Europe flooding period worst in 500 years: study

Patrick Galey, Agence France-Presse

Posted at Jul 23 2020 05:27 AM

Europe flooding period worst in 500 years: study 1
A picture shows the center of Quimperle, western of France, on January 3, 2014, flooded by the Laita river. Britanny has been placed under flood warning due to heavy rain and high tidal coefficient. Fred Tanneau, AFP/File

PARIS - Europe has been struck by more frequent and widespread flooding in recent decades than at any other time in the past 500 years, according to a sweeping analysis of the continent's flood history released Wednesday.

A pan-European team of researchers spent more than eight years poring over nearly 10,000 records of flood events stretching back to 1500. 

They found that not only have the last 30 years witnessed more frequent and stronger flood events than at any other time, but the flooding was happening amid hotter temperatures than the historic average. 

Authors of the research said it could help governments save billions on flood recovery and reconstruction. 

"For flood forecasts of the next decades it is important to understand whether we are now in a completely new situation or whether this is just a repetition of something that has already occurred," said lead author Guenter Bloeschl, from the Vienna University of Technology.

"We found the former is the case, thus we need to make sure that the required safety margins are kept that may be bigger than what we thought before," he told AFP. 

Global temperatures have already risen more than 1 degree Celsius since pre-industrial times, speeding up the water cycle and increasing the frequency and strength of flood events.

But extreme flooding is normally localized, making it difficult to draw conclusions as to how closely the phenomenon is influenced by rising temperatures.

The team identified nine periods across half a millennium where flooding was more common than average.

Whereas previous flood-rich periods tended to be colder than the intervening years, the most recent -- 1900-2016 -- was roughly 1.4C warmer.

The team noted in particular an increase in summer flooding during these years.

Writing in a linked comment piece, Francis Ludlow, assistant professor of medieval environmental history at Trinity College, Dublin, called the research "a major contribution to our understanding of European flood history".

Around 0.03 percent of the European population are thought to have been impacted each year by flooding between 1870-2016 -- representing an annual average cost of close to 1 percent of the continent's GDP.

"Increased flood hazards are widely expected in the future for a substantial area of Europe as a result of climate change, and so, without effective management and adaptation, these losses will potentially be even greater," said Ludlow.