Some people who study climate change believe that addressing it later — when economic growth has made humanity wealthier — would be better than taking drastic measures immediately. Now, though, one of this group’s most influential members appears to have changed his mind. In the early 1990s, Yale’s William Nordhaus was among the first to examine the economics of reducing carbon emissions. Since then, he and colleagues have mixed climate physics with economic modeling to explore how various policies might play out both for global temperatures and growth. The approach attempts to weigh, in present-value terms, the costs of preventative measures against the future benefit of avoiding disaster. Nordhaus has mostly argued for a small carbon tax, aimed at achieving a modest reduction in emissions, followed by sharper reductions in the medium and long term. Too much mitigation now, he has suggested, would damage economic growth, making us less […]