Ocean regions that fuel the world's most powerful hurricanes and typhoons are expanding as unusually warm water extends deeper beneath the surface. Research presented at the American Geophysical Union's 2025 Annual Meeting suggests human-caused climate change is responsible for roughly 60% to 70% of the growth of these tropical cyclone hot spots.

Atmospheric scientist I-I Lin of National Taiwan University, among others, has proposed a Category 6 classification for tropical cyclones with winds exceeding 160 knots (184 mph). Under the current scale, all storms at or above 137 knots (157 mph) are classified as Category 5, even though some can be dramatically more powerful than that. Hurricane Patricia, which reached 185 knots (213 mph) in the Eastern Pacific in 2015, would easily meet the proposed threshold.

Lin and her colleagues identified 18 storms exceeding 160 knots during the past four decades. Eight occurred between 1982 and 2011, while 10 developed between 2013 and 2023.

The researchers found that nearly all of these storms developed over two major ocean hot spots: the Western Pacific east of the Philippines and Borneo, and the North Atlantic near the Caribbean and southeastern United States. These regions contain unusually deep layers of warm water, allowing storms to continue drawing energy from the ocean even after their winds churn the surface.

Climate change is expanding both hot spots, potentially increasing the areas where extreme tropical cyclones can develop. Warm water alone does not guarantee a Category 6 storm, since atmospheric conditions must also be favorable, but the changing ocean environment could increase the likelihood of exceptionally powerful hurricanes and typhoons threatening populated coastlines.