Tuesday, January 11, 2011

Sustainable Population Growth

In Australia we now a minister for sustainable population - Tony Burke. Whilst this is a positive step forwards, it begs the question what does sustainable population growth mean?

The answer, unfortunately, is that no rate of population growth is sustainable. For the nitpickers, a population growing at zero percent is not growing, but yes, if you could somehow arrange a zero population growth rate every year then yes it would be sustainable. Also, a population which attempts to sustain a negative population growth rate will become extinct.
That leaves populations that grow at positive growth rates, which is the main subject of this specific blog post.

Taking Australia's very modest population of roughly 22 million people, just 10 population doublings would result in over 22 billion Australians. How quickly a population doubles depends upon the annual growth rate. At 1%, our population would double roughly every 70 years and at 2% it would double roughly every 35 years. If the population rate varied between these historical rates then the Australia population would double somewhere between 35 and 70 years.

So, who thinks that 22 billion people living in Australia within 350 to 700 years is sustainable? And that's just the Australian population, growing at "modest" historical rates...

David