Earth Overshoot Day isn’t one of those fun holidays, like International Cat Day or Squirrel Appreciation Day. Instead, it’s a depressing reminder that we humans are living well beyond our means. Today (Aug. 8) marks the point when humanity as a whole has used up the resources needed to live sustainably for a year.
The day is declared every year by Global Footprint Network, a nonprofit research group that focuses on sustainability. The first Earth Overshoot Day was in Oct. 2006. It’s been creeping up the calendar ever since, landing on Aug. 19 in 2014, and just last year, reaching Aug. 13. The earlier Earth Overshoot Day falls, the more rapidly we’ve been using the planet’s natural resources.
The exact date of Earth Overshoot Day is determined by a simple formula. Global Footprint Network takes the planet’s biocapacity (pdf), or the amount of natural resources available, divides it by humanity’s ecological footprint, or how much of the planet’s resources we use up, and then multiplies it by the days in a year.