The Sahara under water – Libération

“In the north of the country, even 80-year-olds tell us that they have never seen such torrents rushing down their land.” The Chadian Minister of Regional Planning, Mahamat Assileck Halata, unhesitatingly describes this rainy season as«extraordinaire». Throughout the Sahel-Saharan strip, one of the driest on the planet, the sky has poured exceptional downpours this year. From Mali to Sudan, in just a few weeks, floods have caused more than 1,000 deaths and displaced 3 million people. “And it keeps raining, laments Mahamat Assileck Halata, also vice-president of the National Flood Management Committee. After the devastating violence of the wadis [ces rivières à sec qui se réveillent brutalement à la saison des pluies, ndlr], We fear the flooding of the rivers, which are already abnormally high.”

In 2022, the region had already experienced an intense rainy season, marked by deadly floods. “But this year it’s worse. I’ve never been confronted with such scenes, says Izadine Ali Mahamat Mahamoudi, from the NGO African Humanitarian Action. In Tibesti [région septentrionale du Tchad]people had settled in a wadi that had not flowed for forty years. At night, the water swept them away.” As of September 3, at least 350 people had died in floods in Chad. Tibesti is the region with the highest number of deaths. “There are also gold miners there who have been trapped at the bottom of their wells,” says Izadine Ali Mahamat Mahamoudi.

Tropical Convergence Zone

“It is not often that the Sahara Desert experiences such rainfall. They are normally very rare, less than once a decade on average, but they are usually a sign that something is changing in the Earth’s weather system, indicating an unusual state of the atmosphere as autumn and winter approach,” recalls Andrej Flis, host of the weather website Severe Weather. In a detailed blog post, he notes that the tropical convergence zone – a “band of clouds, showers, storms and precipitation” created by the meeting “trade winds from both hemispheres, creating an upward movement” around the equator – has moved unusually northward this year. A climatic phenomenon that could be linked to the abnormally high temperatures of the Atlantic Ocean and the Mediterranean Sea.

“Over the last thirty days, the amounts of precipitation recorded in the Sahelian belt were generally 120% to 600% higher than the average for the 1991-2020 reference period, describes the bulletin of the Regional Climate Center for West Africa and the Sahel dated September 5. These rainfall amounts exceeded the average by 400% to 600% in northern Chad, northern and central Niger and southeastern Mauritania.” So in September it rained in the middle of the Sahara desert. “More rain fell in four days than in four winters, reports an elected official from the commune of Tessit, in northern Mali. In many villages, about a third or even half of the houses [en terre crue] were destroyed. In Tessalit, where it rains an average of 30 mm per year, 82 mm fell in one go.” A state of national disaster has been declared by the Malian authorities. In mid-August, the ceiling of the Tomb of Askia (1495), an architectural jewel of the city of Gao, listed as a UNESCO World Heritage Site, collapsed.

“Hail destroys millet fields”

In Niger, the oldest mosque in the city of Zinder suffered the same fate at the beginning of September. “In the Agadez region, many mud-brick houses in the old town, listed as UNESCO heritage sites, have also collapsed, testifies a geographer. People are proposing to the authorities to postpone the start of the school year until October since classrooms are occupied by disaster victims in many towns, particularly in the Maradi region.” More than 700,000 Nigeriens have been displaced, according to the NGO Save the Children. 15 kilometers from Abéché, in the east, 15 students from a Koranic school and their teacher died when their house collapsed last week. “But the problem is not just that of homes. There are also losses of crops, and therefore of livelihoods, points out the academic. In the Zinder region, hail is destroying millet fields. In Agadez, several communes in the Aïr massif have seen their onion crops completely submerged by sand carried by floods from the valleys.

Traffic routes have sometimes been cut off by flooding. Niamey, the capital of Niger, has been isolated for several days after bridges were washed away by floods on the outskirts of the city. Roads in the far north, leading to the Algerian border, are still under water. In Chad, “Some cities remain inaccessible to heavy-duty trucks,” indicates Minister Mahamat Assileck Halata. “After the victims, the collapsed walls and the devastated crops, the big worry is the supplies,” explains the prefect of Assoungha, Ali Mahamat Sebey. His department welcomes on its territory the vast camps of Sudanese refugees fleeing the war on the other side of the border. Hundreds of thousands of people are gathered there, dependent on humanitarian aid. «Between Abéché [la grande ville de l’est] and Adré [à la frontière soudanaise], There are currently five large impassable wadis, he explains. Food supplies are completely blocked.”

Africa more exposed to climate change

In Maiduguri, the capital of Borno State in northeastern Nigeria, a dam burst under the pressure of floodwaters. The raging Ngada River poured into the city, destroying thousands of homes. At least 30 people were killed, and 400,000 were displaced. According to Zubaida Umar, the head of the National Emergency Management Agency, “about 40% of Maiduguri” is devastated. “We are still rescuing people and in the end there could be a million displaced people,” she warned in an interview with the BBC.

The summer of 2024 was the hottest ever recorded on the planet. However “Africa suffers disproportionately from climate change,” recalls the World Meteorological Organization. “The continent has warmed at a slightly faster rate than the global average, by around +0.3°C per decade between 1991 and 2023,” indicates a WMO report published on September 2. “climate extremes, including floods and droughts,” more frequent in Africa than elsewhere, “had a major impact on food security.” Consequence: “African countries lose on average 2 to 5% of their GDP to managing these climate extremes, and many reallocate up to 9% to this end.” No one has yet calculated the cost of the rainy season. «extraordinaire» that crosses the Sahel.