“Climate change will likely continue to alter the occurrence of record-breaking wet and dry months in the future,” the study predicts, “with severe consequences for agricultural production and food security.” Heavy rainfall events, with severe flooding, are occurring more often in the central and Eastern United States, Northern Europe and northern Asia.
The number of months with record-high rainfall increased in the central and Eastern United States by more than 25 percent between 1980 and 2013.
In 2017, Hurricanes Harvey, Irma and Maria contributed to a total of $306 billion in damage from extreme weather events in the United States.
The number of record-setting dry months increased by nearly 50 percent in sub-Saharan Africa during the study period.
Jascha Lehmann, a scientist at the Potsdam Institute for Climate Impact Research in Germany and lead author of the study, compared extreme weather events to a high roll of a die.
“That’s not to say models are not good,” Lehmann said in an interview, but his observational data “fits what we expect from physics and what models also show.” Climate models have long predicted that because of the greenhouse gases human activity has pumped into the atmosphere and the warming that results, the world’s wet regions are likely to grow wetter.
Regions that tend to be dry, by contrast, are expected to grow even more parched as higher temperatures dry the soil and air.
“Climate change drives both wet and dry extremes,” Lehmann said.
Given natural weather variability, some extreme weather events were to be expected, so the researchers tried to determine how many events would have occurred without the influence of global warming.
The researchers determined that one-third of the record-dry months recorded in the African regions under study would not have occurred without the influence of climate change.