In light of increasingly powerful storms, scientists are calling for the expansion of the Saffir-Simpson scale to include a level 6 for hurricanes with wind speeds exceeding 308 km/h.
Experts warn that climate change is intensifying the destructive power of storms to unprecedented levels, as seen with Hurricane Helene making landfall in the southeastern United States and Hurricane Yagi (Typhoon No. 3) wreaking havoc in Asia recently.
A recent study published in the United States indicates that global warming is causing tropical storms to occur with greater intensity and frequency.
Hurricane Helene caused severe flooding in Asheville, North Carolina (USA). This hurricane has resulted in at least 189 fatalities, making it the second deadliest hurricane in the U.S. in the past 50 years – (Photo: AFP).
The study indicates that warming ocean surface temperatures are increasing the moisture content in the atmosphere, thereby intensifying storms.
Michael Mann, a climate scientist at Pennsylvania State University, states that the current global temperature increase of 1 degree Celsius has led to an average increase in storm destructiveness by approximately 40%. In a study published in the Proceedings of the National Academy of Sciences (PNAS), he advocates for expanding the Saffir-Simpson scale to include a level 6 for storms with wind speeds above 308 km/h.
Many scientists believe that climate change has intensified Hurricane Helene to category 4—the highest level on the scale. Florida climate scientist David Zierden notes that record-high ocean heat content has contributed to the storm’s strength and extensive damage.
Meanwhile, the phenomenon of “rapid intensification,” where a storm’s wind speed increases by 55 km within 24 hours, is also becoming more common.
Karthik Balaguru, a climate scientist at the Pacific Northwest National Laboratory of the U.S. Department of Energy, suggests that this increase could have severe impacts, especially if it occurs near the coast before the storm makes landfall.
Climate change is also reducing wind shear—the changes in wind speed and direction with altitude—along the Atlantic coast of North America and the Pacific coast of Asia. “Strong wind shear can inhibit storm development and reduce hurricane destructiveness,” Balaguru explains.
Additionally, the temperature difference between land and water surfaces is causing higher humidity along coastal areas, leading to pressure and wind patterns that push moisture into the mid-stratosphere, creating conditions for storm development.
Regarding frequency, some studies suggest that improved fine dust pollution in the U.S. and Europe may be increasing storm frequency in the Atlantic, while pollution in China and India might be preventing storms in the western Pacific.
