PROFESSOR Stewart Franks, a hydrologist at NSW's University of Newcastle, warned in a peer-reviewed scientific article published in 2006 that the risk of serious flooding in southern Queensland and NSW increases significantly when a negative phase of the Interdecadal Pacific Oscillation corresponds with a La Nina event.
The Australian Bureau of Meteorology, given these same conditions, forecast average rainfall last spring!
It was in the late 1800s, a time of significant flooding in Queensland, that meteorologists first noticed a relationship between the Southern Oscillation and rainfall.
But the relationship appeared to break down in the 1930s and was not revived until the late 1980s when the link with the El Nino phenomenon of the eastern equatorial Pacific Ocean was recognised.
Professor Franks has shown that the usefulness of the Southern Oscillation as a predictor of climate, in particular flooding, depends on whether or not the more complex phenomenon also measured by sea surface temperatures known as the Interdecadal Pacific Oscillation (IPO) is in a positive or negative phase.
In a series of scientific papers published since 2003, Professor Franks has shown that when the IPO is negative, as it was from 1946 to 1977, there was a much greater chance of flooding rains associated with a La Nina-Southern Oscillation pattern.
Furthermore, he outlined in the 2006 paper published in the international Journal of Hydrology that the IPO significantly modulated the flood risk in NSW and southern Queensland but not other regions.
In that study he concluded that it was dangerous to calculate flood risk independently of a consideration of whether the IPO was in a negative or positive phase.
This is consistent with the work of other climate scientists who have shown that coastal rivers of NSW, for example, exhibit alternating periods of high and low flood activity, with the flood regime being characterised by significantly more, and usually larger, floods than the intervening lower rainfall regime.
This is of course also consistent with Australian folklore - that we live on a continent of drought and flooding rains.
Yet over recent years in the midst of drought, and with doom and gloom stories associated with the theories of anthropogenic (human-induced) climate change so fashionable, our governments have seemed to willfully ignore the historical record and the work of hydrologists like Professor Franks.
Indeed, because of the prevailing fashion, advice from Professor Franks and others who are variously labelled as climate-change sceptics and denialists, has been ignored.
Professor Franks does not consider himself a climate change sceptic, but rather an objective scientist.
As we entered this spring, the advice from his 2006 paper was extremely relevant.
Given the IPO was negative and we had a strong La Nina, we could have expected impacts to be magnified and the risk of flooding very much increased in south Queensland and NSW.
In complete contrast, the Bureau of Meteorology advised that spring rainfall in 2010 was going to be "average" except in the south-west of Western Australia where they forecast it would be "wetter than normal".
What followed were unusually dry conditions in south-west WA while everywhere else got above average rainfall with many parts of the Murray Darling Basin receiving the highest rainfall on record.
The east coast trough persisted through summer with the virtually stationary weather pattern reforming again and again, dumping more and more rain on already saturated catchments in southern Queensland and NSW resulting in catastrophic flooding and the loss of life.
Already at least one climate scientist - who has made his career from the anthropogenic global warming theory and generally predicting continuing drought in eastern Australia - is now claiming that the increased intensity of rain was caused by global warming.
But there is no evidence to suggest that even the rain that fell on Toowoomba was unusually intense, given the historical record.
There are a lot more people in Toowoomba now than there were during the 1950s, 60s and 70s - the last sustained negative IPO phase.
Over recent decades planning has been based on assumptions of continuing drought. A different mindset is likely to have seen the development of a different drainage plan for that city.
A different mindset, less focused on the fashionable and more focused on the practical, might have even recommended the installation of a flash flood warning systems with rainfall measurement stations, water level sensors and sirens.
I hope that now, in the wake of the devastation of the past month, that rather than blaming the severity of the flooding on human-induced global warming - as the severity of the recent drought was based on human-induced global warming - that planners and politicians start to cast their net a little wider when seeking to understand and come to terms with what has happened and begin to objectively listen to the advice of so-called climate change sceptics, including Professor Franks.
So far the Federal Government has been spending at least $800 million a year on climate research which has mostly been geared to providing ammunition for a carbon tax - rather than improved seasonal weather forecasts.
It is now time this policy and approach was radically overhauled. There is an urgent need for more objectivity in public policy and recognition that natural variability is trumping any impact from increases in levels of atmospheric carbon dioxide.
The best explanation for the recent devastating flooding is that it resulted from inadequate infrastructure and warning systems in the face of a combination of La Nina conditions during a negative IPO, a monsoon trough and already saturated catchments.
* Jennifer Marohasy is a biologist, research scientist and media commentator on environmental issues.
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