Hurricane swarms are something we have to worry about now

In early October 2024, the Hurricanes Milton, Kirk and Leslie occurred in the Atlantic basin – the first time that three Atlantic hurricanes were simultaneously active after September, according to the NOAA. New research warns that the “clusters” of the tropical cyclone are becoming more and more common in this part of the world, aggravating the dangers of the hurricanes season.

The clusters of tropical cyclone occur when two or more hurricanes are active in the same pool at the same time. The west of the North Pacific has historically produced the most clusters, but climate change seems to have moved this Hotspot to the North Atlantic. The study, published on July 31 in the journal Nature Climate Change, identified a ten -time increase in the probability of cluster of tropical cyclone in the North Atlantic, from around 1.4% to 14.3% in the last 46 years. This rate now exceeds that of the western North Pacific, according to researchers.

“We have tried to develop a probabilistic framework to understand this trend,” said Dazhi XI, a climatologist at the University of Hong Kong who co-directed study and developed the methodology, in a version of Fudan University. “If clusters of tropical cyclone are formed by chance, then only the frequency of storms, the duration of the storm and the seasonality of the storms can have an impact on chance.”

To exclude this, XI and his colleagues simulated the formation of clusters of tropical cyclone by probabilistic modeling, considering only these three mechanisms. This model only partially succeeded – he considerably underestimated the chances of clusters of tropical cyclone for a few years. Researchers have found that during these years, waves on a synoptic scale – far from moving atmospheric disturbances which can create conditions conducive to storm formation – increase the chances of clusters of tropical cyclone.

A more in -depth analysis has revealed that the changes observed in the intensity of the waves on a synoptic scale are responses to a global warming scheme “similar to La Niña”, according to the study. This trend is characterized by slower warming in the eastern Pacific compared to the Western Pacific.

“The warming scheme modulates not only the frequency of tropical cyclones in the Basins of the North and Northwest Pacific, but also has an impact on the force of waves on a synoptic scale, causing together the change in the cluster of tropical cyclone from the northwest of the Pacific to the Northern Atlantic Basin”, explained Zheng-Hang A PHD student at Fudan University.

It is not clear if this warming scheme has resulted from natural variations within the climate system or external pressures, such as greenhouse gas emissions, depending on the study. Previous research of XI has revealed that the future probability of multiple hurricanes having an impact on the same area in a short period increased in the moderate and high greenhouse gas emission scenarios, which suggests that global warming focused on the simultaneous formation of the storm.

Although this new study has not specifically examined anthropogenic warming, it suggests that a spectacular change in the warming patterns during the last half century has transformed the North Atlantic into an emerging hotpot for clusters of tropical cyclone. This can worsen the dangers for the Atlantic coastal nations during the hurricane season, including the United States

When several hurricanes have reached a short period of time, this considerably decreases the recovery time between storms, overwhelming emergency intervention systems and damaging the compromised infrastructure. The researchers hope that their results will urge Atlantic coastal communities to develop proactive strategies to deal with the growing risk of loud succession.