Population go boom now?

First published over at the TerraPass Footprint

So when is that population bomb going to happen, exactly? In theory, exponential increases in human population should eventually be constrained by limited, non-renewable resources. One way to track an impending resource crunch -- when high demand hits low supply -- is by watching for a surge in the price of various goods.

In 1980, biologist and author of The Population Bomb Paul Ehrlich wagered economist Julian Simon that demand for five different precious metals, including copper, would result in higher prices for those metals.

After ten years and 800 million more people, the largest increase in a single decade in human history, the inflation-adjusted price of all five metals had gone down. So much for resource catastrophe.

Fast forward 18 years. The New York Times recently reported on the boom and bust cycles of copper extraction in the rural West -- the article was a look at what should be a growing sector of the economy. Turns out that bubble appears to have burst, too. The Times's article made me wonder how the Malthusian predictions are holding up, now that we've steamed past 6.5 billion people.

Surging demand in India and China pushed copper prices to big highs in 2006, only to come crashing down this year. After a few years of looking like we'd finally hit a point of true scarcity, demand for this resource has fallen again and the price is back to historic levels.

So when is the resource limitation/population growth trainwreck supposed to happen? I find myself in a strange position of bracing for an environmental apocalypse (because the earth is obviously finite), but scratching my head because we haven't maxed out yet (although examples of collapsed societies exist). If anybody can predict when, precisely, I should start worrying, please let me know. I'll want to stock up on Twinkies.