Past river activity in northern Africa reveals multiple Sahara greenings during the past 160,000 years

Amazing stuff! It was well known for decades that the Sahara was not always a desert! However, this new research appears to confirm that during the last 160,000 years there were multiple greenings of the Sahara. Any of these greenings may have lasted for several thousand years.

"North African greening phases, during which large rivers ran through the Sahara Desert, occurred repeatedly during the Quaternary and are regarded as key periods for the development of past human populations. However, the timing and mechanisms responsible for the reactivation of the presently dormant fluvial systems remain highly uncertain. Here we present hydroclimate changes over the past 160,000 years, reconstructed from analyses of the provenance of terrestrial sediments in a marine sediment record from the Gulf of Sirte (offshore Libya). By combining high-resolution proxy data with transient Earth system model simulations, we are able to identify the various drivers that led to the observed shifts in hydroclimate and landscapes. ..."

"... It offers a comprehensive picture of when and why there was sufficient rainfall in the Central Sahara to reactivate these rivers. "We found that it is the slight changes in the Earth's orbit and the waxing and waning of polar ice sheets that paced the alternation of humid phases with high precipitation and long periods of almost complete aridity" ...
The fertile periods generally lasted five thousand years and humidity spread over North Africa up to the Mediterranean coast. For the people of that time, this resulted in drastic changes in living conditions, which probably led to large migratory movements in North Africa. ..."

Past river activity in northern Africa reveals multiple Sahara greenings | EurekAlert! Science News The analysis of sediment cores from the Mediterranean Sea combined with Earth system models tells the story of major environmental changes in North Africa over the last 160,000 years

Here is the link to the underlying research paper:

Drivers of river reactivation in North Africa during the last glacial cycle

Credits to:

To a scientist with a hammer (I wish the subject line was not so ridiculous)