Climate change: Does a warming climate mean more wildfires?
While the forest fire raging in Fort McMurray, Alta., can’t be blamed on climate change, it does give us a glimpse into what the future could look like.
Boreal forests account for 1.9 billion hectares around the world, which is 33 per cent of Earth’s forested land. Of that, Canada is home to 552 million hectares or 28 per cent of the world’s boreal zone.
These forests are a mixture of various trees such as pine, spruce, fir, poplar and birch, to name a few. They are also ecologically diverse and incredibly important, home to 150 species of birds and numerous types of wildlife.
But all of this is under threat by a warming climate.
Our planet continues to warm, but no place is warming as quickly and dramatically as the north, particularly the Arctic.
Our boreal forests have already warmed by 0.5 C to 3 C compared to the 1850s. The consequences are numerous, including an effect on tree growth, pests and animal life. But rising temperatures are also linked to drier conditions.
The latest report by the Intergovernmental Panel on Climate Change (IPCC) found that annually, the area of boreal forest burned in North America has doubled over the past 20 years, most notably in the west. Whether or not the changes are anthropogenic (human-caused) or part of a natural variability, however, cannot yet be determined.
When it comes to weather conditions propagating wildfires, there are three key ingredients: hot weather, low humidity and wind. A warming climate could produce two of the three ingredients: warm air is usually associated with drier conditions, ie. low humidity. All you need is a windy day and a forest fire that once seemed manageable — as was the case in Fort McMurray — suddenly becomes uncontrollable.
However, Ross W. Wein, a former professor at the University of Alberta and a conservation and forest fire expert, said that what isn’t clear with climate models is the amount of moisture that’s anticipated with a warming climate.
“If there’s more moisture, the fire risk isn’t as dramatic,” he said.
WATCH: Inside Fort McMurray
The problem arises with dry winters — as was the case with last winter’s extreme El Niño — and earlier springs. The IPCC report cited studies that concluded an earlier start to the fire season and “significant increases in the area experiencing high to extreme fire danger in Canada and Russia.”
The drier weather leaves roots and vegetation ready to ignite, whether it be from a discarded cigarette or a lightning strike. And while they may seem extinguished, that may not be the case. Wein noted that, in extremely dry conditions, fires have been known to smolder underground over a winter, feeding off dry roots and buried vegetation.
Overall health of our forests
J. Harry McCaughey, professor emeritus at Queen’s University’s environmental studies department in Kingston, Ont., said that it’s unclear what the future holds for our forests when it comes to climate change.
“There is no simple answer as to exactly how a forest is going to be affected.”
The main consequence of climate change, he said, will be the disruption of the forests’ carbon balances. “The carbon balance involves a series of different fluxes, but the two primary ones are respiration (carbon loss) and photosynthesis (carbon uptake),” he said. “Some [models] believe strongly in the carbon dioxide fertilization effect where rising carbon dioxide concentration in the atmosphere must increase photosynthesis more than respiration.”
In that sense, he said, climate change could be beneficial to our forests. However, he stressed that the changing lengths of the seasons — such as earlier springs — could alter the outcome of those models. In the end, there is no certainty as to what the future holds.
Preparing for the future
Most models conclude that climate change will likely bring a higher frequency of wildfires to Canada — as numerous studies were cited by the IPCC — and that means we need to be more proactive.
Some of the practices in place already are prescribed burns where, during a low-risk period, fire agencies will do controlled burns. This, in turn, will prevent a wildfire from spreading out of control.
WATCH: Escaping the flames in Beacon Hill
Climate change shouldn’t be confused with global warming: climate change is the overall observed long-term change in climate patterns. Some places on Earth will get warmer, others cooler. There will be increased rain and flooding events in regions that once received average rainfall amounts, or very little; there will be drought conditions in normally temperate regions. It’s all about change. And every change comes with consequences.
“It’s the extreme conditions we need to be prepared for,” said Ross W. Wein, former professor at the University of Alberta, and a conservation and forest fire expert. “And that’s what we’re seeing now at Fort McMurray.”
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