An unstoppable force Drought, climate change, high temperatures and strong winds have created a new type of fire front that is unstoppable and wreaks permanent damage, writes Asa Wahlquist
IT goes off like an atomic bomb. "You are talking about megawatts of energy," explains Rod Incoll, a fire risk management consultant. "It is a nuclear release of energy out of these so-called mega-fires. It is a title that leads oneto exaggerate, but it is probably a fairdescription."
Mega-fire is a US expression, coined in 2003 to describe the series of extraordinary fires that have burned in the US since 2000. The worst, the Biscuit fire in Oregon in 2002, cost more than $US150 million to suppress.
Mega-fires are typically formed from several fires, covering a huge area. They exhibit complex behaviour, create their own weather and are well beyond the most sophisticated attempts to control them.
They occur most frequently on the bush-urban interface, leaving in their wake total destruction of plant and animal life. These fires can pollute water supplies with ash and in subsequent years fill waterways with soil and gravel. Regenerating trees suck up rainfall, reducing water supplies for up to 50 years. Mega-fires also have the capacity to wreak permanent damage.
O'Loughlin says drought and climate change have exacerbated the risk of bushfire this summer. According to the Australian Bureau of Meteorology, most of Victoria received less than half its usual spring rainfall, with the upper northeast experiencing its driest spring on record.
"The drought means we have this huge build-up of fuel and the fuel is extremely dry," O'Loughlin says.
The BoM reports the nation's annual mean temperature for 2005 was 1.09C above the standard 1961-90 average. This year has recorded consistently above-average maximum temperatures. O'Loughlin says although it may seem a small shift, it means more extreme weather days.
"The old hands would say we used to get bad fire seasons every five, seven, nine years," he says.
"But we appear now to be getting these really bad seasons more frequently. It would appear the seasons we have been experiencing in recent years are consistent with the projections about climate change."
Extreme weather days are not just an Australian phenomenon.
O'Loughlin says that "2003 was a fairly extraordinary year. We had the fires in Canberra. In August there were extremely bad fires in Portugal, bad fires in Spain and France, then in Canada. In October, they had the Californian fires with about 3000 homes lost and some 25 lives. So on three continents in the one year you have record areas burned, and extraordinary fire behaviour, mega-fire-type behaviour.
Friday, January 19, 2007
A hotter planet means a burning planet... literally
Climate change brings more frequent and more intense forest fires. One of those many side effects that seems likely to increase along with more intense storms and more frequent tornadoes. Seems obvious that as the climate shifts on so many levels we're likely to see level of climate-related disruptions never experienced by humans. Our planet is beginning to convulse.