Jennifer Marlon, a scientist with the Yale School of Forestry and Environmental Studies, knows about wildfires and lakes. Specifically, she studies thousands of years of sediment deposits in lakes, the layers of which record most of the major wildfires in history. When taking stock of the past 3,000 years, Marlon found that the past 100 years of Earth's history saw the least amount of wildfires on record. She likens it to one of Earth's "mini ice ages."
"The lowest level of burning was during the past 100 years," Marlon said. "It hasn't been matched in the whole record, except for the Little Ice Age. And so this is definitely unusual in our longer history."
With the devastating and shocking wildfire years that Colorado has seen in the past decade or so, that's a remarkable finding. Take a look at the past 100 years and they hardly seem like a "mini ice age." In 2012, the year of the Waldo Canyon and High Park fires, more than 9 million acres burned, and in 2006, a severe drought year in the West, nearly 10 million acres were burned by wildfire. Those years saw the worst wildfire destruction since 1960, according to National Interagency Fire Center records. This year, after the Black Forest fire and catastrophic fires in Idaho and Yosemite, 195,250 have burned in Colorado, 459,422 acres in California, and 674,220 acres in Idaho.
But Marlon has a point. The destruction the West has seen in the past 10 years - no matter how tragic or shocking - pales in comparison to fires that raged and killed 100 or even 200 years ago. The Peshtigo fire burned more than 3 million acres in Wisconsin and Michigan in 1871 and killed 1,500 people; the Great Idaho fire in 1910 killed 85 people. The Giant Berkeley fire in 1923 leveled 50 city blocks and destroyed 624 buildings.
In the grand scheme of the most acres burned and people killed, this year's fire season in Colorado ranks low in the record books. So despite the evidence, and Marlon's research, why have the past two years in Colorado seemed so unprecedented, so shocking and historic?
A few things have changed and have transformed the definition of a wildfire - a natural phenomenon that occurs in isolated forests. Now wildfires are something that every year affects millions of Americans as they are forced to evacuate or grapple with the loss of their homes.
Colorado and the West and Midwest are in a prolonged drought. Valerie Trouet, a professor at the University of Arizona, has connected severe wildfire years to drought years by studying tree rings. High temperatures and little moisture have driven wildfires since the beginning of time, Trouet believes. Other scientists posit that the past decade of fires have been exacerbated by global warming; some simply think the West is going through a cyclical dry spell. Regardless, years of drought make the environment vulnerable to lightning strikes, campfires or sparks shooting from an ATV.
But another major thing has changed the meaning of catastrophic wildfire - people. Since the great Peshtigo fire of 1871, the American West has become settled. People have moved to live in the mountains and in the trees and to own isolated acres of land. They moved into the territories where fires have burned for centuries and they, very naturally, don't want to burn with them. Since the Great Idaho fire of 1910, the U.S. Forest Service tried to change the fire cycle by suppressing fires in the wildlands. Between 2001 and 2010, the agency spent $1.2 billion fighting fires. This year, hardly the worst on record, the agency has run out of firefighting funds. Every year, a third of the agency's firefighting costs are in protecting homes.
This summer, more than 1 million acres were ablaze in Alaska - but for a while, the nation's attention turned to Colorado, where a fraction of that acreage burned but where more people were affected.
Maybe, in the long lens of history, the summer of 2013 was not the worst on record. But a catastrophic wildfire is no longer something that burns millions of acres; it's a fire like the Black Forest fire, which burned only 14,280 acres, destroyed 486 homes and killed two people.
In a county like El Paso where thousands of people live in wildfire zones, maybe what makes a wildfire catastrophic is humans.