How did wetter periods during prehistory change the North African environment?

During prehistoric wetter periods, known as the African Humid Period and earlier cycles, the Sahara underwent a dramatic transformation from an arid desert into a verdant landscape.1

These environmental shifts were driven by changes in Earth’s precession, which increased solar radiation in the Northern Hemisphere. This heating supercharged the West African monsoon, allowing moisture-laden air from the Atlantic to penetrate deep into the interior of North Africa.1

As a result, the region was characterized by:
* Hydrological abundance: The formation of extensive rivers and lakes, evidence of which remains in modern-day basins and dry depressions.1
* Lush vegetation: The growth of woodlands and grasslands that supported diverse plants and animals not found in the region today.1

Scientists confirm these cycles by analyzing marine sedimentary rock and hydrogen isotopes from fossilized plant waxes, which reveal alternating phases of humidity and aridity over the last 800,000 years.1