High-resolution climate simulations of 15 tropical cyclones that occurred over the last decade indicates that climate change has intensified rainfall in these events by 5 to 10%. Relative to pre-industrial conditions, climate change has enhanced the average and extreme rainfall of hurricanes Katrina, Irma Researchers simulated 15 tropical cyclones in 10 times each at 4.5 km resolution. The chart shows average percentage increase in rainfall. Source: LBNLResearchers simulated 15 tropical cyclones in 10 times each at 4.5 km resolution. The chart shows average percentage increase in rainfall. Source: LBNLand Maria, but did not change tropical cyclone wind-speed intensity.

The analysis conducted by researchers from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (LBNL) also suggests that while wind speeds in hurricanes have not been appreciably affected, peak wind speeds could increase by as much as 25 knots, or about 29 mph, under continued climate warming.

The hindcast attribution method used the Weather Research and Forecasting model developed by the National Center for Atmospheric Research to study hurricanes in pre-industrial climates and under current conditions. The difference between scenario findings identified trends attributable to anthropogenic warming.

Future scenarios assuming temperature increases of up to 4° C show potential rainfall increases of 15-35% and wind speed increases by as much as 25 knots; most hurricanes posted increases of 10 to 15 knots.

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