Feeling the heat

California's raging wildfires this summer are a sign of the climate changes already drying up America's great outdoors
Jay Stevens
guardian.co.uk, Monday 14 September 2009 14.00 BST
For more than two weeks, the Station fire has raged in and around California's Angeles national forest, just outside of Los Angeles. So far, it's burned more than 160,000 acres and 80 homes. Two firefighters lost their lives to the blaze when their truck, seeking an exit from a fire-besieged hilltop, plunged into a canyon 800 feet below. A third was airlifted from the fire this weekend. The fire's slowly being brought under control and, while the fire still a threat to the historic Mt. Wilson observatory and several campgrounds, it's likely the worst is over.
Still, at a cost to state taxpayers of $50 million – so far – this and California's other wildfires threaten to upend the already precarious state budget. And that's not even accounting for the dangers of mudslides for those living around the deforested burn areas, or the threat to the Los Angeles County watershed the fire's debris poses. Like the Station fire, California's wildfires have stretched state and local infrastructure, and thrown communities into disarray.
These California fires came earlier this year and needed no high winds to stoke them into major conflagrations. Started by an arsonist, the Station fire was brought to life by high heat and low humidity, feeding on tinder-dry underbrush in the area's steep canyons. As such, it's a harbinger of other, worse fires to come – and not just in California. That's because the environmental conditions that caused California's fires to be virulent are likely to be mirrored across the western US in the coming years as climate change nudges temperatures upwards.
At least, that's what the climate model of a group of Harvard University scientists predicts, according to their report recently published in the Journal of Geophysical Research. The report claims that the US should expect 50% more area burned every year by wildfires by 2055 due to climate change. That estimate rises sharply for the Pacific northwest and Rocky Mountain regions, which should expect a 75 to 175% increase in burned areas during that period, if temperatures rise as expected.
In the Mountain West, even a slight temperature change can have disastrous consequences. Warmer temperatures in these mountain regions mean a lighter snow pack, earlier runoff and an earlier spring for the grasses and other underbrush that – with a few weeks longer to bake under the open sun – act as the tinder for the west's explosive fires. As the Harvard study notes, the increased fires will result in increased air pollution, which, in turn, further accelerates the onset of mountain snow melt. These conditions lead to longer fire seasons, which in turn lead to more and bigger wildfires.
Moreover, the dry conditions caused by a rise in temperature would occur in forests already overloaded with fuel. Ironically, years of aggressive fire suppression (pdf) by the US Forest Service "has led to increased fuel loads on the nation's forests," causing the country's mountains to be choked with dry, dead timber and thick underbrush. Add that to the dead trees left int the wake of an unprecedented mountain pine beetle infestation across the west in and into Candada – also driven by climate change – and it's obvious the conditions for massive fires are in place.
Naturally, as the number of fires escalate, and the severity that they burn increases, costs associated with fighting those fires also rises. But beyond that simple calculation is another factor in the rising cost: rural development. As with California's Station fire, most of the firefighting effort and costs are expended protecting private property. A recent Headwaters Economics study of fires in Montana showed that, as rural development increases, so does the cost of fighting fires. And because Montana, like many other wilderness mountain areas in the west, is a prime location for summer mountain homes and hobby ranches, where zoning is regulated at the local level by local officials loath to check an expanding tax base and an influx of construction jobs, development rapidly continues. Headwaters Economic estimates that, if this development continues unabated, the cost borne by Montana and federal taxpayers protecting this rural-urban interface from wildfires could triple by 2025.
What's more sobering is that these projections are not just conjecture: climate change has already had an effect on fires in the west. A 2007 IPCC report showed that "the wildfire season in the western US has increased [by] 78 days" and the "burn duration" of large fires has quadrupled, from 7.5 to 37.1 days, in the past three decades "in response to a spring-summer warming of 0.87C." And a GAO report (pdf) showed that the federal costs, per year, of managing wildfires has risen from $1.1bn from 1996 to 2000, to $2.9bn from 2001 to 2005 – which doesn't even account for the severe wildfire seasons of 2006 and 2007.
But beyond the risks posed to human health and property, and the cost of battling fires, there's potentially a greater danger posed to the environment and humankind. From a recent Science article (and excerpted in a Grist report on wildfire) on the increasing temperatures and early springs in the West:
Current estimates indicate that western US forests are responsible for 20% to 40% of total US carbon sequestration. If wildfire trends continue, at least initially, this biomass burning will result in carbon release, suggesting that the forests of the western US may become a source of increased atmospheric carbon dioxide rather than a sink, even under a relatively modest temperature-increase scenario.
So this expected increase in wildfires may actually accelerate global warming. And America's west has become the scene of simply one of many catastrophic tipping-points that will hurl us into a new, scorched climate. Right now, the west is renowned for its open spaces, rugged topography, endless forests and its very real aura of a wilderness frontier. But as temperatures rise, and western forests are wracked by ever-increasing wildfires, the region could instead become known for choking clouds of smoke and ash falling from blood-red skies.