Is man or nature at fault for Queensland floods?

January 19, 2011, Macquarie University

This week's flooding in Queensland is yet another reminder of the destructive power of nature. Globally the costs of natural disasters are increasing rapidly, fuelled by societal changes such as increases in population, wealth and inflation, not climate change. Across different natural hazards and jurisdictions, some 22 separate peer-reviewed studies of weather-related natural disaster events now attest to this fact say Macquarie University's John McAneney and Kevin Roche.

McAneney and Roche work for Risk Frontiers, an independent research centre at Macquarie University which is devoted to the understanding and pricing of catastrophe risks for the insurance and emergency management sectors. John McAneney is the Director of the Centre. Kevin Roche is a PhD candidate. Recently Roche’s paper on Policy Options for Managing Flood Insurance was published in the journal Environmental Hazards.

Roche and McAneney say the problem is that we now have more people living in vulnerable areas, with more to lose. And in Australia, migration of people towards the coast has meant that South Eastern Queensland and Northern NSW are amongst the most rapidly growing areas in the country. The footprint of the current Brisbane flooding is very similar to the 1974 flood, but the value of assets and the population at risk has increased enormously in the intervening years.

The researchers say there are those who, as was the case for the losses incurred in the 2009 Black Saturday fires, will lay the blame on global climate change. Comments such as those made by the Greens’ Leader, Senator Bob Brown, blaming the coal industry for the floods are a distraction and do not acknowledge the accumulated and rapidly growing risk that exists in the absence of any change in climate, they say.

To what extent climate change is implicated in terms of the rainfall, is a perfectly legitimate question, though not one easily answered. Seeking to blame the human tragedy in its entirety on climate change, however, is simply looking in the wrong direction, the researchers say.

They note that the city of Brisbane, like many other towns in Queensland, is built on a floodplain. Compared with the current disaster, there have been even bigger floods in the past: in 1841 and 1893 when flood waters topped 8.35 meters, some 3.9 m above the latest peak. After the 1974 floods, the Senior Engineer with the Hydrometeorology Branch of the Bureau of Meteorology, G. Heatherwick, warned that heavier rainfalls were possible over the Bremer river catchment with higher flooding in Ipswich, independent of the flood mitigation effects of the Wivenhoe Dam.

This is not to deny that climate change is a real concern say the researchers – few continue to believe that only positive outcomes will arise from the continued heating of our planet. The latest research, however, just published in the international journal Environmental Research Letters by Risk Frontiers Ryan Crompton and McAneney together with the University of Colorado Boulder’s Roger Pielke Jr. suggests that it may be centuries until we can be confident that is influencing disaster losses.

Roche and McAneney say if we truly wish to reduce the scale of future disasters in Australia, we need risk-informed land planning policies with risks appropriately priced by an active insurance market. In simple terms, for flood and bushfire, this means an end to unmanaged development of flood plains or within bushlands.

In the Black Saturday fires, studies by Risk Frontiers showed that 25 per cent of the home destruction in the most affected towns of Marysville and Kinglake took place physically within bushlands; 60 per cent occurred within 10 m of bushland boundaries. At these distances, chances of home survival are low and not surprisingly few resisted the flames.

At the beginning of last century, lives and property were lost to bushfires as people lived and worked in the bush; today the problem remains as people chose to live in or near the bush for lifestyle reasons. The analogy to floodplains is obvious, the researchers say.

Extreme weather is not new to Australia with some 95 per cent of all property losses in since 1900 attributable to flood, hail, bushfire or tropical cyclones. However, excluding the case of improved construction standards for residential homes in cyclone-prone areas of the country, successive Australian governments, at all levels, have failed to address short comings of land policy solutions to mitigate against the potential impacts of natural disasters, Roche and McAneney say.

In the emotive days after the Black Saturday fires of 2009, they note that the then Australian Prime Minster, Kevin Rudd, stated that we would rebuild impacted communities “brick by brick.” There was no immediate consideration about reducing risks. Roche and McAneney say they hope the official reaction to these floods is more measured.

Explore further: Confronting worldwide disaster losses

More information: An article, published January 4 about their research also appeared in the New York Times: … 22773.html?emc=eta10

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5 / 5 (1) Jan 19, 2011
Very thought-provoking study. It certainly has some important implications for policies in the US as well, although policies in some areas have moved toward taking such risks into account. Many sections of the east coast have done a pretty good job, by and large. Other areas have somewhat lagged behind this, allowing much more development/redevelopment in proven danger areas without adequate thought in many cases to more adequate mitigation or the effects of over-concentration, or over valuation that does not adequately recognize the "cost" of risk.
1 / 5 (4) Jan 19, 2011
The USA created FEMA which provided govt funds to rebuild in flood plains and high erosion beach areas.
5 / 5 (3) Jan 19, 2011
It is an unfortunate truth that as man has settled the earth, so has the demand for food increased. With that, man has increased the clearing of land and the removal of the one surface stabilization phenomena, Trees & their roots. This has created erosion and the associated SILT. Silt has built up in areas (such as the bed of the BRISBANE RIVER) in places it was never meant to. The end result is disastrous floods. REGULARLY. For the continent of AUSTRALIA we should have 47% TREE COVER to sustain the land and avert erosion. At the last time I checked on the situation, we were passing 9% TREE COVER and rapidly decreasing from there on. The Trees, Mangroves (Gold Coast) are the LUNGS of our WORLD, remove them at our own peril, now we see the results. I fear it is too late, Farmers need more crops to stay competitive, so they clear more trees.
2 / 5 (8) Jan 20, 2011
To John McAneney, Kevin Roche and Macquarie University.

This is a well written and researched article that spells out the truth of the situation no matter what the conclusion might of led too.

I hope some global warming followers can take note this is not due to CO2 or Warming! This re-inspires me and gives me hope.
For quite some time know, it seemed that a lot of scientists and researchers were crooked or to be kind misguided. Obviously John and Kevin are not towing the party line that we are bombarded with these days to them truth matters. In today's politically twisted climate that takes guts.

You do your profession proud, well done and many thanks.
2 / 5 (4) Jan 20, 2011
Sorry for the typo, it should read:
For quite some time NOW,
1.5 / 5 (2) Jan 20, 2011
Australia need to build more dams for flood buffer and water storage. This flood showed the importance of the Wivenhoe Dam in protecting the Brisbane area.
3.4 / 5 (5) Jan 20, 2011
I once heard an interesting talk about river management here in the us. The guy from the corps of engineers was saying that it's like an arms race between different areas along a river. If I build my levies higher, it means that the river won't flood in my area, or maybe even just on my SIDE of the river. The guy up stream and the guy on the other bank both need to have their levie higher than mine or they will get the flood. Other places, like around St Louis, they lay down cement slabs on the riverbed to smooth the bottom and speed up flow. The people down stream then have to deal with surges that can overwhelm their levies. It's like the old saying: You don't have to be able to outrun a lion. You only have to outrun your slowest friend.

He was saying that it isn't talked about much, but they actually have some design behind which areas will flood along the big rivers in the US. For example, along the mississippi and missouri rivers, there are rural areas that are left vulnerable.
1 / 5 (4) Jan 20, 2011
there are rural areas that are left vulnerable.

That's what commercial insurance is for, valuing the risk.
1.3 / 5 (3) Jan 21, 2011
You know there's a detail about the Nashville flood that I never saw in the news. Nashville is downstream from the Cumberland Dam and Cumberland Lake. A couple years ago, they found structural problems with the dam, so they drained the lake to about half its normal volume so that they can repair the dam. That lake is still down. They probably could have prevented the Nashville flood if they had held water back at the dam. It was a pretty big oops in hindsight, but they just didn't have the authority to act fast enough. The beauracratic process behind the decision to hold or release water from a dam takes weeks at the least, thanks to the EPA. Gotta protect the ducks and stuff downstream you know.
2.2 / 5 (6) Jan 21, 2011
Well between the Queensland flood of the Aussies and the flood of Brazil for the Southern springs. Then add the great flooding of Pakistan and China during the Northern spring, with in a years time; I think it looks like an effect for Anthropogenic (man-made) global warming. Excess heat lifting more water vapor into the air don't you know.
3 / 5 (2) Jan 23, 2011
Compared with the current disaster, there have been even bigger floods in the past: in 1841 and 1893 when flood waters topped 8.35 meters, some 3.9 m above the latest peak.

It's the same thing as with hurricanes. It takes about 3 generations for people to forget a major hurricane's "wow" factor, and then about 1 or 2 more generations before it can be forgotten all together. Though in the past century photography has helped prevent some of this effect.

Some recent examples are the Hog Island hurricane in New York, which totally destroyed an entire island and was only recently re-discovered by accident, and the Last Island hurricane in Lousiana, which also totally destroyed an island and a resort town, which almost nobody even in Louisiana knows ever existed.

In general, if someone says, "Oh that NEVER happens here," they are either lying, or they are new to the area, or else it's just be 3 or 4 generations since it last happened.
1 / 5 (1) Jan 23, 2011
When I read the title, I knew what the conclusion would be. Gladly, I was wrong.

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