The New Climate Math on Hurricanes
W hen Hurricane Helene slammed into Florida’s shoulder earlier this fall, it brought the largest storm surge ever recorded in the area. The storm had formed just four days earlier as a tropical depression, but when it made landfall, it was already a Category 4 storm, lashing the Tampa Bay area with savage winds and rain, flooding and laying waste to whole communities. Two weeks later, Hurricane Milton deepened the tragedy when it hit the Florida peninsula, unleashing catastrophic flooding and 100-mile-per-hour gusts, killing multiple people, and breaking meteorological records.
Climate scientists have been warning for years that climate change will—and already is—supercharging storms broadly speaking. But connecting specific rates of warming to the ferocity of specific storms was out of reach. Now a team of scientists has developed a model that, for the first time, allows them to calculate how warming ocean temperatures have contributed directly to wind speeds in individual hurricanes. Using this model, they were able to determine, for instance, that climate change bumped Hurricane Rafael earlier this month up two whole categories (from 1 to 3) and pushed another two hurricanes this year into category 5, the highest category, in which wind speeds exceed 157 mph.
“It’s really the evolution of our science on sea surface temperature attribution that has allowed this work to take place,” Daniel Gilford, an atmospheric scientist with the independent nonprofit research outfit Climate Central and the lead author of the study said in a press briefing. Gilford and his colleagues found that due to higher sea surface temperatures, maximum wind speeds were 19 mph higher on average in 84 percent of the hurricanes in the north Atlantic that occurred between 2019 and 2023, and, according to an additional analysis, most all hurricanes thus far in 2024 as well—enough to elevate them an entire category on the Saffir-Simpson scale. Moreover, global warming caused wind speeds in three of the hurricanes to course roughly 34 mph faster than they would have otherwise.
