Green Daily

The interesting thing about the underlying elements of the ecological meta-problem facing humanity these days - climate change, food shortages, polluted water - is that most of them haven't emerged as slow motion disasters just because we're such a careless and untidy species, but because there are so damn many of us on the planet.

Overpopulation isn't just the 800 pound gorilla in the middle of the room that we're ignoring. A better metaphor would be a whole building jammed with hairy ill-tempered primates, with the ground floor on fire and the banana supply just about to run out.

Around the time that the Romans were conquering everybody in sight, there were maybe 100,000,000 people on the planet, enough to fill up modern Tokyo, Beijing, Sao Paulo, and Mexico City, with the rest of the world left to the dolphins and Sasquatches. By the middle of the 20th century, population was about 2.5 billion people - getting a little crowded, but still plenty of elbow room if you wanted to take the time to look for it.

Today it's estimated that the human population is about 6.7 billion, with an astonishing and terrifying 2.5 billion people expected to be added by 2050, by which time, God willing, I won't be around to meet them.

The WorldWatch Institute recently released a report which noted that even though the average fertility rate (i.e. number of children per woman) is dropping, the sheer number of people on the planet meants that we're still increasing our absolute population faster than ever before. In 2007, some 175 million babies were born, most of them, as I think P.J. O'Rourke once said, in places where you wouldn't want to have a summer home.

This rapid population growth has been absorbed with surprisingly little impact, but there has been a hidden cost - overuse of non-renewable resources, and severe degradation of the environment. Pundits are now predicting, and even observing, shortages of all manner of things, including some essential to human life.

Food, for example. Although the Green Revolution of the 60's and 70's managed to increase agricultural production enough to prevent massive famine over the last 4 decades, most of those advances came from technology and chemical fertilizers, both of which are dependent on increasingly scarce and expensive fossil fuels. What's more, the supply of arable land is shrinking as humans build parking lots and housing over former farms. Human population, however, keeps on growing, with the result that the world supply of food is now lower than at any time since measurement began more than 40 years ago. Various experts are now predicting food shortages in the not-at-all distant future.

Climate change, of course, could also be mitigated if there were fewer of us - fewer cars, fewer houses, fewer cattle farting methane into the wild blue yonder. Rainforests woudn't be chopped down to feed our increasing need for land to live on.

The point of course, is that whether you think the carrying capacity of the planet is 9 billion or 12 billion people, it's clearly not infinite, and if we don't get the matter in hand, nature will step in and do it for us (in biological terms, this is known as a "dieback.") Most likely this surprising turn of events will take the form of combination of catastrophes - starvation, disease, resource wars and whatever other tricks and treats that the Four Horsemen are toting around in their saddlebags.

So is there a way out? Well, the one thing besides disaster that does seem to reduce population growth is affluence. Wealthy, industrialized countries typically have stable or declining populations (net of immigration), a fact which seems to be associated with increased status and education for women, ready availability of birth control, and probably a reduced need to raise a large family of farmhands or chimney sweeps.

There's some evidence that a cultural shift is taking place. The World Economic Forum yearly survey on the global gender gap sees it closing, albeit at a fairly glacial pace, and the world economy is still growing as developing countries increase their wealth. These trends argue that the fertility rate should continue to slow down over the next few years. The question is, will it be too little, too late?