Impact = Population  x  Affluence  x  Technology

Our environmental impact on the Earth is not necessarily all deleterious, but if that impact becomes excessive, as indeed I (and others) firmly believe, then the result can be not just deleterious but catastrophic to human-kind and the living world generally.

Environmentalists advise there is a finite limit to the impact which the Earth may sustain over time, and this is clearly shown in the findings of the World Wildlife Fund ( "WWF") as may be seen in its downloadable "Living Planet Report 2006". Presently, the planet is in deficit by about 25% annually - the so-called debt is cumulative! That is what our impact presently produces.

That arises from the combined factors of the PAT equation, so if we wish to reduce that debt and achieve a balance, one or more of those factors need to be reduced. Much attention is presently paid to carbon emissions (arguably fostering climate change and other detrimental consequences) and how these may be reduced by forms of rationing and improved technology. It seems to have occurred to only a few, but were our population to be reduced, so would the environmental impact be reduced also - that is a truism. Were the planet's population to be reduced significantly - say to just 3 or 4 billion, instead of our present 6.7 billion - it could well be that none of the pressures which occupy the minds of the Kyoto Protocol participants would even be felt.

The PAT equation is theoretical and nobody, to my knowledge, has yet expressed it in mathematical terms or dreamt up appropriate units of size (although WWF has introduced a useful "global hectares per capita" for measuring our ecological footprint). It is not a new concept but recently it has been developed in scope and has been re-labelled as the "Kaya equation" (more information may be obtained in the Special Report on Emissions Scenarios, published by the Intergovernmental Panel on Climate Change).

Nevertheless, just for illustration of the interconnecting relationship, let me suggest P = 10, A = 10 and T = 1. The I(mpact) would then amount to 100, with the technology factor providing no effect one way or the other. Let me now assume that an impact of 100 is the Earth's maximum sustainable limit.

Technology, the "T" in the equation, may provide the means by which the population at a particular level of affluence may either increase or reduce the impact on the environment. For instance if a means were found to power motor vehicles cleanly from some as yet undiscovered source, this would reduce the impact yet still allow us to achieve the same level of affluence or life-style comforts, at least so far as transport is concerned. If this were to come to pass, then the value of "T" may be reduced, say to 0.8, and therefore the impact would in turn reduce to 80, well below my perceived maximum sustainable limit. On the other hand, were technology to provide us with access to more and cheaper oil resources, this would provide a potential for greater consumption (more carbon emissions et al) and so the "T" might increase to say 1.2, yielding an impact of 120, well over the maximum sustainable limit.

Of course, we can all see how the "A" (affluence or consumption) factor affects the environment; the more we increase our rate of consumption, the greater the pressure of environmental impact. It is this factor to which "green" pressure groups - they are legion - and responsible governmental authorities direct their attention, the aim being to ration our use of the Earth's resources, both renewable and finite. Laudable though targets of reduced consumption may be in view of the dangers which are perceived, there are few of us inhabiting the globe who are really prepared to curb our respective life-style activities and comforts unless the situation becomes dire.

However, many think the situation is already dire, although many others deride such apocalyptic talk. Anyway most of us are at least prepared to cut out waste, whether as little as squeezing less paste on our toothbrush to as much as cutting our aviation travel or foregoing the pleasure of being a two-car household, and so on. Nationally, many countries try also to cut carbon emissions, recycle materials and otherwise reduce consumption, all of which is to be commended, one assumes. I, on the other hand and without resorting to pointless waste, do not wish to have thrift imposed upon me simply because there are not enough resources to go around. If I have the financial means to do so, I may like to have more than one car and perhaps travel by air whenever the whim takes me. Why not?

The reason why not is of course because I am competing with so many other people for our limited resources. That is where the "P" in the PAT equation comes in. Were there to be sufficiently fewer people occupying the planet, we could even increase our affluence/consumption without increasing the present environmental impact. In my hypothetical mathematical terms, we might have P = 5, A = 15 and T = 1, producing a quotient of 75 - rather improbably I confess, 200% more affluence for each one (fewer) of us yet only producing 75% of the maximum sustainable impact.

My figures are unreal of course, but I have introduced them to labour the point that POPULATION is an important constituent of the global environmental impact and should be addressed as seriously as the affluence/consumption factor that most authorities find it convenient to concentrate upon. Indeed, most authorities give scant attention to the population factor. On the next page, I suggest why this should be so.