Scientists have found that our ancestors were forced out of Africa by pre-historic climate change caused by dramatic shifts in earth’s orientation 125,000 years ago.
The fascinating discovery was made by researchers at the University of Hawaii using complex computer programs to measure the effects of global warming and sea level patterns on human migrations over thousands of years ago.
They found long periods of ice age pushed people towards Asia and Europe through the Arabian Peninsula and the Mediterranean as temperatures fell and humidity rose across what is now North Africa.
Major migrations occurred during four significant and prolonged waves, the first beginning around 106,000 years ago and the most recent starting 45,000 years ago, according to the study published in the journal Nature.
Our pre-historic forebears took advantage of the wetter stages of this glacial era to travel across the land that today makes up the bone-dry Sahara and Arabian deserts of North Africa.
At the time there was enough vegetation and water to provide food for long-distance treks across continents.
Nature said the study, led by Alex Timmermann, uncovered the essential role of climatic variations in “orbital scale” on the distribution of populations across the world.
It said Dr Timmermann and his team used “the most comprehensive model so far, including data on climate, vegetation and human movements”
University of Columbia researcher Peter Demenocal told the journal, today the Sahara and Arabian deserts form an effective barrier against the spread of African wildlife.
But in the past, changes in the Earth’s orientation axis caused a monsoon climate and established wetter conditions, which allowed outward migration paths with vegetation.
Crickey Conservation Society 2019.