Irma and Harvey lay the costs of climate change denial at Trump’s door
Climate change cannot be blamed for the hurricane count in any single season, nor for the occurrence of any single storm, but there are three ways in which it is making the consequences worse.
First, although the intensity of a hurricane depends on many factors, warmer seawater tends to promote stronger storms. Average sea surface temperatures have been rising, and some parts of the North Atlantic and Gulf of Mexico are warmer than average at the moment, which is a key reason why both Harvey and Irma became so strong so quickly.
Second, a warmer atmosphere can hold more water vapour, which can result in heavier rainfall. That is true not only for hurricanes but also for weaker storms across the world. Even relatively mild tropical storms can cause great damage by dropping huge volumes of rain over one area.
Third, apart from strong winds and heavy rainfall, hurricanes cause damage through storm surges as their winds push seawater ahead of them. Storm surges can inundate extensive low-lying coastal areas, sweeping away everything in their path. Sea levels have been gradually rising globally, making storm surges bigger and deadlier.
— NASA (@NASA) September 8, 2017