In this week’s episode of the People Places Planet podcast, Harvard Law Professor Cass Sunstein engages in an illuminating discussion with Vanderbilt Professor W. Kip Viscusi about the social cost of carbon—a hotly debated and frequently litigated number—that is used to quantify the harm caused by one ton of carbon emissions. They are joined by ELI Senior Attorney Linda K. Breggin and Vanderbilt Law student Kyle Blasinsky. This important number is used in developing a range of regulations and soon will be used in federal budgeting and purchasing decisions, as well as National Environmental Policy Act reviews, under a new Biden Executive Order. Professor Sunstein, an Obama Administration Office of Information and Regulatory Affairs Administrator, discusses the key judgement calls that must be made in developing the social cost of carbon, such as the appropriate discount rate and approaches to incorporating equity, and offers his views on developing a number that can withstand arbitrariness review in any renewed effort to challenge the number in court.