In Wisconsin, millennia ago, ancient farmers cleared land to plant wheat and maize, potatoes and squash. And unknowingly, they may have been fundamentally altering the climate of the Earth.
A recent study provides new evidence that ancient farming practices led to a rise in the atmospheric emission of the heat-trapping gases carbon dioxide and methane – a rise that has continued since, unlike the trend at any other time in Earth’s geologic history. It also shows that without human influence, by the start of the Industrial Revolution, the planet would have likely been headed for another ice age.
“Had it not been for early agriculture, Earth’s climate would be significantly cooler today,” says lead author, Stephen Vavrus, a senior scientist in the University of Wisconsin-Madison Center for Climatic Research in the Nelson Institute for Environmental Studies. “The ancient roots of farming produced enough carbon dioxide and methane to influence the environment.”