According to a study by the World Weather allocation, greenhouse gases have multiplied by 80 the probability of intense rains in Nigeria, but also in Niger and Chad.
Le Monde
Climate change has multiplied by 80 the probability of intense rains at the origin of historical floods in Nigeria, which have killed more than 600 people in recent months and devastated agriculture in the most populous country in Africa, According to a scientific study published Wednesday, November 16.
These extraordinary floods, which also touched Niger, Chad and neighboring countries, have moved more than 1.4 million people and ravaged hundreds of thousands of hectares of harvest, in the midst of a food crisis linked to War in Ukraine. Main cause: exceptional precipitation levels in the region around Lake Chad since the start of the rainy season, in June.
Now “climate change caused by human activity has made this event about 80 times more likely and around 20 % more intense”, concludes the World Weather attribution (WWA), author of the report published on Wednesday. Pioneer, this global network of scientists has established itself in recent years by its ability to assess in a short time the link between extreme weather events and climate change, this link is not systematic.
“Losses and damage”
Among its previous studies, WWA concluded that the drought of the last summer in the northern hemisphere had been made “at least 20 times more likely” by the global warming linked to greenhouse gases. Or that the heat wave of 2021 in northwestern Canada and the United States would have been “practically impossible” without climate change. However, that he was not the major factor in the food crisis in 2021 in Madagascar. These results, emergency products and made public without going through reading committee journals, are obtained by combining methods approved by their peers, in the first place historic weather data and climatic models.
In the region of Lake Chad, the “rainfalls higher than the average” noted this year “now have a chance in ten to occur each year”, while they were extremely rare before the climate impact of the use of Fossil energies, estimates WWA. Scientists also examined the peak of precipitation over seven days along the lower basin of the Niger river in Nigeria. They conclude that “climate change has made the event about twice as likely and about 5 % more intense”.
The publication of these conclusions comes in full negotiations in Egypt at the United Nations Climate Conference (COP27), where developing countries have been asking wealthy countries, polluters since the start of the industrial era, to pay to “losses and damage” linked to climate change.
drought in the Sahel
“It is not ours, scientists, to tell the negotiators what they must do. We are only presenting the evidence”, but even 1.2 ° C of global warming, “we already see An increase in risks, “said Maarten Van Aalst, director of the International Red Cross Climate Center, at an online press conference:” This also shows very clearly that these impacts are not future, they occur Today: we therefore need these financing solutions. “
WWA researchers also looked into the drought in the Sahel, which aggravated the current food crisis in Burkina Faso, Chad, Mali, Niger and Nigeria. This shortage “occurred after an erratic rainy season in 2021, which affected agricultural production and reduces food stocks of months later”, recalls WWA: “But scientists have found that the variability of precipitation in the region and The lack of historical weather data […] did not make it possible to determine if the warming due to man had played a role. “
The researchers therefore consider “essential to invest in weather stations” in the region, essential to help populations “very vulnerable to extreme weather conditions”, whether or not attributable to climate change.