Earth Overshoot Day

Ecological Debt Day, also known as “Earth Overshoot Day”, is the approximate calendar date on which humanity’s resource consumption for the year exceeds Earth’s capacity to regenerate those resources that year. It is the annual marker of when we begin living beyond our means in a given year. Earth Overshoot Day is calculated by dividing the world biocapacity (the amount of natural resources generated by Earth that year), by the world Ecological Footprint (humanity’s consumption of Earth’s natural resources for that year), and multiplying by 365, the number of days in one Gregorian calendar year:

$({\text{World Biocapacity}}/{\text{World Ecological Footprint}})\times 365={\text{Ecological Debt Day}}$

When viewed through an economic perspective, Ecological Debt Day/Earth Overshoot Day represents the day in which humanity enters deficit spending, scientifically termed “overshoot”. While only a rough estimate of time and resource trends, Earth Overshoot Day is as close as science can be to measuring the gap between human demand for ecological resources and services, and how much Earth can provide.http://www.footprintnetwork.org/en/index.php/GFN/page/earth_overshoot_day/

Background

Andrew Simms of U.K. think tank new economics foundation originally developed the concept of Earth Overshoot Day. Global Footprint Network, a partner organization of new economics foundation, launches a campaign every year for Earth Overshoot Day to raise awareness of Earth’s limited resources. Global Footprint Network measures humanity’s demand for and supply of natural resources and ecological services. The data is sobering. Global Footprint Network estimates that in approximately eight months, we demand more renewable resources and CO2 sequestration than what the planet can provide for an entire year.http://www.footprintnetwork.org/en/index.php/GFN/page/earth_overshoot_day/ Throughout most of history, humanity has used nature’s resources to build cities and roads, to provide food and create products, and to absorb our carbon dioxide at a rate that was well within Earth’s budget. But in the mid-1970s, we crossed a critical threshold: Human consumption began outstripping what the planet could reproduce. According to Global Footprint Network’s calculations, our demand for renewable ecological resources and the services they provide is now equivalent to that of more than 1.5 Earths. The data shows us on track to require the resources of two planets well before mid-century.

The fact that we are using, or “spending,” our natural capital faster than it can replenish is similar to having expenditures that continuously exceed income. In planetary terms, the costs of our ecological overspending are becoming more evident by the day. Climate change—a result of greenhouse gases being emitted faster than they can be absorbed by forests and oceans—is the most obvious and arguably pressing result. But there are others—shrinking forests, species loss, fisheries collapse, higher commodity prices and civil unrest, to name a few. The environmental and economic crises we are experiencing are symptoms of looming catastrophe. Humanity is simply using more than what the planet can provide.http://www.footprintnetwork.org/en/index.php/GFN/page/earth_overshoot_day/ 

The correlation between the development of a country using HDI and its natural resource consumption

Year	Overshoot Date
1987	December 19
1990	December 7
1995	November 21
2000	November 1
2005	October 20
2007	October 26
2008	September 23
2009	September 25
2010	August 21
2011	September 27
2012	August 22

Earth Overshoot Day Campaign

Earth Overshoot Day draws on the fact that due to finite resources, humanity's recent trend of consuming more resources than Earth can produce each year constitutes an unsustainable path termed “overshoot.” Earth Overshoot Day is conveyed using economic imagery of monetary debt as a means of reaching the general public rather than just the scientific community. The goal of Global Footprint Network’s Earth Overshoot campaign is to bring the idea of limited global resources into people’s minds. The basic question is: What happens when an infinite-growth economy runs into a finite planet?http://www.footprintnetwork.org/en/index.php/GFN/page/earth_overshoot_day/

References

• Global Footprints Annual Report 2011 http://www.footprintnetwork.org/images/article_uploads/2011_Annual_Report.pdf
• Global Footprints earth overshoot campaign http://www.footprintnetwork.org/en/index.php/GFN/page/earth_overshoot_day/
• Global Footsprints Publications http://www.footprintnetwork.org/en/index.php/GFN/page/publications/

Further reading

• Easterling, William E. (2007). "Climate change and the adequacy of food and timber in the 21st century.". Proceedings of the National Academy of Sciences 104 (50): 19679.
• "WWF: human consumption is outpacing earth's capacity". EurActiv.com. October 26, 2004. Updated December 14, 2012.
• Wackernagel, Mathis; Niels B. Schulz, Diana Deumling, Alejandro C. Linares, Martin Jenkins, Valerie Kapos, Chad Monfreda, Jonathan Loh, Norman Myers, Richard Norgaard, and Jorgen Randers (2002). "Tracking the ecological overshoot of the human economy". Proceedings of the National Academy of Sciences 99 (14): 9266–9271. doi:10.1073/pnas.142033699. PMC 123129. PMID 12089326.
• Daily, Gretchen C., and Pamela A. Matson (2008). "Ecosystem services: From theory to implementation". Proceedings of the National Academy of Sciences (105): 9455–9456.