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Animated Australian Population Projections

October 5, 2013

Following from the .gif I posted yesterday, I had a request to animate Australia’s projected population.

In 2008, The Australian Bureau of Statistics modeled 72 permutations of fertility, migration and life expectancy in order to project Australia’s population out to 2101. Of the resulting 72 series, the ABS provide us with three of them as annual time series.  ‘Series A’ uses high growth (HG) assumptions, ‘Series B’ follows current trends and ‘Series C’ uses low growth (LG) assumptions. The specific assumptions of each series can be seen in the table below.

The ABS also modeled the population with zero net overseas migration but that was only modeled (thankfully) so it would be apparent what the impact of NOM on the population is.

The assumptions vary significantly under the different scenarios, so much so that the forecast difference in population between the likely scenario and the HG one is more than 15 million by 2101. The difference between HG and LG is enormous with the HG population nearly double that of the LG one in 2101.  More than anything, this shows the uncertainty, sensitivity and danger generated by compounding projections over a long time frame.

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Below are two versions of the .gif, one with the three growth scenarios plotted and one with just the likely scenario (I like this one more). The ABS estimated the population in yearly age intervals all the way up to 99 years of age then they bundled everyone older into ‘100 or older’. This causes a problem in the charts as is apparent once the projected number of 100+ year old residents start piling up. I stopped the animations at 2080 as I think that is already looking plenty far ahead and that looking too far ahead might detract from the story at hand.

Note that forecasts start from 2011 as I couldn’t find more recent stats in my brief search.

animation

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Apart from the obvious ageing of the population you can also see the increase in the population that occurs either side of the 25 year old mark which is occurring due to NOM.  Australia is essentially getting working age adults for free after we’ve let their home countries bear the cost of raising and educating them – sounds like a good deal to me.

What does it all mean?

As the chart below (implicitly) shows, the percentage of Australians who are of ‘working age’  will fall rapdily into the future. This will put stress on our health system and the public purse. There will be  implications for policy around health, superannuation and the retirement age, as all of these areas will have to accommodate the large shift in the age distribution. As Australia’s population grows we will need to accommodate our new citizens so need the foresight to implement  effective infrastructure spending and urban planning .

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All data sourced from here – http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3222.02006%20to%202101?OpenDocument

Fun Facts(you deserve it if you got this far):

Under Scenario A, Melbourne overtakes Sydney as Australia’s biggest city in 2039.

Under the likely growth scenario, Tasmania’s population will start declining from 2031

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