UCL News


UCL in the News: Climate swings shaped human evolution

19 November 2007

The evolution of our earliest human ancestors was driven by wild swings in eastern Africa's ancient climate, scientists claim today.


Researchers led by Mark Maslin, director of the Environment Institute at UCL, conducted geological surveys of ancient lakes throughout eastern Africa. They found evidence that over the past 3m years, giant lakes up to 300 metres deep formed and then vanished with the changing climate. The disappearances of the lakes were followed by periods of extreme drought.

"At one extreme, the landscape would have been a true Garden of Eden, with beautiful freshwater lakes, beautiful shorelines and forests along the rivers. There would have been open spaces allowing early humans to exist easily, with water and lots of resources," said Maslin. "But occasionally, these quickly flipped into bone dry periods, where it's 45C in the middle of the day and no natural water resources."

Early humans and other primate species, collectively known as hominids, were forced to adapt to the new environment. …

"If you look at the new species of hominid that evolved, 80% of those, or 13 out of 15, appeared during these pulsed climate periods. It suggests new human species evolved when the climate was highly variable. We don't know if it's the wet period, the dry period or the transition that triggers this, but we can say that when the climate is highly variable, you get a big change in species." …

Ian Sample, 'The Guardian'