Will We Avert Ecological Collapse? April 6, 2006

Revised, 4/8/06, 4/9/06

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The cataclysmic consequences of unsustainable development pose a challenge to the world that will make the war on terror seem a mere distraction.

One possible outcome of unchecked population growth. Image source: One possible outcome of unchecked population growth. Image source: e-text population material

So begins a recent article summarizing what Jeffrey Sachs, director of the UN Millennium Project, told participants in a keynote address at the fourth biennial State of the Planet conference at Columbia University. The story didn’t make front page news, but it’s a sign the environmental plight we’re facing is beginning, at least, to emerge into the mainstream media. The message is that there is less time than most assume for the human species to address a collection of factors wreaking havoc on the environment. Those factors are headed by the interaction of population growth and growth of per captia resource consumption.

Understanding exponential growth

Let me explain. Lots of things are characterized by exponential growth. In the absence of intervening factors all animal populations (including humans), for instance, grow exponentially. Economic growth, as well, is often exponential. Population growth and economic growth combine, moreover, to drive the growth of our consumption of natural resources which, therefore, becomes exponential as well.

But how is exponential growth important? Well, when something grows exponentially, its growth will often look relatively unremarkable for a period of time. At a certain point, however, its geometric progression means that the growth suddenly becomes explosive — far more so than one would have guessed just a short time before that point.

An old French riddle makes this clear: Suppose you own a pond, at one end of which is a lily pad. The lily plant is growing and you know it will double in size each day. If it grows without interference, you know it will completely cover the pond in 30 days, blocking sunlight, causing a die-off of all life in the pond. You know that at some point you’ll have to devote a few days to dealing with the lily plant, and decide to wait to do so once until it has covered half the pond. How much time have you left yourself to save the pond from destruction?

To answer that, you have to know on what day the pond will be half covered. Contrary to intuition, that will be the 29th day. On the 30th day the plant will double in size, completely covering the pond. Therefore, you have left yourself only one day to save the pond! Could you have seen that coming just from watching the plant’s growth and using common sense to guess when you would really need to intervene? Not likely. Notice that on day 24 only 1.56% of the pond was covered. On day 28 the pond is 25% covered. Even that might not be particularly alarming. It would only become alarming if you should project accurately ahead to realize the lily’s growth had taken off like a rocket and had now exceeded your ability to intervene in time to save the pond.

Where we stand today

Sadly, when we look today at the human ecological footprint a good deal of evidence suggests we’re approaching day 30 faster than most people would think. World population growth and our rate of resource consumption (driven largely by economic growth) have been following an essentially exponential path. In recent years cultural and other factors have slowed the rate of population growth, but the growth is still exponential. [1] We’ve come to the kind of explosive growth seen in the last few days of the pond above.

The result has been unprecedented environmental destruction. We’re seeing climate change, depletion of the oceans’ fishes and coral reefs, profound effects of deforestation, a 1,000 fold increase in the normal rate of species extinction to a current conservative estimate of about 27 species per day (based on 1,000 species per million lost per year, and a conservative estimate of 10 million species), the global spread of chemical toxins throughout the environment, and many other environmental stresses. To make matters worse, we are also at a point of increased risk of disease purely as a result of our increased numbers in a time of great mobility.

The environmental stresses listed above are signs we have now overshot the earth’s carrying capacity. The addition of several billion humans and counting, and its impact on environmental systems nudges us steadily and quickly toward an ecological breaking point.

The need for coordinated worldwide efforts at analysis and intervention is now something we are foolish to ignore. Unfortunately most people are oblivious to the problem because they’re applying only common sense. If one merely looks around without doing some research or without a keen appreciation for exponential growth, the state of the “pond” might not yet appear so alarming. It might look like day 28, for instance. But what’s going to happen in just a “day” or two? To see this more clearly we need only look at a graph of human population growth over history:

Clearly, we are in the explosive growth phase! And with each step in that population growth comes the expected increase in environmental impact. That means we have little time left to take steps to avoid what may be profoundly regrettable worldwide societal and environmental consequences. Scientists have been warning us of the problem of population growth and the associated growth in our ecological footprint for some years now. They continue today. We are at a crucial time in human history.

What if we ignore this?

What if we don’t intervene? As Al Bartlett explains so clearly, population growth will stop. Exponential growth (or any kind of growth) cannot continue forever on a finite planet. At current or even slower rates, if nothing happened to stop it, humans would soon cover the planet with people jammed toe to toe. But things will happen. We are part of, and depend for our very lives on the ecosystem in which we live. Stress it too far and we will lose its support.

Population growth will stop, then, in one of two ways. Either nature will take over and choose its own methods for stopping population growth or we can act first and choose our own methods. Which would be preferable? Nature’s methods are not pleasant. They include such things as famine, disease, and war. We see this in animal species. They can result in die-offs of large numbers of a population, returning it to previous, sustainable levels.

If we wait to let nature take its course, moreover, we must contemplate the level of environmental loss we will by then have witnessed.

We have options

There’s another way. As humans we have the unique cognitive capacity to choose our own, less painful methods for ending population growth. We need to address important correlates of population growth such as poverty and the lack of opportunities for women in developing countries. As Meadows et al make clear, poverty causes population growth which causes poverty. We need, as well, national media campaigns and family planning programs.

Population growth in the U.S. is especially destructive to the worldwide environment as our per capita consumption of natural resources is among the highest in the world. So, with regard to environmental impact, adding one new U.S resident is like adding several people to a typical third world country. To respond to this, some experts believe the U.S. needs to implement some level of immigration reform. Understandably, this is a controversial point. At the time if this writing the contoversy is being played out on Capital Hill as lawmakers struggle with the immigration issue, and in the streets as massive numbers of marchers express opposition to proposed legislation.

Others contend that programs to reduce fertility rates here slightly should alone be sufficient to stabilize the population soon enough to avert disaster. This could likely be brought about through a diversion of less than 1% of the military budget to media campaigns and family planning services. In any case, at present we are barely addressing the problem in any way. We’re doing a smidgen more to address consumption levels, but woefully little there as well.

It’s easy enough to see that to reduce resource consumption we need to do more in familiar areas such as energy conservation while we commit much more to clean, renewable energy sources. Less obvious to most, and sounding like blasphemy to many, is the suggestion that we need to move away from the endless-growth imperative which dominates the corporate world. It’s a prime driver of our increasing ecological footprint. Our best bet may lie in aiming for for a healthy steady state economy.

We can do our part locally by ceasing activities such as the building of subdivisions which only accommodate population growth while encouraging our automobile dependency. If we do not take such actions now, if large scale programs are not soon initiated on national and global levels, our children and grandchildren may well be faced, at the least, with a markedly lower standard of living than we now enjoy. Perhaps more likely, they will be forced to deal with profoundly troubling social and environmental events resulting from ecological collapse. That is precisely the alarm Jeffrey Sachs is sounding. In his words, such a collapse is “the central challenge we face on the planet.” It’s time we recognize it.

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For an authoritative, highly readable discussion of the ideas in this essay, I recommend the book Limits to Growth: The 30-Year Update

[1] On a positive note, the populations of some European countries have very recently come close to stabilizing or have actually stabilized. It’s a good step, but no credible projections see any similar stabilization for world population any sooner than about 2075. By then, world population is likely to have grown from the current 6.5 billion to about 8.9 billion according to the United Nations’s best guess, their medium scenario (large PDF). (It could range as high as 10.6 billion. or as low as 7.4 billion according to the high and low scenarios respectively.) Note that those projections are, of necessity, based on an assumption of no ecological collapse intervening before 2075. No meaningful projection could otherwise be made. The risk of such a collapse is a matter apart from the U.N.’s projections. The projections, moreover, may be optimistic.