The Disaffected Lib: It's Here - Earth Overshoot Day, This Year 20 August, 2013: Tuesday, August 20, marks Earth Overshoot Day for 2013. This is not a record to celebrate. It tells us that, in under eight months, mankind exhausts an entire annual supply of renewable resources. After that, we're eating our seed corn. Another way of looking at it is that, at current rates of biomass consumption we need 1.5 planet Earths.