It remains to be seen just how much destruction Hurricane Florence will wreak when it makes landfall, likely as a Category 3 storm in North Carolina on Thursday. But we can already be 100 per cent sure that the damage will be worse than it would otherwise be because of global warming.
Over the past century, sea level in North Carolina has risen 30 centimetres as a result of climate change, of the Potsdam Institute for Climate Impact Research and colleagues. The rising waters are already 鈥� the barrier islands off the coast 鈥� and causing during normal high tides.
Highers seas mean higher storm surges wherever they occur. While 30 cm might not seem like much, in places it could determine whether the hurricane-driven surge overcomes flood defences and thus greatly increase the damage.
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The greatest threat posed by Hurricane Florence, though, is inland flooding caused by extreme rainfall, which will also be increased by climate change.
High temperatures
For starters, abnormally high sea surfaces temperatures in the area Florence is moving over mean it will pump far more water into the atmosphere, which will eventually fall as rain. This .
Water vapour is the fuel that drives hurricanes, so this is also why Florence has grown so large and powerful. Globally, rising sea surface temperatures are making .
In addition, Florence is forecast to slow to a crawl as it moves over land 鈥� like 鈥� and slow-moving storms dump far more rain in any one place than fast-moving ones. According to and therefore leading to higher rainfall.
Lastly, most hurricanes that follow the path of Florence usually veer north away from the East Coast. Florence 鈥� like Hurricane Sandy in 2012 鈥� has continued straight because of a 鈥渂locking high鈥� that has spun off from the jet stream, the strong winds that influence much of Earth鈥檚 weather.
Rapid warming in the Arctic is affecting the jet stream and making such blocking events more likely, says Rahmstorf. In other words, were it not for global warming Florence might not be making landfall at all.
鈥淚t probably has made it more likely that the storm goes into the coast,鈥� Rahmstorf says. 鈥淏ut this is speculation because we can鈥檛 rerun the situation without global warming.鈥�
