Date: Wednesday, August 2, 2023
Sponsor: Global Footprint Network
Earth Overshoot Day is annually calculated and disclosed to raise awareness of Earth’s limited resources and their annual changes, so as to promote sustainable development.
The Earth Overshoot Day campaign was marked for the first time in 2006.
The concept of Earth Overshoot Day was first conceived by Andrew Simms of the UK think tank New Economics Foundation. In 2006, Global Footprint Network launched the first global Earth Overshoot Day campaign. In 2007, Worldwide Fund for Nature (WWF) – the world’s largest conservation organization – participated in the Earth Overshoot Day campaign. Since then, Earth Overshoot Day is supported by dozens of other nonprofit organizations such as the Global Nature Fund and the Club of Rome.
Definition of Overshoot Day
As stated by the WWF, overshoot day is the date on which the demand for ecological resources and services of humanity in a specific year exceeds what the Earth can regenerate in that year. In other words, overshoot day highlights the annual excess of carbon dioxide that humanity releases above what the ecosystem can absorb.
Each year, the exact date of Earth Overshoot Day is calculated by the Global Footprint Network, an international research organization, using the latest UN statistics and the most updated accounting methodology. Global Footprint Network also calculates Earth Overshoot Day for all past years since 1971.
In addition to the overarching Earth Overshoot Day, Global Footprint Network also calculates Country Overshoot Day for individual countries every year.
How is Earth Overshoot Day calculated?
To determine the date of Earth Overshoot Day, Global Footprint Network calculates the number of days that the planet’s biocapacity (supply of natural resources) can provide for humanity’s ecological footprint (demand for natural resources) in a year. When the demand for ecological resources exceeds the supply, the planet runs an ecological deficit (overshoot).
Earth Overshoot Day is calculated by dividing the world’s biocapacity (the amount of ecological resources that can be generated by Earth in a given year), by humanity’s ecological footprint (humanity’s consumption of natural resources in that year), and multiplying by 365, the number of days in every year:
(Earth’s Biocapacity / Humanity’s Ecological Footprint) x 365 = Earth Overshoot Day
To measure the planet’s biocapacity and human’s ecological footprint, five areas of change are included: land, cities, population, energy, and food.
On the supply side, the planet’s biocapacity represents its natural resources such as forests, agricultural land, fishing grounds, and built-up land.
On the demand side, humanity’s ecological footprint is measured by the amount of population’s demand for food, fish products, timber and other forest products, space for urban infrastructure, and forests to absorb CO2 emissions.
All measures are expressed in hectares. A hectare is equivalent to 10,000 square meters or 2.47 acres. Similar calculations are also applied on a country-by-country basis to determine Country Overshoot Days each year.
Almost in every year, the first country to exhaust biocapacity is Qatar, which only needed 40 days (February 10) to consume the resources, with ecological deficit for the rest. In contrast, Jamaica does not exhaust its resources until 20 December.
Why do we mark Earth Overshoot Day?
Earth Overshoot Day marks the calendar date on which humanity’s consumption of natural resources exceeds the planet’s biocapacity to regenerate those resources in a year. It represents the day by which the planet’s annual regenerative budget is spent, and humanity enters environmental deficit spending in the year.
With population growth, industrialization and urbanization, humanity has used numerous natural resources to build cities and roads, to provide food and create products, and to release a large amount of CO2 that contributes climate warming. Until 1970, the rate of CO2 emissions was well within Earth’s budget.
Since 1970, humanity’s consumption of natural resources has outstripped what the planet could reproduce. In terms of Earth Overshoot Day, it has moved backward gradually from 30 December before 1970 to 2 August 2023, meaning that humanity has exhausted the planet’s annual renewable resources in seven months.
According to Global Footprint Network’s calculation, our humanity’s annual demand for natural resources is now equivalent to that of more than 1.7 Earths. By the mid of this century, humanity may require natural resources of two planets. The costs of natural resource depletion will be unaffordable for our human soon.
Earth Overshoot Day is an extraordinary and extremely meaningful awareness-raising tool. Although the Overshoot Day index has not yet been widely adopted into policymaking at the national governance level, this tool has proven its worth in raising public awareness for environmental crises.