If you doubt that climate change is transforming the American landscape, go to Santa Fe, New Mexico. Sweltering temperatures there have broken records this summer, and a seemingly permanent orange haze of smoke hangs in the air from multiple wildfires.
Take a ride into the mountains and you'll see one blackened ridge after another where burns in the past few years have ravaged the national forest. Again, this year, fires in New Mexico and neighboring states of Colorado and Arizona are destroying wilderness areas.
Fire danger is expected to remain abnormally high for the rest of the summer throughout much of the Intermountain West. But "abnormal" fire risks have become the new normal.
The tragic death of 19 firefighters in the Yarnell fire near Prescott, Arizona last Sunday shows just how dangerous these highly unpredictable wind-driven wildfires can be.
The last 10 years have seen more than 60 mega-fires over 100,000 acres in size in the West. When they get that big, firefighters often let them burn themselves out, over a period of weeks, or even months. These fires typically leave a scorched earth behind that researchers are beginning to fear may never come back as forest again.
Fires, of course, are a natural part of the forest lifecycle, clearing out old stands and making way for vigorous new growth out of the carbon-rich ashes. What is not natural is the frequency and destructiveness of the wildfires in the past decade -- fires which move faster, burn hotter, and are proving harder to manage than ever before. These wildfires are not exactly natural, because scientists believe that some of the causes, at least, are human-created.
For one thing, the intensity of the recent fires, researchers say, is in part the result of a warming and drying trend which has been underway for over a decade, and which some climate scientists believe will become a permanent condition as anthropogenic climate change continues to increase.
Experts also blame the fire-suppression policy which has been in effect for much of the last century. In the past, frequent low-intensity lightning fires left behind a park-like patchwork of woodlands and open meadows. The Smokey the Bear philosophy of fire prevention interfered with this natural pattern. By always putting fires out rather than letting them burn freely, forests throughout the West have become thick and overgrown.
This well meaning but unwise policy decreased fire dangers in the short term, but increased them exponentially in the long run on 277 million acres of fire-prone public lands. When forests do burn now, instead of the gentler, meandering fires of the past, the unnaturally high fuel loads often make for rampaging fire-storms that typically destroy everything in their path.
In earlier low-grade wildfires, the trees that survived seeded recovery in the next generation. Nowadays, by contrast, the fierce heat of the mega-fires frequently incinerates all of the conifer seeds and seedlings and sterilizes the soil, making it all but impossible for the forest to regenerate.