any report under section 302 includes a recommendation under section 302(2)(B) for regulatory action by a Federal department or agency, and such regulatory action is within the authority of such department or agency (under law other than this subsection), the head of such department or agency shall, not later than 2 years after the submission of such report, finalize a rulemaking— (1) to carry out such regulatory action; or (2) to explain the reasons for declining to act. (c) Additional regulations The regulations promulgated under subsection (a) may include additional regulations to reduce emissions of United States greenhouse gases from any source or sector. Any such regulations that address sources whose greenhouse gas emissions are regulated pursuant to section 111(d) of the Clean Air Act ( 42 U.S.C. 7411(d) ) shall account for the compliance schedule promulgated pursuant to such section 111(d). Regulations under this section may include market-based measures, emissions performance standards, efficiency performance standards, best management practices, technology-based requirements, and other forms of requirements. (d) Relation to other authority The authority vested by this title is in addition to the authority to regulate greenhouse gas emissions pursuant to other provisions of law. 304. Savings clause Nothing in this title shall be interpreted to preempt or limit State actions to address climate change. 305. Definitions In this title: (1) Greenhouse gas The term greenhouse gas means— (A) carbon dioxide; (B) methane; (C) nitrous oxide; (D) hydrofluorocarbons; (E) perfluorocarbons; (F) sulfur hexafluoride