The West in Flames

by William deBuys

Dire fire conditions, like the inferno of heat, turbulence, and fuel that recently turned 346 homes in Colorado Springs to ash, are now common in the West.

A lethal combination of drought, insect plagues, windstorms, and legions of dead, dying, or stressed-out trees constitute what some pundits are calling wildfire’s “perfect storm.”

They are only half right.

This summer's conditions may indeed be perfect for fire in the Southwest and West, but if you think of it as a “storm,” perfect or otherwise - that is, sudden, violent, and temporary - then you don’t understand what’s happening in this country or on this planet.

Look at those 346 burnt homes again, or at the High Park fire that ate 87,284 acres and 259 homes west of Fort Collins, or at the Whitewater Baldy Complex fire in New Mexico that began in mid-May, consumed almost 300,000 acres, and is still smoldering, and what you have is evidence of the new normal in the American West.

For some time, climatologists have been warning us that much of the West is on the verge of downshifting to a new, perilous level of aridity. Droughts like those that shaped the Dust Bowl in the 1930s and the even drier 1950s will soon be “the new climatology” of the region - not passing phenomena but terrifying business-as-usual weather. Western forests already show the effects of this transformation.

If you surf the blogosphere looking for fire information, pretty quickly you’ll notice a dust devil of “facts” blowing back and forth: big fires are four times more common than they used to be; the biggest fires are six-and-a-half times larger than the monster fires of yesteryear; and owing to a warmer climate, fires are erupting earlier in the spring and subsiding later in the fall. Nowadays, the fire season is two and a half months longer than it was 30 years ago.

All of this is hair-raisingly true. Or at least it was, until things got worse. After all, those figures don’t come from this summer’s fire disasters but from a study published in 2006 that compared then-recent fires, including the record-setting blazes of the early 2000s, with what now seem the good old days of 1970 to 1986.

The data-gathering in the report, however, only ran through 2003. Since then, the western drought has intensified, and virtually every one of those recent records - for fire size, damage, and cost of suppression - has since been surpassed.

New Mexico’s Jemez Mountains are a case in point. Over the course of two weeks in 2000, the Cerro Grande fire burned 43,000 acres, destroying 400 homes in the nuclear research city of Los Alamos. At the time, to most of us living in New Mexico, Cerro Grande seemed a vision of the Apocalypse.

Then, the Las Conchas fire erupted in 2011 on land adjacent to Cerro Grande’s scar and gave a master class in what the oxygen planet can do when it really struts its stuff.

The Las Conchas fire burned 43,000 acres, equaling Cerro Grande’s achievement, in its first fourteen hours. Its smoke plume rose to the stratosphere, and if the light was right, you could see within it rose-red columns of fire - combusting gases - flashing like lightning a mile or more above the land. Eventually the Las Conchas fire spread to 156,593 acres, setting a record as New Mexico’s largest fire in historic times.

It was a stunning event. Its heat was so intense that, in some of the canyons it torched, every living plant died, even to the last sprigs of grass on isolated cliff ledges. In one instance, the needles of the ponderosa pines were not consumed, but bent horizontally as though by a ferocious wind.

No-one really knows how those trees died, but one explanation holds that they were flash-blazed by a superheated wind, perhaps a collapsing column of fire, and that the wind, having already burned up its supply of oxygen, welded the trees by heat alone into their final posture of death.

It seemed likely that the Las Conchas record would last years, if not decades. It didn’t. This year the Whitewater Baldy fire in the southwest of the state burned an area almost twice as large.

Half Now, Half Later?

In 2007, Tom Swetnam, a fire expert and director of the laboratory of Tree-Ring Research at the University of Arizona, gave an interview to CBS’s 60 Minutes. Asked to peer into his crystal ball, he said he thought the Southwest might lose half its existing forests to fire and insects over the several decades to come. He immediately regretted the statement. It wasn’t scientific; he couldn’t back it up; it was a shot from the hip, a WAG, a wild-ass guess.

Swetnam’s subsequent work, however, buttressed that WAG. In 2010, he and several colleagues quantified the loss of southwestern forestland from 1984 to 2008. It was a hefty 18%. They concluded that “only two more recurrences of droughts and die-offs similar or worse than the recent events” might cause total forest loss to exceed 50%.

With the colossal fires of 2011 and 2012, including Arizona’s Wallow fire, which consumed more than half-a-million acres, the region is on track to reach that mark by mid-century, or sooner. But that doesn’t mean we get to keep the other half.

In 2007, the Intergovernmental Panel on Climate Change forecast a temperature increase of 4ºC for the Southwest over the present century. Given a faster than expected build-up of greenhouse gases (and no effective mitigation), that number looks optimistic today.

Estimates vary, but let’s say our progress into the sweltering future is an increase of slightly less than 1ºC so far. That means we still have an awful long way to go. If the fires we’re seeing now are a taste of what the century will bring, imagine what the heat stress of a 4ºC increase will produce.

And these numbers reflect mean temperatures. The ones to worry about are the extremes, the record highs of future heat waves. In the amped-up climate of the future, it is fair to think that the extremes will increase faster than the means.

At some point, every pine, fir, and spruce will be imperiled. If, in 2007, Swetnam was out on a limb, these days it’s likely that the limb has burned off and it’s getting ever easier to imagine the destruction of forests on a region-wide scale, however disturbing that may be.

More than scenery is at stake, more even than the stability of soils, ecosystems, and watersheds: the forests of the western United States account for 20% to 40% of total U.S. carbon sequestration. At some point, as western forests succumb to the ills of climate change, they will become a net releaser of atmospheric carbon, rather than one of the planet’s principle means of storing it.

Contrary to the claims of climate deniers, the prevailing models scientists use to predict change are conservative. They fail to capture many of the feedback loops that are likely to intensify the dynamics of change. The release of methane from thawing Arctic permafrost, an especially gloomy prospect, is one of those feedbacks.

The release of carbon from burning or decaying forests is another. You used to hear scientists say, “If those things happen, the consequences will be severe.” Now they more often skip that “if” and say “when” instead, but we don’t yet have good estimates of what those consequences will be.

Read more: http://www.utne.com/environment/west-in-flames.aspx#ixzz21zDPtLxj