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Why George Monbiot is wrong to downplay population question

The original title of this article was "Monbiot's flawed linear thinking could lead many astray"

Monbiot's statement below reveals a dangerous use of arithmetic and linear thinking.

In other words, if we accept the UN's projection, the global population will grow by roughly 50% and then stop. This means it will become 50% harder to stop runaway climate change, 50% harder to feed the world, 50% harder to prevent the overuse of resources.

It is certainly tempting to throw these concepts around because we all have a tendency to think linearly (the exception being that perhaps most people now at least realize that human population growth is exponential). Unfortunately, nature rarely works in such linear ways and there are thousands of examples of non-linear responses, threshold effects, and synergistic processes that undermine simple 1:1 relationships. So, increasing population by 50% will not necessarily result in a 50% more effort required to combat climate change (or whatever). It may mean that it takes 4 times the effort or who knows, that we cross a threshold where no amount of effort will result in a desired response.

Similarly, the recent use of the simple model that total consumption ("economy") is the product of population and the per capita consumption assumes that the two variables (per capita consumption and number of people) are independent and work in isolation. What we need to do is qualify this relationship by the phrase "all things being equal". So, for example, if population doubles and per capita consumption is cut in half, then total consumption remains unchanged all things being equal. Of course, all things are rarely equal and non-linear effects kick in, expected or unexpected. I doubt whether this relationship will ever really hold in this simple fashion.

This relationship also assumes steady state operating conditions and ignores indivisible baseline per capita consumption such as per capita use of oxygen, water etc. and upfront resource use needed to reduce human per capita consumption.

For example, in a de Jong world, (Frank de Jong is Ontario Green Party leader) we might imagine a projection of population of Ontario to double and might then go about (yeah right!) aiming at reducing per capita consumption to 50% of current levels in order to achieve no net increase in total consumption. However, doubling the population will entail upfront or continuing natural capital to achieve that lower consumption level and to simply meet baseline requirements of a larger population, regardless of its ultimate consumption level. Such up-front or one time capital is never included as an additive factor in the simple arithmetic relationship. Similarly, I am remined of China where the mean family size was reduced but the number of dwellings increased non-linearly with population due to the (unexpected?) desire of new generation Chinese to live without in-laws. You can all think of much better examples than mine but the bottom line is that we need to impress on people that nature is typically non linear and that we should qualify our simple arithmetic models with statements such as all things being equal and under steady state conditions. The more we use this kind of language the more we will be able to raise awareness of the myriad of caveats that are inherent in our (suboptimal) arithmetic.

Can you imagine for example the effect of a Green Party official saying something like:

If we double the population of Ontario and reduce per capita consumption by 50%, then, all things being equal and barring any non-linear responses by nature acting on our increased population, any unforseen threshold effects related to nature's goods and services (including abiotic and biotic), then under steady state conditions that ignore any first time start up consumption of resources, our total consumption will remain unchanged.

Keith Hobson is a biologist with the Canadian Wildlife Service in Saskatoon, Saskatchewan and a member of our pan Canadian Malthusian discussion group sinkinglifeboat|AT|topica com

Posted by Tim Murray