Why does the Sahara turn green every 20000 years?

Answer 1

The Sahara Desert experiences cycles of greening approximately every 20,000 years due to changes in the Earth's axial tilt and orbit, known as Milankovitch cycles. These variations affect the distribution of sunlight, leading to increased rainfall and the expansion of vegetation in the region. During these periods, the once arid landscape can support grasslands and forests, creating a more hospitable environment for wildlife and human habitation. As the cycles progress, the climate shifts back to arid conditions, returning the Sahara to its desert state.