Australia — Climate change has yet again been blamed for another natural disaster, this time the recent bushfires in NSW. But much more important is the role of poor land-use planning decisions that are increasing our nations vulnerability to fire, and other natural perils. We examine these issues in the light of Australias history of building losses to bushfire over the last century.
Bushfire losses in Australia
Prime Minister Tony Abbott was correct to assert that bushfires are a fact of life in Australia. Conflagrations may occur whenever favourable combinations of fuel, weather and ignition sources exist. When communities are in the way, large losses are always possible.
Back in 1947, James Foley, in his treatise on bushfire risk in Australia, gave descriptions of historic fires in NSW. These were laced with comments such as the worst in the memory of the oldest residents; most disastrous bush fire known; most serious fires for years; one of the most disastrous fires known, and so on.
Each fire it seems is always worse than the last.
One way of measuring the severity of a fire is to look at the loss of property. While raw losses from bushfires, as for most other natural disasters, show an increasing trend towards higher costs, the graph below shows what this history looks like after losses have been normalised to take into account that we now have more homes in harms way.
Theres no trend in the graph. Bushfire losses can therefore be explained by the increasing exposure of dwellings to fire-prone bushlands. No other influences need be invoked. So even if climate change had played some small role in modulating recent bushfires, and we cannot rule this out, any such effects on risk to property are clearly swamped by the changes in exposure.
The result is unsurprising given that it has been a consistent conclusion from many other studies in different countries and across many different hazards, in fact some 30-odd different peer-reviewed studies to date. And the IPCC (2012) underscored this conclusion.
What about New South Wales?
So much for the national picture. What about NSW: are losses in this state this early in the season unusual?
We answer this question again using Risk Frontiers PerilAUS database, which lists natural peril events causing material property damage or loss of life. PerilAUS suggests that since 1926 early season fires (August-September-October) have occurred in about 25% of years. They do not always herald losses later in the season.
And narrowing our focus even further to the Blue Mountains, research shows that destructive bushfires have affected all townships in the Blue Mountains, from Blackheath in the west, to Emu Heights in the east. The most common months for damaging bushfires have been November and December. But October fires are hardly out of the ordinary.
One fire occurred on October 7, 1926, 10 days earlier than the date of the most recent destruction (October 17, 2013). It is likely that this fire (or fires) had been burning even earlier but this was the date on which most of the damage occurred.
So from a historical perspective our recent fires are not at all uncommon and are certainly not unprecedented.
Increasing the risk
So if its not earlier fires or more frequent fires, what is causing changes in bushfire losses? The answer lies in exposure.
Some years ago Risk Frontiers was asked by a reporter to prepare the graphic map below. It depicts the vulnerability of homes in the Blue Mountains in respect to distance from bushland. This single factor is demonstrably the most important in determining the likelihood of home destruction given a fire.
When were mapping fire risk to properties we look at distance from bush. In the Blue Mountains some 38,000 addresses fall within the 200m category, some 30,000 within 100m, and at many of these addresses homes back onto bushland. In many cases trees overhang homes. And just to ensure that embers can be easily carried across to homes on the other side of the road, the council has kindly planted gums down each side of the street.
Back in 1977, when fires threatened Springwood at Burns Road where houses sit like fleas on a camels back, Tim Dare of the Sydney Morning Herald wrote:
Disaster struck in 1957, 1968 and now 1977. Suburbia has pushed into the bush, into the tinderbox, heedless of the fact that the Blue Mountains is one of the most fire-prone settlements in Australia. Cheaper housing, and the lure of the bush which can turn against them with awesome intensity, are stronger than any doubts they might have [SMH 19/11/1977].
Of those affected by the recent fires, many were well aware of the fire risk.
What they were not prepared for last Thursday was the speed of the fire and its ferocity. In other words the reality of fire. There was simply no time to act. And there was no water pressure.
We understand that some did stay and successfully defend their homes, sometimes with the providential interventions by fire services.
These days the resources fire agencies have to deploy are far more numerous and sophisticated than was formerly the case. Nonetheless, under very extreme conditions very high winds and in difficult terrain, the ability of fire fighting operations to affect outcomes in terms of building losses is limited.
What do we do now?
Some would like to see these latest fires as the climate change tipping point, the harbinger of things to come. But extraordinary claims demand, as they say, extraordinary proof and from the evidence available, this does not seem to be here yet.
Perhaps one day we will have conclusive evidence of a link between climate change and bushfire losses, but even then the suite of policy actions that make sense will continue to focus on land use planning, not emissions reduction, for which there are better arguments for action than bushfires.
We need to get serious about land-use planning. It is not a very sexy topic, it may not constitute the great moral challenge of our time, but reducing our vulnerability to natural disasters is important and stands to benefit all Australians, directly or indirectly, now. Regardless of what you might think about climate change.