Friday, 14 March 2008

What loss will Peter Cullen prove?

Although I had heard a couple of days ago that water expert Professor Peter Cullen was ill, it was a shock to me that he has actually died at the age of sixty-five.

His research, more practically oriented and less abstract than Thomas Aquinas McMahon, certainly impressed the public much more. Whereas what McMahon did has shown little more than how great the hydrological variability of Australia's water systems is and the extraordinary storage sizes needed for river regulation in Australia - viz. ten times as much as in similar climates in Europe or North America or New Zealand, most of Cullen's work was utterly practical advice about what to do.

The trouble is that, whilst even in a naturally varying climate Australia is subject to droughts and occasional big floods, Australia appears to be remarkably sensitive to anthropogenic global warming, which in a decade has reduced Melbourne's rainfall - with the same reputation for reliability as southwest WA - by 30 percent. Even in the generally dry era over the continent from 1922 to 1938 Melbourne still averaged the same as its 1885 to 1996 mean of 643 millimetres.

The present heatwave suggests - as I have been predicting privately with my family - that we are actually in for something far, far worse.

What we will see I think is in fact a complete elimination of southern winter rainfall from Australia and the southern coastal system within a few years - say by 2013. This will leave, owing to Australia's abnormally low runoff ratios, permanently dry streams where there was once relatively reliable water, as in rivers like the Yarra, Goulburn and Ovens. Efforts to conserve are naturally useless if anthropogenic climate change leaves no water to conserve and a land decimated by misuse when water did exist.

I am by no means sure that there will exist a replacement for him or the brilliant Tom McMahon, whose knowledge of the unusual behaviour of Australian streams is actually more significant. Because Australia's future youth are coming from a narrow range of socially conservative families, environmental issues are not likely to be significant for this generation, even if climate change becomes as bad as I think it will.

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