The EPA has quietly proposed new, dramatically higher, estimates for the societal costs incurred by greenhouse gas pollution. The proposed EPA calculations offer a range of potential estimates for the social cost of CO2 pollution ranging from 2.4- to 6.7 times higher than the current interim estimate of $51 per metric ton. The newly-proposed calculations do not dramatically increase the social cost of methane but do substantially increase the social cost of nitrous oxide, though not by as much as CO2.

The calculations were first made public when President Biden announced EPA’s proposed supplemental methane safeguards earlier this month at COP27, though they were not used in that rule but were instead included in a 137-page supplemental document dated September 2022. The proposed EPA social cost calculations are separate from the Interagency Working Group calculation expected in April, but an EPA spokesperson told E&E the IWG could incorporate EPA’s draft technical report into its work.

Republican attorneys general have tried and so-far failed to use litigation to block the Biden administration’s use of social cost calculations. A recent study in Nature also determined the interim social cost of CO2 is substantially lower than the true cost borne by society. (E&E $, Politico Pro $; Proposed calculations on page 9 of EPA .pdf)