What is World Overshoot Day?

Beginning on October 9th and continuing through the end of the year, the world will be living beyond its ecological means. Ecological Footprint accounting shows that, as of October 9th, humanity will have already consumed the total amount of new resources nature will produce this year.

Each year Global Footprint Network calculates humanity’s Ecological Footprint (its demand on cropland, pasture, forests and fisheries) and compares it with global biocapacity (the ability of these ecosystems to generate resources and absorb wastes). Ecological Footprint accounting can be used to determine the exact date we, as a global community, begin running our annual ecological deficit. Designated “World Overshoot Day,” this year demand begins outstripping supply on October 9.

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Overshoot has been called ‘the biggest issue you’ve never heard of.’ Yet despite its lack of publicity, its causes and effects are as simple as they are significant.In any given year, if trees are cut down faster than they grow back, then forests become smaller than the year before. If more fish are caught each year than spawn, there will be fewer fish in the sea. The consequences of our accumulating ecological debt also include global climate change, species extinction, insecure energy supplies, water shortages, and crop failure. 

As humanity’s consumption of resources increases, World Overshoot Day creeps earlier on the calendar. Humanity’s first Overshoot Day was December 19, 1987. By 1995 it had jumped back a month to 21 November. Today, with Overshoot Day on October 9, humanity’s Ecological Footprint is almost thirty per cent larger than the planet’s biocapacity this year. In other words, it now takes more than one year and three months for the Earth to regenerate what we use in a single year.

What is Overshoot?

Today, humanity uses about 30% more in one year than nature can regenerate in that same year. This is called “overshoot”. An ecological overshoot of 30% means that it takes one year and about three months for the Earth to regenerate what is being used by people in one year, creating an ecological deficit.

We currently maintain this overshoot by liquidating the planet’s natural resources. For example we can cut trees faster than they re-grow, and catch fish at a rate faster than they repopulate. While this can be done for a short while, overshoot ultimately leads to the depletion of resources on which our economy depends.

Overshoot is like ecological overspending. Just as any business that does not keep financial books will go bankrupt over time, we must document whether we’re living within our ecological budget or running an ecological deficit that will eventually deplete our renewable assets.

How is Overshoot Day Calculated?

[ world biocapacity / world Ecological Footprint ] x 365 = Overshoot Day

Put simply, Overshoot day shows the day on which our total Ecological Footprint (measured in global hectares) is equal to the biocapacity (also measured in global hectares) that nature can regenerate in that year. For the rest of the year, we are accumulating debt by depleting our natural capital and letting waste accumulate.

The day of the year on which humanity enters into overshoot is calculated by calculating the ratio of global available biocapacity to global Ecological Footprint and multiplying by 365. From this, we find the number of days of demand that the biosphere could supply, and the number of days we operate in overshoot.

This ratio shows that in just 282 days, we demand the biosphere’s entire capacity for the year 2006. The 282nd day of the year is October 9th.

If you have further questions about World Overshoot Day or would like to set up an interview with someone at Global Footprint Network, please contact Brooking Gatewood at: [email protected] or 1-510-839-8879 x 102