Stalagmite reveals carbon footprint of early Native Americans

Apr 15, 2010
This stalagmite, found in a West Virginia cave, showed a major change in the carbon record at about 100 B.C. (Courtesy Gregory Springer, Ohio University.)

A new study led by Ohio University scientists suggests that early Native Americans left a bigger carbon footprint than previously thought, providing more evidence that humans impacted global climate long before the modern industrial era.

Chemical analysis of a stalagmite found in the mountainous Buckeye Creek basin of West Virginia suggests that native people contributed a significant level of greenhouse gases to the atmosphere through land use practices. The early Native Americans burned trees to actively manage the forests to yield the nuts and fruit that were a large part of their diets.

"They had achieved a pretty sophisticated level of living that I don't think people have fully appreciated," said Gregory Springer, an associate professor of geological sciences at Ohio University and lead author of the study, which was published a recent issue of the journal The Holocene. "They were very advanced, and they knew how to get the most out of the forests and landscapes they lived in. This was all across North America, not just a few locations."

Initially, Springer and research collaborators from University of Texas at Arlington and University of Minnesota were studying historic drought cycles in North America using carbon isotopes in stalagmites. To their surprise, the carbon record contained evidence of a major change in the local ecosystem beginning at 100 B.C. This intrigued the team because an archeological excavation in a nearby cave had yielded evidence of a Native American community there 2,000 years ago.

Springer recruited two Ohio University graduate students to examine stream sediments, and with the help of Harold Rowe of University of Texas at Arlington, the team found very high levels of charcoal beginning 2,000 years ago, as well as a history similar to the stalagmite.

This evidence suggests that Native Americans significantly altered the local ecosystem by clearing and burning forests, probably to make fields and enhance the growth of nut trees, Springer said. This picture conflicts with the popular notion that early Native Americans had little impact on North American landscapes. They were better land stewards than the European colonialists who followed, he said, but they apparently cleared more land and burned more forest than previously thought.

"Long before we were burning fossil fuels, we were already pumping greenhouse gasses into the atmosphere. It wasn't at the same level as today, but it sets the stage," Springer said.

This long-ago land clearing would have impacted global climate, Springer added. Ongoing clearing and burning of the Amazon rainforest, for example, is one of the world's largest sources of emissions. Prehistoric burning by Native Americans was less intense, but a non-trivial source of greenhouse gases to the atmosphere, he said.

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User comments : 5

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Bob_Kob
3 / 5 (2) Apr 16, 2010
I don't believe there is any substantial connection between the two. More self bashing..
iknow
1 / 5 (1) Apr 16, 2010
Burning of forests a non-trivial source? ok ...

.. what about millennia of using wood as heating and coal and natural forest fires and volcanoes ... ad infinitum?
muddy
5 / 5 (1) Apr 16, 2010
Am I missing something here? Couldn't higher carbon content in the stalagmites just be caused by the Native Americans burning fires in the cave? If the researchers made the assumption that the air in the cave had the same carbon content as the outside atmosphere then they need to rethink this thing.
archaedude
1 / 5 (1) Apr 22, 2010
I wonder if this will eventually found to be a contributing factor to the Younger Dryas.
Daniel_Knight
Apr 27, 2010
This comment has been removed by a moderator.
XQZME
2 / 5 (4) May 01, 2010
If they are receiving a global warming grant or are seeking one, then their conclusions are not credible.