Hurricanes Are Lingering Longer. That Makes Them More Dangerous

Hurricanes Are Lingering Longer. That Makes Them More Dangerous

Hurricanes Are Lingering Longer. That Makes Them More Dangerous

Study author James Kossin of the National Oceanic and Atmospheric Administration says Harvey is a great example of what he found.

Tropical cyclones have slowed more in the Northern Hemisphere, which is significant because that is where a majority of storms occur each year.

Dr Kossin came to his conclusion by studying the tropical cyclone record, which spans from 1949-2016.

Climate change is tinkering with and slowing down atmospheric circulation patterns - the wind currents that move weather along, Kossin said. It's 20 percent when storms reached land.

'The laws of thermodynamics reveal that, as the atmosphere warms by 1°C, the amount of moisture it can hold increases by 7 per cent.

Scientists expect climate change is going to make tropical cyclones - including hurricanes - more severe.

If Harvey is any indication of what hurricanes will look like in the future, this will create a considerable strain on countries' ability to respond financially to storms.

First, he noted that over the more than 60-year period of the study, there may be natural, decades-long cycles in the climate system that could affect the steering of storms and have little or nothing to do with global warming. "Not quite like a cork in a stream, but similar", he said.

In an editorial accompanying Kossin's work, she points out that it raises several new questions.

"I went in with that hypothesis and looked at the data, and out popped the signal that was much bigger than anything I was expecting", Kossin said.

In a warming world where atmospheric circulations are expected to change, the atmospheric circulation that drives tropical cyclone movement is expected to weaken.

"Inland flooding, freshwater flooding, is taking over as the key mortality risk now associated with these storms", Kossin said. "And when you start getting more and more lines of evidence that all point in the same direction, you get more confident in the answers".

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