Ross Gittens has an article in the Age on the relationship between the economy and the environment (taking a few swipes at PM Rudd's pretend climate policy along the way), and noting glumly recent reports on our large projected population increase - It's the ecosystem, stupid.
Everyone (rightly) condemns economists for their failure to foresee and warn us about the global financial crisis, but here's a climate crisis we've seen coming for years and we can't take it seriously. Even the economists who brought us the emissions trading scheme don't adequately appreciate the problem we've got. They think all we've got to do is switch to low-carbon energy sources (ideally by finding a way to capture all the carbon emitted by burning coal) and the economy can go on growing as if nothing had happened. Being economists, they see us as all living in an economy, with this thing at the side called the environment that occasionally causes problems we need to deal with. As usual, wrong model.

In reality, the economy exists within the ecosystem, taking natural resources from that system, using them and then ejecting wastes, including sewage, garbage and all forms of pollution and greenhouse gases.

The global economy grows as the world's population grows and as people's material living standards rise. The problem is that the human population and material affluence have grown so much in the past 200 years that our economic activity is putting increasing pressure on the ecosystem that ensures our survival. On the one hand we're chewing through non-renewable resources at a rapid rate and using renewable resources faster than their ability to renew themselves. On the other, we're spewing out wastes faster than the ecosystem can absorb them.

Global warming is, of course, an example of the latter. But it's just the most acute respect in which global economic activity is undermining the healthy functioning of our ecosystem. Think of the way we're destroying the world's fish stocks, the way farming practices are causing acidification, desertification and erosion of land, the way dams and irrigation are destroying our rivers and the way human ''progress'' is destroying species.

All this is happening with only about 15 per cent of the world's population enjoying high material living standards similar to ours. Now consider what happens to the global economy's use of natural resources and generation of wastes when China and India - accounting for almost 40 per cent of the world's population - get on a path of rapid economic development to raise their citizens' standard of living to something approaching ours. Since the rich countries are reluctant to countenance a decline in living standards, to put it mildly, and the poor countries most assuredly won't abandon their quest for affluence, there's one obvious variable that could be used to limit global economic activity's deleterious impact on the ecosystem: population growth.

Limiting population growth in the developing world and allowing population to continue on its established path of decline in the developed world wouldn't be easy, but it would be easier than trying to prevent rising living standards among those already living.

Hence my dismay when Treasurer Wayne Swan's announcement last week that Australia's population in 40 years time is now expected to be 6.5 million greater than was expected just three years ago was received without the blinking of an eyelid. Ho hum, tell me something interesting.