Is global warming driving Australia's bushfires?
The deadly wildfires that tore across southeastern Australia this past week have prompted some experts to look beyond the arsonists, lightning strikes, and carelessly discarded cigarette butts to a more complex culprit: climate change.
While all agree that it is impossible to link any single event – no matter how extreme – to global warming, scientists say that the extreme heat and dryness that helped spread the fires are becoming more common as human activity continues to produce greenhouse gases.
According to the UN's Intergovernmental Panel on Climate Change's Fourth Assessment Report, released in 2007, heatwaves and brush fires are "virtually certain to increase in intensity and frequency" in Australia. Many parts of that country have been in the grips of a seven-year drought, the worst in recorded history.
As an article in Time magazine notes, in 2007 Australia's national science agency predicted that, if climate change continues unabated, by 2020 there could be up to two-thirds more "extreme fire-danger days" compared with 1990. The organization found that there could be up to a threefold increase in such days by midcentury.
Writing in the Guardian, Tim Flannery observes that Victoria, the state where the fires raged, has become hotter and drier in recent years. Mr. Flannery is a zoologist and conservationist at Sydney's University of Macquarie and author of "The Weather Makers: The History and Future Impact of Climate Change." He describes how Victoria's shifting winds and high temperatures, which this month have topped 115 degrees F., have in the past helped drive deadly brush fires.