Extreme Rainfall Increases Drastically With Global Warming, Study Finds

According to a recent study by scientists from Germany’s Potsdam Institute for Climate Impact Research, some newer climate models greatly underestimate the extent to which global heating leads to extreme rainfall.

The study predicts more frequent disastrous flooding unless humans reduce greenhouse gas emissions.

“Extremes appear to intensify faster with global warming than the models predict,” said Anders Levermann, one of the authors of the study and a climate scientist at the Potsdam Institute of Climate Impact Research, as New Scientist reported. “Extreme rainfall will be heavier and more frequent. Society needs to be prepared for this.”

The researchers examined the frequency and intensity of daily land-based precipitation extremes in 21 climate models classified as “next generation” that were used by a United Nations body to conduct global assessments, reported AFP.

The research team compared historical changes with those predicted by the climate models and found that almost all the models greatly underestimated the rates of precipitation increases alongside worldwide rises in temperature.

“Our study confirms that the intensity and frequency of heavy rainfall extremes are increasing exponentially with every increment of global warming,” said Maximilian Kotz, lead author of the paper and environmental economist, climate physicist and postdoctoral researcher with the Potsdam Institute, as AFP reported.

The study, “Constraining the pattern and magnitude of projected extreme precipitation change in a multi-model ensemble,” was published in the Journal of Climate.

As nations gear up for the United Nations COP28 Climate Conference in Dubai, which begins on Thursday, the pressure is on to ramp up the shift to renewable energy as the prospects of limiting planetary warming to 1.5 degrees Celsius and avoiding the most disastrous effects of human-caused climate change become less and less likely.

The rainfall increases are roughly in line with the Clausius Clapeyron equation in physics, which says that warmer air contains more water vapor.

“While these rates approximately match expectations from the Clausius-Clapeyron relation on average across models, individual models exhibit considerable and significant differences. Monte-Carlo simulations indicate that these differences contribute to uncertainty in the magnitude of projected change at least as much as differences in the climate sensitivity,” the study’s authors wrote.

The authors said the discovery highlighted the idea that temperature is primarily responsible for worldwide changes in extreme rainfall, rather than wind, reported AFP.

Increases in the frequency and intensity of rainfall were documented in high latitude regions like Northern Canada and across the tropics, like in Southeast Asia, the study said.

“The good news is that this makes it easier to predict the future of extreme rainfall. The bad news is: It will get worse, if we keep pushing up global temperatures by emitting greenhouse gases,” Levermann said, as AFP reported.