Extreme rainfall, and the extreme lack of it, affects untold numbers of people, taxing economies, disrupting food production, creating unrest and prompting migrations.
“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 those regions, rainfall from hurricanes can be costly. Munich Re, the reinsurance giant, said the 2018 hurricane season caused $51 billion in losses in the United States, well over the long-term annual average of $34 billion.
Parts of Africa, on the other hand, are experiencing more months with a pronounced lack of rain. 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. “On average, one out of six times you get a six,” he said. “But by injecting huge amounts of greenhouse gases into the atmosphere, humankind has loaded the dice. In many regions, we throw sixes much more often with severe impacts for society and the environment.”
To conduct the study, which appears in the journal Geophysical Research Letters, Lehmann’s team searched databases of the Global Precipitation Climatology Center in Germany. 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 one-third of the record-dry months recorded in the African regions under study would not have occurred without the influence of climate change.
This article originally appeared in The New York Times.