Why Global Warming May Be Fueling Australia's Fires

Firefighters in the town of Labertouche, east of Melbourne, on Feb. 7, 2009

The raging infernos that have left more than 160 people dead in southern Australia burned with such speed that they resembled less a wildfire than a massive aerial bombing. Many victims caught in the blazes had no time to escape; their houses disintegrated around them, and they burned to death. As firefighters battle the flames and police begin to investigate possible cases of arson around some of the fires, there will surely be debates over the wisdom of Australia's standard policy of advising residents to either flee a fire early or stay in their homes and wait it out. John Brumby, the premier of the fire-hit Australian state of Victoria, told a local radio station on Monday that "people will want to review that ... There is no question that there were people who did everything right, put in place their fire plan, and it [didn't] matter — their house was just incinerated."

Although the wildfires caught so many victims by surprise last weekend, there has been no shortage of distant early-warning signs. The 11th chapter of the second working group of the 2007 Intergovernmental Panel on Climate Change, for example, warned that fires in Australia were "virtually certain to increase in intensity and frequency" because of steadily warming temperatures over the next several decades. Research published in 2007 by the Australian government's own Commonwealth Scientific and Industrial Research Organization reported that by 2020, there could be up to 65% more "extreme" fire-danger days compared with 1990, and that by 2050, under the most severe warming scenarios, there could be a 300% increase in such days. "[The fires] are a sobering reminder of the need for this nation and the whole world to act and put at a priority the need to tackle climate change," Australian Green Party leader Bob Brown told the Sky News. (See pictures of Australia's wildfires.)

Destructive wildfires are already common in Australia, and it's not hard to see why climate change would increase their frequency. The driest inhabited continent on the planet, Australia has warmed 0.9°C since 1950, and climate models predict the country could warm further by 2070, up to 5°C over 1990 temperatures, if global greenhouse-gas emissions go unchecked. Beyond a simple rise in average temperatures, climate change will also lead to an increase in Australia's extreme heat waves and droughts. Southwestern Australia is already in the grip of a prolonged drought that has decimated agriculture and led to widespread water rationing; the region is expected to see longer and more extreme dry periods in the future as a result of steady warming.

It's important to acknowledge that no single weather event can be definitively caused by climate change — and it's possible that the current inferno in Australia might have been as intense and deadly even without the warming of the past several decades. Police are beginning to suspect that many of the fires may have been deliberately set, and the sheer increase in the number of homes built in fire-danger zones in southern Australia today puts more people in harm's way, raising the potential death toll. Still, heat waves and drought set the table for wildfires, and temperatures in the worst-hit areas have been over 110°F (43°C) while humidity has bottomed out near zero. Climate change will continue to be a threat multiplier for forest fires. (See the top 10 green ideas of 2008.)

That's one more reason why the world must work together to reduce global carbon emissions to minimize the impact of climate change. The trouble is, though, CO2 cuts won't be enough. As a recent paper in the Proceedings of the National Academy of Science points out, even if we are successful in cutting carbon emissions rapidly — hardly an easy task — the momentum of climate change will continue for centuries. That means our ability to adapt to the impacts of warming, including more aggressive responses to wildfires like those in Australia, will become all the more critical, lest natural disasters turn into human catastrophes. But it also means that the world we've become accustomed to will change, perhaps irrevocably. The wildfires in southern Australia are already the worst in the nation's history — but they surely won't be the last.

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