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.

Neighbouring 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 U.S. 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."

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 U.S. 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 to 90 per cent 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.