It’s a suite of monetary estimates that quantify the damage done by a metric ton of greenhouse gases emitted. Specifically, it contains per-ton damage estimates for carbon dioxide, methane, and nitrous oxide–three of the most common greenhouse gases. These estimates are collectively called the “social cost of greenhouse gases.”

The social cost of greenhouse gases is often referred to as the social cost of carbon (or SCC), especially historically. In fact, the social cost of greenhouse gases actually refers to a suite of values that includes separate damage estimates for carbon dioxide, methane, and nitrous oxide. The damage estimate for carbon dioxide is known as the “social cost of carbon.”

There are numerous advantages to using the social cost of greenhouse gases in policy analysis. First, the social cost of greenhouse gases captures many different climate impacts in a single metric. Second, the unit of that metric—dollars—facilitates simple comparison to other monetized effects, such as a policy’s compliance cost. Third, the metric provides policymakers aiming to price greenhouse gases emissions (through emissions fees or royalties, in procurement protocols, or elsewhere) with a specific and scientific price.

Many economic experts have developed values for the social cost of greenhouse gases. Since the George W. Bush administration, the federal government has endorsed specific values based on these independent estimates. The most recent and robust available federal metrics were published in 2023 by the Environmental Protection Agency (EPA). EPA places a central estimate of $210 per metric ton of carbon dioxide emitted in 2024 (in 2020$), with a range from $130 to $360. For the full tables, see here.