Atlantic hurricanes take longer to weaken after touching down than they did 50 years ago, thanks to climate change. For the past 50 years, the warmer ocean waters have fed storms, giving them more staying power after roaring on land, scientists report in the November 12 issue of the journal Nature. That could potentially extend the destructive power of storms further inland, the researchers say.
When ocean waters warm, tropical cyclones – called hurricanes in the Atlantic Ocean – are likely to gain intensity, according to studies (SN: 9/28/18). They can also retain more moisture, causing seemingly incessant rainfall (SN: 13/09/18). And they can move more slowly, allowing more time to shed that rain on coastal communities. All this increases the potential danger on land (SN: 6/6/18).
Once a storm hits the earth, its energy begins to dissipate. But that relief is coming later than before, according to physicists Lin Li and Pinaki Chakraborty, both of the Okinawa Institute of Science and Technology in Japan.
Li and Chakraborty analyzed the intensity of historic Atlantic hurricanes during the first 24 hours after the landing. In 1967, the intensity of a typical storm dropped by 76 percent on the first day after landing. But for 2018, the storms were only 52 percent less intense after 24 hours. That trend, the researchers say, is in line with rising sea surface temperatures in the Gulf of Mexico and the western Caribbean Sea.
This is because the strong winds of cyclones feed on moisture and heat collected from warm waters and warmer air can also hold more moisture. Thus, as the oceans heat up, they not only add more moisture, which makes hurricanes rainier, but they also add more heat, like a portable engine that the storm uses to feed its fury a little more.