I'm in the "Malthus was right" camp. To me, the lack of a population crash thus far isn't evidence against his theory. Let me explain.
Malthus was certainly right in the trivial sense: exponential population growth cannot continue forever. But was he wrong for failing to predict the rise of the industrial agriculture and chemical fertilizers that have managed to feed our exponential growth? No. These developments didn't negate Malthus' theories. In fact, these discoveries may have worsened their eventual consequences.
Humans didn't find a brand new way to permanently increase our food supply. Instead, we started a straightforward oil for food program, where we pumped oil and natural gas from the ground, changed it into fertilizer and pesticide, and sprayed it all over the planet to increase our harvests. It's akin to the difference between getting a better job and finding a pile of money under a rock.
As a non-renewable resource, oil is a terrible basis for population growth. Once it runs out, the population supported by oil will need to either change their food source or shrink until it comes back in line with what the Earth can sustainably produce. If the supply of oil drops too suddenly, you end up with six or seven billion people living on a planet that can only really support a billion, all looking for their next meal.
Having that temporary infusion of resources has allowed humanity to far exceed the numbers that the planet can legitimately support. Malthus predicted that as we reached the limits of growth, there would be increasing downward pressure on the population, to the point that we could never overshoot carrying capacity by much. What he didn't foresee was a situation where the population didn't just reach the limits of subsistence, but rocketed past them, making the consequences of the eventual crash far more calamitous.
That's why I was a bit rankled by this post. Malthus' "limits of subsistence" are defined by the amounts that humans need in order to survive. It seems possible to reduce population growth by allowing each individual to consume far, far more resources than survival dictates. But whether the increased demands on resources come from our increasing numbers or our increasing consumption per capita, we're still putting ever greater stress on the planet's ability to sustain us.
Solving the population problem by bringing everyone up to a First World standard of living is a non-starter. The planet cannot keep up with the demands for resources humanity currently places on it. We need to scale back resource usage by either cutting back on people or resources used per capita.
Wednesday, August 1, 2007
From Salon: We're all going to die!
Malthus fascinates me. When someone mentions him, I have to chime in. Reposted from here for anyone who doesn't want to click on the link: