Scientists dismiss link with global warming : The Weathermen : European Floods Disaster

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The Independent Online
Scientists yesterday dismissed suggestions that global warming was responsible for the floods that have devastated much of North-west Europe. Brian Hoskins, one of Britain's leading meteorologists, let out a quiet sigh and said: "Global warming just isn't like this. You can't waken up one morning and say, `This is it.' "

As Professor of Meteorology at Reading University, Dr Hoskins takes global warming very seriously. He has completed a scientific paper which predicts that the storm track over north-western Europe "could be more invigorated" as a result of the world's changing climate.

But, he warned, there is no evidence that the past fortnight's rainfall and flooding is correlated with global warming. Nor does he agree with attempts to link Europe's weather to el Nino, the periodic reversal of ocean currents in the Pacific off the coast of Peru. "I would be extremely surprised if anyone could show any correlation with such an event."

He said southern England had experienced even heavier rainfall in December 1989 and there was no Nino that year.

The speed and extent of the flooding in North-west Europe have been made worse by the development of the land within the catchment area of the Rhine and its tributaries, according to scientists at the Institute of Hydrology at Wallingford in Oxfordshire.

Mark Robinson, a hydrologist at the institute, said: "Land use has not caused this flood, but it has probably made it far worse." In its natural state, land in a river catchment acts like a sponge, holding water for many days after heavy rain, releasing it into the river system and slowing down the effect of a flood. He said better draining, tarmac roads and removal of hedges and trees increase the speed with which rainfall enters a river. Canalisation, when a river is straightened, also increases the overall flow rate downstream.

"So, instead of the lower reaches of the river having to transport a certain volume of water over several days, it may have to do it in several hours and it may not have this capability."

The scientists calculated that the medium-scale floods that affected the Rhine region in the 19th century would cause major floods today. A flood in December 1882 resulted in a peak flow rate in the river of 4,680 cubic metres a second, equivalent to about three Olympic swimming pools full of water.

The same flood a hundred years later would have occurred three days earlier and resulted in a peak flow of 6,400 cubic metres a second, or more than four swimming pools.