Only 6,000 years ago, the Sahara Desert was a lush, green savanna filled with lakes and wildlife.

The African Humid Period occurred roughly between 15,000 and 5,000 years ago. This transformation was driven by Milankovitch cycles, which are periodic changes in Earth's tilt and orbital shape. During this time, Earth's axial tilt was approximately 24.1 degrees, compared to today's 23.5 degrees. This shift increased solar radiation in the Northern Hemisphere by about 7% to 8% during the summer months.This extra heat strengthened the West African Monsoon system, drawing moisture-laden air from the Atlantic Ocean deep into the continent. Research published in the journal 'Nature' by climate scientists like Peter deMenocal suggests that the Sahara was once home to 'Mega-Lake Chad.' At its peak, this lake covered over 139,000 square miles, making it larger than all the North American Great Lakes combined.Archaeological evidence from sites like the Cave of Swimmers in Egypt and the Tassili n'Ajjer plateau in Algeria confirms the presence of diverse fauna. Rock paintings dating back 7,000 to 10,000 years show humans hunting buffalo and elephants in what is now hyper-arid desert. The transition back to desert conditions around 5,000 years ago was remarkably swift, likely due to vegetation-atmosphere feedback loops that accelerated the drying process.