Faculty of Science

Symposium Tracks Climate, Wildfire and Public Health Risks

By Mitchell Zimmer

The American Association for the Advancement of Science (AAAS) annual meetings are among the most famous gatherings for science researchers in the world.  The February event held in Vancouver gave those from varied disciplines a chance to compare notes and freely present findings in a number of forums.  One of these was a symposium organized by the Western’s Dean of Science, Charmaine Dean which examined forest fires in Canada and the impacts of climate change and fire smoke.

Five researchers from across Canada and one from Tasmania shared their views on the phenomena and dynamics that shape our forests, how these processes interact and how they are affected by humans.

These researchers have substantial expertise in fire management, the analysis of local fire history using paleontological and statistical methods, and the investigation of the health impacts of forest fire smoke exposure. They demonstrate the changes and impacts of extremes in fire occurrence, discuss innovative smoke exposure assessment methods using remote sensing and impacts of smoke on health, as well as provide historical evidence of notable changes in fire occurrence in the past, with linkages to historical aboriginal suppression activities.

While fire directly causes loss of life, forests and property, the work of Mike Brauer of the University of British Columbia and Fay Johnston of the Menzies Research Institute in Tasmania focuses on the insidious facet of smoke exposure.  Brauer’s review of the literature concerning fine particles from vegetation fire smoke reveals a generally-consistent relationship between smoke exposure and increased risk of respiratory symptoms, hospital admissions, emergency room visits and decreased lung function.  His investigation brings to light that fine particulates can persist in regions for days or weeks after a fire and can penetrate into homes.  In view of these observations, Brauer suggests that there are some strategies to lessen the effect on people with pre-existing heart or lung conditions such as using HEPA type filters in the home or establishing clean air centres.  Johnston’s work has a broader scope as it deals with estimating landscape fire smoke exposure and the associated mortality at a global scale. Her group seeks to account for the differences in regional exposure assessments in order to garner consistent and reliable data and to determine if different global climatic conditions have an influence on these observations. They found that the worse affected region (highest mortality) was sub-Saharan Africa and Southeast Asia. "What's missing from the debates about deforestation is the health impacts," she notes. "Fires in savannahs and forests will occur. There's a baseline number of fires that are unavoidable. But it's time to look at deforestation impacts on fires which in turn affect human health."

Of course, where there is smoke there is fire and Douglas Woolford of Wilfrid Laurier University in his presentation asked how climate change may be impacting the risk of lightning-caused forest fire.  The fact that lightning-caused fires account for approximately 45% of ignitions and 80% of the annual area burned by wildfires in Canada gives this research added significance. He asked whether or not the peak ignition risk is increasing over time and/or the “fire season” is becoming longer each year.   By developing statistical models his group investigated these questions and applied them to fire ignition data going back 40 years in the provinces of Alberta and Ontario.  In Ontario, he finds no significant changes in the timing or the length of the fire season.  However, in a portion of northwestern Ontario in which most fires are actively suppressed, he detects a shift towards an increased risk of fires during the fire season.  As it turns out, at the end of February, the Alberta government declared that March 1. On the other hand, the Alberta fire season appears to be both starting earlier and ending later and, as it turns out, this year at the at the end of February, the Alberta government declared that March 1 as the start of the 2012 fire season – a full month earlier than the usual April 1st start of fire management operations. This is a result of a mild winter which left many areas with little or no snow, and dry forest conditions forcing early firefighting preparations. Richard Routledge of Simon Fraser University confirmed this last point where he stated that recent uncontrollable fires sweeping through some western North America communities have renewed public debates over the management of the dry forest ecosystems. The century long campaign of effective fire suppression has made people aware that frequent, small fires may well have played a key role in reducing the likelihood of major, devastating wildfires.  His research delves in to the historical and anthropological evidence seeking whether aboriginal inhabitants such as those who lived in the Okanagan Valley of southern British Columbia were actively using fire for landscape management or passive observers of natural fire activity.

As Routledge pondered the past, Mike Flannigan of Natural Resources Canada and the University of Alberta looked at the future of fire management in light of climate change and the associated day to day weather. He agreed with Woolford that fire seasons are lengthening for temperate and boreal regions and opined that this trend should continue in a warmer world. If the climate shift results in drier conditions then there will be changes in fuel moisture that directly influence fire occurrence and fire spread. In terms of fire management, Global Early Warning Systems that accurate predict the spatial and temporal variability in fire activity could help adapt to a warmer world.  He also stressed the need for more research on the role of policy, practices and human behaviour on fire activity. He is very concerned that our current carbon emission estimates do not accurately account for the impacts of peat fires. "This could lead to a positive feedback mechanism," he said; drought years are when peat lands become vulnerable to fires. Again, as with Routledge and Woolford, Flannigan notes that attitudes toward fire management should change. "Smokey the bear had two messages: you can prevent forest fires, and all fires are bad, and that's false." He noted, however, that it's a complex issue since fire smoke has health impacts. He notes further that mercury is released when peat is burned.

Gordon McBean of Western University said that policy makers and others have been demanding answers about whether there are attributable changes in frequency and/or intensity of extreme weather and climate events. His group shows that a human influence is detectable globally, and in many regions, in the extremes of daily maximum and minimum temperatures.