This past Saturday, I joined hundreds of thousands of people, on seven continents, in marching for science. In one sense, the march was (to quote our newest Supreme Court Justice) “disheartening and demoralizing.” The fact that we need to march in support of evidence-based facts—and with a climate-change-denying, anti-vaxxer, EPA-and-NIH-opponent president in the White House, we absolutely do—is worrisome. As Neil deGrasse Tyson put it on Twitter: “Show me a Nation with a science-hostile government, and I'll show you a society with failing health, wealth, and security.”
But in another sense, the March for Science provided a shot of inspiration. The sustained civic engagement since Trump’s inauguration—from the Women’s March to the Tax March to the March for Science—shows little sign of abating. People are staying invested, and staying involved. What’s more, the March for Science was a particularly fun one. The nerdy science signs were amazing. And (at least from my own experience, and the anecdotal experience of others) there were a ton of young people present—from toddlers to teenagers to college students.
It makes sense that young people would be invested in the March for Science, because the Trump Administration’s war on science is, at bottom, an assault on their future. Young people will shoulder the bulk of future costs associated with the Trump Administration’s rollback of climate control policies. The Trump budget, moreover, proposes deep cuts to an array of publicly funded research—on topics ranging from cancer treatment to infectious diseases to alternative energy to coastal ecosystems. That research, if completed, could one day save lives, save money, and make the world a better place to live. Trump’s proposal to starve research darkens otherwise bright outlooks.
All of these points were reflected (often in clever fashion) by the youthful marchers on Saturday.
Yet there is also another, subtler way the Trump Administration threatens to impose future costs on young people: the way in which it calculates costs themselves. Numerous laws require administrative agencies to conduct a cost-benefit analysis prior to deciding whether, and how, to regulate. Indeed, after the Supreme Court’s 2015 decision in Michigan v. EPA—which emphasized that “reasonable regulation ordinarily requires” an analysis of costs and benefits—such cost-benefit analyses appear to be presumptively required for regulating agencies.
Yet even after Michigan, agencies are still granted a great deal of discretion as to how costs and benefits are calculated. Seizing on that discretion, the Trump Administration has already begun to come up with new formulas which will downplay the costs imposed by pollution. For example: President Trump has instructed EPA to revise a metric known as the “social cost of carbon.” That crucial metric places a monetary figure on the costs imposed by greenhouse-gas emissions. The Trump EPA’s revision, however, is almost certain to artificially minimize the costs imposed by carbon emissions—thereby justifying the Trump Administration’s planned rollback of greenhouse-gas regulation.
And the “social cost of carbon” revisions are unlikely to be the only cost-benefit shenanigans in which the Trump Administration engages. The Trump Administration may next take aim at agencies’ historic practice of considering “co-benefits”—that is, incidental benefits that result from a rule geared towards alleviating a different harm. The quintessential example of “co-benefits” is an Obama-era rule geared towards reducing mercury emissions from power plants. Reducing mercury emissions, the Obama EPA concluded, would also have the “co-benefit” of reducing particulate matter emissions. And reduction of those particulate-matter emissions would save 11,000 lives per year. Thus, when calculating the costs and benefits of mercury regulations, the Obama EPA took the particulate-matter “co-benefits” into account. And logically so. After all, the point of a cost-benefit analysis is to understand a regulation’s real-world impact. Why would 11,000 potential deaths per yearbe ignored?
Nevertheless, the practice of considering co-benefits has been challenged, in connection with the mercury regulation, in the U.S. Court of Appeals for the D.C. Circuit. That court has not yet ruled. But ominously, one of the parties challenging consideration of co-benefits was then-Oklahoma attorney general, and current EPA Administrator, Scott Pruitt. It is not farfetched to think that the co-benefits practice may be next in the Trump Administration’s crosshairs.
All of these potential changes to the cost-benefit structure are wonky and subtle. None is likely to grab headlines. Indeed, despite the youthful, wonderfully nerdy energy at the March for Science this weekend, I didn’t see a single sign urging (for example) Donald Trump to “keep his tiny hands off our regulatory cost-benefit analysis.”
But the wonkiness of cost-benefit analysis does not make any less important. A subtle change in the way we calculate pollution costs could exacerbate those costs. Perhaps the next march should be a March for Regulatory Logic.
 Why, you might ask, doesn’t the Trump Administration just eliminate the social-cost-of-carbon metric? Because it legally cannot. A 2007 ruling by the United States Court of Appeals for the Ninth Circuit expressly (and correctly) rejected the Bush Administration’s attempts to calculate the costs of carbon emissions as zero.