Overshoot, Collapse, and Creating a Better Future


In 2016, Earth Overshoot Day happened on August 8—the day when we’ve exhausted the planet’s resources for the year, and are essentially borrowing from future years to maintain our existence today.

Perhaps you celebrated this day with a counter-solution: a vegetarian meal, telecommuted, or turned off the air conditioning. There’s a lot more you could be doing.

In 2012, on the 40th anniversary of the publication of Limits to Growth, one of the study’s authors Jorgen Randers revisited their findings and offered his global forecast for the next 40 years. The result was the book 2052.  As you’ll read in the excerpt below, in order to avoid inadvertent overshoot, it is important to have a forward-looking attitude and to act in time. If you do not, you increase the chance of unsustainability.

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The forty years since the publication of Limits to Growth (LTG) have proven how difficult it is to establish “overshoot and collapse” as a widely understood and used concept in global decision making. This is a pity. Being aware of the tendency toward overshoot and collapse, and sensitive to its consequences, is of tremendous use if the goal is to avoid unsustainability.

It is worthwhile to briefly summarize how the LTG book was received after it appeared in 1972. It led to a public debate that has lasted until this day, with strong views both for and against its alleged message. By its supporters, LTG was seen as a useful and constructive warning that global society ought to choose a different, more ecological road ahead. In their eyes LTG described the need for sustainable development—although that label was not invented until long after: LTG used the word “global equilibrium” to describe the same idea. For the critics, and they were in the majority, LTG was seen as misinformed and even dangerous hackwork predicting immediate collapse to the current social order because of resource depletion.

During the first twenty-five years after its publication, no one seemed to pick up the real message of the study, which is that overshoot is a likely consequence of slow societal decision making, and that once in overshoot, there is only one way out, namely, decline back down into sustainable territory. The general view was that LTG had been proven wrong, because oil had not in fact run out. The story of the public debate is well told by Italian scientist Ugo Bardi, who reminds us that the treatment of LTG in this period resembled the more recent mistreatment of the IPCC by climate skeptics inside and outside the energy industry.

But in the year 2000 a revival of LTG as a respectable analysis began, initiated by a most surprising source, namely, Texas oilman and investment banker Matthew Simmons. Simmons looked at rising energy prices since 1972 and concluded that they were early warnings of future bottlenecks in the production of oil and gas, and he was proven right four years later when gas prices in the United States exploded. In 2008 Australian scientist Graham Turner helped the revival by showing that the world had actually followed the “standard run” (the business-as-usual scenario from 1972) of the LTG World3 computer model. And lately, in 2012, the well-regarded New Scientist crowned this process by bringing the story of the fall and revival of LTG to a broader scientific audience.

But it was only the New Scientist paper that clearly pinpointed the connection between societal reaction delays and the risk of overshoot and collapse; or, in other words, long delays will make the quest for sustainable development even more difficult because they will tend to create a bumpy ride.

Sustainable development has emerged over the last twenty-five years as a good label, politically speaking, because it provides a goal but still gives room for all kinds of strategies. But therein lies its weakness: the goal of sustainable development is not particularly helpful in telling you what to do next. So instead of working for sustainable development, I suggest you should rather be working to avoid unsustainability. This is best done by identifying and removing unsustainabilities one at a time.

You should start with the least sustainable element in your surroundings—that is, you should identify what is going to blow up in your face first, if you do not change your ways. This might mean you start reducing your climate gas emissions before the local newspaper finds out you are not, or reduce your use of gasoline and heating oil before you are unable to pay your fuel bills, or find an alternative supplier of coffee if your current brand comes from a plantation not paying a living wage to its workers. This is sustainable development in practice.

The behavior mode of overshoot and collapse is important to understand because it signals that something is not sustainable. Through his book Collapse, Jared Diamond made the collapse part of this behavior mode well known. But the core of the problem, from a policy point of view, is to be found in the first part of the behavior mode: the growth into overshoot. The core problem lies in the systems and policies that allow or drive expansion beyond what is sustainable—in growth beyond carrying capacity.

The concept of overshoot and collapse is more easily grasped and adopted by natural scientists, and particularly life scientists with practical experience from the dynamics of natural systems. They know well that animal populations routinely overshoot their food supply and then starve, sometimes destroying the food supply in the process. They also know well that the food supplies have to recover before those animal populations can revive. Think, for instance, about how a herd of deer might fare on a finite mountain plateau with no wolves or other predators to keep its population stable. The number of deer would increase as long as there was enough food. Eventually, a final wave of young deer would add just enough grazing pressure to make the herd eat up the available grassland and trample it to dust.

For people who buy the analogy that we are behaving like the deer in this scenario, the policy implications are obvious. It is important to know the carrying capacity of your environment. It is important to know what drives your expansion into this environment. It is important to avoid placing a burden on your environment that exceeds its carrying capacity. For if you do so, you may destroy its regenerative capacity—for a while or, in the worst cases, forever. In order to avoid inadvertent overshoot, it is important to have a forward-looking attitude and to act in time. If you do not, you increase the chance of unsustainability.

Let us go through the reasoning behind this in six detailed steps.

1.    Humanity Has an Ecological Footprint

The human ecological footprint is a measure of the burden humanity puts on the physical environment. It is a broad concept and includes in principle all human use of natural resources and all environmental impacts—irrespective of sort or kind. In very approximate terms it is the sum of human resource extraction and human pollution emissions, defined so as to include the destruction of biodiversity.

As discussed in chapter 6, one can measure the nonenergy ecological footprint as the land area necessary to produce the food, meat, wood, and fish we consume, and the land we cover with cities and infrastructure. I call this the nonenergy footprint because it excludes the land area necessary to mine the energy we use and the forest area we would need in order to absorb all the CO2 emitted from our use of fossil energy.

The good news is that the nonenergy footprint per person is no longer growing much, and in some countries it is even declining. The bad news is that the total nonenergy footprint is still being pushed up by increases in the population: we do need ever more biologically productive land to feed and clothe humanity. And furthermore, the total ecological footprint, which also includes the energy aspects, is even bigger and now equals 1.4 planets.

Much confusion could have been avoided in the “growth vs. no-growth” debate over the last generation if one had used the concept of “ecological footprint” rather than imprecise constructs like “growth” or “physical growth” when trying to describe the negative impact of human activity on the planet.

But the human ecological footprint did not really emerge as a credible label until the late 1990s, when the first regular reports tracking the footprint in quantitative terms emerged. Prior to this, confusion dominated the debate, as most people interpreted the word “growth” as identical to “economic growth” or “growth in GDP,” even when it was meant to describe “growth in the ecological footprint.”

2.    The Human Footprint Is Expanding

The human ecological footprint did expand continuously over the period for which we have data, and certainly since 1972. It became heavier both because human population expanded and because the amount of resources consumed and pollution generated per person per year expanded. But in parallel, technological advance did consistently lower the footprint, by reducing the area necessary to obtain a certain amount of resources or absorb a certain amount of pollution.

Jorgen Randers

3.    The Footprint Can Expand beyond Planetary Limits

It is possible for the human ecological footprint to expand beyond the carrying capacity of planet Earth, but only for a while. It is possible to exceed the maximum sustainable harvest, but only for a while.

For instance, you can cut more trees per year than what will grow back, as long as you start with a full forest. You can harvest more fish per year than will replenish, as long as you start with a big stock of fish. You can eat more food per year than is grown, as long as you start with a full storehouse of grain. But only for a while. The consumptive parts of the human footprint can only remain in unsustainable territory for a finite period of time, until whatever buffer that existed has been absorbed.

It is also possible to emit more pollution into a pond than is broken down by its bacteria, but only if you stop before you kill the bacteria. It is possible to reduce biodiversity by letting species go extinct, but only until the ecosystem collapses. It is possible to emit more CO2 into the atmosphere than is absorbed by oceans and forests, but only until the global warming becomes unlivable. And again, only for a while. If the practice is continued, it will destroy the carrying capacity and force the practice to a halt

4.    Decision Delays Increase the Chance of Overshoot

When the human footprint is approaching a limit, society normally reacts, but only after some delay. First society spends time discussing the reality of the limit—and continues expanding while debating. It is only once the limit has been thoroughly exceeded that its position can be clearly established and the overshoot measured and documented. Only then does debate give way to a tentative decision to slow down. And while the debate and decisions linger on, growth continues and brings the footprint into unsustainable territory.

It will take time (decades?) to observe and agree that current global activity does indeed exceed the long-term carrying capacity of the planet. It will take time (decades?) for national and global institutions to pass the necessary legislation to stop overexploitation of the world’s resources and ecosystems.

And it will take time (decades?) to implement this legislation and make the necessary changes on the ground. So, growth in the footprint is unlikely to stop until long after global limits have been exceeded.

LTG’s message of “overshoot caused by decision delays” is not generally understood. This was not surprising one generation ago, for in 1972 (when the human ecological footprint was around one-half of today’s) it was seen as rather inconceivable that global society would allow itself to grow beyond the sustainable carrying capacity of the globe. By today we know better. Currently the human demand on the biosphere exceeds the global bio-capacity by some 40%. Global greenhouse gas emissions are twice the sustainable levels. Many global fisheries have been overharvested to the point that commercial fish stocks have steeply declined. The tropical rain forests are still being cleared.

The world of 2012 is “in overshoot.”

5.    Once in Overshoot, Contraction Is Unavoidable

Humanity cannot—in the long run—use more physical resources and generate more emissions every year than nature is capable of supplying or absorbing in a sustainable manner. Or, in other words: the human ecological footprint cannot continue to grow indefinitely because planet Earth is physically limited. Overshoot is a temporary phenomenon.

In each instance of overshoot, humanity has to move back into sustainable territory, either through “managed decline” or through “collapse induced by nature,” the latter caused by the unmitigated working of “nature” or “the market.” An example of managed decline would be to limit the annual catch of fish to a sustainable level through legislation and planned scrapping of fishing vessels and gear. An example of collapse would be the elimination of fishing communities through bankruptcies when there is no more income because the fish are gone (or to be precise: reduced to such low numbers that it no longer makes economic sense to continue the catch).

The world has not yet experienced large-scale environmental collapse. But there have been some instances of local overshoot, followed by contraction.

The most famous case of “managed decline” is the effort to eliminate ozonedestroying chemicals through the Montreal protocol in 1987, upon discovery that the ozone layer over Antarctica was thinning. The measure seems to have worked in that at least the ozone hole is no longer growing. The most famous example of “collapse” is the collapse in the Canadian cod fisheries after 1992. Here the situation is less hopeful: after two decades without fishing, the fish stock has not yet recovered. Some argue that contraction—forced or planned—is nothing but a normal element in the process of economic growth, and thus nothing to worry about.
In this view overshoot and contraction is simply a process of one resource being replaced by another; or, more generally, one technology simply giving way to another. This view can be defended if the transition is smooth—if it occurs without temporary decline in human well-being. But if the transition to the new solution involves a temporary decline in human well-being when the old solution (for instance, cheap oil) is being phased out before the new solution (for instance, solar-based hydrogen) is in place, the transition must be said to involve an element of contraction, or welfare loss as the economists call it.

6.    Overshoot Can Be Avoided through Forward-Looking Policy

By looking ahead, society will normally be able to tell that limits are approaching and to set in swing the proactive initiatives necessary to avoid crashing into the limits. The challenge of overshoot and collapse is solvable—at least in principle. But it is hard to solve in practice, because forward-looking policy normally requires sacrifice today to get a better tomorrow. Wise policy must ensure that the human footprint is not allowed to grow into unsustainable territory. That means refraining from expansion that would otherwise have given a short-term benefit. This is difficult in a democracy dominated by shortterm voters and in markets dominated by short-term investors.
Many oppose the idea of forward-looking policy and would rather rely on the automatic “technological fix.” In essence they oppose the idea that the world is finite—even in the physical interpretation. They believe instead that technology will remove the planetary limits faster than we approach them. In other words: technological advance will continue to push back limits and increase the carrying capacity of the planet.
I don’t trust in such automatic technological optimism. I believe the world for all practical purposes is finite. And that overshoot is likely when there are significant reaction delays in a system: lags in the perception of and localization of limits; in the time-consuming, multi-stakeholder decisions to stop expansion; and in implementing the slowdown. Once in overshoot, contraction is the only way out. The way down to sustainability is longer if the underlying ecosystem has been damaged during the overshoot.

In recent decades, while the globe has been in overshoot, much discussion has taken place in various forums in order to find a path to sustainability through coordinated global action. The UN Millennium Development Goals are probably the most concrete description of what needs to be done, and some progress has been achieved and measured. But we are far from having agreed decisions that when acted on will start to reduce the human ecological footprint. The world might better understand the urgency of the challenge if it better understood the behavior mode—or the dynamics—of overshoot and collapse.

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