Humans: warming the globe for 15,000 years.

New Scientist steals my innocent view of humankind before the Industrial Revolution. It turns out we were probably messing up the climate in the Ice Age, too:

Last year, researchers at the University of Wisconsin-Madison studied fossil pollen and spores of a dung fungus found in sediment cores drilled from a North American lakebed and established that the decline in megafauna populations preceded the change in vegetation.

“There is a strong connection between when humans arrived, when mammoths went extinct and when you see this big increase in vegetation,” says [Christopher Doughty of the Carnegie Institution of Science in Stanford, California]. “They overlap almost exactly.”

If humans played a role in the extinction of the mammoths, then they had a hand in the climate change that followed. “I see it as humans’ first big impact on the planet,” says Doughty.