The Sahel is the transition zone between the Sahara Desert to the north and the wetter savannas and tropical forests of central Africa to the south. It runs roughly 5,000 kilometres east-west across the continent, from Senegal on the Atlantic coast to Sudan and Eritrea on the Red Sea coast, passing through Mauritania, Mali, Burkina Faso, Niger, Nigeria (northern parts), Chad, and Sudan. The Sahel is not a country or political entity but a geographic and climatic zone — a 200-to-400-kilometre-wide belt of semi-arid grassland and scrub that receives 200 to 600 millimetres of rainfall per year, mostly during a single short summer monsoon season. About 100 million people live in the Sahel today, distributed across a region that is one of the most climate-stressed, food-insecure, and politically unstable parts of the world. The Sahel has been one of the most consequential climate-and-security zones in the modern era, and the implications of its trajectory are increasingly evident in European migration patterns and in the wider Mediterranean security landscape.
The Climate Story
The Sahel's climate is dominated by a single annual monsoon. Tropical air rises over central Africa, drawing in moisture-laden air from the Gulf of Guinea to the south. The northern limit of this monsoon air mass — called the Inter-Tropical Convergence Zone — moves northward in summer (June through September) and brings rain across the Sahel. The rest of the year is dry, with the hot, dry harmattan wind blowing south from the Sahara across the entire region. The exact location and intensity of the monsoon's northern limit varies year to year and decade to decade, and these variations produce the boom-and-bust rainfall pattern that has shaped Sahelian agriculture and pastoralism for thousands of years. Recent decades have seen substantial shifts in the monsoon pattern, with implications that the next several pages discuss.
The Great Drought
The most consequential climatic event in the Sahel's recent history was the multi-decadal drought of 1968 to 1985. Beginning in the late 1960s, rainfall across the Sahel dropped substantially below long-term averages and stayed there for nearly two decades. Mali, Niger, Burkina Faso, Chad, and northern Nigeria all experienced severe and prolonged drought conditions. Pastoralist economies that had depended on the regular northward expansion of grasslands during the monsoon season collapsed. Livestock died in their millions. Agricultural systems failed. Famine spread. Between 100,000 and 250,000 people died across the region in famine-related causes; population estimates vary because of difficulties in documentation. The drought ended in the mid-1980s and rainfall partially recovered, but the social and political consequences continued to compound. Many Sahelian governments were destabilised by the drought's effects, and the dietary and demographic patterns of the region have been substantially shaped by what happened during those decades.
The Rebound and the Greenening
From the mid-1980s onwards, rainfall in the Sahel partially recovered. Satellite imagery from the 1990s through 2010s showed substantial "greenening" of the Sahel as vegetation returned to areas that had been functionally desert during the drought. The greenening trend was substantial enough to be visible from space and substantial enough to be a measurable global carbon sink. Several causes have been proposed: shifting Atlantic and Indian Ocean temperature patterns, increased atmospheric CO₂ promoting plant growth, large-scale reforestation efforts (particularly in Niger's Maradi-Zinder region, where a farmer-led system of regenerative agroforestry has expanded native tree cover across millions of hectares), and shifting monsoon dynamics under regional climate change. The greenening is real but incomplete; rainfall remains below pre-1960 long-term averages in many areas, and the recovery is unevenly distributed across the region. It is, however, one of the few regional bright spots in the global climate-and-vegetation picture.
The Tuareg and the Pastoral Question
The Sahel's traditional way of life centred on nomadic and semi-nomadic pastoralism — primarily of camels, cattle, sheep, and goats — across the semi-arid grasslands. The Tuareg people, who range across parts of Mali, Niger, Burkina Faso, Algeria, and Libya, have been the most prominent of the Sahelian pastoralists, with their distinctive blue-dyed textiles, complex social hierarchy, and centuries of trans-Saharan caravan trade. Fulani and Wodaabe pastoralists in West Africa, Toubou in Chad, and other groups have similar pastoral traditions. The 20th century's changes — the drying climate, the establishment of national borders that constrained traditional grazing routes, the conversion of grassland to settled agriculture, the collapse of the caravan economy with the development of motor transport, and the various political conflicts of the post-independence era — have substantially compressed traditional pastoral livelihoods. Pastoralists are often marginalised politically in countries dominated by settled agricultural majorities. Climate change is accelerating these tensions, particularly through pressure on water and grazing resources.
The Jihadist Crisis
The Sahel has become one of the major centres of jihadist insurgency in the world. The 2011 NATO intervention in Libya and the subsequent collapse of the Libyan state opened a flow of weapons and trained fighters across the central Sahel. Various Al-Qaeda- and Islamic State-affiliated groups (JNIM, ISGS, Boko Haram in northern Nigeria and the Lake Chad basin, Ansaroul Islam in Burkina Faso, and others) have controlled or contested territory across northern Mali, central Mali, eastern Burkina Faso, western Niger, and northeastern Nigeria. The French military intervention in Mali — Operation Serval in 2013, expanding to Operation Barkhane across the broader Sahel from 2014 to 2022 — was the most substantial Western military commitment to the region in decades. The intervention slowed the immediate jihadist advance but did not eliminate it. French forces withdrew from Mali in 2022 and from Burkina Faso, Niger, and Chad in 2023-24 amid a series of military coups in those countries and the rise of Russian-aligned mercenary operations as partial replacements. The current security situation across the central Sahel is the worst it has been in living memory.
The Coups
The political instability of the past several years has produced a cluster of military coups across the central Sahel: Mali (in 2020 and again in 2021), Burkina Faso (in 2022, twice), Niger (in 2023), Chad (a transitional military takeover in 2021), and Guinea (in 2021, slightly outside the Sahel but politically related). The "coup belt" running across the central Sahel has been one of the major political stories of the early 2020s. Each of the coup governments has, to varying degrees, pursued more nationalist and less Western-aligned foreign policies, with Russia (and to a lesser extent China and Iran) replacing France as the dominant external partner in several cases. The Wagner Group and its successor, Africa Corps, have deployed troops to Mali, Niger, Burkina Faso, and the Central African Republic. The combined effect is to remove one of the more stable post-colonial political orders in the region and to leave its replacement uncertain.
The Great Green Wall
One of the more ambitious responses to the long-term climate and ecological challenges of the Sahel is the Great Green Wall initiative, launched by the African Union in 2007. The original idea was to plant a continuous belt of trees from Senegal to Djibouti across the southern Sahel, creating an 8,000-kilometre-long, 15-kilometre-wide ecological barrier against desertification. The actual project has evolved considerably. The "wall" is now understood as a mosaic of regenerative practices — agroforestry, water conservation, soil restoration, sustainable agriculture — rather than literally a row of planted trees. Funding has been intermittent, with substantial commitments at international climate conferences not always translating into ground-level implementation. Niger's farmer-led natural regeneration programme is the most successful element so far, with somewhere between 5 and 7 million hectares of regenerated tree cover across the country. Other countries have made less progress. The Great Green Wall is one of the more interesting test cases for large-scale climate adaptation in a regionally vulnerable area.
The Coming Decade
The Sahel's trajectory in the next decade depends on the interaction of several major forces. The climate trajectory will continue to shape rainfall patterns, agricultural productivity, and water availability. The security situation will determine whether large areas remain governable. The demographic trajectory will continue — Sahelian populations have grown substantially over the past 40 years, with several countries in the region having among the highest birth rates in the world, and the youth bulge in the population creates both economic potential and political instability risks. The relationship with the post-French security architecture in the region will determine whether external partners can re-establish productive engagement with the new political orders. The migration patterns flowing from the Sahel to North Africa and on to Europe will continue to interact with European politics. The Sahel is one of the regions where the combined pressures of climate change, demographic change, political volatility, and migration are most concentrated, and what happens here over the next 10-20 years will shape outcomes far beyond the region itself.