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

Devastating floods this [northern hemisphere] summer and fall [autumn] 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.

  • The rainy season in West Africa was 20% 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.

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.

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.

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.

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%.