Union of Concerned Scientists Supports Tripling Social Cost of Carbon in New EPA Estimate

The Union of Concerned Scientists (UCS) sent a letter on February 13, signed by almost 400 experts including climate scientists and economists, supporting the U.S. Environmental Protection Agency’s (EPA’s) draft issuance to more than triple the so-called social cost of carbon emissions.

The social cost of carbon is a dollar figure representing the approximate economic damages of emitting one metric ton of carbon dioxide. The cost takes into account four components — socioeconomics and emissions, climate, damages, and discounting — described in detail in the EPA draft proposal, Report on the Social Cost of Greenhouse Gases: Estimates Incorporating Recent Scientific Advances. The EPA estimate relies on information from the National Academies of Sciences, Engineering, and Medicine (NAS) and other independent researchers. 

‘True Cost’

“What’s new for the EPA is the central estimate that is cost,” Brenda Ekwurzel, UCS senior climate scientist and director of climate science, told EcoWatch. “We have much better understanding of the true cost of climate change, based on, unfortunately, the damages that are happening. Leading economics say the former rate was so out of touch.” 

Previously, the dollar figure had been $51/ton. With this new proposal, that figure almost triples to $190/ton, reflecting the current science. 

“It brings it to the fore for the American public, the true cost for every emission of a heat-trapping gas for the United States and the world,” Ekwurzel said. 

As the historical leading emitter of fossil fuel emissions, it is vital that the EPA continues to study their figures, as it is required to do an economic analysis of any regulation they have on the books periodically. The letter from the 400 concludes with: 

We commend the EPA for making important updates to the SC-GHGs and look forward to seeing them quickly finalized and used by federal agencies and others. Such efforts are critical to ensuring our nation’s policies and investments in climate solutions are appropriately robust and responsive to the scale and urgency of the actions needed to limit the worst impacts of climate change.

“As a scientist who has signed this letter and joining many other scientists and experts who understand the social cost of carbon and what it means, we believe the EPA is heading in the right direction with this new draft proposal to increase the rate,” Ekwurzel told EcoWatch. 

The impact of this increased figure might be felt at the legislative level. 

“When you have this one number, any regulation that deals with greenhouse gases, such as trying to honor the Paris agreement, the EPA can send information to Congress and the public to say, how much do we save from public health outcomes that are adverse – such as major extreme damages from extreme event, sea level rise, extreme heat, loss of lives of outdoor workers, lost labor hours,” Ekwurzel explained.

Still, even in the draft EPA proposal, the EPA acknowledges that the calculated figure of $190/metric ton might not be high enough. As the report emphasizes: 

The modeling implemented in this report reflects conservative methodological choices, and, given both these choices and the numerous categories of damages that are not currently quantified and other model limitations, the resulting SC-GHG estimates likely underestimate the marginal damages from GHG pollution.