With a 2015 population of 367 million (UN, 2015), West Africa is home to 5 percent of the world’s population. This is a five-fold increase in population since 1950, when 73 million people lived in the region, which makes West Africa the fastest growing of any of the world’s regions. For comparison, the world population has increased less than three-fold during the same time period. The young age structure of the West African population — almost half of West Africans are 15 years old and younger — assures continued population growth into the near and medium future. Assuming a medium fertility model, the population of the region is projected to exceed one billion by 2059, when almost one in 10 of the world’s people will be West African (UN, 2015).
The age structure of West Africa’s current population forms the shape of a pyramid with a wide base and concave sides, indicating a high birth rate and a relatively high death rate, resulting in rapid growth. By comparison, the age structure of the global population has moved toward a more rectangular shape, describing a population that is only slowly expanding, with lower birth and death rates and more people living to old age.
West Africa’s population is unevenly distributed throughout the region, reflecting differences in the physical environment as well as the history of human settlement (see map above). In the arid northern part of the region, only a small, sparse population can be sustained. In the arable regions, where soils are fertile and the climate is favorable for crop cultivation, higher population densities are found. Thus, the Peanut Basin of western Senegal, the Niger-Nigeria border region, central Burkina Faso, and southwestern Chad stand out by their relatively high rural population densities.
Settlements are also concentrated in the riverine plains of the Senegal and Niger rivers, where perennial water availability supports irrigated agriculture of rice and high value garden crops. In the densely forested southern part of the region, which has historically been more difficult to develop, rural population densities are generally lower than in the open savanna. However, along the coast, population densities are driven up by a large number of coastal settlements, including some major urban agglomerations.
The map of population densities (above) shows higher population densities in Nigeria than in any other West African country. Indeed, almost half of West Africans are Nigerian, and with over 172 million inhabitants, Nigeria is the most populous country in the entire African continent. The remaining 16 countries account for the other half of the West African population, with Ghana coming in at a distant second (7.5 percent of West Africa’s population). What might explain this noticeable difference between Nigeria and the rest of West Africa? People tend to settle where the climate is clement, the soils are fertile, and economic opportunities are present. Nigeria encompasses an extensive savanna region, without the extreme aridity found in the northern countries, and a large delta and coastal plains. Two important perennial rivers, the Niger and the Benue, as well as their tributaries, assure sufficient water provision. While civilizations flourished across the region in the 15th through 19th centuries, the high concentration of kingdoms, empires and particularly city states — such as Kano, Katsina, Oyo, Ife, Benin, Nri, Igbo and others— is unique to the territory that became modern Nigeria. Two out of the three ancient trans-Saharan trade routes originating from North Africa and Arabia ended in Nigeria, which brought an influx of people to settle and trade. As an already very densely populated country today, Nigeria provides a preview of the pressures on the land resources that other parts of West Africa will likely have to face in the future.
Not only has West Africa’s population been growing rapidly at an average annual rate of 2.75 percent, it has also become more urban, with some major cities recording mean annual growth rates of up to 9 percent.
A majority of West Africans still live in rural areas, yet the urban population has increased from only 8.3 percent in 1950 to almost 44 percent in 2015. The changes in lifestyle and consumption patterns associated with a progressive urbanization of the population affect land use and land cover patterns beyond the obvious increase of built-up area (Rindfuss and others, 2004). Dietary demands of the urban population translate into land demands in the urban periphery, in particular for the cultivation of high-value, perishable crops, such as fruits and vegetables. Part of the wages earned in the city reach the rural areas in the form of remittances to the homelands of the new urbanites, where they spur investments in economic activities that potentially affect the land cover, such as through abandonment or intensification of agriculture. These are just a few of the linkages between population and land use/land cover (Lambin and others, 2001).