Berlin CNN  — 

European officials have said climate change contributed to this week’s extreme flooding, which has left entire towns submerged and more than 120 people dead.

Scientists have for decades warned that climate change will make extreme weather events, including heavy rain and deadly flooding, more likely.

Around 100 of those killed after torrential rainfall since Wednesday were in Germany’s western states of Rhineland-Palatinate and North Rhine-Westphalia, where local leaders are urging the world for swifter action on climate change as villages under their watch become a new and unexpected epicenter of global warming.

Neighboring Belgium has also been hit hard by the floods, which have killed 20 people in the country and could rise further, Interior Minister Annelies Verlinden said Friday at a press conference.

European Commission President Ursula von der Leyen said Friday that flooding in northwestern Europe was evidence of the need for urgency in acting on climate change.

“Science tells us that with climate change, we see more and more extreme weather phenomenons that last longer,” said von der Leyen, two days after unveiling an ambitious package of climate change proposals for the EU.

“It is the intensity and the length of these events when science tells us this is a clear indication of climate change and that this is something that really, really shows the urgency to act.”

German Chancellor Angela Merkel on Thursday met with US President Joe Biden in Washington, DC, where she welcomed America’s return to the Paris agreement on climate change, saying it would strengthen this year’s annual climate talks – known as the Conference of the Parties – in Glasgow, Scotland, later this year.

“We talked about the challenges of climate change, and I’m very, very glad that the United States have returned to the Paris Accord, and that this gives us a very different basis in Glasgow to fight for more climate protection at the Conference of the Parties,” she said.

“I think the meteorological events – whether it’s fires hitting the United States, dramatically high temperatures, or just sudden irregular rainfalls – indicate that the number of extraordinarily weather events has increased dramatically in recent years. We need to respond to that.”

An aerial view of the flooding in Erftstadt, in Germany's North Rhine-Westphalia state on Friday.

Her comments echoed those of her environment minister, Svenja Schulze, who tweeted Thursday: “Climate change has arrived in Germany.

“The events show with what force the consequences of climate change can affect us all, and how important it is for us to adjust to extreme weather events in the future.”

There is growing acknowledgement and acceptance now from many politicians that anthropogenic – or human-induced – climate change plays a role in extreme weather events.

Biden, for example, recently linked the extreme heat and prolonged drought in the US to climate change.

Scientists are now able to estimate just how big a role climate change has played in a particular event. It’s too soon to make conclusions about current flooding in Europe, but estimates are likely to be made in coming days.

A similar, though less extreme, flooding event in Western Europe in 2016 that killed 18 people in Germany, France, Romania and Belgium, for example, was found to be 80-90% more likely to occur than it was in the past before anthropogenic climate change.

While officials at the national and EU level are sounding the horn on climate, so too are local leaders on the disasters’ front lines.

The premier of North Rhine-Westphalia in Germany – Armin Laschet, who is also the Conservatives’ candidate to succeed Merkel – said the floods in his state were “a catastrophe of historic proportion,” calling on the world to speed up its efforts to both mitigate and adapt to climate change.

“The floods have literally pulled the rug from under people’s feet,” Laschet said.

“We will be faced with such events over and over, and that means we need to speed up climate protection measures, on European, federal and global levels, because climate change isn’t confined to one state,” he said.

What’s causing this heavy rainfall?

As the Earth’s atmosphere warms, it can hold more moisture, which in some cases leads to unprecedented rainfall. It may be that the total average rainfall in an area doesn’t change, but extremes are amplified, which can mean longer dry periods or more intense storms.

Flash flooding occurs when rain falls faster than the ground can absorb it. It is “flash” because its onset is rapid – water levels can rise meters in minutes.

When there is more water vapor in a warmer atmosphere, rainfall rates can increase and flash flooding is more likely to occur.

And drought can actually compound this effect. Very dry soil can’t absorb water efficiently – think of trying to wet a very dry sponge. While the rain is ultimately beneficial, if a region that has been experiencing intense drought gets hit with heavy rain, flash flooding is more likely to occur.

That’s the dynamic in Germany and Belgium at the moment. Just a few months ago, there were historically low water levels on the Rhine in Cologne, which were disrupting shipping along the river, but now the river has swelled from two months of rain falling in just one day.

The projections for how much the Earth would warm have largely been correct, said Myles Allen, a climate scientist at the University of Oxford. But there have been outliers – namely, the warming in Europe has been faster than predicted.

Allen said scientists expected more extreme weather events, but records are being blown away at a concerning clip – the unprecedented heat wave in the Northwest US in late June is another recent example.

“Extreme events happen and records get broken all the time,” Allen said, “but it is worrying that we’re seeing such rapid intensification.”

With more action, he said, climate change could be addressed in a generation. Deadly flooding and heatwaves serve as a reminder of the climate crisis’ reach.

“A problem is that every climate documentary starts with an image of a polar bear, which send the message that climate change happens in the Arctic, on the other side of the world,” Allen said. “But these events show that’s not true.”

CNN’s Angela Dewan reported from London, Brandon Miller reported from Atlanta, Nadine Schmidt reported from Berlin and Ulrike Dehmel reported from Bonn.