USA –-The West is burning. The early weeks of summer have been marked by brutal forest fires in states like Montana, Wyoming, Utah and most of all Colorado, where that state is grappling with the worst fires in its history. According to the National Interagency Fire Center, as of July 3, 45 large active wildfires were burning through 15 states, and since January 1, fires have incinerated nearly 2.2 million acres across the country. And while the weather has calmed somewhat in recent days, allowing firefighters to get on top of some of the worst blazes, the expectations are that flames will continue to burn throughout the long, hot summer of 2012.
So why are so many wildfires blazing out of control? Blame the weather firstthe unusually warm winter meant that the fire season started earlier than usual, while the lack of snowfall meant that dry forests literally became tinder waiting for a spark. Add in the brutally hot and dry weather much of the country has experienced so far this summerthe national weather map looks like a U.S.-shaped burn markand youve got the perfect ingredients for wildfires, often ignited by lightning or even tossed cigarettes, that will burn hot and long, destroying homes and forcing thousands to flee for safety.
If the weather has primed the ground for the wildfires, though, whats behind the weather? To many scientists and environmental advocates, the answer is simple: climate change. 2012 has been extraordinarily warm throughout much of the country since the first day of January, but that only continues a trend of increasing temperatures and longer, hotter summers. 3,215 daily high temperature records were broken this June alone. So far this summer is, as the climate scientist Jonathan Overpeck told the APs Seth Borenstein, what global warming looks like The extra heat increases the odds of worse heat waves, droughts, storms and wildfire.
But as important as global warming is to the raging fires in charred states like Colorado, its not the only factorand no scientist would go so far as to say that climate change had caused one fire or another. While were changing the climateloading the dice, in the climate scientist Michael Manns term, to make extreme weather more likelywere also changing the situation on the ground, moving ever larger numbers of people into fire-prone zones. Its as if were adding fuel to the fire on both endswhich means well be doubly burned.
The great I-News Network has done an excellent job on the wildfires in Colorado, focusing not just on the immediate weather causes and the severe devastation of the fires themselves, but on the policies that have led so many Coloradans to build houses in whats known as the red zoneterritory on the edge of the wilderness that is prone to fire. (Hat tip to Andrew Revkin of Dot Earth for pointing out the I-News coverage.)
Over the past two decades, a quarter million more Coloradans have moved into the red zone, which means that one in four Colorado homes are already at risk from fires:
The growth of population in the red zone slowed some after the giant Hayman Fire near Colorado Springs ten years ago this month. But the 2010 census shows 100,000 more Coloradans Bozzell and Roth among them moving into a red zone:
As the number of people in red zones has exploded, so has the number of fires and the damage each did.
In the 1960s, Colorado averaged about 460 fires each year that burned about 8,000 acres annually, according to Colorado State Forest Service records. In the past decade, Colorado saw an average of about 2,500 fires a year burning nearly 100,000 acres.
As more people move into the red zone, that obviously puts more people and more property at risk every time a fire starts. Any individual fire is therefore likely to do more damage, both in dollar value and in the number of people who may be forced to flee their homes. But its not just that. Humans are often the direct cause of a wildfireeither accidentally, through a stray cigarette or burning, or even deliberately. Put more people in fire-prone areas, and youre likely to see more fires started as wellsomething I wrote about in a cover story for TIME in 2007 about the enormously destructive wildfires in California, a state where a growing number of houses are built on the edge of the wilderness:
Those houses, especially if owners fail to prioritize fire safety, are often more sensitive to fire than are untouched forests, and just a few scattered houses in the woods can amplify a wildfire. Isolated homes surrounded by natural vegetation are probably the most dangerous combination for fires, says Jon Keeley, a research ecologist with the U.S. Geographical Survey (USGS). Beyond providing fuel for the flames, new dwellings also concentrate the single biggest cause of wildfires: us. The downed power lines, careless barbecues and abandoned campfires that frequently spark fires dont happen in the absence of people. And then there is the wicked wild card of arson. Perhaps only one person in a community of thousands has a hand in triggering a blaze, but the very presence of those thousands is what turns an otherwise messy event deadly. The same fires happening wouldnt be anywhere near as serious without this development pattern, says Volker Radeloff, a forest ecologist at the University of Wisconsin.
When a lot of houses are built in the red zoneRevkin notes that the population in the Colorado county of El Paso, ground zero for the fires, has quadrupled since 1960theres also added pressure to suppress any fires that do break out. This even though wildfires in the West are a natural and sometimes even ecologically beneficial event at times. Thats one reason why despite the headlines, fire activity in the West has actually been much lower over the past century compared to the previous three millennia. Put simply, weve been putting out fires thatin the days before the U.S. Forest Service existedwould have blazed uncontrollably.
But in an article for the Daily Climate, the journalist Tom Yuslmanwho lives in Boulder, Coloradonotes that fire suppression may have an unexpected side effect: we may be building up a fire deficit:
Bartlein and his colleagues point to a number of factors for the change, including the introduction of cattle, which reduced fuel loads by eating and trampling grasses; fragmentation of the landscape; and vigorous suppression of any fires on public lands that did break out.
Recent trends suggest the fire deficit is now being paid back. Since the 1980s, fire frequency in the West has increased more than 300 percent, and the annual acreage burned has jumped 500 percent, according to Anthony Westerling of the University of Californias Sierra Nevada Research Institute.
Again, none of this is meant to downplay the role that climate change is likely having on the frequency and intensity of the fires burning the West right nowand perhaps more importantly, on the fires to come. A June study predicted that wildfires will become more common in temperate zonesincluding much of the American Westas the climate warms, even as they become less common in the tropics. Wildfire is one more threats well have to grapple with as the planet gets hotter, but its at least as important to grapple with the risks on the ground, including increased population and property in the red zone. Especially since the latter will be easier to deal with than the former.