Green City: Climate change could spark more wildfires


GREEN CITY Imagine a future in which hundreds of thousands of people in the more arid parts of the country flee wildfires. Imagine a future in which many of those people never return home when the winds shift and the temperature drops because the blazes have left their property a smoldering husk. Imagine this happening with ever more increasing frequency until it's hard to tell where one fire season ends and the next begins.

Hard to imagine a future like that?

Then maybe it's easier just to remember last summer's fire season, when the fires in the American West and Southwest forced the evacuation of more than a half-million people and burned thousands of homes. That terrifying summer could become a more regular reality under our current climate-change trajectory.

Scientists generally don't describe ecological changes in such apocalyptic terms. But it's hard not to when faced with the early results of major experiments being conducted at the Nevada Desert Research Center. These experiments are designed to show the impacts on desert environments of climate change caused by soaring levels of atmospheric carbon dioxide.

"We need to see how natural ecosystems are responding to changes in the global climate," Desert Research Institute scientist and project director Lynn Fenstermaker said. "In particular we are interested in how well certain ecosystems are going to be able to sequester [contain in the soil] the additional carbon that's being produced by fossil fuel burning."

Rising CO2 levels in the atmosphere are one of the main causes of global warming and could create all kinds of environmental mischief, particularly in sensitive desert ecosystems.

These changes could have devastating consequences, with effects including increased growth rates for plants, increased rain, and shifting varieties of plants and animals. These transformations may allow invasive, nonnative species to gain footholds, scientists warn. And with the additional fuel on the ground come bigger and more destructive fires.

The Nevada Desert FACE Facility is hosting one project to study these effects. FACE stands for Free-Air CO2 Enrichment. It's a 10-year collaboration between several Nevada universities, the Desert Research Institute, the National Science Foundation, Brookhaven National Laboratory, and the Department of Energy. The two-square-kilometer desert facility is located on the Nevada Test Site, 65 miles north of Las Vegas.

FACE allows scientists to raise the CO2 level of large plots of land. For this project the concentration of CO2 is raised 50 percent above the present atmospheric levels in three plots in the Mojave Desert, North America's driest ecosystem. It's done by essentially fumigating the area with the greenhouse gas.

"Early results have shown that when we have a wet winter, an El Niño winter, we have invasive grass species producing a lot more and a lot bigger plants [including red brome, a relative of cheat grass]. This particular species leaves a lot of dead biomass [plant matter] on the surface, and then you get lightning strikes and then these nice rangeland fires," Fenstermaker said.

The worst part is that the wildfires also contribute to the carbon load in the atmosphere.

Experiments like those at the Nevada Desert Research Center are necessary because some 40 percent of the earth's land surface is arid or semiarid, with more land becoming desert each year. This process — the degradation of formerly productive land, often caused by humans — is called desertification. It's already responsible for an unknown number of deaths.

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