Newly discovered African ‘climate seesaw’ drove human evolution

Glacial-interglacial cycles strongly impact patterns of climate change in many parts of the world and were also assumed to regulate environmental changes in Africa during the critical period of human evolution.

New Delhi: Ancient El Nino-like weather patterns were the primary drivers of environmental change in sub-Saharan Africa when humans were evolving, according to research involving UCL, London’s university.

Scientists have shown that over the last 6,20,000 years these alternately wet and dry patterns had more profound impact in sub-Saharan Africa than colder, dryer glacial-interglacial cycles, which until now have been more commonly linked to human evolution.

Professor Mark Maslin of UCL Geography, who contributed to the international study, published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), said the findings challenge previous theories on the impact of changes in the climate on the earliest ancestors.

“The detailed analysis of the past climate of Africa, led by Stefanie Kaboth-Bahr (University of Potsdam), has revealed an oscillation between wet and dry conditions across the continent. This means for at least the last 6,00,000 years there has been continual environmental change as wet lush conditions moved from the east to the west and then back again,” said Professor Maslin.

“This drove significant changes in plant and animal migration patterns and contributed to the evolution of new hominin species. This study shows that the long-term El Nino and Southern Oscillation (ENSO)-like climate shifts across Africa had a profound effect on the evolution of early humans,” he added.

It is widely accepted that climate change drove the evolution of our species in Africa, but the exact character of that change and its impacts have not been fully understood.

Glacial-interglacial cycles strongly impact patterns of climate change in many parts of the world and were also assumed to regulate environmental changes in Africa during the critical period of human evolution.

In this latest research, this influence of glacial-interglacial cycles has been challenged as the scientists identified ancient El Nino-like weather patterns as the drivers of major climate changes in Africa, allowing them to re-evaluate the existing climatic framework of human evolution.