What has driven the changes in West Africa's land use and land cover over the past 40 years, and what patterns do they show? To find out, the U.S. Geological Survey's West Africa Land Use Dynamics project worked with CILSS — the Comité permanent Inter-états de Lutte contre la Sécheresse dans le Sahel — and the U.S. Agency for International Development in West Africa to map the region's land in 1975, 2000 and 2013. The result is a 219-page atlas, Landscapes of West Africa: A Window on a Changing World, which uses satellite images, maps and photographs to tell a complex story of change, regionally and country by country. Its case studies include some that give cause for concern and others that offer real hope.
The story the atlas tells
The atlas covers the 17 countries of West Africa, from Mauritania to Chad and from the Sahel to the Gulf of Guinea, including the Cabo Verde islands. Using 1975, 2000 and 2013 as benchmarks, it describes the major changes in land cover in each country and across the region, and discusses their causes and their environmental, social and economic effects. Maps and statistics show how fast, how much and where the land changed, and photographs and satellite images make the changes easier to grasp for people in West Africa and beyond.
At the centre are the region's roughly 335 million people — about three times as many as lived there nearly four decades earlier. That rapid growth has driven dramatic losses of savanna, woodland, forest and steppe, mostly to farming: the cultivated area doubled between 1975 and 2013. Much of the harvest feeds a growing rural population, but more and more goes to cities such as Lagos, Ouagadougou, Dakar and Accra, as the share of West Africans living in towns and cities has risen from 8.3 percent in 1950 to nearly 44 percent in 2015. The region's people and leaders face an ever more complex task: meeting the immediate needs of a growing population while protecting the environment that must sustain it. Written for decision-makers and the public alike, the atlas aims to raise awareness of the changes — many worrying, some hopeful — under way across the land.
Wooded savanna turned into farmland — millet and peanut, after harvest — in central Senegal, south of Kaffrine, between 1994 (left) and 2010 (right). Photographs by Gray Tappan, USGS.
The data behind it
The analysis rests on the West Africa Land Use Land Cover Time Series, which maps land use and land cover at 2-kilometre resolution across sub-Saharan West Africa for 1975, 2000 and 2013. Built from visual interpretation of hundreds of satellite images, it gives an accurate, unique basis for analysing land change systematically across the region.
Land can be restored by planting trees or letting vegetation regrow naturally: native acacias planted along terraces on the Ader-Doutchi Plateau, Niger. Photograph by Gray Tappan, USGS.
Getting the atlas and data
The atlas was published in English and French. Its few printed copies went to national and regional decision-makers, but the atlas and the data can be downloaded free from the project website, eros.usgs.gov/westafrica, with no restrictions on later use, sale or redistribution.
Sources
- U.S. Geological Survey, Earth Resources Observation and Science Center (contact Gray Tappan), The Landscapes of West Africa—40 Years of Change, Fact Sheet 2017–3005, February 2017 (also published in French). https://doi.org/10.3133/fs20173005
- CILSS, 2016, Landscapes of West Africa—A Window on a Changing World. https://doi.org/10.5066/F7N014QZ
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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