As human ancestors rose on two feet in Africa and began their migrations across the world, the climate around them got warmer, and colder, wetter and drier. The plants and animals they competed with and relied upon for food changed. Did the shifting climate play a direct role in human evolution?
The evidence so far is thin, said Richard Leakey, the renowned paleoanthropologist and conservationist who joined a score of scientists delivering their findings at a conference on climate change and human evolution this week, held at Columbia’s Lamont-Doherty Earth Observatory.
“Is there evidence for a direct connection between changing climate and human evolution?” Leakey asked during a keynote address Thursday. “The answer so far is no. I don’t see it yet.”
Still, a number of scientists are on the hunt. Speakers talked about changes in plants and animals, and how fluctuations in temperature and rainfall would have altered the landscapes. They’re studying what carbon isotopes in soil can tell us about changing plant life and temperature; what hominid teeth suggest about changes in diet; and what sediment cores from the bottom of the ocean have to say about variations in monsoon rainfall.