Did Ancient Climate Change Drive Human Evolution?
Rift Valley, Ethiopia A. Davey via Wikimedia Commons Millions of years ago, slow changes in the Earth's orbit changed the climate in East Africa dramatically. Every 20,000 years ago, the region vacillated between very dry and very wet periods. These extreme changes may have played a vital role in driving human evolution, according to what's called the pulsed climate variability hypothesis. A new paper from the researcher who first introduced the idea in 2009, University College London geography professor Mark Maslin, links periods of change in the East African Rift Valley—namely the increase in freshwater lakes—with evidence of human evolution. “It seems modern humans were born from climate change," Maslin explained in a press statement, "as they had to deal with rapid switching from famine to feast—and back again." This, he says, was what drove the evolution of...