From China to Germany, floods expose climate vulnerability

At least 25 people in central China’s Henan province died on Tuesday, including dozens who were trapped in a city subway train as water flowed through the region’s capital Zhengzhou after several hours. torrential rainy day.

After floods killed at least 160 people in Germany and 31 others in Belgium last week, disaster reinforced the message that significant changes would have to be made to prepare for similar events in the future.

“Governments should first realize that the infrastructure they have built in the past or even those recently is very vulnerable to these extreme weather events,” said Eduardo Araral, Associate professor and co-director, Water Policy Institute, at Singapore’s Lee Kuan Yew School for Community Policy.

In Europe, climate change is likely to increase the number of large, slow-moving storms that can last longer in an area and cause storms like those seen in Germany and Belgium, according to a study published June 30 in the journal Geophysical Research. Letters.

As the atmosphere warms with climate change, it also holds more moisture, which means that as rain clouds melt, more precipitation will occur. By the end of the century, such storms could be 14 times more frequent, the researchers found in the study using computer simulations.

While the floods that devastated large swaths of western and southern Germany occurred thousands of kilometers away from the events in Henan, both cases highlight the vulnerability of densely populated areas. shelter from catastrophic floods and other natural disasters.

“You need engineering measures, strengthening levees and flood barriers. But we also need to remodel cities,” said Fred Hattermann at the Potsdam Institute for Climate Impact Research. There is increasing focus, he said, on so-called “green adaptation” measures, such as polders and floodplains that can be flooded, to prevent water from flowing too quickly.

“But when there’s heavy rain, all of that might not help, so we have to learn to live with it,” he said.

Reinforcing dikes and climate-resilient housing, roads and urban infrastructure will cost billions of dong. But dramatic mobile phone footage of people struggling on subway trains submerged in chest-deep water in Zhengzhou or crying in fear as mud and debris swept through medieval German towns have clearly shows the cost of doing nothing.

“It was shocking and I must say scary,” said John Butschkowski, a Red Cross driver involved in rescue work in western Germany. “It’s spooky, there’s no people anywhere, just trash. And can’t imagine this happening in Germany.”

END A YEAR IN THREE DAYS

Koh Tieh-Yong, a weather and climate scientist at the Singapore University of Social Sciences, said an overall assessment of rivers and water systems in areas vulnerable to climate change is needed. post, including cities and farmland.

“Flooding is often caused by two combined factors: one, heavier-than-usual rainfall, and two, rivers not being able to discharge the additional collected rainwater,” he said.

In both China and northwestern Europe, the disaster followed a period of unusually heavy rainfall, equivalent to the Chinese case where a year’s rainfall fell in just three days, completely overwhelming the ability to flood protection.

After several severe floods in recent decades, buffer zones have been strengthened along Germany’s major rivers such as the Rhine or Elbe but last week’s extreme rainfall also turned small tributaries. like the Ahr or the Swist into terrifying whirlpools.

In China, urban areas built with insufficient water to evacuate and large dams that alter the natural flow of the Yellow River basin could also contribute to the disaster, scientists say .

But measures such as improving the resilience of buildings and elevating riverbanks and improving drainage are unlikely to stop the impact of severe flooding on their own. As a last resort, warning systems, heavily criticized in Germany for giving people insufficient time to react, would have to be improved.

“It really needs to be tied to the actual knowledge that people have in order to be able to do it,” said Christian Kuhlicke, head of the environmental risk and extreme events working group at the Helmholtz Center for Environmental Research. they know what to do.

“If you can’t keep the water back, if you can’t save your buildings then at least make sure all the vulnerable are moved out of these places.”