Extreme flooding is not solely caused by climate change, a study has found.
Floods over the past 8,000 years have exceeded the extremes seen in recent decades, researchers at the University of Exeter discovered. [emphasis, links added]
Recent floods, such as those in Valencia, Spain, and across the UK last winter, have been linked to climate change and accompanied by warnings of being “unprecedented”.
However, Prof Stephan Harrison, from the university’s College of Life and Environmental Sciences, said the new study found that many previous floods had exceeded the recent extremes.
By dating individual sand grains in floodplain sediments and analysing their size, the researchers were able to assess the frequency and scale of floods going back several thousand years.
“In recent years, floods around the world, including in Pakistan, Spain, and Germany, have killed thousands of people and caused enormous damage,” said Prof Harrison.
“Such floods are seen as ‘unprecedented’ – but if you look back over the last few thousand years, that’s not the case. In fact, floods we call unprecedented may be nowhere near the most extreme that have happened in the past.”
The study [published in the journal Climatic Change] examined paleoflood records for the Lower Rhine in Germany and the Netherlands, the Upper Severn in the UK, and rivers around Valencia.
In the Rhine, records over the past 8,000 years show at least 12 floods that are likely to have exceeded modern peaks.
The Severn analysis shows that floods in the last 72 years of monitoring are not exceptional compared to what can be seen in records going back 4,000 years.
The largest flood in the Upper Severn occurred around 250 BCE and is estimated to have been 50 percent larger at its peak than the floods in the year 2000, which damaged 10,000 homes and led to new flood defences.
Prof Harrison said climate change modeling was limited in what it could reveal about floods as it relied on records that date back only as far as 120 years ago, whereas natural variability can only be seen on a longer timescale.
“This is really the first time that anyone’s put together this idea that some past floods were enormous,” he said.
“Compared to the narrative put out by some climate attribution specialists who say the floods we’re having now are so big that they could only be caused by human-induced climate change.
“These recent floods have been enormous, but not as enormous as some of the things in the past.”
He added: “We said clearly, a few years ago, the climate modeling community have got it wrong.”
Read rest at The Telegraph
