Australia is an immense country, but most of it is arid desert or semi-desert and the population clings to the coast. As an Australian poet said, "It has a wet rim where the people clot / Like mud". So it would be difficult to support a huge population. However, enthusiasts for "sustainable development" think that its meagre 21 million are already far too many for its fragile ecology. The national president of Sustainable Population Australia recently argued that the country needed a one-child policy to reduce the population from 21 million souls to just 7 million.

Writing in the Melbourne Age, Chris Berg, the editor of the IPA Review, had an original criticism of this familiar tune.

But we could spend all day debating the impact of population on the environment. I'm more concerned about another thing: can you imagine how excruciatingly boring Australia would be with only 7 million people?

Last week's Sunday Age reported that a large proportion of "tree-changers" regretted their decision to move from the suburbs to the quieter countryside. Shockingly, in remote and regional Victoria there are fewer and less varied jobs available, fewer services and less commercial activity than in the cities.

An Australia with just 7 million people would be like a mandatory tree-change for everybody, with those who survived the great population decline skulking about the ruins of this once-busy nation.

Australia already suffers because of its small population. We have a small audience for culture. We have a small market for goods and services, and a small base to produce them from. If it weren't for the fact that we can trade stuff with other countries, it would hardly be worth having an Australia at all.

Pretty much everything interesting and exciting about the world is the direct result of human action. Fewer people would mean fewer people doing cool stuff. How would life be without basil pesto, the British version of The Office, single malt whisky, SuperTed or Facebook? Nasty and brutish, sure, but agonisingly long.

And let's face it — whatever meaning has been imposed on the environment has been imposed by people. So when deep greens exalt nature as morally superior to humanity, it comes across as just a little bit stupid. When the chips are down, surely our loyalty lies with the human race.