Global Footprint Network, a sustainability think tank, calculates that today is Earth Overshoot Day, “when humanity’s annual demand on nature exceeds what Earth can regenerate in that year.” Last year, overshoot day was Aug 19. The think tank says that in 2000, the date fell in early October. “The costs of this ecological overspending are becoming more evident by the day, in the form of deforestation, drought, fresh-water scarcity, soil erosion, biodiversity loss and the buildup of carbon dioxide in the atmosphere,” says the think tank, which calls for worldwide action to mitigate climate change.