The Obama administration has been fighting climate change with a rogue wave of regulations whose legality comes from a very small base: The Social Cost of Carbon.
The purpose of the “social cost of carbon” (SCC) estimates presented here is to allow agencies to incorporate the social benefits of reducing carbon dioxide (CO2) emissions into cost-benefit analyses of regulatory actions that impact cumulative global emissions. The SCC is an estimate of the monetized damages associated with an incremental increase in carbon emissions in a given year. It is intended to include (but is not limited to) changes in net agricultural productivity, human health, property damages from increased flood risk, and the value of ecosystem services due to climate change. From the Technical Support Document: -Technical Update of the Social Cost of Carbon for Regulatory Impact Analysis -Under Executive Order 12866
A recent Bloomberg article informs on how the SCC notion was invented, its importance and how it might change under the Trump administration.
How Climate Rules Might Fade Away; Obama used an arcane number to craft his regulations. Trump could use it to undo them. (here)
In February 2009, a month after Barack Obama took office, two academics sat across from each other in the White House mess hall. Over a club sandwich, Michael Greenstone, a White House economist, and Cass Sunstein, Obama’s top regulatory officer, decided that the executive branch needed to figure out how to estimate the economic damage from climate change. With the recession in full swing, they were rightly skeptical about the chances that Congress would pass a nationwide cap-and-trade bill. Greenstone and Sunstein knew they needed a Plan B: a way to regulate carbon emissions without going through Congress.
Over the next year, a team of economists, scientists, and lawyers from across the federal government convened to come up with a dollar amount for the economic cost of carbon emissions. Whatever value they hit upon would be used to determine the scope of regulations aimed at reducing the damage from climate change. The bigger the estimate, the more costly the rules meant to address it could be. After a year of modeling different scenarios, the team came up with a central estimate of $21 per metric ton, which is to say that by their calculations, every ton of carbon emitted into the atmosphere imposed $21 of economic cost. It has since been raised to around $40 a ton.
Trump can’t undo the SCC by fiat. There is established case law requiring the government to account for the impact of carbon, and if he just repealed it, environmentalists would almost certainly sue.
There are other ways for Trump to undercut the SCC. By tweaking some of the assumptions and calculations that are baked into its model, the Trump administration could pretty much render it irrelevant, or even skew it to the point that carbon emissions come out as a benefit instead of a cost.
The SCC models rely on a “discount rate” to state the harm from global warming in today’s dollars. The higher the discount rate, the lower the estimate of harm. That’s because the costs incurred by burning carbon lie mostly in the distant future, while the benefits (heat, electricity, etc.) are enjoyed today. A high discount rate shrinks the estimates of future costs but doesn’t affect present-day benefits. The team put together by Greenstone and Sunstein used a discount rate of 3 percent to come up with its central estimate of $21 a ton for damage inflicted by carbon. But changing that discount just slightly produces big swings in the overall cost of carbon, turning a number that’s pushing broad changes in everything from appliances to coal leasing decisions into one that would have little or no impact on policy.
According to a 2013 government update on the SCC, by applying a discount rate of 5 percent, the cost of carbon in 2020 comes out to $12 a ton; using a 2.5 percent rate, it’s $65. A 7 percent discount rate, which has been used by the EPA for other regulatory analysis, could actually lead to a negative carbon cost, which would seem to imply that carbon emissions are beneficial. “Once you start to dig into how the numbers are constructed, I cannot fathom how anyone could think it has any basis in reality,” says Daniel Simmons, vice president for policy at the American Energy Alliance and a member of the Trump transition team focusing on the Energy Department.
David Kreutzer, a senior research fellow in energy economics and climate change at Heritage and a member of Trump’s EPA transition team, laid out one of the primary arguments against the SCC. “Believe it or not, these models look out to the year 2300. That’s like effectively asking, ‘If you turn your light switch on today, how much damage will that do in 2300?’ That’s way beyond when any macroeconomic model can be trusted.”
Another issue for those who question the Obama administration’s SCC: It estimates the global costs and benefits of carbon emissions, rather than just focusing on the impact to the U.S. Critics argue that this pushes the cost of carbon much higher and that the calculation should instead be limited to the U.S.; that would lower the cost by more than 70 percent, says the CEI’s Mario Lewis.
Still, by narrowing the calculation to the U.S., Trump could certainly produce a lower cost of carbon. Asked in an e-mail whether the new administration would raise the discount rate or narrow the scope of the SCC to the U.S., one person shaping Trump energy and environmental policy replied, “What prevents us from doing both?”