What does population growth mean for environmental policy? asks the Australian Conservation Foundation's Charles Berger.

“Growth doesn’t have to be a dirty word,” Queensland Premier Anna Bligh said ahead of the Growth Management Summit she hosts today and tomorrow.

Of course, she’s right: “growth” is no more good or bad in the abstract than the direction west. It all depends on where you are and where you want to go.

At the Growth Management Summit we’ll hear lots about planning for population growth, but very little about why we would want our population to be rapidly growing. For a conference about growth, the relative merits of slow versus fast population growth, let alone population stabilisation, are curiously off the agenda.

The Queensland government has developed a clever online tool for the conference, which allows users to play with a range of variables for south-east Queensland. You can rank different priorities, such as public transport, large houses and preservation of agricultural land, and see how your choices affect the overall urban form of the region.

In many ways, it’s what we need more of from government — engaging tools that allow us to think about future options and trade offs. But there’s one variable you can’t tinker with: population growth. It’s taken as a given.

The point of the conference, then, is to persuade us that very rapid population growth is desirable, inevitable and manageable.

Well, I’m all for better management. So let’s get our hands dirty and look at what rapid population growth really means for environmental policy.

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First, carbon pollution. The Rudd government has committed to reduce Australia’s pollution levels to 60% below 2000 levels by 2050. If our population stabilises at 27 million in 2050, that means a per capita reduction of about 72%. That’s tough enough already. But if our population is 36 million by 2050, a 79% per capita reduction is required to meet the same goal, with even more ambitious reductions thereafter as our population continues to grow. So carbon-intensive activities such as eating meat and flying in planes will have to be more expensive in the high-growth scenario.

Next, water. The Victorian government has set Melburnians a water use target of 155 litres per person, per day. If the city grows from its present population of 3.8 million to 5 million, Melburnians will have to cut their water use to 118 litres per person per day. If Melbourne goes to 6 million, the daily target should be 98 litres. Say hello to level-eight water restrictions.

Finally, land and biodiversity. Population growth is causing environmental degradation on such a scale that ACF last week nominated it as a threatening process under the Environmental Conservation and Biodiversity Protection Act. Restoring ecosystem health is much more than just protecting what’s left. Re-connecting fragmented habitats through biodiversity corridors is a centrepiece of many state environmental strategies. The SE Queensland Regional Plan recognises the need to identify “areas currently developed or cleared that can be rehabilitated to restore connectivity”.

Currently developed land, to be restored for biodiversity? That will be hard enough as it is, but nearly inconceivable when you consider the housing demands of a rapidly increasing population.

So if they are being honest about the management challenges of a growing population, advocates for rapid growth must be prepared to spell out their plans for 79% per capita cuts in emissions, water use of below 100 litres per person per day and housing densities that allow for the reversion of currently developed land to biodiversity corridors. And that’s just to be consistent with current government environmental policies.

I would genuinely like to see such a plan, but it doesn’t exist and isn’t in the works.

In fact, the best existing regional and urban planning frameworks — Perth’s “Directions 2031”, the SE Queensland Regional Plan, Melbourne 2030 — are all at risk of being superseded by population growth.

Perhaps we should return to the original question: is rapid population growth a good idea in the first place?

Recent polling suggests most Australians don’t believe rapid growth is economically beneficial or environmentally benign. And the government may not even believe its own rhetoric: just last year, the Australian government told the United Nations that population growth is one of the “major current and long-term threats to Australia’s biodiversity”.

Perhaps growth isn’t a dirty word, but neither should it be pursued for its own sake.