This is the first in a series of columns addressing various issues related to climate disruption in the West Kootenay. Greg Utzig is a local conservation ecologist who has been working on climate change issues for two decades.
Many people are wondering if and how this summer of catastrophic wildfires relates to climate change.
Here’s what science has to say.
Mike Flannigan, a wildfire specialist from Alberta, points to the four main factors that affect wildfires: forest fuels, human activity, ignition sources and weather.
Forest fuels are mainly determined by the type of forest we have and its history. Human activities, such as fire fighting and harvesting, affect the amount and distribution of fuels and humans also supply ignition (such as abandoned campfires).
Climate primarily drives weather patterns (temperature and precipitation) and the major source of ignition: lightning.
Historical climate data clearly demonstrates that July and August temperatures in the West Kootenay have risen by 1 to 3 degrees Celsius over the past few decades. This includes both average temperatures, and maximum temperatures that tend to drive extreme fire behavior. Precipitation in those months has either remained roughly constant or decreased slightly.
Climate projections indicate that average and maximum summer temperatures are likely to rise an additional 1 to 3 degrees by the 2050s. Projections of summer precipitation changes are more uncertain. Some climate models indicate little change, while others project significant decreases. There is agreement that spring snowmelt will occur earlier, making for longer summers.
Climate models also project changes in the distribution of precipitation. In the past, we’ve generally experienced periodic gentle rains, with occasional intense storm events. The future may look more like this summer’s heatwaves and drought, punctuated with more frequent high intensity storms.
In our area, intense summer storms are often accompanied by lightning. Some storm modeling is suggesting a modest increase in the frequency of lightning as well.
Consistent with the increase in temperatures, studies of historical wildfire occurrence in the western US and Canada have shown two things. One is that the average area burned per year has increased. And, second, the fire season itself is longer.
One University of Idaho wildfire study for the western US concluded that since the 1980s, the increased fuel drying due to increasing temperatures has contributed to a doubling of the area burned over what would have occurred without climate change.
Another study in the western US showed the fire season has increased in length by over 50 percent since the 1970s. Large fires are occurring earlier in the year, but also burn for longer periods once they get started. The current BC fires are an example of the same trend.
What does that all that mean for us?
Projected climate trends for the West Kootenay indicate that forest fuels are getting drier, and that trend will continue. Other indirect impacts of climate change may also contribute to an increase in wildfire impacts. Trees dying due to drought, windstorms, and increased insect and disease attacks all create more dry fuel for fires.
Virtually all published studies on the occurrence of wildfires for Canada and the US project a continuing increase in the number of fires and in the average area burned for the coming decades.
For example, a recent study was completed for the BC Government by local scientists. It projected that the average annual area burned in the West Kootenay may increase from about 1500 hectares per year (the average for the latter half of the last century) to approximately 9,000 hectares per year by the mid 2020s. In comparison, approximately 5,000 hectares have burned so far this year in the West Kootenay.
These trends are not limited to western North America. This past winter Chile, Australia and New Zealand had catastrophic wildfires. This summer there are not only ongoing devastating wildfires in BC, but also in France, Portugal, Israel and Italy.
Here in the West Kootenay we haven’t experienced the dramatic increase in area burned that other places have – yet. However, we have experienced the lengthening of the fire season, as well as the increased days of high and extreme fire hazard.
The West Kootenay has been very lucky the last few years because we’ve received precipitation at crucial times. But the statistics indicate our luck will not hold forever.
Can we do anything?
There are three main things we can do right now. We can reduce our emissions of greenhouse gases to slow the advance of climate change; we need to convince our governments to act decisively now. We can support the interface fuel treatment programs initiated by the RDCK and the City of Nelson to reduce forest fuel loads around our communities. And we can fire-smart our own properties to make it easier to defend them from wildfiires.