PRESIDENT DONALD TRUMP doubts that man-made climate change is a thing. According to his administration it is a clear, present and future danger to the United States. That conclusion—unsurprising to anyone who has been paying attention to climate scientists—emerges from the Fourth National Climate Assessment, compiled by 13 federal agencies and released on November 23rd. If the White House had hoped to bury the 1,600-page tome, part of a four-yearly exercise which it is obliged to prepare and make public by a law from 1990, under turkey-laden tables, the absence of news over the Thanksgiving weekend promoted it to the front pages.
The findings made for grim reading. The report details how climate change is already affecting America—through more frequent floods and droughts—and what to expect from falling crop yields, the spread of disease-carrying bugs, fiercer hurricanes and much else besides. Sea levels, up by 16-21cm in the past 120 years, may rise by another metre over the next 80, threatening $1trn in coastal property. Rising temperatures could force Texans to work fewer hours (and pay 10-20% more for energy). Wildfires should cause less devastation by 2090 than they do today—but only because many forests most prone to them will have burned to a crisp. All told, unchecked greenhouse-gas emissions could lop a tenth off American GDP this century.
Some politicians are heeding the warnings. On November 27th a bipartisan group in the House of Representatives introduced a bill to tax emissions and redistribute the proceeds as a cheque to citizens, though this looks doomed so long as Mr Trump’s fellow Republican climate sceptics control the Senate. In any event, action by America would not be enough on its own to limit the damage. Curbing global warming requires a global effort. A UN report released this week estimates that national commitments made so far by the 197 signatories of the Paris climate agreement add up to barely a third of what is needed to keep warming below 2°C (3.6°F) relative to pre-industrial times. Even if this goal were met, climate change could shave $200-430bn a year off American output.
Asked about the gloomy economic forecasts, the president said that he does not believe them. They do warrant some caution. Projecting climate and growth decades from now is fraught with uncertainty; so is counting on other countries to act. Another president would read the report as a blueprint for adapting America to a warmer world. Mr Trump appears instead to treat it as a work of fiction.