August 21st marks an unfortunate milestone: the day in which we exhaust our ecological budget for the year. Once we pass this day, humanity will have demanded all the ecological services – from filtering CO2 to producing the raw materials for food – that nature can provide this year. From that point until the end of the year, we meet our ecological demand by liquidating resource stocks and accumulating carbon dioxide in the atmosphere.
What is Earth Overshoot Day?
Every year, Global Footprint Network calculates nature's supply in the form of biocapacity, the amount of resources the planet generates, and compares that to human demand: the amount it takes to produce all the living resources we consume and absorb our carbon dioxide emissions. Earth Overshoot Day, a concept devised by U.K.-based new economics foundation, marks the day when demand on ecological services begins to exceed the renewable supply.
What is Overshoot?
For most of human history, humanity has been able to live off of nature's interest -- consuming resources and producing carbon dioxide at a rate lower than what the planet was able to regenerate and reabsorb each year.
But approximately three decades ago, we crossed a critical threshold, and the rate of human demand for ecological services began to outpace the rate at which nature could provide them. This gap between demand and supply -- known as ecological overshoot -- has grown steadily each year. Global Footprint Network's most recent data show that it takes one year and five months to generate the ecological services (production of resources and absorption of CO2) that humanity requires in one year.
The Cost of Ecological Overspending
Of course, we only have one Earth. The fact that we are using (or “spending” natural capital) faster than it can replenish is similar to having expenditures that continually exceed income. In planetary terms, the results of our ecological overspending are becoming more clear by the day. Climate change – a result of carbon being emitted faster than it can be reabsorbed by the forests and seas – is the most obvious and arguably pressing result. But there are others as well: shrinking forests, species loss, fisheries collapse and freshwater stress to name a few.
How is Earth Overshoot Day Calculated?
Put simply, Earth 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 and begins adding to our ecological debt 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.
f you have further inquiries about Earth Overshoot Day, please contact http://www.footprintnetwork.org/
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