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Posted by on Jun 26, 2020 in At TMV, Featured, History, Nature, Science & Technology | 0 comments

The Sahara was once completely covered with vegetation.

The Sahara was once completely covered with vegetation, as the following science reports explain.

“Enhanced summer insolation during the early and mid-Holocene drove increased precipitation and widespread expansion of vegetation across the Sahara during the African Humid Period (AHP).” – Anne Dallmeyer et al.1

“During the last deglaciation, climatic changes allowed human societies to develop and flourish in the subtropical zone from North Africa to Asia.”Science magazine2

“The onset and termination of the African Humid Period mark the most dramatic changes in North African climate of the past 20,000 years. During the African Humid Period (~15-5 ka), the modern-day Sahara was the site of multiple large lakes as well as extensive vegetation, animal life and human settlements. These conditions are thought to relate to a precessional increase in local summer insolation, which led to an intensification of the North African summer monsoon.” – David McGee, PhD, Department of Geology and Geophysics, University of Minnesota

“Paleoclimate and archaeological evidence tells us that, 11,000-5,000 years ago, the Earth’s slow orbital ‘wobble’ transformed today’s Sahara desert to a land covered with vegetation and lakes.”Nature Education3

“Following the last glacial period and the Younger Dryas, climate warmed around much of the world and human settlements expanded. In Africa, the monsoon rains grew stronger and spread northward into the Sahara. Instead of being the sandy desert we now know, the Sahara was a steppe, covered in grasses and shrubs. In this inviting environment, hunters domesticated buffalo and goats and developed an early system of symbolic art.” – National Centers for Environmental Information. NOAA.

“We know that the African Humid Period in North Africa is mostly related to changes in the Earth’s orbital cycle. Due to small wobbles in the Earth’s rotation, summer sunlight in the Northern hemisphere 11,000 years ago was much stronger than today. This strong heating period warmed up the land surface, caused stronger winds to blow in from the ocean, and led to more rainfall.”– James Russell, PhD, Department of Earth, Environmental, and Planetary Sciences, Brown University4

“During the African Humid Period (AHP), which occurred about 14,800 years ago to 5,500 years ago, the West African summer monsoon was stronger than today. It reached much farther north, bringing significant rainfall to today’s Sahara desert and supported a landscape almost entirely covered in vegetation. These differences in climate and vegetation are related to differences in the orbital parameters of the earth, which resulted in a 5% increase in solar radiation over the Northern Hemisphere during the summer.” – Kerry H. Cook, PhD & Christina M. Patricola, PhD.


Featured Image by Oleg Seliverstov.
Image licensed under the Creative Commons Attribution 3.0 Unported license.

1Dallmeyer, A., Claussen, M., Lorenz, S. J., and Shanahan, T.: The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years, Clim. Past Discuss., https://doi.org/10.5194/cp-2019-86, in review, 2019.

2Out of the African Humid Period. Science 15 Nov 2013: Vol. 342, Issue 6160, pp. 808-809. DOI: 10.1126/science.1246519

3Tierney, J.E., & deMenocal, P.B. (2012). Green Sahara: African Humid Periods Paced by Earth’s Orbital Changes. Nature Education Knowledge 3(10):12. Retrieved from https://www.nature.com/scitable/knowledge/library/green-sahara-african-humid-periods-paced-by-82884405/

4Stacey, K. (2014, December 5). Reconstructing the African humid period. Brown University. Retrieved from https://phys.org/news/2014-12-reconstructing-african-humid-period.html