Severe hurricanes 'set to double this century'

Posted by Emma Woollacott

US hurricane damage will rise by a third this century, a new climate study concludes.

While there will be fewer hurricanes overall, those that do hit will be far more ferocious, with the number of category 4 and 5 storms set to double.

Scientists from NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) used a new approach to get round the fact that most climate models can't reproduce the strongest hurricanes.

They began by creating an average climate change projection based on 18 global climate models, and then fed this projection into a regional model with much higher resolution to simulate entire hurricane seasons.

Finally, they used their hurricane prediction model to re-simulate each storm generated by the regional model - but at a still higher resolution. This let them simulate the most intense hurricanes - categories 4 and 5.

The models showed a fall in the total number of hurricanes by the end of this century, but still indicated a near-doubling of category 4 and 5 hurricanes. The greatest increase in intense hurricanes was seen in the Western Atlantic region (between 20°N and 40°N).

These category 4 and 5 hurricanes account for nearly half of all hurricane damage in the US, although they represent only six percent of the total number. The authors reckon this will mean a 30 percent increase in potential damage.

"The increase in intense hurricanes may not be evident until late in the 21st century, because of year-to-year variations in storm activity and multi-decadal fluctuations that are known to exist in the Atlantic," say the researchers. "Persistent change can only be detected using many decades of recorded observations, to look for trends that emerge over the long-term."