Might not be as difficult as you describe.
https://en.wikipedia.org/wiki/National_Emergencies_Act
Emergency powers[edit]
Congress has delegated at least 136 distinct statutory emergency powers to the President upon the declaration of an emergency, with only 13 of these requiring a declaration from Congress.[15]
Emergency presidential powers are dramatic, and have ranged from suspending all laws regulating chemical and biological weapons, including the ban on human testing (50 U.S.C. § 1515, 1969); to suspending any Clean Air Act implementation plan or excess emissions penalty upon petition of a state governor (42 U.S.C. (f) § 7410 (f) 1977); to authorizing and constructing military construction projects (10 U.S.C. (a) § 2808 (a), 1982) using any existing defense appropriations for such military constructions ($10.4 billion in FY2018[16]); to drafting any retired Coast Guard officers (14 U.S.C. § 331, 1963) or enlisted members (14 U.S.C. § 359, 1949) into active duty.
Although the one mentioned about the "Clean Air Act" might interesting as it pertains to David's question about Climate Change. If a President can suspend a portion of an act of Congress surely a future President can reverse the previous use of Emergency Powers.