A numbers game

Earth Island Journal, Summer, 2009 by Jason Mark

At least since the days of Malthus, people have wondered when the planet will be too full of people. During the last several generations as the number of humans has grown exponentially and our use of resources has skyrocketed the question has taken on particular force. This place can feel intolerably crowded, and it seems only reasonable to ask: How many more souls can we possibly fit?

But I think that to wonder in 2009 when Earth will be overpopulated misses the point. It seems obvious to me at least that we are already well past full. The clearest proof of that are the 1.1 billion people who live without clean water, the more than 900 million people who are hungry, the 16,000 children who die every day from hunger-related causes.

Yes, I know that modern, chemical-based agriculture can grow enough food to feed 6.8 billion people and perhaps many more. But the fact that millions still die from filthy water or insufficient food just shows that we are grappling with political scarcity as much as ecological scarcity. And for those whose lives are all too nasty and short, the distinction doesn't matter one bit.

According to most projections, we will reach the 9 billion mark sometime around 2045 and then begin leveling off. I suppose that the planet can accommodate that many Homo sapiens. If we all lived modest lives as, say, farmers, pastoralists, and craftsmen and took good care of our ecological life-support systems, it just might work. But 9 billion of us can't live as Americans, or even like the slightly thriftier Europeans. There are simply not enough resources.

That fact is why discussions of population are so complicated: It's not just how many of us there are, but how much each of us consumes. The tension between population and consumption is part of the reason why debates over US immigration's environmental impact is so fraught, as Karl Lydersen reports in "Border War" (page 34). It clouds environmentalists' personal views on how many children to bear ("The Division Over Multiplication," page 44). As Deborah Rich writes in "Hold Steady" (page 40), resolving the push-and-pull between population and consumption is key to efforts to create some kind of green economy.

When discussing human population and ecological sustainability, then, it's insufficient simply to cite numbers. A tricky kind of calculus must also be figured in.

In a recent essay,; eco-intellectual Bill McKibben wrote that we can't address global climate change with addition alone: that is, one CFL at a time, one new bike lane town by town. Saving the atmosphere will also require the multiplier effect of government policies that amplify individuals' actions. The math metaphor is also useful for thinking about overpopulation. There's no question that we need to first stabilize our numbers and then start to decrease them. But subtraction won't be enough. We will also need to use some division. For those already living in affluence, that division function will mean a radical reduction of material possessions; for those who are poor, the division could bring an improvement in their quality of life. On the far side of the equal sign, we will hopefully find a little more global equality.

On paper, the equation looks pretty straightforward. The real question is whether we are smart enough to solve it in real life.