This bill aims to significantly alter how federal agencies conduct environmental and regulatory analyses. Its central provision prohibits any federal agency from considering the social cost of carbon , social cost of methane , social cost of nitrous oxide , or the social cost of any other greenhouse gas in their decision-making processes. Specifically, these social costs cannot be used in cost-benefit or cost-effectiveness analyses required by law or executive orders, during rulemaking, when issuing guidance, or as a justification for any agency action. The bill defines these social costs by referencing various technical support documents from interagency working groups and the Environmental Protection Agency, as well as any other estimates of monetized damages from incremental greenhouse gas emissions. Furthermore, the legislation mandates that in permitting and regulatory processes, federal agencies may only consider environmental factors explicitly required by an Act of Congress, prohibiting the use of any other environmental considerations. Agencies must also employ the most robust methodology of assessment available and avoid arbitrary or ideologically motivated approaches when evaluating environmental impacts. Finally, the bill requires federal agencies to ensure that any estimates used to assess the value of changes in greenhouse gas emissions, including considerations of domestic versus international effects and discount rates, are consistent with Office of Management and Budget Circular A-4 from September 2003. Agencies are also directed to initiate processes to modify existing rules, regulations, policies, or actions to achieve this consistency. Within 120 days of enactment, each federal agency must report to Congress on their past use of these social costs since January 2009.