Taken together, these two studies suggest that climate change is already increasing the dangers posed by hurricanes and typhoons in far more ways than previously thought, and it will continue to compound numerous hazards, especially the threat of severe flooding.
In the last 70 years the storms have slowed by ten per cent.
In the Atlantic basin, the slowdown is just 6 percent.
The effect has been more profound north of the equator, with the western North Pacific Ocean one of the most hard hit regions. Kossin works at the National Oceanic and Atmospheric Administration's National Centers for Environmental Information.
The study is in Wednesday's journal Nature. But Kossin thinks the slower speed of movement - which naturally adds more rainfall to any region the storm crosses may actually be a bigger deal than the simple increase in rain overall.
The authors say the slowdown is likely to contribute to worsening destruction alongside the associated increase in rain rates caused by global warming.
"Nothing good can come of a slower storm", Kossin told Mashable.
As storms move slower, they can unload more heavy rain and pound coastal areas longer, increasing damage potential.
Still, the shift is precisely what he and other cyclone experts said would be expected from climate change.
Kossin said the findings were of great importance to society.
Unhurried hurricanes also mean strong winds blowing more often over the same place and possibly more storm surge, Kossin said.
That means a storm that may already hold more moisture will have time to drop more of it in each spot.
"What we're seeing nearly certainly reflects both natural and human-caused changes", Kossin said.