The news that the human population now numbers more than 7 billion - and the projection that it may grow to 15 billion - has caused the re-emergence of many ancient population fallacies.

Australia is a centre of one of the most dangerous myths to infect civilisation: that population and economic growth have no limits. The "big Australia" fallacy is pushed by unscrupulous developers, politicians, media moguls and their buddies, who will personally profit from growth.

In fact, Australian population growth will promote further destruction of the fragile environment of Australia. And it will attack global life-support systems by adding more greenhouse gas-emitting super-consumers to the human population.

Fortunately, most poor and middle-class Australians realise that the growth boosters will push the costs of further overpopulation onto them and the rest of Earth's people, while reaping the benefits for themselves. Indeed, Australia leads all the rich countries in at least having a debate about population and consumption, and having a leader such as Dick Smith to galvanise it.

Let's look at some of the silliest ideas. There's the half-baked idea that overpopulation isn't the problem - it's overconsumption. Yes, most of humanity's environmental problems trace to too much total consumption, but that consumption is due to population size and per-capita consumption.