Tropical cyclones are tracking closer to land globally

Tropical cyclones are shifting towards land as their paths drift poleward and westward, according to a new statistical analysis. The findings could herald an increase in the risk of these damaging storms for coastal populations worldwide. Tropical cyclones are one of the most devastating and costly natural disasters. Nearly a third of the world’s population currently resides within their reach. Recently, it’s been observed that these storms are becoming stronger and occurring at higher latitudes than in the past. While it’s thought that the effects of human-mediated climate change drive these changes, their potential impact on coastal areas remains unclear. An understanding of these trends is crucial to better gauging how coastal tropical cyclone risk may change in the future. Shuai Wang and Ralf Toumi investigated global tropical cyclone activity over the period 1982-2018 and found that in addition to their poleward migration, cyclone activity has been drifting closer to land globally. According to the findings, the distance between each storm’s point of maximum intensity and land has decreased by roughly 30 kilometers per decade. What’s more, the fraction of tropical cyclones entering coastal regions – defined as the offshore area with a distance to the nearest land less than 200 kilometers – has increased each decade as well, they say. Wang and Toumi revealed a westward shift in the paths of tropical cyclones; tropical cyclone activity is being shifted westward in the West Pacific, East Pacific, and North and South Indian Ocean, they say. While the underlying reasons for these shifts remain unclear, the authors suggest that they could be due to variations in the large-scale Walker and Hadley atmospheric circulation systems.

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