Controlled burns to manage bushfires wont work: expert
Controlled burns to manage bushfires wont work: expert
22 October 2013
published by www.afr.com
Australia — Even a tenfold increase in controlled burns will not be enough to protect homes from bushfires and many people may have to give up their bush homes, especially if predictions of climate change are borne out.
As NSW braces for an unprecedented bushfire in the Blue Mountains on Tuesday, Ross Bradstock, director of the centre for the management of environmental risk from bushfires at the University of Wollongong, has argued those who claim the problem can be solved by controlled burns are fooling themselves.
What is coming will blow away any feasible solution by controlled burns and we will have to look at more draconian solutions, Professor Bradstock said.
The state government has invoked emergency powers as it considers evacuating townships west of Sydney and the number of houses wrecked by the fires tops 200.
With temperatures expected to stay high for the next few days, the fires scattered around the region could join up, isolating some communities.
CONSIDERABLE RESIDUAL RISK
Almost a thousand fire fighters are now deployed and NSW Health issued an alert for poor air quality levels because of the clouds of ash as far away as central Sydney.
The fires in NSW have revived a debate about strategies to fight bush fires and concerns that climate change will increase the risks.
Professor Bradstock published research in August which argued it would be prohibitively expensive to use controlled burns to manage bushfire risk. To halve bushfire risk with controlled burns across south-eastern Australia would cost $200 million a year which was more on average than the cost of houses damaged by bushfires.
Currently, controlled burns are conducted on about 1 per cent of the areas exposed to high fire risk each year but the annual rate of controlled burns would have to be boosted to 7 per cent to 10 per cent of the gum forests in south-east Australia just to halve the risk of bushfires.
The paper found that it would take another 50 per cent increase in controlled burns over current levels to counter the expected higher risk of bushfires because of climate change by 2050.
In the wake of the Black Saturday fires, Victoria has committed to controlled burns covering 5 per cent of its forests each year but Professor Bradstock said there was still considerable residual risk.
He said many houses would still burn and development might have to be further restricted in fire prone areas or people would have to accept that their houses would burn.
DAMAGE SURPASSED BLUE MOUNTAINS FIRES OF 1968
The losses from the fires in the Blue Mountains over the past week could grow but as of Monday night they were still only a fraction of the Black Saturday fires in Victoria which destroyed over 2000 homes and claimed 173 lives.
The damage has, however, already surpassed the last big bushfires in the Blue Mountains in 1968 when 123 homes were destroyed. Professor Bradstock said the spread of development into more fire-prone areas in the past 40 years had magnified the risks.
Several fire experts argued that the current fires were not unprecedented but their timing was.
Dr Bradstock said the huge fires were certainly a touch early this year compared to previous major fires in the region in the 1950s and 1960s, a development which was consistent with predictions that climate change would raise the risk of bushfires.
He said the change was still incremental but he expected fires to increase by about 20 per cent by 2050 under the most recent climate change scenarios.
HOTTEST SEPTEMBER ON RECORD
Richard Thornton, director of CSIROs co-operative research centre for bushfires and natural disasters, said it was difficult to say whether any individual bush fire was caused by climate change but there was evidence of drier winters that turned forests into potential fuel and more days with a very high fire risk earlier in the season.
Fires of this magnitude are not unprecedented, and fires at this time of year are not unprecedented, but fires of this magnitude at this time of year are highly unusual, Dr Thornton said.
Temperatures in September were the hottest on record.
While some have called for controlled burns to reduce bushfire risk, a study for the Australian Business Roundtable for Disaster Resilience and Safer Communities in June argued that so-called fuel management was among the least cost-effective ways to reduce bushfire risk.
The Deloitte Access Study, which was funded by businesses including Westpac, Insurance Australia Group, Optus, Investa Group and Munich Re found that improved vegetation management, including controlled burns, had a cost-benefit ratio of 1:3 while building more resilient housing in high risk bushfire areas had a ratio of 1:4.
The most cost-effective measure was to bury electricity cables to reduce the risk of spot fires which yielded more than threefold for each dollar spent.
The study said that 50 per cent of all properties destroyed by bushfires are within 15 metres of bushland.
