President Donald Trump’s efforts to boost fossil fuel extraction face a courtroom hurdle of his own making. His March 28 executive order “promoting energy independence and economic growth” rescinded the Obama administration’s calculation of the “social cost of carbon” — a metric that had been central to the process of crafting and justifying government rules addressing human-driven climate change. All government regulations are subject to cost/benefit analysis. The “social cost of carbon” was developed in large part to compare long-term costs from coastal flooding and other impacts of emissions of climate-warming carbon dioxide with upfront costs to the economy from curbing the burning of fossil fuels, the main source of such emissions. The value at the end of the Obama presidency was set at roughly $40 for each ton of carbon dioxide, the main greenhouse gas emitted by human activities, or equivalent amounts of other gases such as methane.