Earth Overshoot: Living Large in the 21st Century

This post is revised from the April 2017 original

The years are getting shorter for planet Earth. Long before completing her annual trip around the sun, she has given a year’s worth of natural resources.  It may seem counter-intuitive at first. How can we take more than the Earth makes for decades on end?

Have you ever run out of money before running out of month? If not, pat yourself on the back. You know how to manage your resources consistently. For the rest of us, we borrow against our future to fill in the gaps and keep things flowing. What about running out of Earth before running out of year? We all do that.

So what happens now?

Buying on Credit

We go into debt, outpacing nature’s ability to regenerate what we take, borrowing against the planet’s future. More carbon is emitted than can be absorbed, more topsoil eroded than restored, and more water is pumped out of aquifers than recharged.

Current patterns of production and consumption externalize much of the actual cost, most notably the cost of depleting natural capital or biocapacity. Measuring humanity’s ecological footprint against the biocapacity determines ecological overshoot.  Globally, it takes the regenerative resource capacity of 1.7 Earths to meet human demands.

The Economics of Biocapacity and Earth Overshoot

Earth Overshoot Day is hosted by the Global Footprint Network, a research organization focused on “changing how the world manages its natural resources and responds to climate change,” said Dr. Mathis Wackernagel, co-founder and CEO of GFN. I recently spoke with Wackernagel to learn more about Earth Overshoot Day, his work, and his philosophy of living in a world of constraints.

Wackernagel laid the groundwork for the ecological footprint for his doctoral dissertation. The ecological footprint metric was further developed, becoming the foundation for Earth Overshoot Day. More importantly, it informs Global Footprint Network’s ongoing collaboration with business leaders, countries, cities, and regions, and more than 70 global partners. GFN’s work establishing the core database of “National Footprint Accounts” and its open-source, public data platform demonstrates the collective self-interest in preserving natural capital.

“We’re trying to show two key things,” says Wackernagel:

First is understanding that, beyond the fossil fuels that now seem so crucial to our existence, the  “ultimate resource” upon which humanity depends is Earth’s renewable capacity. The highest value is Earth’s ability to absorb carbon and renew itself. We call it the natural carbon cycle. Global Warming is a function of more carbon in the atmosphere than can be absorbed. Which is to say, the issue is not the carbon itself but our use of it.

Second, by looking at the world from the perspective of countries as farms, the “self-interest becomes more obvious,” Wackernagel says.

Tied to the Land

Both biocapacity and ecological footprint are expressed as global hectares. A “global hectare” is a hectare of “biologically productive land and sea area with world average bioproductivity.”

In other words, we are all, ultimately, tied to the land. A modern, industrialized, resource-intensive country or economic sector’s ability to compete is weakened by diminishing biocapacity like a farmer’s soil turning fallow.

“Countries in a world that uses more and more resources aren’t resource secure themselves; they put themselves more at risk,”  Wackernagel says.

“It’s fundamentally linked to the self-interest of each nation and city to recognize the context and accordingly invest.”

Wealthier countries can and do outrun their risk “in the short run,” says Wackernagel, by having more income than others. In the long run, however, not everybody can have more income than others.“It puts more and more pressure on a limited resource. It puts everybody at risk.”

Any economic entity—from individuals to nations and global economies—not fully and accurately assessing its costs eventually becomes overextended. Something has to give.

An Engineer’s Invitation

Wackernagel considers himself and his colleagues as “engineers of sustainability,” sorting out for the rest of us how to conceptualize and quantify biocapacity and ecological footprint. From there, we can “build a bridge.”

“I’m an engineer,” Wackernagel says (he earned his degree in mechanical engineering from the Swiss Federal Institute of Technology). “I believe in the possible… boosting a vision about hope, not the bad seed of despair.”

Calculating Earth Overshoot Day isn’t all that complex, says Wackernagel. What is complex, he says, is “how to solve it… because many people think it’s a tragedy.”

“In terms of building the bridge and winning everybody’s participation, we have to frame the conversation as an invitation, not as a lens. We need to have everybody’s success in mind. Not ‘you’re good or bad’ or whatever. The moral language can push people off.”

We’re all tied to the land, we’re all in this together. Is our world really manageable by adhering to simple platitudes? Perhaps more than we realize.

“What the Hell is Water?”

Humanity went into global overshoot in the early 70s, before many people reading this article were born. In fact, between 1975, considered the first year of overshoot, and today, about 3.4 billion people have arrived. Nearly half of the global population is born into an overburdened planet.

It’s like the story of one fish asking another, “How’s the water?” The other fish replies, ”What the hell is water?” We are swimming in a world that is only “normal” to us: here, now  (and even that is arguably not so normal anymore).

David Foster Wallace explains it best in This is Water:

“The immediate point of the fish story is that the most obvious, ubiquitous, important realities are often the ones that are the hardest to see and talk about. Stated as an English sentence, of course, this is just a banal platitude — but the fact is that, in the day-to-day trenches of adult existence, banal platitudes can have life-or-death importance.”

It is often hard to see things as they are when they are right before us. History is replete with examples of civilizations overshooting their resource base, leading to collapse. The Romans, the Mayans. In hindsight, we can see how they overextended, yet it is difficult to recognize the same thing in our own time.

The Essential Bottom Line

A graphic showing how many "Earths" countries consume annually

Global Footprint Network defines biocapacity as “the ability of an ecosystem to regenerate biological resources and absorb wastes generated by humans.”

Ecological footprint measures the “amount of biologically productive land and sea area required to produce all the resources a population consumes and to absorb its waste.

Formula: PB/EF X 365 = Earth Overshoot Day

where PB = planetary biocapacity and EF = ecological footprint

Photo by Denys Nevozhai on Unsplash

Thomas Schueneman
Thomas Schueneman
Tom is the founder and managing editor of and the PlanetWatch Group. His work appears in Triple Pundit, Slate, Cleantechnia, Planetsave, Earth911, and several other sustainability-focused publications. Tom is a member of the Society of Environmental Journalists.

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