Cyclones slow down

Nature 558, 104–107 (2018).

Tropical cyclones have the potential to cause significant socio-economic damage. With anthropogenic warming, it is generally expected that their translation speed — that is, the speed at which they move — will slow down. As evidenced by Hurricane Harvey in 2017, such sluggish movement substantially increases the risk of loss of life and destruction. Using global observations of tropical cyclone ‘best track’ data, James Kossin from NOAA’s National Centers for Environmental Information, USA, examines how tropical cyclone translation speeds have changed since 1949.

NASA

Cyclone speeds are found to have decreased globally by ~10%, plausibly related to a weakening of the background tropical atmospheric circulation. For landfalling systems, however, which have societally relevant impacts, changes have been more pronounced: storms in the western North Pacific, North Atlantic and Australian regions have slowed by 30%, 20% and 19%, respectively, increasing local rainfall totals and corresponding storm-induced damages. Further analysis is required to determine the sensitivity of cyclone speed to anthropogenic warming, but when factoring in a projected poleward extension of cyclone tracks, increased adaptation efforts seem necessary to minimize destruction.