Reuters / Climate change is likely to worsen floods on rivers such as the Ganges, the Nile and the Amazon this century while a few, including the now-inundated Danube, may become less prone, a Japanese-led scientific study said June 9.
The findings will go some way to help countries prepare for deluges that have killed thousands of people worldwide and caused tens of billions of dollars in damage every year in the past decade, experts wrote in the journal Nature Climate Change.
Given enough warning, governments can bring in flood barriers, building bans on flood plains, more flood-resistant crops and other measures to limit damage.
Overall, a “large increase” in flood frequency is expected in southeast Asia, central Africa and much of South America this century, the experts in Japan and Britain wrote.
Severe floods would happen more often on most of the 29 rivers reviewed in detail, including the Yangtze, Mekong and Ganges in Asia, the Niger, the Congo and the Nile in Africa, the Amazon and the Parana in Latin America and the Rhine in Europe.
Flooding would become less frequent in a handful of river basins including the Mississippi in the United States, the Euphrates in the Middle East and the Danube in Europe.
The experts predicted that northwestern Europe, where the Rhine flows, would be damper while a band from the Mediterranean Sea through eastern Europe — including the Danube region — into Russia would be drier.
The scientists said there were wide bands of uncertainty.
Tens of thousands were forced to leave their homes and at least a dozen people died in floods that hit Germany, Austria, Slovakia, Poland and the Czech Republic last month.
Climate scientists say that, overall, rising temperatures increase the risk of floods because warmer air can absorb more moisture and so cause more rain. Changes in winds and other factors mean some areas are likely to get wetter, others drier.
Professor Mojib Latif, a meteorologist at the Helmholtz Centre for Ocean Research in Germany, who was not involved in the study, said there are few reliable rainfall records on which to build forecasts.
Still, he predicted that floods like those now in Europe would become more likely as temperatures rise. “We’re seeing an increase in flooding events… Research shows that the probability of heavy precipitation will increase,” he said.
Worldwide, average surface temperatures have risen by 0.8 C since the Industrial Revolution, a trend the UN panel of experts blames mainly on human emissions of greenhouse gases from cars, factories and power plants.