Wednesday, June 2, 2010

Will climate change equal bigger fires?

Scientists say a warming Idaho will faced increased risk of longer wildfire seasons

Express Staff Writer

A large air tanker drops a load of fire retardant on the 2007 Castle Rock Fire, which burned 48,500 acres in the Smoky Mountains west of Ketchum. Ongoing research indicates that climate change could mean more large fires like the Castle Rock, which burned to within yards of homes and ski runs in the Ketchum area. Photo by Willy Cook

According to ongoing research, the Idaho of the future will be a place where winter snowpacks melt out earlier and summer wildfire seasons arrive sooner and last longer due to climate change.

The effects of that will likely translate into bigger and longer-burning blazes that will be difficult or impossible to extinguish, one Boise-based researcher stated during the recent May 21-23 Wild Idaho Conference hosted by the Idaho Conservation League at Redfish Lake Lodge.

Further, there's significant evidence that these changes on the local landscape are already visible across the forests and ranges of Idaho. According to Dr. Jennifer Pierce, an associate professor in the Department of Geosciences at Boise State University, Idahoans shouldn't expect these trends to end.

Pierce, a geomorphologist who studies how natural processes such as glaciers, rivers and fires helped shape the Idaho we know today, is using this knowledge to investigate how human-induced climate change could impact how the state is shaped in the years to come.

In many ways, Pierce said, the No. 1 issue in the West will be declining snowpacks. She pointed to information from the Intergovernmental Panel on Climate Change, a scientific body established by the U.N. Environment Program that assesses the risk of human-induced climate change, that indicates that while precipitation may actually increase due to climate change, more will fall as rain.

Scientific models indicate that climate change will have a dramatic impact on Western North America's snowpacks, both in Idaho and to the north and south, Pierce said.

"It declines, especially when you get to southern areas," she said.

With the length of Idaho summers lengthening appreciably, events like the 2007 Castle Rock Fire in the mountains west of Ketchum could become more commonplace, Pierce said in an interview. That 48,500-acre blaze combined with numerous other fires across Idaho that summer to burn upwards of 1.7 million acres across the state in that single season alone.

In the aftermath of the 2007 fire season, wildfire managers said the extent of the summer blazes were magnified due to the effects of a poor prior winter, a warm and dry spring and an especially hot summer. By June 2007, Idaho fire officials were reporting the type of dry conditions more typically seen in August.

Data from the Intergovernmental Panel on Climate Change also indicate that summer temperatures will increase by as much as 5.5 degrees, which would further exacerbate the early snowmelt and reduce summer streamflows.


Researchers with whom Pierce is working are studying various types of data to see how ancient wildfires helped shape the Idaho landscape. They're investigating such things as fire scars contained in the growth rings of still-standing trees as well as charcoal data collected from very old fire-related deposits or mudflows that were the result of ancient blazes that left hillsides denuded and ripe for slides.

A surprising conclusion of the research suggests that wildfire suppression may not be having as big an impact on the instances of really big fires as had been thought. It now appears that that climate is far and away the biggest culprit contributing to the size and severity of wildfires in places like Idaho, Pierce said.

Pierce said tree-ring research in the Sawtooth Valley indicates that unusually warm and dry weather translated into severe burning in 1632. The years of 1734 and 1842—both extra-dry years based on tree ring data—also witnessed massive burns in the Sawtooth Valley.

These fires impact all forest types indiscriminately, Pierce said, including lodgepole pine, ponderosa pine and Douglas firs.

Modern wildfire prevention attempts have been very successful at stopping smaller wildfires, she said. But that's not the case with huge fires, which are generally stopped by natural processes like autumn snowstorms.

"We've been unsuccessful at putting out big fires," she said.

Pierce's conclusions on the potential impacts of climate change on Idaho wildfires and the ability of humans to snuff out the largest blazes is backed up by research, including that released in 2006 by Anthony Westerling of the Sierra Nevada Research Institute. That study, published in Science Magazine, stated that the greatest increases in the length of wildfire seasons has occurred in mid-elevation forests of the northern Rocky Mountains where land-use histories have had relatively little effect on fire risks.

The study—which compiled information on large wildfires in Western forests since 1970—states that the length of wildfire seasons is due to increased spring and summer temperatures and an earlier spring snowmelt.

Separate climate change research that Pierce and two of her students at Boise State—doctorate student Mel Kunkel and undergraduate student Travis Kramer—are in the process of conducting also indicates a potential downside for the state's agricultural industry. Though it isn't completed, their study of barley growing in Camas County—Blaine County's neighbor to the west—shows a correlation between earlier snowmelts and lower barley yields.

"This is something that could impact our agricultural systems," Pierce said.

She said the study was actually the idea of Kramer, a third-generation farmer from Fairfield in Camas County. It uses long-running streamflow tallies and Camas County agricultural records.

Pierce said the results—if further studies bear them out—could have serious implications for how farmers in Idaho operate. She said Camas County barley growers once planted their crops during the winter, but in recent years began planting them later in the spring. Early data from the study suggests they may want to consider a return to planting their barley earlier in winter.

In July, Pierce and others will meet with barley farmers in Camas County to discuss the implications of their research.

Jon Duval:

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