COUNCIL CHRONICLE – A new study claims to have found out one of the reasons why our human ancestors left Africa, the continent called by many “the cradle of life”. Based on this latest research, the continent’s climate went from wet and teeming with life to very dry some 60,000 years ago.
Genetic research had previously indicated that humanity migrated from Africa into Eurasia somewhere between 70,000 to 55,000 years ago.
“There has always been a question about whether climate change had any influence on when our species left Africa,” states Jessica Tierney, of the University of Arizona.
Drying Land and Climate Change
Research had already suggested that the climate in Africa must have been wetter at the time when humanity was first living there. This would have been a necessary condition, one that would have allowed their crossing the Horn of Africa and also the Middle East to get to Eurasia.
Now, the new study suggests that northeast Africa was a drying land or was already arid as our ancestors left the continent. The researchers established that, more than 70,000 years ago, the Horn of Africa was passing through a “Green Sahara” wet phrase.
Then, some 70,000 years ago, this shifted and started getting drier, becoming even more arid than it is today. Also, the area must have become colder.
The study team determined these facts by studying a core of ocean sediment. This was taken from the Gulf of Aden’s western end in 1965.
By studying it, scientists were able to estimate rainfall and temperature records. They also analyzed sediment layers looking for marine algae.
Based on the data gathered from it, the researchers believe that people were “forced out” of Africa by the climatic changes.
The fact that the climate was drier might have been a “motivating source” for the incoming migration. Detailed study results are available in a paper published in the journal Geology.
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