A Germany-Sized Lake Once Covered the Sahara

In the heart of the world's largest hot desert, there was once a lake the size of Germany. This is the story of the Green Sahara: how a wobble in Earth's orbit turned the desert green, the people who lived on its shores, how it all disappeared, and why its dust still feeds the Amazon today. CHAPTERS 0:00 A Lake in the Desert 1:45 Rivers Under the Sand 3:06 The Living Desert 5:07 Gobero 7:09 A Wobble in Space 9:09 The End of the Green 11:30 The Gift of the Nile 13:28 A Dead Lake, a Living Forest KEY SOURCES McCauley, J. F. et al. (1982). Subsurface valleys and geoarcheology of the eastern Sahara revealed by Shuttle radar. Science 218. Drake, N. & Bristow, C. (2006). Shorelines in the Sahara: geomorphological evidence for an enhanced monsoon from palaeolake Megachad. The Holocene 16. Schuster, M. et al. (2005). Holocene Lake Mega-Chad palaeoshorelines from space. Quaternary Science Reviews 24. Sereno, P. C. et al. (2008). Lakeside cemeteries in the Sahara: 5000 years of Holocene population and environmental change. PLOS ONE 3(8). Kutzbach, J. E. (1981). Monsoon climate of the early Holocene. Science 214. deMenocal, P. et al. (2000). Abrupt onset and termination of the African Humid Period. Quaternary Science Reviews 19. Kröpelin, S. et al. (2008). Climate-driven ecosystem succession in the Sahara: the past 6000 years. Science 320. Kuper, R. & Kröpelin, S. (2006). Climate-controlled Holocene occupation in the Sahara: motor of Africa's evolution. Science 313. Malville, J. M. et al. (1998). Megaliths and Neolithic astronomy in southern Egypt. Nature 392. Wright, D. K. (2017). Humans as agents in the termination of the African Humid Period. Frontiers in Earth Science 5. Brierley, C., Manning, K. & Maslin, M. (2018). Pastoralism may have delayed the end of the green Sahara. Nature Communications 9. Yu, H. et al. (2015). The fertilizing role of African dust in the Amazon rainforest. Geophysical Research Letters 42. MAPS, 3D & DATA Earth imagery: NASA Blue Marble Next Generation (NASA Earth Observatory), NASA Black Marble / VIIRS night lights, NASA cloud imagery Elevation: Terrain Tiles on AWS (Mapzen / Linux Foundation), built from SRTM, ETOPO1, GMTED2010 and other open datasets Lake Mega-Chad extent modelled from elevation at a 325 m shoreline; vegetation extents and some site positions are illustrative All 3D scenes rendered in Blender IMAGE & FOOTAGE CREDITS Cave of Swimmers, Wadi Sura — Photo: Roland Unger / Wikimedia Commons, CC BY-SA 3.0 Gilf Kebir — Photo: Ilan Molcho / Flickr via Wikimedia Commons, CC BY 2.0 László Almásy — Photo: unknown author / Wikimedia Commons STS-2 launch — NASA, Public Domain SIR-C/X-SAR radar image (1994) — NASA/JPL Tassili n'Ajjer rock art — Photo: IssamBarhoumi / Wikimedia Commons, CC BY-SA 4.0 Rock art — Photo: Linus Wolf / Wikimedia Commons, CC BY-SA 3.0 Tadrart Acacus rock art — Photo: Luca Galuzzi / Wikimedia Commons, CC BY-SA Lake Chad 1973–2001 — NASA GSFC Scientific Visualization Studio / Landsat 7 Project Science Office Lake Yoa — Photo: Jacques Taberlet / Wikimedia Commons, CC BY-SA 3.0 Gobero triple burial — Sereno et al. (2008), PLOS ONE, CC BY Nile at night from the ISS — NASA / Scott Kelly, Public Domain Nile Delta at night — NASA, ISS025-E-9858, Public Domain Nabta Playa stones (reconstruction, Nubian Museum, Aswan) — Photo: Raymbetz / Wikimedia Commons, CC BY-SA 3.0 Giza pyramids — Photo: Morhaf Kamal Aljanee / Wikimedia Commons, CC BY-SA 3.0 Bodélé dust storm (MODIS) — NASA / MODIS Rapid Response Team, NASA GSFC Stock footage (desert, savanna, wildlife, rain, Nile, Giza, Amazon, night sky, spinning top) — Pexels (Pexels License) Music, sound effects and narration voice — ElevenLabs #Sahara #GreenSahara #History #Documentary