Can we feed a 'Big Australia'?

Finally, let’s take a quick look at future trends that might impact on our food production.

As the driest continent spanning a tropical to temperate climatic zone Australia is very vulnerable to the effects of climate change. There are estimates that, for every 1C rise in temperature over 30C during crop flowering, grain production falls by ~10 per cent. We now appear to be locked in for at least a worldwide average 2C rise and, in that case, Australia can expect to experience an even greater change. Thus, we can expect a decline in grain production considerably greater than 20 per cent. The droughts of 2006-7 and 2007-8 - that slashed grain production by about half - may be a preview of that. The drying of the Murray-Darling basin (that has been attributed to climate change) and the resultant collapse of fruit and vegetable production (that has already affected our self-sufficiency in this area) may be a warning of what is to come.

Another severe and underappreciated limit on agricultural production - especially for Australia with its ancient and nutrient-poor soils - is future fertiliser availability. One method for predicting future minerals production is Hubbert linearisation (PDF KB) (HL) analysis. HL analysis of phosphate rock production by Déry and Anderson shows that ~75 per cent of the world’s easily accessible phosphate may already have been mined!

This conclusion is supported by an analysis of annual and cumulative production curves by Ward (PDF 293KB). As a recent investigation in the scientific journal Nature noted: “… estimates [of phosphate reserves] all suffer from a lack of reliable data. Most of the world's phosphate-mining companies are integrated with fertiliser firms and the mines are either owned by the companies or are under state control. … As a result, it is difficult to get accurate, independent information on phosphate reserves.”

The spectacular price rises for phosphate, nitrogen and potassium fertilisers in recent years (see page 97 of ABARE’s “Australian Commodity Statistics 2009” (PDF 1.45MB)) do not bode well for fertiliser availability/affordability in coming decades.

Australia’s broadacre agriculture is also highly dependent on oil and gas production - for powering farm machinery, producing pesticides and herbicides, generating nitrogenous fertiliser and for transport. A recently published analysis (PDF 831KB) by those scientists who have been most successful in predicting recent oil production trends indicates that the world’s maximum possible level of oil production (the “peak”) was most likely reached in July 2008 and the long term trend of oil production will be down in future.

By 2030 - which is only half way to 2050 - we can expect crude oil production to be, at very best, 7 per cent lower than today and it will probably be far lower.. By 2050, when Australia’s population is thought to be reaching 36 million, global oil production will be in its twilight. The green revolution - and the globalisation of world agricultural markets that cheap oil has supported - may be at an end. If we cannot then produce sufficient food for ourselves, there will be no other nation to turn to for help.

By 2050, if Australia is to survive as a nation, our agriculture will need to have adapted to climate change, instituted radical measures to recapture and recycle nutrients (e.g. using human and animal wastes as fertiliser) and have, somehow, compensated for the loss of cheap and plentiful fuel. We have not even begun to move in the direction of the more local, intensive but lower energy agriculture that will be necessary and we have less than four decades to accomplish it! In the face of these challenges it is highly unlikely that we will be able to support 36 million people. Indeed, even supporting our current population might prove a significant challenge.

In light of everything described above, we would be very well advised to restrict our population growth as much as possible, as soon as possible. Our ageing demographic profile - the “baby-boomer bulge” - represents an opportunity to do this in an organised and humane manner. We should not be desperately importing new mouths to feed in a vain attempt to either build more houses or support the baby boomer generation through their retirement. For the sake of our children’s future we should, instead, do what is necessary to cope with the passing of the ageing bulge using our own people. This will be difficult, but an informed Australia can accept and meet this challenge. Moreover, our children will be left with a far more robust and food-secure nation. The alternative, “Big Australia” is not really an alternative at all.