Tropical cyclones have generally slowed more in the Northern Hemisphere where they are also known as hurricanes and typhoons and where more of these storms typically occur each year. But he says there's good evidence that the warming planet could weaken the global winds that push storms around.
In the last 70 years the storms have slowed by ten per cent.
Dr Kossin said: 'Tropical cyclones over land have slowed down 20 per cent in the Atlantic, 30 per cent in the western North Pacific, and 19 per cent in the Australian region.
The study, released Wednesday in the scientific journal Nature, showed a 10% decrease in forward speed globally between 1949 and 2016, though there is some variation among ocean basins.
With wind speeds that can top more than 180 miles per hour, hurricanes are not usually thought of as slow. A slow storm increases the risk of damaging floods.
As storms move slower, they can unload more heavy rain and pound coastal areas longer, increasing damage potential.
Kossin said the findings were of great importance to society.
By plugging storm data into computer models representing a future with temperatures that are up to five degrees warmer, they found that these cyclones moved 9 percent slower and were far, far wetter.
"If the atmosphere can hold more water vapor, then things are going to tend to rain more", Kossin said.
But Kossin, in his paper, writes that he wouldn't expect big changes in his results due to different means of measurement, since "estimates of tropical-cyclone position should be comparatively insensitive to such changes". So it isn't clear just how much of the change that Kossin found is actually attributable to human-induced climate change.