Debate about the cause of the flood: What role does climate change play? – Domestic policy

While the terrible extent of the flood catastrophe in West Germany is gradually becoming apparent, one question is much discussed: Was the fatal heavy rain just bad luck, as it happens every few decades? Or the consequences and signs of man-made climate change, a foretaste of extreme weather phenomena that will hit us more and more frequently in the future if we don’t act?

The policy was quickly determined: Green politician Katrin Göring-Eckhardt (55) made the start, already claimed on Wednesday morning at “ntv”: “These are the effects of the climate catastrophe. And that’s another call to make yourself clear: It’s already there, it’s already here with us. ”

Laschet and Seehofer on the line of the Greens

Unsurprising point of view for a Green politician. But Union Chancellor candidate Armin Laschet (60, CDU) and Interior Minister Horst Seehofer (72, CSU) quickly made direct connections to global warming.

Seehofer told BILD: “These extreme weather capers are the consequences of climate change.” Laschet said the accumulation of heavy rain and heat episodes was “linked to climate change”. “That means that we need more speed with the measures for climate protection – European, nationwide, worldwide.”

Federal President Frank-Walter Steinmeier (65) hit the same line in his address on Friday: “Only if we take up the fight against climate change decisively will we be able to keep extreme weather conditions such as we are now experiencing within limits.”

Interior Minister Horst Seehofer sees climate change as the reason for the current flood Foto: Getty Images

All four politicians are thus on the line of the public broadcasters who already presented the climate track in the main news on Wednesday evening.

But it’s not that clear at all. And that’s not what climate skeptics or deniers say, who want to stir up all sorts of doubts about the undoubted global warming. But government agencies like the German Weather Service (DWD) in Offenbach.

DWD expert: “That’s the weather”

DWD graduate meteorologist Andreas Friedrich zu BILD: “Such a regional storm is a single event, that is weather. The claim that climate change is to blame is not tenable. ”

On the other hand, there is something to the feeling that storms with extreme precipitation are increasing. “Our climatologists have noticed an increase in such severe weather events over the past 20 years – since then we have been able to record this precisely across Germany using a radar network system.”

The statistics show the most violent spike in 2018.

Storms with heavy rain increase slightly - infographic

However, the amount of data is not yet sufficient for conclusions: “Weather experts are very careful, calculate exact mean values ​​after 30 years at the earliest and only then make statements about the climate. We’re not there yet. “

“Blocking weather conditions” bring record amounts of rain

At least there is agreement in the description of the weather phenomenon: a high over north-eastern Europe and a high over the Atlantic held a low pressure area over Germany “captive”, it hardly moved. In such cases, meteorologists speak of “blocking weather conditions”.

But even before the viewers of the ZDF “heute journal” saw this on the weather map, moderator Claus Kleber (65) explained the alleged cause of these dangerous weather conditions: “The fact that they are becoming more frequent is because the Arctic and the The air above it is getting warmer and warmer and the power of the jet stream, which drives the weather, is withdrawn ”.

Sounds plausible, it also got a lot of approval on Twitter. However, the connection is unproven and controversial among scientists. In addition: According to climate researchers, there is absolutely no accumulation of blocking weather conditions in Central Europe.

ZDF man Kleber is still sure of his cause. In his moderation on Thursday he concluded that climate sins ultimately kill: “That’s it for us on the day when the violence of nature and the consequences of human action and inaction cost at least 58 people their lives.”

200 liters per square meter: In Hagen (North Rhine-Westphalia) the fire brigade was temporarily powerless against the masses of water

200 liters per square meter: In Hagen (North Rhine-Westphalia) the fire brigade was temporarily powerless against the masses of waterPhoto: Alex Talash

ARD meteorologist: “More evaporation from the oceans”

The colleagues in “Tagesthemen” also see climate change as the cause, but justify it differently. ARD meteorologist Karsten Schwanke (52) concludes in view of the amount of precipitation (up to 200 liters per square meter) in Hagen or Cologne: “These are enormous amounts that would not exist without climate change.”

His classification: “These are exactly the effects of climate change that we have been expecting for many years. High temperatures and droughts like recently in Canada. And a warmer atmosphere simply allows more water to evaporate from the oceans. The atmosphere has more water vapor, more energy. And then something exactly happens that we have experienced. ”

Physically this is true with the water vapor and the energy. But what the viewer did not find out: Despite global warming, the principle has not led to an increase in summer precipitation in Germany since records began 140 years ago.

Federal Environment Agency: There is no increase in rain in summer

“So far, there has hardly been any change in the summer months,” says the Federal Environment Agency (“Monitoring Report 2019 on the German Strategy for Adaptation to Climate Change”). According to the much-cited federal authority – in times of drought – the amount of rain has even decreased, by 3.8 percent since 1881. “However, from this minimal decline, which is in the range of natural variability, it is not even possible to infer a trend,” the experts write.

And in all clarity: “A single flood event cannot be explained by climate change.”

Potsdam experts: “We are in the midst of climate change”

The classification of the renowned Potsdam Institute for Climate Impact Research (PIK) is still missing. Its scientists described as early as 2015 “a clear upward trend in unprecedented rainfall”, which between 1980 and 2010 was most pronounced in Southeast Asia. With partly devastating damage and casualty records.

Meteorologist and climate researcher Peter Hoffmann from the Potsdam Institute for Climate Impact Research on BILD. “The experience of the last extreme years has made it very clear that we are in the midst of climate change. Extreme weather events can cause great damage not only elsewhere, but also here. ”Climate research has warned“ for a long time ”about this.

The fact is: as early as 2015, the Potsdam researchers demonstrated a connection between storms and climate change. “One in ten record rains in the past thirty years can only be explained by the influence of long-term global warming. And in the last year examined, 2010, it was even one of four record rainfall, ”according to the study.

Conversely, this also means: In three out of four cases it is not the case. The “Welt” quotes DWD climate researcher Florian Imbery as saying that a heavy rain event like this is statistically “significantly less than once in 100 years”.