Our comment primarily concerns the DOE’s use of the social cost of carbon (SCC) in the cost/​benefit analysis of the Energy Conservation Program: Energy Conservation Standards for Walk-In Coolers and Freezers proposed rulemaking. The determination of the SCC is so discordant with the best scientific literature on the equilibrium climate sensitivity and the fertilization effect of carbon dioxide — two critically important parameters for establishing the net externality of carbon dioxide emissions — that, until this situation can be rectified, it should be barred from use in this and all other federal rulemaking.