Climate change implicated by a flood of data


Multinational study reveals different flooding trends across Europe.


The flooded Lyth Valley in Cumbria, UK, after Storm Desmond in December 2015.

CEH

Flooding is becoming increasingly severe in northwestern Europe, including the UK, but decreasing in severity in southern and eastern Europe, according to a major new study.

The multinational research team, which looked at river flow data from thousands of locations over half a century, says its findings provide the clearest evidence yet, at the European scale, of the link between climate change and flooding.

The changes range from an 11% increase in flood levels in northern England and southern Scotland to a 23% reduction in parts of Russia.

The study, which is published in the journal Nature, was led by the Vienna University of Technology, Austria, and involved research institutions in 24 countries.

Lead author Günter Blöschl says it was known that climate change is shifting the timing of floods in a year, but the question remained as to whether it also controls the magnitude of flood events.

“Our study did in fact find there are consistent patterns of flood change across Europe and these are in line with predicted climate change impacts, such as a contrast between increasing severity of flooding in the north and decreases in the south," he says.

Almost 50 scientists from 35 institutions analysed records from 3738 flood measurement stations across Europe from 1960 to 2010.

They found that floods are becoming more common in central and north-western Europe – between Iceland and Austria – because rain, snow, sleet and hail are increasing, making soils wetter.

In southern Europe, on the other hand, flood levels are decreasing, as climate change results in declining precipitation and the higher temperatures cause increased evaporation of water in the soil.

However, in Mediterranean areas, small rivers floods may be becoming larger due to more frequent thunderstorms and land management changes such as deforestation.

In Eastern Europe, flood levels are also decreasing, due to shallower snowpacks in winter associated with the higher temperatures.

"Processes differ across Europe, but the regional patterns all correspond well with predicted climate change impacts," says Blöschl. "This shows us that we are already in the midst of climate change."

If these trends continue, major increases in flood risk can be expected in many regions of Europe, the researchers say. The total annual bill from flood damage already is estimated to be $100 billion worldwide.

"Flood management must adapt to the realities of our changing climate and associated flood risk over the coming decades," says co-author Neil Macdonald, from the University of Liverpool, UK.

  1. https://www.nature.com/articles/s41586-019-1495-6
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