Climate change made extreme rainfall events of the kind that sent deadly torrents of water through parts of Germany and Belgium last month at least 20% more likely to occur in the region, said Scientists Tuesday, writes Isla Binnie, Reuters.
The downpour was probably made worse by climate change. A rainy day can now be up to 19% more intense in the region than it would have been if global air temperatures had not risen by 1.2 degrees Celsius (2.16 degrees Fahrenheit) at- above pre-industrial temperatures, according to a study published by the World Weather Attribution (WWA) scientific consortium.
“We will certainly have more in a warmer climate,” said Friederike Otto, co-leader of the group, climate scientist at the University of Oxford.
“The extreme weather conditions are deadly,” Otto said, recalling that she had urgently contacted family members who live in the affected areas to make sure they were safe when the floods hit. “For me, it was very close to home.”
With extreme weather events hitting the headlines in recent years, scientists are under increasing pressure to determine exactly how much climate change is to blame.
In the past year alone, scientists have discovered that drought in the United States, a deadly heat wave in Canada, and wildfires in the Siberian Arctic have been made worse by the warming of the atmosphere.
The July 12-15 rains in Europe triggered floods that swept away homes and power lines and killed more than 200 people, mostly in Germany. Dozens of people have died in Belgium and thousands have also been forced to flee their homes in the Netherlands. Read more.
“The fact that people are losing their lives in one of the richest countries in the world is really shocking,” said climatologist Ralf Toumi of the Grantham Institute at Imperial College London, who did not participated in the study. “Nowhere is safe.
Although the flood was unprecedented, the 39 WWA scientists found that local precipitation patterns are highly variable.
They therefore conducted their analysis over a larger area covering parts of France, Germany, Belgium, the Netherlands, Luxembourg and Switzerland. They used local weather readings and computer simulations to compare the July flooding with what one would expect in a world unaffected by climate change.
Because warmer air retains more moisture, summer showers in this region are now 3 to 19% heavier than they would be without global warming, the scientists found.
And the event itself was 1.2 to 9 times – or 20% to 800% – more likely to have occurred.
This wide range of uncertainties was due in part to a lack of historical data, WWA said, and made worse by flooding that destroyed equipment that monitored river conditions. Read more.
Still, “the study confirms that global warming played a big role in the flood disaster,” said Stefan Rahmstorf, scientist and oceanographer at the Potsdam Institute for Climate Impact Research, who did not participated in the study.