A recent study has provided insight into the periodic humid periods in North Africa, explaining why the Sahara Desert was occasionally green. According to the research, these wet phases were driven by changes in Earth’s orbit around the sun and were suppressed during ice ages. The study simulated the historic “greenings” of the Sahara, revealing that they were influenced by remote effects from large ice sheets in the Northern Hemisphere. These periods of vegetation growth were crucial in allowing the dispersal of various species, including early humans. The findings highlight the remarkable environmental changes that have occurred in the Sahara over the past 800,000 years.
https://phys.org/news/2023-09-reveals-sahara-green.html