A new, Yale-led study suggests the 21st century will see an expansion of hurricanes and typhoons into mid-latitude regions, which includes major cities such as New York, Boston, Beijing, and Tokyo. Phys.Org reports: Writing in the journal Nature Geoscience, the study’s authors said tropical cyclones — hurricanes and typhoons — could migrate northward and southward in their respective hemispheres, as the planet warms as a result of anthropogenic greenhouse gas emissions. 2020’s subtropical storm Alpha, the first tropical cyclone observed making landfall in Portugal, and this year’s Hurricane Henri, which made landfall in Connecticut, may be harbingers of such storms. “This represents an important, under-estimated risk of climate change,” said first author Joshua Studholme, a physicist in Yale’s Department of Earth and Planetary Sciences in the Faculty of Arts and Sciences, and a contributing author on the United Nations’ Intergovernmental Panel on Climate Change sixth assessment report published earlier this year. “This research predicts that the 21st century’s tropical cyclones will likely occur over a wider range of latitudes than has been the case on Earth for the last 3 million years,” Studholme said.
For the study, Studholme, Fedorov, and their colleagues analyzed numerical simulations of warm climates from Earth’s distant past, recent satellite observations, and a variety of weather and climate projections, as well as the fundamental physics governing atmospheric convection and planetary-scale winds. For example, they noted that simulations of warmer climates during the Eocene (56 to 34 million years ago) and Pliocene (5.3 to 2.6 million years ago) epochs saw tropical cyclones form and intensify at higher latitudes. “The core problem when making future hurricane predictions is that models used for climate projections do not have sufficient resolution to simulate realistic tropical cyclones,” said Studholme, who is a postdoctoral fellow at Yale. “Instead, several different, indirect approaches are typically used. However, those methods seem to distort the underlying physics of how tropical cyclones form and develop. A number of these methods also provide predictions that contradict each other.” The new study derives its conclusions by examining connections between hurricane physics on scales too small to be represented in current climate models and the better-simulated dynamics of Earth’s jet streams and north-south air circulation, known as the Hadley cells. The findings have been published in the journal Nature Geoscience.