Ken Henry, Treasury Secretary, says Australia's sustainable population is about 15 million.

Ken Henry has delivered his last speech as Treasury Secretary, and in it has suggested that Australia's sustainable population is about 15 million persons, some 8 million less than currently, and less than half what it is predicted to have by 2050.

In 2009 Ken Henry ignited the population debate by remarking that he was "profoundly pessimistic" about Australia's ability to safeguard its environmental heritage if population grew as predicted.  (He was referring to a Treasury projection that Australia's population might grow from 22 million to 36 million by 2050.) 

As a result, ABC TV's veteran current-affairs presenter Kerry O'Brien woke from a 20-year slumber on the population issue and asked Prime Minister Kevin Rudd a question about Ken Henry's remarks.  Rudd, whose minders seemingly hadn't briefed him to expect a question on population, promptly claimed responsibility for the recent blow-out in Australia's annual population growth.  (This had reached a more-than- Third-World rate of 2.1%, and without the slightest electoral mandate. Rudd when running for office had concealed his intention to raise immigration). Public reaction was savage. Even the pro-growth Australian newspaper admitted in an editorial that "Labor's focus groups went ballistic".  Rudd's stock's tumbled, and Labor's approval rating never again passed 50%.

Six months later Rudd fell, nearly taking Labor with him. The story is told at more length in the preface to the 4th edition of Overloading Australia: How governments and media dither and deny on population, by Mark O'Connor and William Lines, available from http://www.australianpoet.com/docs/oa_order_form.pdf  

Now in a speech on March 4th, his last working day as Treasury Secretary, Henry has returned to the population issue.

According to a transcript of the ABC TV program Lateline he told his audience at the Giblin Lecture:

A sustainable population for Australia, well I don't know, maybe 15 million, something like that, that's one-five not five-zero.

It is evident in the environmental degradation that one sees, the loss of biodiversity, species extinction and so on, it's very clear that the population growth that we've experienced to date, to give us a population of 21, 22 million has not been sustainable population growth in that sense.

However Henry seems to have something in common with those growth-economists who assure us that environmental problems can be solved by good "planning",  without the need to cap population, since he added

And yet I can imagine a set of policies, a set of regulations, a set of taxes which would be commensurate with a sustainable population considerably larger than the one we have today.

Perhaps he differs from the extreme optimists, like Glenn Withers and Peter McDonald, in his willingness to recognise that we have limited ability to improve the current system, and that therefore under current circumstances more people = more environmental damage.