Rising ocean temperatures are driving hurricanes to carry more moisture, allowing them to stay stronger for longer once they’ve made landfall and reach communities farther inland, according to new research published in the journal Nature. Today’s hurricanes, the study found, weaken almost twice as slowly once over land as they did 50 years ago.
The new research comes amid a devastating and record-breaking Atlantic hurricane season, with 31 named storms so far this year, more than any other in 170 years of record-keeping. Twelve storms have made landfall in the United States in 2020, impacting both the Gulf and East coasts, The Washington Post reported. Louisiana alone has been hit by five hurricanes. Hurricane Iota made landfall in Nicaragua this week as a Category 4, impacting portions of Central America still recovering from another Category 4 storm, Hurricane Eta, which hit the region just two weeks ago.
“The implications [of these new findings] are very important, especially when considering policies that are put in place to cope with global warming,” Pinaki Chakraborty, lead author of the new study and a scientist at the Okinawa Institute of Science and Technology Graduate University in Japan, said in a statement. “We know that coastal areas need to ready themselves for more intense hurricanes, but inland communities, who may not have the know-how or infrastructure to cope with such intense winds or heavy rainfall, also need to be prepared.”
While previous research has shown a connection between rising ocean temperatures and the increasing severity of hurricanes over the open ocean, the new study is the first to look at how climate change is impacting hurricanes that make landfall.
The scientists found a direct link between the time it takes for a hurricane to weaken once over land and sea surface temperatures. It also found that of storms that hit land in the same category, those that formed over warmer ocean waters took longer to break apart. That’s because they hold more moisture, so can last longer after being cut off from a hurricane’s energy source — the ocean. Storms that form over warm water are also wetter, the study found, unleashing high volumes of rainfall — such as happened with Hurricane Harvey, which dumped more than 40 inches of rain over a four-day period in parts of Texas and Louisiana in 2017.
“Overall, the implications of this work are stark,” Chakraborty said. “If we don’t curb global warming, landfalling hurricanes will continue to weaken more slowly. Their destruction will no longer be confined to coastal areas, causing higher levels of economic damage and costing more lives.”