Wednesday, March 17, 2010

I=PAT proves nothing

I=P×A×T (commonly pronounced “eye-pat”) is a formula, often cited, describing the factors that cause environmental degradation. In this formula, I stands for impact; P stands for Population; A stands for Affluence (or amount consumed); T stands for Technology.

The population, multiplied by the “affluence” (or amount of stuff consumed), multiplied by the technology used to produce the stuff that is consumed, gives the impact of humans.

At first glance this is an indisputable description of the overall impact of humanity taken as a whole. It’s use lies in this division of impact into different factors: having done so, we can consider how each separate factor works in our further inquiry.

But by itself, eye-pat is really not a useful description of the problem. It is almost mathematically meaningless, because A and T simply describe averages, per capita. Taken together, they add up to the average ecological footprint of each unit of population (each person, that is). So the total impact equals the average impact multiplied by the number of people. The mathematics of this is as profound as saying that a number equals half of itself multiplied by two.

The formula is also based on, and biased toward a population focus. It divides impact by person, not by income bracket, nation, bio-region, or any of the other possible ways of dividing up society’s overall impact. This predisposes the formula to an individualist and consumerist approach to solving environmental impact and it predisposes the formula to suggesting population control measures. Yet population is just one arbitrary factor among many that could have been chosen, and our impact as individuals is only caused by our interactions with others, through work as much as through consumption.

To take apart the formula some more, it is commonly (and fairly) criticised that “affluence” takes no account of the vast differences between rich and poor, or the consumption and technology in which we have no direct say – like the resources used to maintain the world’s war machinery and armies for example.

To really examine how an increase in the amount of consumption (or what is consumed) can impact, you have to look at who is doing the consuming and why – not a statistical average of the whole world or whole nation. Population, equally, has to be analysed as an independent factor with its own dynamic of change driven by social and environmental factors to gain any real insight.

But more profoundly, the formula says nothing about how pollution/impact grows in relation to the three factors: each is given an equal weight, independent of way they interact with each other, which is only measured in the end figure of “I”.

Population grows incrementally, generation after generation, at various rates around the world. In Australia, it is only growing due to immigration, as the birth rate is currently below the rate of replacement. Growth due to immigration is not growth in population overall, because population is a global phenomenon. The whole world’s population is projected to peak this century, and its rate of growth has already begun to slow.

Changes in technology and consumption, however, can leap in rapid bounds. Any changes in consumer items or production practices are multiplied through the social mechanism of the market economy. Imagine a newly released consumer item is put on the market and rapidly taken up by consumers. This addition of one technologically produced consumer item results in an impact that is rapidly multiplied by that part of the population that buys it. Markets tend to expand because capitalism is a system that requires economic growth to survive, so if an item is successful in a part of the market it is sold fairly quickly to the whole population, or large parts of the population. This applies to SUVs or McMansions as much as iPods or fresh produce imported by fast refrigerated air-freight.

So an increase in technology is rapidly multiplied by the whole population. Yet an increase in population does not multiply by the whole ecological footprint of everyone else added up: it only multiplies by the average of their footprints. (Here I am taking ecological footprint as equivalent to A×T). So population growth only adds incrementally to overall impact, whereas changes in technology and production for the market multiply the impact.

Taken on a regional or national level, many factors are quite unrelated to population. Coal for export will continue to be mined and shipped, whether Australia’s population doubles or halves, unless political measures entirely independent of the individualist I=P×A×T paradigm are taken.

A simplistic reliance on eye-pat to “prove” the importance of population controls for environmental protection is very wrong. Population cannot be reduced to one of only three factors that determine ecological impact. Quoting a mathematical formula might look smart, but algebra is only meaningful when it is given a meaningful content. I=PAT does not impart much meaning.


  1. Your logic is so flawed. You mention that technology is rapidly taken up by the populace, and is therefore rapidly multiplied by the population.

    So by this logic, wouldn't people coming to live in Australia also adopt our ecological footprint; migrants often use cars, they have access to electricity as well which generally means more greenhouse gas generation from coal.

    Granted, recent arrivals may not live as regally as many other Australians at first but essentially, in Australia the I=PAT "equation" still largely holds as an indicator of stress on the land.

    I don't understand your stance of vehement support for population, do you think that groups advocating a slow down in population growth are somehow against humanity. And as you point out, world population growth is slowing, so should not also we slow it in Australia as well? People like youself that think population is not really a factor in stress upon the environment are living in denial. I can't understand your motivation. Perhaps you would care to enlighten us?

  2. I think you haven't understood the maths of my article. A new consumer item, e.g. the iPod which has taken off in recent years, becomes a normal posession that most people own, through marketing etc. This means that the new item's impact is rapidly multiplied by the whole population, or a major part of it. Yet a new arrival to Australia only adds one more footprint, rather than increasing everyone's footprint. It is an incremental addition, not a multiplying effect. This is why the world's pollution has increased so markedly while population growth has slowed in the last 20 years or so.

    "Stress on the land" is measured in many ways. Land clearing, fresh water use/pollution, urbanisation, atmospheric pollution, etc are all different impacts. Each is caused by various human activities, mediated through technology which is in turn mediated through social/political choices. Choices like: Australia doesn't burn so much coal because there's no alternative, it is because the coal companies are politically powerful. Urbanisation is not simply governed by population growth, it is about urban planning, which can accomodate all sorts of population densities, either more or less sustainably. Land use and all the others are the same.

    Many ecological impacts are not narrowly national. Climate is the most obvious. It doesn't matter whether CO2 is emitted in Britain or Bangladesh.

    For Australia, population growth is solely about immigration. Do you think preference should be given to immigrants from high-polluting countries like the USA and Canada, because their carbon footprint won't grow much if at all? I would rather have an equitable immigration policy and tackle our own high rate of pollution.

    The other point is that individuals don't determine their own level of pollution. We never had a referendum on continuing with coal power stations, or on clear felling old growth forest, or on urban sprawl vs sustainable urban growth. These questions are decided in corporate boardrooms and public service offices. I=PAT slates all the blame with individuals. This is not just unfair, it doesn't provide any clues about the solution.

    I'm not arguing *for* population growth as such, but groups which campaign against it are attacking a symptom not the actual problem. At best, they are ineffectual; at worst, they distract from finding real solutions.

    NB: There's more interesting comments on this article at where it was re-posted.

  3. Jeff White posted this comment to the article on climate and capitalism:

    “The myth of overpopulation is one of the most pervasive myths in Western society, so deeply ingrained in the culture that it profoundly shapes the culture’s world view. The myth is compelling because of its simplicity. More people equal fewer resources, and more hunger, poverty, environmental degradation, and political instability. This equation helps explain away the troubling human suffering in that “other” world beyond the neat borders of affluence. By procreating, the poor create their own poverty. We are absolved of responsibility and freed from complexity.

    “The population issue is complex. To put it into proper perspective requires exploring many realms of human experience and addressing difficult philosophical and ethical questions. It entails making connections between fields of thought that have become disconnected as the result of narrow academic specialization. It demands the sharpening of critical faculties and clearing the mind of received orthodoxies. And above all, it involves transcending the alienation embodied in the very terms “population bomb” and “population explosion”. Such metaphors suggest destructive technological processes outside human control. But the population issue is about living people, not abstract statistics.

    “The myth of overpopulation is destructive because it prevents constructive thinking and action on reproductive issues. Instead of clarifying our understanding of these issues, it obfuscates our vision and limits our ability to see the real problems and find workable solutions. Worst of all, it breeds racism and turns women’s bodies into a political battlefield. It is a philosophy based on fear, not understanding.”

    - Betsy Hartmann, Reproductive Rights & Wrongs: The Global Politics of Population Control, rev. ed. 1995, p. 4.

  4. It seems to me, Ben, that you are looking for sinister meanings where there are none. I=PAT correctly gives equal importance to Population, Affluence and Technology. Why you think that it focuses on population is a mystery. Betsy Hartmann does the same thing claiming all sorts of evils where there aren't any. Sustainable Population Australia isn't trying to turn women's bodies into a political battleground, they are just saying throw out the Baby Bonus. That is just correcting a bad policy.
    Using a title like "I=PAT means nothing, proves nothing" sends the message that you think that population, affluence and technology has no part in environmental impact. It is easy to find more sinister meanings in a title like that then in anything that environmental groups are saying.

  5. Ben, SPA is all about finding ALL the solutions to the problems, it's just that it tries to show people that talking about population, as a critical factor in environmental issues, shouldn't be a taboo subject, and is indeed part of a holistic approach. There are powerful interest groups that aim to keep population growth high in Australia, for their own profit-bearing interests and the detriment of Australians (as planning cannot keep up with it). Thus, SPA focusses mainly on local issues but is cognizant that population is first and foremost a global issue. On the global scale, SPA have never victimised people from poor countries with high birthrates, they see that we need to provide foreign aid and educate and this will improve the lot of women in those countries and the level of prosperity. Bringing in a few tens of thousands of economic migrants, whilst benevolent, will not solve the world's problems. If guilty of anything, it could be said that SPA is selfishly focussing on Australia first rather than the rest of the world. Fine. I admit it, as a member, I wish to ensure that my backyard is not destoroyed by millions more crowding in to the big cities of Australia. I don't care where they come from - born here or overseas - it doesn't matter. And why shouldn't we take heed of rampant population growth which in Australia depends on an ever-dwindling supply of oil. Prove to me that Australia can handle 50 million people, and can house them in cities that are pleasant to live in and easy to move around in, and I'll give you a green light...

    I suggest that you address your preconcieved notions of what SPA stands for. You might find it has a lot more in common with your beliefs, than you mgiht somehow care to admit. It is comprised mainly of environmentalists with a socialist slant - I imagine that you are somewhat similar. If there are closet racists in our group - I haven't met any.

  6. Ben,
    You are a unwitting stooge of big business and globalisation which loves people like you doing the heavy lifting for them...all in the name of naive political correctness.

    Why do you think big business wants massive population growth ?

    1. to sell more things ( read more greenhouse )
    2. to keep wages low for higher profits (read exploitation of workers..less scarce labour is, the less it's worth, like any other commodity)
    3. to lend on housing with massive mortgages
    (read mortgage/rent slaves) Housing cost inflation and speculation is caused by increase in demand through population growth.

    Finally, you are a specist. That is you don't care about the destruction of all the other species we share the planet with, by having the forests and water habitats wrecked, by the needs of more of our species.

    Come out of your seedy manipulation and promote having around 2 children at 30 years of age and replacement immigration ( ie 80,000 leave bring in 80,000 ) and the Planet will breath a sigh of relief.

    Your a talented person....become a force for good.

    Cheers and best wishes for your new future,


  7. Rohan GaiswinklerApril 01, 2010 2:04 PM

    This article demolishes the arguments put forward by Ben's critics:

  8. The IPAT formula is nonsense because it is far too simplistic to account for the complex array of interactions that take place between it's variables. IPAT catagoriseS "Technology" as something only harmful to the planet. Yet it's totally obvious that things are not so straigt-forward. If one is against "Technology" then one is against high tech wind farms, solar energy, computerisation, etc, etc. Interestingly, IPAT proponents never speak out against these things. The reason is that the whole IPAT formula is a propaganda exercise by socially reactionary ecologists who have little or no concern the impoverished Third World and believe in Malthusian rubbish about the poor breading the world into oblivion.


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