Bill Totten's Weblog

Friday, January 07, 2005

What will it REALLY take to tackle the human over-population crisis?

by Oneida Kincaid

Earth Crash Earth Spirit (November 12 2003)

Probably the major environmental problem the world faces is human overpopulation. The way I like to dramatize this is to ask people to imagine what would happen if all 6.3 billion of us humans somehow miraculously switched tomorrow to living as hunter/gatherers (the original "sustainable" mode of human existence). In many areas of the world there wouldn't be one deer, rabbit, bear, duck, monkey or gorilla left inside of three months, and in some areas, like Europe or Japan, what little wildlife still remains would probably be gone in less than a week.

Indeed, already large swaths of what is left of Africa's rainforests suffer from what biologists call "empty forest syndrome" due to the hunting of wildlife for the so-called "bushmeat" trade. And in October 2002, a study by Columbia University's Center for International Earth Science Information Network and the Wildlife Conservation Society, published in the journal BioScience, found that 83 percent of the world's total land surface and 98 percent of the areas where it is possible to grow the world's three main crops - rice, wheat, and maize - are now directly impacted by human activities such as cities, farming, mining, fishing, logging, roads, waterways, dams, and electrical power grids. Given a human ecological footprint that damn near covers the entire earth, it shouldn't come as any surprise that we now face a mass extinction crisis, collapsing fisheries, a growing number of "dead zones", and other signs of global ecological collapse.

In short, if we don't soon start really dealing with human overpopulation instead of continuing along with the same old, obviously ineffectual efforts, all of the so-called "sustainable-use" technology in the world - solar and hydrogen energy, recycling, straw-bale homes, et cetera - won't mean a thing.

Before digging any further into this discussion of what it would mean to really deal with the overpopulation crisis, let's quickly define a few terms so we're all in the same ballpark:

Scientists define "carrying capacity" as the population of a given species that can be supported indefinitely in a defined habitat without permanently damaging the ecosystem upon which it is dependent.

"Drawdown" refers to the process by which a species uses up the resources in its habitat faster than they can be replaced and so ends up having to "borrow" resources, in one form or another, from other places and other times.

"Overshoot" is the result of continued drawdown - when a species' population and use of resources in an ecosystem exceeds its carrying capacity - and there is no way to recover or replace what was lost.

A population "crash" or "die-off" is the inevitable consequence of overshoot, that is, it is a precipitate decline in species numbers. When a species exceeds the capacity of its environment in one life-giving respect or another, there is nothing that can be be done until that species' population is reduced to the level at which the resources can recover. In extreme cases of overshoot, a population crash or die-off can become a "die-out" (extinction).

The biological record is replete with examples of the process of drawdown, overshoot, and die-off/extinction. Perhaps the simplest example is what happens when yeast are added to crushed grapes in order to make wine. The yeast cells eagerly gobble up nutrients from the sugary crushed grapes around them and rapidly expand their population without a thought to the consequences of drawdown. Within weeks, however, the "pollution" they produce - alcohol and carbon dioxide - have so filled their environment that they are unable to survive. The resulting crash means an acute die-off and then extinction of that population of yeast.

Another example of the process of drawdown, overshoot, and die-off is David Klein's classic study of the reindeer on Saint Matthew Island off Alaska. In 1944, a group of 29 reindeer were moved to the island (which previously had no reindeer), but without the corrective (negative) feedback of such predators as wolves and human hunters. In just nineteen years, the population first swelled to 6,000 and then "crashed" in three years to a total of 41 females and one male, all in miserable condition.

Even worse is that the ecological impacts of the "overshoot" permanently reduced the island's carrying capacity for reindeer. Klein estimated that the original carrying capacity of the island was about five reindeer per square kilometer, but at the population peak there were eighteen per square kilometer. After the crash there were only 0.126 animals per square kilometer and even this was probably too many because the overpopulation of reindeer had stripped the island of most of its lichens. Recovery of lichens under zero population conditions takes decades; with a continuing resident population of reindeer it may never occur. Overshooting the carrying capacity of Saint Matthew Island thus resulted in a reduction of its carrying capacity for reindeer by at least 97.5 percent.

Over and over, scientists have documented what happens when a species' population spins out of control - inevitably its population "crashes". Such population crashes are not pretty, typically involving mass starvation and/or epidemic disease. A human population crash will most likely be much, much uglier, given our historical proclivity for resorting to violence - war, genocide, et cetera - to settle conflicts over shortages of critical resources such as adequate living space, clean water, and food. Easter Island is a good, if sobering, example.

When it was first settled by humans a thousand years ago, Easter Island was a rich, forested land covered with palms and a small native tree called the sophora. On its sixty-four square miles a prosperous and literate culture developed organizational and engineering skills that enabled it to erect the massive stone statues along the coastline for which the island is now famous.

But the population of the island also eventually increased to an estimated 4,000 people, leading to a steady drawdown of vegetation that eventually deforested the entire island and exhausted its soils. Eventually a situation of overshoot was reached, resulting in conflict over scarce food acreage, and ultimately warfare, cannibalism and social chaos and decay. By the time of Captain Cook's voyage to the island in 1775, there were barely 630 people left eking out a marginal existence; a hundred years later, only 155 islanders remained. [See Jared Diamond's excellent article, Easter's End <1>.]

Scientists have discovered mathematical equations based on body weight that predict how many herbivores (plant-eating mammals) and carnivores (meat-eating mammals) a natural ecosystem can support. These equations indicate a average global carrying capacity of 0.12 individuals per square kilometer for a carnivorous mammal the size of modern Homo sapiens weighing an average of roughly 65 kilograms (142 pounds), and 2.1 per square kilometer for a herbivore of the same weight. Pre-agricultural humans, however, were omnivorous, eating both plants and meat. A liberal estimate of the average population density our species would likely have maintained without agriculture is therefore around 1.0 to 1.5 individuals per square kilometer, similar to the average density at which hunter-gatherers lived until most of them were wiped out by "civilization".

If humans were to occupy and live on every bit of Earth's habitable terrestrial surface (about 130 million square kilometers) at densities around 1.0 to 1.5 persons per square kilometer, the human population would only be about 130 million to 200 million people. Instead, our current population is over six billion, that is, over thirty times what the population of a omnivorous mammal of our size Earth is ecologically prepared to deal with. According to the United Nations, in 1999 the average global human population density was about 44 people per square kilometer, substantially above what the human population should "naturally" be. (See, for example, "Nature's Place: Human Population and the Future of Biodiversity" by Richard P Cincotta, PhD. and Robert Engelman, available at <2> as a 3.9 megabyte pdf file.)

In order to sustain the current level of human overpopulation, we now take for human use something around fifty percent of what scientists refer to as Earth's "net primary productivity" or NPP - that is, the total growth of plants, trees, et cetera, produced each year from the solar energy that reaches the Earth. In other words, just one species out of tens of millions is now taking for its own purposes roughly fifty percent of what plant growth Earth produces each year, leaving the rest of Earth's millions of species in a desperate and often losing struggle to survive on a planet that has effectively been reduced in size by half. Given these facts, it's therefore hardly comes as a surprise that life on Earth is now facing a sixth mass extinction "event".

The global ecological situation has now become very dire due to the accumulated impacts of human overpopulation. [If you don't believe that, please take some time to review the articles in the Life Disintegrating (Earth Crash) <3> part the weblog and the older parts of this site <4> <5> <6>.] And the situation is soon going to get worse, much - much worse - despite all the soothing bromides regularly issued by various "experts" assuring us that the human population growth rate is gradually dropping and supposedly will reach the much-vaunted "zero population growth" rate in forty to eighty years. That may indeed be true, but it is completely beside the point - Earth's ecosystems are collapsing now under the crushing pressures of human overpopulation, not forty to eighty years in the future. "Stabilizing" the global human population at eight or ten or twelve billion people forty to eighty years from now will be too late - instead we need to start to dramatically reduce human population now. The only real question before us is how.

Given that humans are not exempt from the rules of population biology (despite our pretensions otherwise - see Nature's Little Rule Book <7>), it is inevitable that the human population will eventually "crash" - the only question left is if it will be in the form of an horrific, starvation and disease-driven collapse like the reindeer on Saint Matthew Island, or from a nuclear holocaust or other form of massive warfare as ever-increasing numbers of people struggle over ever-increasing shortages of arable land, water, and other natural resources, or whether - in the hope of avoiding a global holocaust - we immediately begin taking the necessary steps to rapidly and significantly reduce human population levels.

How do we "rapidly and significantly" reduce human population? There are really only two ways: kill a lot of people, or for most people to immediately stop having babies. Although I dearly love babies (and toddlers and kids in general), like most people I would much prefer the second option.

There could, of course, just be an outright ban on anyone having children for the next thirty or forty years, but I think people psychologically need babies and children in their lives. So although it results in a somewhat less rapid population decline, this is best way I can see the second option working: Everyone in the world (with the possible exception of indigenous peoples threatened with extinction) comes together into (hopefully compatible) groups of twenty or so people with the agreement that the group will only have two children and that all group members will help with the support and parenting of those children. (Note that I haven't worked out all of the mathematics of this approach in terms of exactly how many children could be allowed per group in order to reduce the human population to a truly ecological sustainable level within the next thirty years or so. Perhaps someone with access to population forecasting software can run some scenarios on that?)

I will be the first to admit that such an approach is neither appealing (at least on its face) nor likely. However, as much as I have searched for an alternative, I just can't see any other way out of the mess we humans have got ourselves (and the rest of life on Earth) into in the face of the rising crescendo of ecosystem collapses now occuring - increasing numbers of "dead zones", water shortages, collapsing fisheries, rapidly accelerating extinction rates, massive deforestation, and so on.

At any rate, one more question remains to be addressed in this discussion: What exactly constitutes a "truly ecological sustainable" human population. Most "experts" within what I call the "sustainability industry" (the Worldwatch Institute, et cetera) seem to suggest about one to two billion people would be "sustainable" - for humans, at least. I would argue, however, that the figure of 130 to 200 million cited above, based on Earth's actual ecological carrying capacity for an human-sized omnivore, is the only population target supported by science, not wishful thinking. Indeed, the optimum human population is probably now considerably less than that, given that, as occurred on Saint Matthews Island due to overbrowsing by reindeer, human-caused ecosystem degradation through such activities as deforestation, agriculture, overfishing, and pollution has significantly reduced Earth's general carrying capacity (for all life, not just human).

It should be noted, too, that the estimate of an ecologically optimal human population of 130 to 200 million is based on the assumption that all of those people are essentially living as hunter-gatherers, and is therefore must be significantly reduced if we decide we can't live without books, computers, factories, et cetera, given the ecological footprint of even the most supposedly "green" or "sustainable" technologies.

Finally, it must be acknowledged that there is, of course, no guarantee that such a population reduction program (assuming its unlikely acceptance by the world's people in the near future) will in fact successfully avoid general ecological collapse across the globe. Although nature indeed contains an awesome amount of resilency, it also contains an equally awesome level of inertia once it begins to "fall". I liken it to the felling of a giant tree:- although one must cut through much of its base before it begins to ever-so-slowly lean and then, having passed some critical threshold, suddenly accelerates into a rapid crash to the ground, it's almost impossible to stop it from falling all the way to the ground once it does begin to fall.

The big question here, of course, is how close the "tree of life" on Earth is to crashing to the ground. It's a difficult question to answer, because, seen through human eyes, nature moves in slow motion. But after having been immersed for eight to twelve hours almost every day over much of the last four years in documenting the continuing ecological destruction around the globe and the beginning signs of collapse in terms of such things as widespread crashes in amphibian populations, et cetera, I personally think the tree has definitely started to lean. It's hard to say just when the critical threshold will be crossed, after which the tree basically cannot be stopped as it crashes to the ground, but my sense is that it's not very far off - maybe twenty years at the most, and more likely less.

So why bother advocating a radical population reduction program like the above if the tree of life has already started to lean and it's just a matter of time before we're all doomed to "crash" with it? Well, that's why this site is called Earth Crash Earth Spirit.

Seriously, ECES is an unusual hybrid - a mix of rigorous science in looking at the environment and what ten thousand years of so-called "progress" and "civilization" has done to both people and the planet, and an understanding that there are realms beyond the physical world - an understanding based on experiences tested as rigorously as any scientific theory. In the end, if the tree of life on Earth is to be healed, it will be through a spiritual healing much more than by physical actions alone such as reducing human population. In other words, please check out the Another Way of Living (Earth Spirit) section <8>, because it's really the most important part of this site.

Oneida Kincaid










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