How Do We Define the Cost to Society of Climate Pollution? By Elizabeth Shogren, High Country News, 1/27/16. “In a 2007 [U.S. Court of Appeals] ruling on a dispute concerning fuel economy standards for cars, a judge sent a clear message to federal agencies. They could no longer continue business as usual and fail to account for climate change when assessing the costs and benefits of regulations… Judge Betty B. Fletcher’s ruling challenged government officials to come up with a dollar amount that represents how much a ton of carbon pollution will ‘cost’ society over the long run. Economists refer to this as the social cost of carbon. The concept is still evolving and will only become more important to understand as governments grapple with how to address climate change in the most effective and least costly manner…

“In early 2009 White House officials decided… to develop a unified way for agencies to estimate the social cost of carbon… The interagency group turned to academic researchers who had been studying the economics of climate change.. The government opted to utilize three widely-used models, taking the average of the three to derive the federal government’s official estimate. First, the models estimate how a metric ton of carbon pollution will impact concentrations of greenhouse gases in the atmosphere. Second, the models estimate how those concentrations will affect temperature on Earth. Third, they analyze how increases in temperature will translate into a range of impacts such as the loss of usable dry land because of sea level rise; stresses to agriculture from droughts; and increased need for air conditioning… the interagency working group asked advice from the National Academy of Sciences, Engineering and Medicine, which appointed a group of engineers, climate scientists and economists to review the government’s estimates and consider ways to update the methodology. Its first report, in January 2016, did not recommend any major short-term changes but suggested ways to better communicate uncertainties. A more comprehensive and final report is expected in 2017.”