The study, published in the journal Nature Climate Change, found that the annual number of global hurricanes, typhoons and tropical storms — or tropical cyclones, more generally — declined by roughly 13% as the planet warmed during the 20th century. Warmer sea surface temperatures intensify tropical storm wind speeds, giving them the potential to deliver more damage if they make landfall. Over the 39-year period from 1979-2017, the number of major hurricanes has increased while the number of smaller hurricanes has decreased.