There’s still four and a half months to go in 2015, yet we’ve already used up our ecological budget for the year. Earth Overshoot Day–the point at which human demand exceeds the limits of what the planet can regenerate–fell on August 13.
The calculation comes from the Global Footprint Network, a California nonprofit that calculates the Earth’s ecological budget every year. It divides the planet’s productive land and sea area (its biocapacity) by humans’ ecological footprint–that is, all our demand for plant-based products and livestock, the area we set aside for urban development, and the forests we need to suck up carbon emissions going into the atmosphere. Earth Overshoot Day is when our ecological footprint exceeds its biocapacity.
Earth Overshoot Day has been getting earlier because we’re using more resources relative to reserves. It was four days earlier last year and fell in October back in 2000. Fossil fuels, in one way or another, account for the largest part of the footprint: 55% overall. Carbon emissions, which have doubled since the 1970s, have been a big factor in the day moving forwards, says Mathis Wackernagel, president of Global Footprint Network.
GFN produces a handy interactive map of footprints, where you can find out biocapacity-to-footprint ratios for different countries. The amount of land we use per person, measured in “global hectares,” has actually fallen since 1970. The U.S. biocapacity is still well in deficit and depleting every year. It’s estimated currently that we need the resources of 1.9 United States to support the real one.
Wackernagel says if we go on as we are, with the same rising energy demand, population growth and so on, by 2030, we’ll use up twice as much as the Earth can regenerate. Overshoot Day would fall in June. But he also says some countries are reacting proactively to their situation and reducing their burden–Germany and Denmark, for example.
“Some countries are reacting by design,” he says. “We need foresight, because it’s not possible to move economic models as quickly as you hope. Because of the way houses, roads, and power plants are built, they can’t be adjusted fast. So, we need to start making the changes now.”