The Earth鈥檚 atmosphere is hotter than it was just a few decades ago, and scientists are starting to grapple with how hurricanes and storms have already changed in the warmer world 鈥� and how they might continue to change in the future.
The latest research paper to tackle the issue suggests that climate change may be why stronger hurricanes are forming 鈥漵ignificantly鈥� earlier in the season. It also finds, however, that the impact seems less apparent in the Atlantic Ocean basin, the breeding ground for hurricanes that threaten Florida and the rest of the United States coastline.
The study, , found a worldwide trend: Category 4 and 5 hurricanes are occurring about 15 days earlier across the planet than they were in the 1980s. In this case, 鈥渆arlier鈥� is defined as June through August, while the 鈥渓ate鈥� end of the season is considered September through November.
That鈥檚 a big deal, the authors said, because the earlier part of storm seasons around the world usually coincide with rainy season, increasing the chances for big floods.
Researchers also found that rapid intensification 鈥� the process where a storm gets significantly stronger over a short period of time 鈥� is now occurring about two weeks earlier in the season, said Fengfei Song, a co-author and researcher at the Ocean University of China in Qingdao.
鈥淭he seasonal advance of intense tropical cyclones made us wonder if the rapid intensification events may also experience a similar change, which was proved to be the case,鈥� he wrote in an email.
The paper didn鈥檛 find a similar pattern for storms of all strength, just the most powerful ones. And although researchers found evidence of this trend around the globe, there were differences in some basins.
The pattern was strongest in the western North Pacific. But the Atlantic basin, where all of the storms that hit the Caribbean, and U.S. East and Gulf coast originate, showed less evidence of the trend.
That didn鈥檛 surprise Bryan Norcross, Fox Weather鈥檚 hurricane specialist. While he agreed overall with the study鈥檚 findings, he said he鈥檚 skeptical of the conclusions drawn about the Atlantic basin.
鈥淭he factors that they鈥檙e talking about might have some contribution to storms developing a little sooner, but we have all these other things going on,鈥� he said. 鈥淭he Atlantic is a unique basin because it鈥檚 so small, so there鈥檚 always many factors that affect the season.鈥�
For one, Norcross said, the authors only reviewed storms from 1981 to 2017. During that period, the world dramatically cut down on air pollution, which made the world a safer and healthier place for many.
But, scientists found out years later, that air pollution clouded the skies above places like the Atlantic Ocean, cooling the water below and suppressing storm activity. Now, with less pollution in the air, the Atlantic is experiencing more storms than it did with dirtier air.
鈥淲e know the atmosphere over the Atlantic from 1981 to 1995 was different from what it is now, so comparing across that time period where half of that time period was in this suppressed situation, doesn鈥檛 work,鈥� he said.
The complexities of the Atlantic basin, and the many factors that weigh into how, where and whether a hurricane forms, make it tough for scientists to untangle the effects of climate change specifically.
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However, a growing body of research suggests that the warmer world is already changing hurricanes and hurricane season. Last summer, a team of researchers found climate change was warming sea surface temperatures and pushing the start of hurricane season two weeks earlier than the official start date on June 1.
Even before the study came out, the National Hurricane Center shifted its team of forecasters to begin daily operations in mid-May instead of June.
Other studies have also linked global warming to more storm surge, rainier hurricanes and more frequent rapid intensification, although research also suggests that climate change could produce fewer 鈥� but stronger 鈥� hurricanes in the future.
RELATED: What we know 鈥� and don鈥檛 鈥� about how climate change impacts hurricanes like Ian
This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative founded by the Miami Herald, the South Florida Sun Sentinel, The Palm Beach Post, the Orlando Sentinel, 港澳天下彩Public Media and the Tampa Bay Times.
