Adapt, Move or Die: Prehistoric Climate Change

Artist's illustration of the prehistoric elephant found in West Runton

hide captionThe skeleton of a prehistoric elephant found on a beach in England raises questions about ancient changes in global climate. Scientists estimate that the elephant was 10 tons — twice the size of today's African elephants.

Watch a slideshow about the excavation of the massive elephant skeleton.
Sam Brown, Norfolk Museums and Archaeology Service
The beach and cliffs at West Runton where the prehistoric elephant remains were found. i i

hide captionThe prehistoric elephant bones were found protruding from the cliffs at West Runton after a winter storm. Geologists analyze the layers of sediment in the cliffs for clues about the ancient climate.

Joe Palca, NPR
The beach and cliffs at West Runton where the prehistoric elephant remains were found.

The prehistoric elephant bones were found protruding from the cliffs at West Runton after a winter storm. Geologists analyze the layers of sediment in the cliffs for clues about the ancient climate.

Joe Palca, NPR

Today, the climate in Britain is pleasant. But every hundred thousand years or so, it goes from pleasant to abominable — part of a natural cycle that is caused by the way the earth tilts and wobbles as it orbits the sun.

The discovery of a skeleton of an enormous, prehistoric elephant on the coast of England is an example of this ancient cycle of warm and cold. The bones of the 10-ton elephant were found protruding from seashore cliffs after a winter storm.

Under an Ice Sheet

Anthony Stuart, a geologist with the University College London, says that if you flew over Britain when it was under an ice sheet, it would look like Greenland or the Antarctic — covered by ice two or three miles thick.

Under an ice sheet, life grinds to a halt. Plants, animals and people have three basic choices during these chilly times: find a way to adapt to living on a block of ice, move out of the way, or die. Eventually, the ice retreats, and life gets easier.

"Once the ice sheets start to roll back... they go back fairly quickly," says archaeologist Clive Gamble. "There's even a phrase for it: instant deglacierization."

By "instant," Gamble means a geologic instant — centuries, or more likely, a millennia or two. It is only after the region warms up that plants, animals and people can return.

England's Elephants

At the seaside town of West Runton in Britain, there is evidence of this ancient climate change. The beach at West Runton is a narrow strip of sand, with the North Sea on the left and a 40-foot cliff face on the right.

On the cliff are broad layers of various colored sediments. Each layer tells a dramatically different story: Boulder clay is evidence of an ancient ice sheet. A black bed at the base of the cliff is more organic — packed with finely-shredded plant material and bits of wool and seed. The black bed was laid down about 700,000 years ago, when Britain was reasonably warm.

Several years ago, the cliffs at West Runton bore yet a further surprise: after a winter storm some local naturalists found several elephant bones protruding from the sediment.

"We then did a rescue dig," says geologist Anthony Stuart, "and we recovered vertebrae from the backbone, the lower jaw, and almost all of the rest of the skeleton, including the skull and the tusks."

Scientists estimate that the elephant weighed 10 tons: nearly twice the weight of a modern African elephant. The animals, which are the largest species of elephant to have ever lived, once roamed throughout England.

Slicing into Sediment

Forty miles to the south of West Runton in the town of Saham Toney, scientists from Britain's top universities are excavating a large pit near the ninth tee of the Richmond Park Golf Club. They are trying to figure out how small changes in climate — a degree or two like we are experiencing now — impact the Earth.

Nigel Larkin of the Norfolk Museum and Archeology Service is taking part in the excavation. In his shovel he holds a slice of sediment that looks like a piece of layer cake. Each layer is only a few inches thick. Instead of seeing changes on a 100,000-year scale, he can see changes in the sediment that took place in just a few thousands of years.

By studying the layers of sediment, Larkin and his colleagues are trying to understand the gradations in climate that Britain has experienced. They have already discovered that the climate near Saham Toney was once less English countryside, and more Mediterranean beach resort — elephants and all.

Today, we associate elephants with warm, tropical parts of the world. But Anthony Stuart says that if you look at things from a geological perspective, the question really is: Why aren't there any elephants running around North America or Europe today?

From our human perspective, it is hard to comprehend how big a role climate plays in life: We don't see elephants in Britain now, so we assume they've never been there. But we do see humans, and we assume we have always been here.

In fact, humans only get our turn on Earth's stage when the climate lets us. When the climate gets tough, we exit.

Adapt, Move or Die

Chris Stringer is a paleontologist at London's Natural History Museum. Stringer runs a project that studies how climate and human migration interact. His office is littered with bones and skulls of the animals and humans whose scenes have ended.

"Each time it was warm," Stringer says, "Britain was potentially a good place for people to be. Each time it was cold, it was a bad place for people. And at the peaks of these cold stages... people probably disappeared from Britain completely."

Stringer says basically when the climate went bad, people had those three choices: adapt, move or die. It is a pattern of natural change that has been going on for hundreds of thousands of years.

"Now we're getting something that's not part of the cycle of natural change," Stringer says. "So we're entering a new phase, and it certainly seems to me that this is now not a natural cycle, but something that is being produced by the action of one species — us."

Maybe humans have reached a point where we'll be able to adapt to whatever climate changes lie ahead... maybe.

Produced by Rebecca Davis

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