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.