The editorial board YESTERDAY

Seventeen of California’s 20 worst recorded fires have struck since the start of this century — five of those in the past 18 months. The most recent, which destroyed the poignantly named town of Paradise in Northern California, has taken at least 76 lives so far. More than 1,000 people in the area are still missing. The signs are that the breathtaking scale and spread of the so-called Camp Fire is a harbinger of worse to come. Similar rises in frequency and severity are true of coastal flooding in Florida, the hurricane season in America’s flood plains and storm surges across its east coast. The same can be said of droughts in Europe and Australia and killer heatwaves in the Middle East.

The question is what to do about it. The most urgent step is to acknowledge the growing impact of global warming. The recent report by the International Panel on Climate Change says that the world must cut carbon emissions by 45 percent by 2030 to prevent global warming from reaching 1.5C over the coming decades. In effect, we must cut emissions by half within a decade. Even assuming such a drastic action, temperatures would still rise by significantly more than the increase we have already witnessed.

The scope for so-called mitigation remains huge. It does not help when Donald Trump, the US president, who leads the world’s second-largest emitter after China, repeatedly denies that man-made climate change has anything to do with such disasters. Mr Trump has blamed California’s latest fires on poor forest management. He repeated those claims during a visit to the affected area this weekend, where he declared the devastation “sad to see”. In fact, most fires are taking place in scrublands that had already experienced fires in the last few years, which makes the president’s accusations doubly mistaken: forests have little to do with it; nor does failure to clear undergrowth.

The chief culprits are California’s recurring droughts and average temperature rises. More than 600 missing in California blazes Droughts increase the combustibility of trees and the speed with which they burn. The same is true of what we once called “100-year floods” — meaning they were of a severity to be expected only once in a century. Houston has suffered three of these in the past three years. There is no scientific dispute that global warming is behind the growing intensity of such disasters, even if it is hard to pinpoint the precise amount. In spite of Mr Trump, the US is to some extent becoming part of the solution. America’s carbon output has fallen by almost a fifth in the last decade because of a switch from coal to gas and better energy efficiency. Many US cities and states continue to tighten emission standards.

But more effective global action is stymied by Mr. Trump’s withdrawal from the Paris agreement on climate change, which is the only game in town. His move has set a terrible precedent. Brazil’s new president Jair Bolsonaro dubbed the “Trump of the tropics”, has indicated he could pull out of the Paris accord with potentially disastrous results. Mr. Bolsonaro wants to scrap limits on the deforestation of the Amazon, the planet’s largest single absorber of carbon other than the oceans. The second response is adaptation.

The US government continues to provide flood insurance for people who build homes in vulnerable coastal areas. Some homes have been rebuilt multiple times. That makes no sense. The world must assume the future will be at least as severe as the recent past. That means removing people from harm’s way. Here, at least, there are obvious things Washington can do to set a better example.