GLOBAL warming change is dramatically raising the threat of river floods around the world.
Noting that river floods are already the most common and devastating natural disasters, German scientists have cal-culated the required increase in flood protection until the 2040s worldwide.
They say if decision-makers choose to ignore the issue, disaster will come.
The Potsdam Institute for Climate Impact Research (PIK) report says the increase in river flood risks will be driven by the amount of greenhouse-gases already emitted and does not depend on whether or not global warming is slowed.
“However, without limiting human-caused warming to well below 2° Celsius, river flood risks in our century will increase in many regions to a level that we cannot adapt to,” PIK head of global adaptation research Anders Levermann says.
“To keep people safe, climate-change-induced risks must be taken seriously and money must be spent for adaptation. If we act now, we can protect against the risks of the next two decades.”
But he says further climate change must be limited by cutting greenhouse gas emissions from fossil fuels to avoid risks that surpass the abilities to adapt.
“The time has come where mitigating future climate change must be accompanied by adapting to the climate change that we already caused,” he says.
“Doing nothing will be dangerous.”
The research shows the need for adaptation is greatest in the United States, parts of India and Africa, Indonesia, and in Central Europe.
Researcher Sven Willner says inaction will expose many millions of people to severe flooding.
“More than half of the United States must at least double their protection level within the next two decades if they want to avoid a dramatic increase in river flood risks,” he says.
Without additional adaptation measures – such as enhancing dykes, improved river man-agement, increasing build-ing standards, or relocating settlements – the research published in the journal Science Advances, says the number of people affected by the worst 10 per cent of all river flooding events will increase.
In South America the number of people affected will likely double to 12 million, in Africa from 25 million to 34 million, and in Asia from 70 million to 156 million.
“We have been surprised to find that even in developed countries with good infrastructure, the need for adaptation is big,” Levermann says.