Carrying Capacity Reexamined

Published online 15 May 2009.

This diary hopes to examine the applicability of the concept of “carrying capacity” to human society, and specifically the idea that the Earth has a carrying capacity, that it can stand only so much “economic growth” before the products of this growth, namely people and their machines, can no longer be sustained by the natural substrate for this growth, namely, the planetary retinue of “resources.”  Here I will suggest that the limits attributed to “carrying capacity” do not apply to human beings per se, because humans are versatile enough to manage ecosystems to their preference.  Rather, “carrying capacity” applies to capitalist economic systems, because said systems must “grow” compulsively.

(Crossposted at Docudharma)

Issues of carrying capacity have been granted new meaning in light of recent   political and economic discussion.  This piece in today’s Alternet is especially interesting.  It begins:

Nobel laureate Doris Lessing’s 1971 novel, Briefing for a Descent Into Hell, imagines other planets sending volunteers to try and save Earth because its death would threaten them all. The volunteers are first informed of the scope of their mission and nature of the planet’s inhabitants during a “briefing” session.

The basic problem, the briefer explains, is that human beings have not learned that everything is interconnected and “have not yet evolved into an understanding of their individual selves as merely part of a whole, first of all humanity, let alone achieving a conscious knowledge of humanity as a part of Nature.

Here’s an alternative formulation: people once had a clue about the relationship between themselves and their societies, species, and planet, but no longer do.  Why?  See below.

*****

So what is carrying capacity?

Carrying capacity, put in simple ecological terms, is the ability of a piece of land to sustain a certain number of organisms.  The standard graph of carrying capacity can be found in any discussion of environmental  issues: here is one from the State of Wisconsin about wolf populations:

So as the wolf niche fills up, the wolf population will supposedly stabilize, because there really isn’t more room for more wolves on a particular region.  This is a standard aspect of evolutionary theory: much of Darwin’s The Origin of Species is about how natural selection favors those species which can find niches within larger ecosystems to claim as habitats.

Does the idea of “carrying capacity” apply to human beings?

Human beings are of course different from the rest of the animal kingdom, and the word “intelligent” does not really capture the ecological aspect of this difference.  Human beings are versatile — and thus capable of surviving in a wide variety of different niches.  Human beings are also capable of technology, and can thus create their own niches — this, of course, is how it is so that most of us live “indoors” in one sense or another.

Yet we can nevertheless imagine a human version of “carrying capacity,” given that nature can only take so much of a beating before it becomes wasteland, and thus unable to support people in the sense in which it once could support them.  There are meaningful historical examples of societies which have ruined the land, and thus could no longer survive on their terms: I refer the reader to Jared Diamond’s book Collapse for a short list of them.  One can also, from 20th century American history, look at the “Dust Bowl” of the 1930s, the dissipation of farmland caused in part by inadequate crop rotation practices.

A page on the neo-Malthusian “Dieoff” website quotes William Rees, who formulates human carrying capacity as follows:

“Ecologists define ‘carrying capacity’ as the population of a given species that be supported indefinitely in a defined habitat without permanently damaging the ecosystem upon which it is dependent. However, because of our culturally variable technology, different consumption patterns, and trade, a simple territorially-bounded head-count cannot apply to human beings. Human carrying capacity must be interpreted as the maximum rate of resource consumption and waste discharge that can be sustained indefinitely without progressively impairing the functional integrity and productivity of relevant ecosystems wherever the latter may be. The corresponding human population is a function of per capita rates of material consumption and waste output or net productivity divided by per capita demand (Rees 1990). This formulation is a simple restatement of Hardin’s (1991) ‘Third Law of Human Ecology’:

(Total human impact on the ecosphere) = (Population) x (Per capita impact).

There is also the I = P x A x T equation made famous by Ehrlich and Holdren, from the same source:

“Early versions of this law date from Ehrlich and Holdren who also recognized that human impact is a product of population, affluence (consumption), and technology: I = PAT (Ehrlich and Holdren 1971; Holdren and Ehrlich 1974). The important point here is that a given rate of resource throughput can support fewer people well or greater numbers at subsistence levels.

The idea behind both of these formulations is that, sure, people can live practically anywhere on Earth’s landmass, from the Arctic Circle to the Amazon jungle.  With the aid of technology, they can live well.  But technology takes its toll upon the natural environment, because building and using it requires the use of resources.

The idea of “I,” or impact, is encapsulated in the notion of the “ecological footprint”:

The Ecological Footprint is a measure of the “load” imposed by a given population on nature. It represents the land area necessary to sustain current levels of resource consumption and waste discharge by that population.

But the math behind the I = PAT formulation doesn’t quite hold up.  There are two reasons behind this:

  1. Different technologies can be more or less efficient in their use of resources.  More efficient technologies can get by with a smaller “ecological footprint,” as Rees would describe the aggregate human impact upon an environment.  Technologies which have ecologically-destabilizing byproducts (e.g. fossil fuels) also count differently than technologies which do not (e.g. wind power).
  1. The total human “impact” upon an environment is not, and can’t be, summarized by the idea of “ecological footprint.”  In reshaping the land, human beings can create new systems, some of which can in fact be sustainable.  Rees is also inaccurate in his depiction of “waste” in an ecological context.  “Waste” is a human-centered concept.  What counts to a person as “waste” will in all cases be recycled, or more properly, composted, back into the  ecosystem.  Whether that results in an addition to, or a subtraction from, an ecosystem depends upon the type of waste that we are talking about.  One can, for instance, throw glass, paper, aluminum etc. away in landfills, where it will compost over rather tediously large stretches of time; or one can recycle said materials right away.  One can treat human manure via a sewer system, in which case it may be mixed with other industrial wastes (with uncertain usefulness as a soil amendment), or through a compost toileting system.

Thus there may be a human carrying capacity, but it does not necesssarily stand in direct relation to how many humans there are.  Human “impact” can, ideally, be minimized (or even reduced to zero) by proper ecosystem management.

The problem, of course, is that we are not doing such proper ecological management at this time.  The problem, of course, rests in human economy: our form of economy (from the Greek oikonomia, meaning “household management”) does not favor this form of ecosystem management.

So, in the end, we are stuck with a modified form of carrying capacity.  In this version, we look at the growing capitalist economy as it chews up our planet, and measure it thusly: there is only so much capitalist growth which our ecosystems can stand.  When that “so much” point has been reached, that’s planetary carrying capacity.

So why are we stuck with carrying capacity?

Because capitalist economies are addicted to growth.

(NB — this is to say NOTHING about so-called “socialist” economies.  The word “socialism” is, in this sense, unable to help us.  In its primary sense, “socialism” means public control over the means of production, and in this sense the Soviet Union, not to mention Sweden, Denmark et al., do NOT count as “socialist” countries.  Moreover, what the public VOTES TO DO with its control over the means of production is left as a completely open question.  Thus the phrase “socialist” economy cannot tell us much.  Capitalist economy, on the other hand, is easily defined: see below.)

In a capitalist economy, practically everything is a commodity, for sale on an open market.  And competitive businesses are meant to fetch “effective demand,” which is calculated by multiplying the number of paying customers by the price of each item purchased.

Capitalist production, then, chases money.  So anyone who wishes to become a producer (and all who wish to survive must have something to exchange!)  must find some way of catering her or his production to those with money.  After all of the essential needs of the wealthiest participants are satisfied, then, the capitalist producers must be able to “invent new needs” to separate money from its possessors, if they wish to make a buck.   Thus what you see in most of capitalist production is malignant, as Stan Cox notes in great detail in his book Sick Planet.

Capitalist economies, moreover, must conduct ever-increasing quantities of this malignant business, because, in an economy based on exchange, new efforts to “sell” must be mounted in order to keep the economy from “freezing up,” regardless of the ecological virtues (or vices) displayed in these sales efforts.  Our present-day capitalist economy has (in the eyes of most of humanity) largely frozen up, as global wealth has concentrated itself in the hands of 793 billionaires, while marginalizing a bottom half of humanity which lives on less than $2.50/day.  Capitalist economies must grow in order to continue to sell “capitalism” as the response to the poverty of the latter group.

Capitalist economies must also grow so that lending money may continue to be a profitable activity.  Laws were often passed against usury in the pre-capitalist world, because in an economy not based upon compulsive growth, the lending of money at interest typically resulted in impoverished borrowers.  Without capitalist growth, borrowing at interest becomes a losing proposition.  Thus the losers of this process, the debtors, tended now and then to open revolt.

Finally, capitalist economies must continue to grow because the obligation of for-profit corporations, reflected in the fiduciary duty of management to stockholders, is the pursuit of profit.  Profit means the wealth of these corporations must endlessly grow; and if the wealth of the rest of us is not to shrink by at least an equal amount, the economy must continue to grow.

Capitalism, to be sure, is a historical phenomenon, and a rather recent one in historical terms.  The capitalism system can really be said to have come into full flower with the genesis of the first real capitalist state — the post-1688 United Kingdom — but was mostly limited to the Anglo-American world until after the French Revolution.  Its historical growth, spreading alienation and commodification everywhere as its size has increased, is discussed in brief in this diary here.  At some point, however, (and here it’s hard to say when), this history must come to an end, and a new history will begin in its place: the history of post-capitalist society.  Only one thing will be certain in this history: the fact that capitalist growth will meet its limits in Earthly carrying capacity, and will be able to proceed no further from there.

So why are there ecosystem limits to capitalist growth?

Because what capitalist growth means, above all, is accumulation: accumulation into the hands of the billionaires, accumulation of goods and services, accumulation of precious metals and so on.  The natural world, on the other hand, means the constant throughput of everything: living beings going through lifespans, their bodies eventually dying and being composted for the seedbeds of the future.

Capitalist production is not quite synchronized with this movement: natural resources become raw materials, which become consumer productions which become trash.  Trash can, at best, be recycled into raw materials, and this typically requires more use of energy input: with each turn of the capitalist production cycle, something of the original complexity of the “natural resource” environment is degraded.

Thus the capitalist economy conforms to Herman Daly’s version of economic affairs:

As the capitalist economy approaches the “Full World” model on the bottom, its ability to depend upon the further growth afforded it through the throughput of the global ecosystem is strained.

As for real economic growth, William K. Tabb pointed out in a recent issue of the Monthly Review (based on Angus Maddison’s OECD stats) that in each decade after 1973, the last year of the Golden Age of Capitalism (1948-1973), the global growth rate has gone down.  Last year’s global economic shrinkage should only have accelerated that decline.

Can’t the capitalist system just become more efficient, and thus evade the limits of carrying capacity?

Only to a limited extent.  Efficiency will only be pursued in a capitalist economy to the extent that it’s the cheapest option.  Energy is a primary example of this: a capitalist economy will choose an energy source not for the sake of preserving ecosystems, but because said energy source is cheap.

Thus the best-laid plans of environmentalists to “stop global warming” and minimize the effect of abrupt climate change through alternative energy developments will likely come to naught, because alternative energy will, under the current economic circumstances, only supplement the fossil-fuel burning habits.  People will continue to burn oil and coal and natural gas as long as these commodities are cheap.  Attempts to get around this through prohibitive carbon taxes will meet unstoppable political resistance.

Moreover, under capitalism, efficiency will typically lead to increases in productive scale, thus even higher consumption of natural resources in toto.  See John Bellamy Foster’s discussion of Jevons’ Paradox for further elaboration of this principle.

Efficiency is something we do for ourselves, not something we do for the natural environment.  The natural world is not “efficient” — but its productive activities are, more or less, sustainable.  Sure, there are ecosystem catastrophe’s now and then — but there aren’t many of these, and we humans happen to be one of them.

Thus with the oil running out, a rather extreme abrupt climate change effect in the offing, the oceans fished out, the forests disappearing, and so on, it’s hard to say how “efficiency” will do much to solve the dilemma in its aggregate form.  Technological developments and improved efficiency do help us cope with the problems created by capitalist growth; but it’s a problem of rates, and at this point the solution appears to be slower than the problem.

What are the alternatives?

As I said, a sustainable economy is possible — but what it means is the productive use of everything we “waste.”  It also means a production for the direct satisfaction of human needs, and no more — rather than the endless pandering after money in a money and property system characterized by an oligarchic control over the means of production and a pyramidal concentration of wealth and power.

Whether or not “population” will still be a problem is still a matter of debate.  Certainly there are natural limits to the number of people our planet Earth can handle — but we’ll never know what these really are until an economic system is installed, globally, that mimics nature’s capacities for sustainable throughput.  Until that time, we can assume that the Earth has a limited “carrying capacity” for capitalist growth: only so much capitalist growth, and no more.

(Obama administration staffers take note!  Your attempts to “revive the economy” will only go so far, as capitalist growth will at some point meet carrying capacity — you had best concentrate, then, on attempts to make the economy more humane, less ecologically damaging, and thus less capitalist.)

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