The warning comes as Poland battles some of its worst flooding in decades. Towns and villages in the hill-covered southwest of the country have been left devastated after rivers burst their banks following days of torrential rain caused by Storm Boris.
The Czech Republic and Austria have also been badly affected.
The flooding across Central and Eastern Europe, which has been compared to the "flood of the century" that claimed 56 lives and left 7,000 people homeless in 1997, resulted from, according to Polish experts, a combination of natural factors and human-caused environmental changes.
"Any mountainous region is vulnerable to extreme weather, but deforestation speeds up the flow of rainwater," said Iwona Wagner, from the Climate Crisis Committee at the Polish Academy of Sciences. She added that a recent dry spell in the region had contributed to the disaster because “parched soil doesn’t absorb water well, which worsens the flooding.”
Szymon Bujalski, editor of the Nauka o Klimacie (Science on Climate) portal, added that river engineering projects have also worsened the situation.
Flooding on the Odra, Poland’s second longest river, led to large parts of the southwestern city of Wrocław being submerged in the great flood of 1997, and the city is bracing itself now as flood waters from the south slowly make their way down river.
“The Odra River is now much shorter and deeper, with concrete banks and fewer natural meanders to slow down the flow from the mountains," Bujalski told TVP World.
As part of attempts to mitigate the risk of flooding, Poland has spent some $5 billion since 1997 on flood control measures, with money being spent on retention reservoirs, embankments, and other structures.
However, these efforts have their critics. Climate activists argue that the usefulness of the various structures built since 1997 has been undermined by the relentless growth of urbanization that has led to construction on natural floodplains. So, when rivers flood, there is going to be damage and destruction.
This problem has, apparently, been exacerbated by lax and slack planning regulations that let people build in places where they should not.
"In Poland, chaotic planning is the norm,” said Marek Józefiak, Greenpeace’s spokesperson. “According to data accepted by Parliament, it costs the economy $20 billion annually," he continued, citing official figures published first by the Polish Academy of Science.
While tightening planning rules and pouring concrete may reduce some of the risk of flooding, ecologists and scientists say that Poland should also look to the "re-naturalization" of its rivers as a solution.
"We need to let rivers return to their natural courses," Bujalski said, adding that “man cannot win against nature.” He highlighted the rewilding approach that aims to reduce human interference in the course of rivers. Rewilding allows the rivers to “get messy” by meandering and spreading, which, in turn, encourages plants to grow while reducing the chances of destructive rapid-flowing currents forming.
Rewilding has formal backing in the form of the EU’s 2024 Nature Restoration Law. Falling under the umbrella of the EU’s Green Deal, the law aims to turn 25,000 kilometers of European rivers into free-flowing waterways by 2030.
But the law and lofty goals of letting rivers flow could come to nothing, scientists warn, if climate change is not checked.
“These floods used to happen every 100 years. Now they occur every decade. It’s climate change on steroids,” said Józefiak. “Unless we shift away from fossil fuels, we may look back on the 2024 floods as a mild event."
And while Polish scientists agree that more extreme weather is inevitable, predicting exactly when such events will occur remains challenging. “In hydrology, we can predict the increased probability of floods, but not their timing,” Wagner added.
