[D66] [JD: 147] Climate scientists shocked by scale of floods in Germany | The Guardian

[R.O.]

theguardian.com
<https://www.theguardian.com/environment/2021/jul/16/climate-scientists-shocked-by-scale-of-floods-in-germany>



  Climate scientists shocked by scale of floods in Germany

Jonathan Watts
5-7 minutes
------------------------------------------------------------------------

The intensity and scale of the floods in Germany
<https://www.theguardian.com/world/germany> this week have shocked
climate scientists, who did not expect records to be broken this much,
over such a wide area or this soon.

After the deadly heatwave in the US and Canada, where temperatures rose
above 49.6C two weeks ago, the deluge in central Europe
<https://www.theguardian.com/world/europe-news> has raised fears that
human-caused climate disruption is making extreme weather even worse
than predicted.

Precipitation records were smashed across a wide area of the Rhine basin
on Wednesday, with devastating consequences. At least 58 people have
been killed
<https://www.theguardian.com/world/2021/jul/14/firefighter-drowns-and-army-deployed-amid-severe-flooding-in-germany>,
tens of thousands of homes flooded and power supplies disrupted.

Parts of Rhineland-Palatinate and North Rhine-Westphalia were inundated
with 148 litres of rain per sq metre within 48 hours in a part of
Germany that usually sees about 80 litres in the whole of July.

01:45

'It went so fast': villagers describe destruction as flooding hits
western Germany – video

The city of Hagen declared a state of emergency after the Volme burst
its banks and its waters rose to levels not seen more than four times a
century.

The most striking of more than a dozen records was set at the
Köln-Stammheim station
<https://twitter.com/Kachelmannwettr/status/1415563977694777344/photo/1>,
which was deluged in 154mm of rain over 24 hours, obliterating the
city’s previous daily rainfall high of 95mm.

Climate scientists have long predicted that human emissions would cause
more floods, heatwaves, droughts, storms and other forms of extreme
weather, but the latest spikes have surpassed many expectations.

01:00

Germany floods: stranded residents rescued by helicopter from rooftops –
video

“I am surprised by how far it is above the previous record,” Dieter
Gerten, professor of global change climatology and hydrology at the
Potsdam Institute for Climate Impact Research, said. “We seem to be not
just above normal but in domains we didn’t expect in terms of spatial
extent and the speed it developed.”

Gerten, who grew up in a village in the affected area, said it
occasionally flooded, but not like this week. Previous summer downpours
have been as heavy, but have hit a smaller area, and previous winter
storms have not raised rivers to such dangerous levels. “This week’s
event is totally untypical for that region. It lasted a long time and
affected a wide area,” he said.

Scientists will need more time to assess the extent to which human
emissions made this storm more likely, but the record downpour is in
keeping with broader global trends.

“With climate change we do expect all hydro-meteorological extremes to
become more extreme. What we have seen in Germany is broadly consistent
with this trend.” said Carlo Buontempo, the director of the Copernicus
Climate Change Service at the European Centre for Medium-Range Weather
Forecasts.

The seven hottest years in recorded history have occurred since 2014
<https://www.theguardian.com/environment/2020/dec/30/floods-storms-and-searing-heat-2020-in-extreme-weather>,
largely as a result of global heating, which is caused by engine exhaust
fumes, forest burning and other human activities. Computer models
predict this will cause more extreme weather, which means records will
be broken with more frequency in more places.

The Americas have been the focus in recent weeks. The Canadian national
daily heat record was exceeded by more than 5C
<https://www.theguardian.com/environment/2021/jul/02/canadian-inferno-northern-heat-exceeds-worst-case-climate-models>
two weeks ago, as were several local records in Oregon and Washington.
Scientists said these extremes at such latitudes were virtually
impossible without human-driven warming
<https://www.theguardian.com/science/2021/jul/07/world-must-step-up-preparations-for-extreme-heat>.
Last weekend, the monitoring station at Death Valley in California
registered 54.4C
<https://www.theguardian.com/us-news/2021/jul/12/health-warnings-as-death-valley-scorches-in-544c-heat>,
which could prove to be the highest reliably recorded temperature on Earth.

People watch the Ruhr in flood from the Brehminsel dam

People watch the Ruhr in flood from the Brehminsel dam. Photograph:
Action Press/Rex/Shutterstock

Daniel Swain, a climate scientist at the University of California in Los
Angeles, said so many records were being set in the US this summer that
they no longer made the news: “The extremes that would have been
newsworthy a couple of years ago aren’t, because they pale in comparison
to the astonishing rises a few weeks ago.” This was happening in other
countries too, he said, though with less media attention. “The US is
often in the spotlight, but we have also seen extraordinary heat events
in northern Europe and Siberia. This is not a localised freak event, it
is definitely part of a coherent global pattern.”

The far north of Europe also sweltered in record-breaking June heat, and
cities in India, Pakistan and Libya have endured unusually high
temperatures in recent weeks. Suburbs of Tokyo have been drenched in the
heaviest rainfall since measurements began and a usual month’s worth of
July rain fell on London in a day. Events that were once in 100 years
are becoming commonplace. Freak weather is increasingly normal.

Some experts fear the recent jolts indicate the climate system may have
crossed a dangerous threshold. Instead of smoothly rising temperatures
and steadily increasing extremes, they are examining whether the trend
may be increasingly “nonlinear” or bumpy as a result of knock-on effects
from drought or ice melt in the Arctic. This theory is contentious, but
recent events have prompted more discussion about this possibility and
the reliability of models based on past observations.

“We need to better model nonlinear events,” said Gerten. “We scientists
in recent years have been surprised by some events that occurred earlier
and were more frequent and more intense than expected.”

  *

    /This article was amended to remove an outdated regional name./

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