This article, POPULATION: THINKING ABOUT OUR FUTURE, was posted on the Oil Drum today (the 13th of Sept). When you get a chance it's worth a read.
Here is a different example, still using crude oil. The United States reached its peak oil production in 1970, when our population was about 203 million. Had it been necessary for us to live within our means with respect to oil after 1970, we would have needed to reduce our population, reduce our per capita use of oil, or some combination of the two. However, since 1970 crude oil production in the United States has steadily declined, whereas the population has grown to 310 million. Our demand for oil grew, whereas our oil production declined. We could meet that demand, but only because we were able to import more and more crude oil from elsewhere (and because we have never been willing to calculate the real cost of doing this, including both environmental costs and the cost of maintaining major military commitments in the Middle East and elsewhere). Now extend this same thinking to the world, where we keep promising economic growth to all, and ask yourself a simple question: When the world population reaches the point where its demand for oil exceeds supply, where is Earth going to import more oil from?
We do not know for sure how much of the world’s population growth over the last two centuries has been a direct result of our use of fossil fuels, but we do know that that growth has been totally different from that in any earlier period of our history as a species, which takes us back about 200,000 years. Whatever the current share of world population is that we might attribute directly to oil, that share will begin to decline once we have reached a peak in oil production. If we were prudent, we would realize that and act now to decrease the world’s population in humane ways, mainly by decreasing birth rates below death rates and keeping them there for a very long time.
For those who want to argue that other energy sources are on their way and that we needn’t worry so much about oil, I would suggest that you read Vaclav Smil’s book, Energy Transitions: History, Requirements, Prospects. He concluded that “Energy transitions have been, and will continue to be, inherently prolonged affairs, particularly so in large nations whose high levels of per capita energy use and whose massive and expensive infrastructures make it impossible to greatly accelerate their progress if we were to resort to some highly effective interventions.”
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Find article here: http://www.theoildrum.com/node/6949#more