Is the Atlantic hurricane season cranking up earlier? Study says yes, thanks to climate change

• The earlier onset is likely linked to climate-change-driven warming in the western Atlantic Ocean in spring.
• Traditionally, the start of the hurricane season is June 1.
• “Preseason” storms formed in May each year from 2015 to 2021, according to NOAA.

Although this season has been rather quiet so far, a study released Tuesday shows that the first storms of the Atlantic hurricane season have been firing up about five days earlier per decade since 1979.

Traditionally, the start of the hurricane season is June 1.  

The study also found that the first named storm to make U.S. landfall has been trending earlier, by about two days per decade since 1900.

This trend toward earlier onset is likely linked to climate-change-driven warming in the western Atlantic Ocean in spring, the study said, which has also shown an increasing trend during the same period. 

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Shifts unlikely just ‘chance’

“These shifts are unlikely to have been caused by chance or differences in observing technology alone,” study lead author Ryan Truchelut, president of private forecasting firm Weather Tiger, told USA TODAY. “These changes are taking place because of a more favorable environment for tropical cyclone formation in the western Atlantic, Gulf of Mexico and western Caribbean in the late spring.”

Tropical cyclones include hurricanes and tropical storms.

“The environmental changes are almost exclusively driven by warming ocean temperatures in this region, and not other environmental changes like shear or humidity,” he said.

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Season peaks in August, September, October

An average Atlantic season spawns seven hurricanes and peaks in August, September and October, according to the National Oceanic and Atmospheric Administration. The season officially begins June 1 and runs through Nov. 30, parameters that were first established in 1965.

“Preseason” storms formed in May each year from 2015 to 2021, according to NOAA. Although the majority of these recent May storms have been rather benign, some have not: “At least 20 deaths have occurred from late May storms since 2012, with about $200 million in total damage, and one of these systems was a 60-knot (70 mph) tropical storm at landfall,” according to the World Meteorological Organization.

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This trend could soon change the current definition of the North Atlantic hurricane season, and a NOAA panel is currently weighing whether to adjust the current season to start earlier, Truchelut told ABC News.

What’s the connection to climate change?

As for a connection to global warming, Truchelut cited the Intergovernmental Panel on Climate Change, which has said it’s “very likely” that warming sea-surface temperatures in the tropical oceans are driven by human-caused climate change.