WHY indeed ? ? ? ? ? ?

Stop all immigration now. Hunt down people here illegally and send them packing. Don't vote for any politician who supports immigration.

Neatly reasoned questioning, Kevin. One of the essential components of an increased population is space - space to live, space to relax, space to grow food.
We should also realise that a bigger population means a larger domestic economy - our goods and services thus gain a far larger market than at present.
I guess one of our inhibiting factors may well be cultural. We've grown accustomed to living in this 'wide, brown land' and the idea of a larger population living in it with us could fill some with dismay.

One possible policy consideration could be to incentivise rural living expansion by allocating worthwhile taxation concessions for those who choose to live outside of existing high density cities, whether simply as residents and consumers, or to set up businesses.

With this would flow the critical infrastructure expansion of things such as transport, power and water supplies, hospitals, schools and universities, and resulting commercial ventures based around the support of local economies and lifestyles.

Many of our migrants come from densely populated parts of the earth; it just may be possible to market a less crowded, freer lifestyle whilst still retaining close cultural bonds.

>'Has anyone in the "high immigration" tent perhaps wondered whether the current disastrous drought across much of southeastern Australia might not presage early signs of climate change and compromising of the country's future physical "carrying capacity"'

Of course. But carrying capacity is not fixed. The limits to what we can produce are economic not technical.

>'A lot is said about a larger population being necessary for economic growth? But is that the only drumbeat to which a civilised society should march? What about residential liveability, social cohesion and inclusion, quality of life, environmental quality, etc?'

Yes, these are all important. But they can be achieved whether or not we have high population growth.

>'We are told Sydney and Melbourne are on the path (principally through immigration) to population sizes of around 8 million. How likely is it that an addition of 3 million people to both cities will make them better places to live? Some people undeniably look forward to those mega-city developments. But many certainly do not.'

I remember seeing on TV Dick Smith lamenting Balmain not being how it used to be. And I thought: so what? If you want to live somewhere resembling a country town, we have plenty of actual country towns available! And so it is with our big cities: they will get bigger, but there will be plenty of alternatives available.

Unless we limit couples to a maximum of just two children, the population will continue and possibly double in the next fifty years, Even as many jobs are replaced by automation! Including many white collar jobs.

Our cities are already too full for their infrastructure and our arable land and water is both limited and shrinking via desertification. This is bite bullet time.

Decisions cannot be endlessly deferred or kicked down the road because they're hard or politically unpopular.

We could accommodate five-six times our present numbers if we built an inland canal to guarantee viable water and irrigated arable land.

The key and an essential is ultra-cheap energy. That cheap, clean, safe energy is MSR thorium!

Typical muddling backbiting politics won't do anything but worsen the situation. And none of our current visionless self-serving pollies are up to the job!

Can't even say nuclear, so instead, say technology agnostic. And then only if we can get some tax avoiding, price gouging, profit repatriating foreign firm to do it for us?

Or maybe we should just throw our hands in the air as the climate worsens, our food production becomes parlous, and we hit our mineral peak.

As our hopeless leaders forever blame shift or max out the credit card, as their only (allowed) response!

Let the cattle starve and the fruit rot on the ground as the other crops wither and die as we wait for rain or a leader with the imagination and testicular fortitude to take on the unavoidable challenge!

And a hopelessly divided Australia, will never ever hold them to account? Until it's way too late! Go figure?
Alan B.

The homeless population isn't large enough yet and need to double or treble to put downward pressure on wages? As well a send real estate prices skyrocketing through the roof!? And we haven't got enough Professors driving taxicabs or Ubers yet either.

Perhaps if things are just allowed to drift toward some lowest possible common denominator and the lamebrains start blaming this or that ethnic community, the Chinese can just walk in and take the joint over.

Who'll stop them? A nation divided against itself and by deliberate design for base political purpose?
Alan B.