How Have Hominids Adapted to Past Climate Change?
Scientists attempt to understand how human ancestors adapted–or not–to previous periods of climate change

By Gayathri Vaidyanathan and Climatewire

CLUES FROM THE PAST: Our ancient ancestors can offer insight into our species’ ability to survive and adapt over millions of years scientists say.

“Climate is certainly complex and atmospheric carbon dioxide is higher that at any other time since the origin of our species” says Rick Potts head of the Human Origins Program at the Smithsonian National Museum of Natural History. “This is setting up for conditions that are equal to conditions our ancestors faced in terms of novelty. We want people to contemplate how well a species is equipped to deal with true novelty.”

The Smithsonian exhibit at the Hall of Human Origins of which Potts is curator explores the idea that defining evolutionary events like the discovery of fire or migration out of Africa could be direct results of a changing climate.

Fossils of hominids — all two-legged species related to human beings — document a history of human evolution from the ape-like Lucy (the first known Australopithecus afarensis) to the hand axe-carrying Homo erectus to the climate-changing masters of the planet that we are today. Now at the outset of another climatic change triggered by human behavior scientists say the past can offer clues about our species’ ability to survive and adapt over millions of years.

“People think we’re such a successful species nothing can happen to us” said Potts. But he pointed out most of our ancestors sooner or later went extinct. Homo erectus the forerunner of modern humans lived for 1.5 million years he said. Homo sapiens by comparison has been around for only 200000 years. Yet even they decreased in population size to between 600 and 10000 breeding pairs when hit with mega-droughts heavy monsoonal rains and the eruption of a volcano near Sumatra about 70000 years ago.

A growing body of work in paleoanthropology is showing that at least some of these evolutionary events occurred together with drastic and periodic changes in African and Eurasian climate.

“The idea that human evolutionary changes happen in response to static environments doesn’t hold water anymore” Potts said.