" The whole new layer on top of what I was thinking about in the nineteen-seventies is climate change,” Lovejoy told me. He has written that “in the face of climatic change, even natural climatic change, human activity has created an obstacle course for the dispersal of biodiversity,” the result of which could be “one of the greatest biotic crises of all time. "

― Elizabeth Kolbert , The Sixth Extinction: An Unnatural History