African Climate Zones and Sahel Desertification
GeographyRegions & CountriesAges 12–13
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Regions & Countries
A hand-drawn map of Africa shows climate zones lying almost symmetrically across the Equator: humid equatorial in the middle, sub-equatorial savanna on either side, then dry tropical zones with the Sahara and Kalahari deserts, and Mediterranean subtropical at the outer edges. Drag the latitude arrow on the map to read off the climate zone and landscape at that latitude. Click Run to simulate the Sahel: changing rainfall and grazing pressure shows vegetation cover and the desert boundary shifting south (desertification) or retreating as the land recovers.
Lesson: Physical geography of Africa; desertification
What it shows
Africa straddles the Equator, so its climate zones form an almost mirror-image pattern: humid equatorial rainforest in the middle, savanna with one wet and one dry season on either side, dry tropical deserts around the tropics, and Mediterranean climates at the northern and southern edges. The second panel models desertification in the Sahel, on the southern edge of the Sahara. Vegetation cover depends on rainfall and grazing pressure; when too many animals graze in dry conditions, plants cannot regrow, bare soil is eroded by wind and the desert boundary advances south.
How to use
Drag the Latitude on map from 34°S to 36°N and note how each climate zone and landscape reappears on the other side of the Equator. Then set the Average annual rainfall in the Sahel and the Grazing pressure in the Sahel, press Run and watch vegetation cover and the desert boundary change year by year. Keep rainfall fixed and change only grazing to separate human causes from climatic ones.
Parameters you can change
- Latitude on map (negative = Southern Hemisphere) -34–36 °
- Grazing pressure in the Sahel 0–4 head/ha
- Average annual rainfall in the Sahel 100–800 mm
- Simulation speed 0.5–10 years/s
Questions to explore
- Why are Africa's climate zones arranged almost symmetrically north and south of the Equator?
- With rainfall held constant, how does raising grazing pressure affect the position of the desert boundary?
- Which combination of rainfall and grazing lets Sahel vegetation recover and the desert retreat north?
