How many people can live sustainably on the Australian continent?

Are we capable of having a public conversation about this topic, or should it only be discussed privately by scientists?

Why don't we have a plan?

A proper discussion about what Australia's population should look like in the future would examine a range of connected issues.

It would include projections for climate change, demographic trends, biodiversity, water usage, food security, energy, infrastructure, geopolitics, immigration, and more.

If you condensed it into a single question, you might ask: what's our "population plan"?

But as things stand today, Australia doesn't have one.

Professor David Lindenmayer, a world-leading expert in biodiversity conservation, says it's crazy that Australia doesn't have a population plan.

"You've got to have a plan about what you want to do," he told me.

"Without that we're just going to lurch from one crisis to another. We've got a healthcare crisis, a housing crisis, a housing price crisis, we've got a water crisis, and all of these things are tied to our management of population.

"It's a complex subject because it has many dimensions, but it actually needs a dedicated body, that truly is independent, to look at it deeply and say 'Well, these are the options for Australia.'

"And you might want it to commission a report from some body, like the Academy of Science, that basically says, 'OK, well, what's the science of demography? What's the science of climate change? What's the biodiversity science say? What's the science of water use say?'

"We've really got to have those kinds of conversations.

"If Australia's going to have 100 million people, then you're going to have five or six cities that have 10 million each. Is that what you want? Or do we want a population of 35 million that looks like 'this', or [some other size]?"

At the moment, Australia's population is a little over 27 million. 

In the 2023 intergenerational report, Treasury officials projected Australia's population was on track to reach 40.5 million in 2062–63.

There are many dimensions to consider

Other experts agree that Australia is clearly bad at managing population growth. 

A common complaint is the lack of formal planning for housing supply and related infrastructure in line with population growth.

But regarding the question of having an "environmentally sustainable" population, some say Australia's population isn't much of a sustainability issue per se.

As an example, they say, the question of food security isn't an issue in Australia. 

In 2020, the Australian Bureau of Agricultural and Resource Economics (ABARES) found Australia was one of the most food secure nations in the world (we export more than 70 per cent of our agricultural production).

Or they explain that Australia doesn't have an impact on the world's population, what impacts Australia is how many people there are in the world. 

In that vein, they say people who migrate to Australia probably end up earning slightly higher incomes on average than they would have otherwise, and they probably consume slightly more goods and services in Australia. But Australia's environmental standards are quite good compared to other countries.

Or they point out that Australia is making progress in the energy transition, too.

The world-renowned Professor Andrew Blakers likes to explain that the fastest energy change in history is currently underway, and solar and wind have "hands-down won the energy race."

Professor Blakers says Australia's energy generation sources are moving from 85 per cent fossil fuels in 2017 to 75 per cent solar / wind in 2030 (plus 7 per cent hydro), and the exponential growth of solar energy globally is fast enough to completely decarbonise the world by 2042.

The slide below comes from a speech he gave to the Academy of Science in September.

However, when it comes to the "sustainability" of Australia's population, some experts say one of the genuine problems we face is land clearing and nature loss.

But that's not necessarily related to population, they say.

They say almost all of that is connected to our export industries (minerals, agricultural), and very few of the people who are doing land clearing for agricultural reasons are making any money from the practice. They say land clearing is a cultural hangover from the past that needs to stop.

So, agree with those points or not, but they're the types of things we'd talk about if we had an ongoing national conversation about our vision for Australia.

Global heating is getting worse

Back in 2015, Australia's chief science agency, the CSIRO, released a paper titled Australian National Outlook.

In that paper, CSIRO staff argued that Australia had all the tools to achieve economic growth and environmental sustainability — we just had to choose to use them.

Here's how they summarised the competing arguments:

"Few topics generate more heat, and less light, than debates over economic growth and sustainability.

"At one end of the spectrum, 'technological optimists' suggest that the marvellous invisible hand will take care of everything, with market-driven improvements in technology automatically protecting essential natural resources while also improving living standards.

"Unfortunately, there is no real evidence to back this, particularly in protecting unpriced natural resources such as ocean fisheries, or the services provided by a stable climate. Instead, the evidence suggests we are already crossing important planetary boundaries.

"On the other end of the spectrum, people argue that achieving sustainability will require a rejection of economic growth, or a shift in values away from consumerism and towards a more ecologically attuned lifestyles. We refer to this group as advocating 'communitarian limits'.

"A third 'institutional reform' approach argues that policy reform can reconcile economic and ecological goals – and is attacked from one side as anti-business alarmism, and from the other as indulging in pro-growth greenwash."

Four years later in 2019, the CSIRO published its second Australian National Outlook, which was more comprehensive.

It asked: what will Australia be like economically, socially and environmentally in 2060?

Both reports argued that if we had a plan for where we're going, we could achieve some good outcomes. But if we didn't have a plan, our outcomes would be rubbish.

And last week, we got a reminder of what rubbish outcomes look like when the CSIRO and Bureau of Meteorology released their latest State of the Climate report.

The report didn't mince words.

It says Australia, on average, has warmed by 1.51°C since national records began in 1910, with most warming occurring since 1950. Every decade since 1950 has been warmer than preceding decades.

Australia's warmest year on record was 2019, and eight of the nine warmest years on record have occurred since 2013. The long-term warming trend means that most years are now warmer than almost any observed during the 20th century.

Oceans around Australia are becoming more acidic, with changes happening faster in recent decades. The ice sheets and ice shelves of Antarctica and Greenland are losing ice due to a warmer climate, and contributing to global sea level rise.

It goes on.

It says scientists can approximately say how much the world will warm in the next 10 years, but the impact that warming will have on extreme weather is unpredictable. And who knows how things will look in 2060.

Is it time for a population plan yet?