Our weather is going to take a turn for the worse in the coming years as the climate warms and rainfall amounts increase.
It will lead to more storms and torrential rains that will trigger flooding, a prominent climate scientist has warned. The fairly bleak prospects were explained yesterday at the British Science Association's annual festival of science in Newcastle.
Prof Hayley Fowler of Newcastle University described how 2,000km long, 200km wide "atmospheric rivers" high above the earth can dump as much rain as the amount of water that flows from the mighty Amazon river.
It was one of these filaments of concentrated moisture that splashed down 50mm of rain in two hours onto Newcastle in the north of England in June 2012, she said during her Joseph Lister Award lecture. This same "basic physics" related to the planet's water cycle will also see Ireland suffer storms of greater intensity and drenching rain said Prof Peter Lynch, professor of meteorology at University College Dublin.
“The atmospheric cycle of water is becoming more energetic,” he said. Higher temperatures mean more moisture and more energy to be released. Ireland also lies under a region where these filaments pass overhead and so we too face this increased risk of flooding, he said.
The Newcastle region has long endured major flooding that swamped the city over the past centuries, she said. But things are going to get worse.
Global average temperatures rose by almost a degree over the past 100 years and the higher temperature means more water can be carried by the atmosphere, she explained. This moisture will fall out as rain as the air moves northward and cools which means heavy rainfalls.
Data from the UK and US indicates this is already happening, she said. The chance of experiencing the worst storm you might see in 50 years had increased by 12 per cent for the UK as a whole over the past 20 years. For Scotland alone the risk increased by 29 per cent.
One of the great difficulties was current climate models were poor at predicting these summer storms, she said. Her research group developed new models, however, that are able to give useful predictions. "It is the first time we might be able to say something about heavy rainfall in the summer," she said.
While storms during the winter cover wide areas, summer storms are much more local, depending on when an atmospheric river dumps its water. These are the events most likely to cause heavy flooding so being able to anticipate them is important. "These extreme events seem to be increasing but the hope is we can bring together information from past storms plus the prediction models to prevent this type of thing in the future," she said.
This would also mean changed thinking about the designs of cities and how able they are to deal with flooding.