WEATHER NEWS: Climate change made deadly floods in West Africa 80 times more likely


Devastating floods this summer and fall displaced 1.5 million Nigerians and killed 612. In all of West Africa, more than 800 people died. Researchers have determined that human-caused climate change made the excessive rainfall behind the flooding 80 times more probable, according to a new analysis published Wednesday.

The researchers, from the World Weather Attribution group, which evaluates the impact climate change has on extreme-weather events, made several related findings:

  • The rainy season in West Africa was 20 percent wetter than it would have been without the influence of climate change.
  • Throughout West Africa, prolonged rain events such as the one just experienced now have a 1 in 10 chance of happening each year; previously they were exceptionally rare.
  • Short periods of intense downpours, which worsened the recent floods, have become twice as likely in the Lower Niger Basin region because of climate change.

In their analysis, researchers uncovered what they described as a “very clear fingerprint of anthropogenic,” or human-caused, climate change.

The analysis employed weather data and climate models to compare present climate conditions to the past. The researchers focused on the Lake Chad Basin, which saw a wetter-than-average rainy season, and the Lower Niger Basin, which saw short spikes in very heavy rain, to analyze climate change impacts.

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Running simulations with and without the influences of greenhouse gas emissions and aerosol pollution, the researchers were able to quantify how climate change altered the risk of extreme rainfall.

Nigeria, Niger, Cameroon, Chad and Benin were among the countries hit hardest by the flooding. Nearly 200 Niger residents and 22 people in Chad were killed.

The disastrous flooding was another example of extreme weather — intensified by climate change — disproportionately affecting vulnerable zones.

“In regions such as West Africa … there is less data and less scientific attention than in richer parts of the world,” said Maarten van Aalst, a researcher and director of the Red Cross Red Crescent Climate Center, one of the analysis’s authors. “The floods resulted in massive suffering and damages, especially in the context of high human vulnerability.”

West Africa’s typical rainy season spans from May to October, but this year’s rainy season started early. Nigeria and Niger were the first to experience sweeping floods.

In Nigeria alone, flooding injured 2,776 people, damaged 123,807 homes and inundated 392,399 hectares of farmland, said Sadiya Umar Farouq, the minister of humanitarian affairs, disaster management and social development.

“We sympathize with the families of those who lost their lives, those who have lost their livelihoods and property. This is very unfortunate,” Farouq said in a statement.

“These are natural disasters, and we pray we don’t see this again,” she added.

But the analysis concluded that the area will see such flooding with even greater frequency in the decades ahead.

The increased prevalence of these flood events will leave already vulnerable communities more susceptible and less able to bounce back.

“This can be in a physical sense, for instance if flood-protection measures have been destroyed, or houses are rebuilt with more vulnerable materials,” van Aalst told The Washington Post. “But also in terms of human vulnerability, for instance if people have invested their assets or savings to pick up their lives and then don’t have that buffer anymore if a next shock arrives.”

Along with its analysis of climate change role’s in the West Africa flooding, researchers attempted to learn the part it played in 2021’s drought in the Sahel region. The semidesert region, which depends on annual rain for crop production, took a major hit when less than 40 percent of its crop water needs were met that summer. Because of limited available data, however, the researchers were unable to determine whether human-caused warming was a factor.

The report from the researchers said both analyses point to West Africa’s vulnerability to swings in precipitation, which will only get worse as temperatures warm.

Some scientists are calling for wealthier countries, particularly in the West, to financially address the impacts of extreme weather events and climate change in suffering poorer countries.

“It is only fair that we see that challenge as part of the global responsibility to address the climate crisis: We all need to reduce emissions to avoid risks getting further out of hand but also invest much more in adaptation to reduce vulnerability to increasing hazards, and enhance capacity to cope with impacts, especially in the most vulnerable communities,” van Aalst said.

Twenty-two researchers were involved in the analysis of the floods in West Africa and 18 for the Sahel drought study.

The World Weather Attribution project has also analyzed more than a half-dozen other extreme-weather events this year to assess the influence of climate change. For example, it found that climate change made the record-setting heat in Britain in July 10 times more likely, and the extreme heat in India and Pakistan during May and June 30 times as probable. It also determined that climate change increased the rainfall that triggered summer flooding in Pakistan by 50 to 75 percent.

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