Climate change has increased the wind speed of storms by an average of 29 km/h

As if the Hurricanes needed another shot.

Human-caused climate change is increasing the intensity of Atlantic hurricanes by an entire category on the Saffir-Simpson Hurricane Wind Scale, which rates hurricanes based on their maximum sustained wind speed, researchers report Nov. 20 in two new studies.

From 2019 to 2023, climate change increased hurricane peak wind speeds by an average of about 29 kilometers per hour (18 miles per hour), or about the width of a Saffir-Simpson category, researchers report in Environmental Research: Climate. Climate change similarly increased the intensity of all hurricanes in 2024 by an average of about 18 mph (29 km/h), escalating the risk of wind damage, an accompanying analysis from Climate Central shows.

As climate change warms the equator, nature seeks to redistribute that heat to other parts of the world, says Daniel Gilford of Climate Central, a climate scientist based in the Orlando, Fla. area. “The way our atmosphere does it is with hurricanes .”

Gilford and colleagues developed a new attribution framework to rapidly measure the impact of climate change on the wind speed of a recent storm. Drawing on historical sea surface temperature records spanning over a century and computer simulations of Earth’s climate, the researchers generated simulations of the modern North Atlantic Ocean in a world without climate change. They then calculated what the wind speeds of recent hurricanes would be over these cooler Atlantic Oceans, and finally compared the hypothetical speeds to observed hurricane wind speeds.

Of the 38 hurricanes that occurred from 2019 to 2023, 30 reached approximately one category higher in intensity due to climate change. Three – Lorenzo in 2019, Ian in 2022 and Lee in 2023 – became Category 5 hurricanes.

Similarly in 2024, climate change increased the maximum intensity of each hurricane by 14 to 43 km/h (9 to 28 mph). Hurricanes Helene and Milton’s maximum sustained winds increased by approximately 25 km/h (16 mph) and 40 km/h (23 mph), respectively, pushing them from a Category 4 to a Category 5 (SN: 10/1/24; SN: 10/9/24).

Hurricane Rafael was strengthened by a whopping 45 km/h (28 mph), going from a Category 1 to a Category 3 as it made landfall in Cuba in November. “Climate change is now allowing very intense storms to continue later in the season,” says Gilford.