Weatherwatch: forests could save us from the worst storms

https://www.theguardian.com/news/2019/jul/26/weatherwatch-forests-could-save-us-from-the-worst-storms

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Plant enough trees and you’ll be able to take the oomph out of damaging storms. That’s the message that is coming out of a study published in Environmental Research Letters, which suggests that major reforestation across Europe has the potential to reduce the number of extra-tropical cyclones by as much as 80%.

Scientists from the Swedish Meteorological and Hydrological Institute used a climate model to compare the number and intensity of cyclones under two scenarios: Europe devoid of trees and Europe covered in trees. Forests make the land bumpier (than a field of wheat say) and the results suggest that this extra friction helps to slow cyclones down. The results show that a tree-covered Europe would have around 10% fewer cyclones on western European coasts, rising to 80% fewer cyclones in eastern Europe. That’s because most cyclones approach from the west, meaning those that reach eastern Europe have to bounce over more trees.

One downside to fewer storms could be a reduction in rainfall, but it’s likely that increased evapotranspiration from extra trees would help to make up the shortfall. Other things, like wind turbines or skyscrapers, could also increase surface roughness and slow cyclones down, but they’d likely reduce rainfall too.