Tokyo (Business Emerge) October 4: Japan’s typhoon season this year may seem relentless, but the reality reveals a different trend. The frequency of these intense storms is actually decreasing, as global climate change continues to reshape weather patterns. However, experts remain divided over what this shift means for the future.
Although the Japan Meteorological Agency has recorded 18 tropical storms so far this season, Weathernews, a private weather company, expects that number to reach 21 by the year’s end. In comparison, 17 tropical storms were tracked in 2023, marking a significant decline from the historical average of 25.1 storms per year.
Japan’s classification system for typhoons differs from that used for hurricanes, and the terminology used in Japanese and English also varies. In Japanese, storms are referred to as typhoons once they reach tropical storm intensity, while the Japan Meteorological Agency differentiates between tropical storms and typhoons when conveying information in English.
While certain regions, such as the North Atlantic, have observed an uptick in tropical cyclones, a 2022 study by the National Oceanic and Atmospheric Administration (NOAA) in the United States concluded that the annual occurrence of such storms has fallen by 13% worldwide over the last century.
“Our study, utilizing climate models, indicates these shifts are not merely due to natural variations over time,” stated Hiroyuki Murakami, a research scientist at NOAA and co-author of the study. “Human-driven climate change is a key factor in shaping these evolving patterns.”
The Intergovernmental Panel on Climate Change (IPCC) modeling study projected a 14% decrease in cyclone occurrences globally if average temperatures rise by 2 degrees Celsius.
However, Murakami also noted that this reduction in tropical cyclones would not be consistent across the globe. “For instance, some studies anticipate an increase in storm numbers in specific regions, like the Central Pacific,” he said.
Alexander Baker, a research scientist at the U.K.’s National Center for Atmospheric Science, emphasized that the fluctuations in storm frequency would exhibit significant regional variations, pointing out that “the latitude where tropical cyclones form and peak has shifted northward,” with more storms being observed in the North Atlantic over the past 30-40 years.
Yet, Weathernews spokesperson Yoshie Nakamura advised against jumping to conclusions about Japan’s lower typhoon count. “The lower number of typhoons this year might be attributed to a weaker-than-usual monsoon trough in September and October, which leads to reduced convective activity,” she explained.
While the reduced number of cyclones may seem like positive news for Japan, experts agree that those which do form are increasingly severe, delivering stronger winds and heavier rainfall.
The IPCC projects that the occurrence of Category 4 and 5 storms—the most powerful types—could rise by 10% if global temperatures increase by 1.5°C, and by 20% with a 4°C rise.
Japan’s Agency for Marine-Earth Science and Technology also predicts that by the end of this century, the number of intense tropical cyclones will rise by 6.6%, coupled with an 11.8% increase in rainfall.
Murakami cautioned that heavier rainfall, when combined with rising sea levels, could trigger more severe storm surges—cyclone-induced flooding—potentially threatening coastal communities.
Baker added that tropical cyclones are becoming harder to predict, leading to less accurate forecasts and complicating disaster preparedness efforts.