Incremental CH 4 and N 2 O mitigation benefits consistent with the US Government's SC-CO 2 estimates

Benefit-cost analysis can serve as an informative input into the policy-making process, but only to the degree it characterizes the major impacts of the regulation under consideration. Recently, the US, amongst other nations, has begun to use estimates of the social cost of CO 2 (SC-CO 2 ) to develop analyses that more fully capture the climate change impacts of GHG abatement. The SC-CO 2 represents the aggregate willingness to pay to avoid the damages associated with an additional tonne of CO 2 emissions. In comparison, the social costs of non-CO 2 GHGs have received little attention from researchers and policy analysts, despite their non-negligible climate impact. This article addresses this issue by developing a set of social cost estimates for two highly prevalent non-CO 2 GHGs, methane and nitrous oxide. By extending existing integrated assessment models, it is possible to develop a set of social cost estimates for these gases that are consistent with the SC-CO 2 estimates currently in use by the US federal government. Policy relevance Within the benefit-cost analyses that inform the design of major regulations, all Federal agencies within the US Government (USG) use a set of agreed upon SC-CO 2 estimates to value the impact of CO 2 emissions changes. However, the value of changes in non-CO 2 GHG emissions has not been included in USG policy analysis to date. This article addresses that omission by developing a set of social cost estimates for two highly prevalent non-CO 2 GHGs, methane and nitrous oxide. These new estimates are designed to be compatible with the USG SC-CO 2 estimates currently in use and may therefore be directly applied to value emissions changes for these non-CO 2 gases within the benefit-cost analyses used to evaluate future policies.