As the climate crisis accelerates, Canada is enduring its most devastating wildfire season to date. The situation paints a grim portrait of the potential impact of uncontrolled forest fires on climate change, air quality, and biodiversity.
According to recent reports from the Canadian Interagency Forest Fire Centre, the country has witnessed an astonishing 4,774 fires since the beginning of the year until July 26.
The destruction cuts across more than 121,000 square kilometers, an area larger than South Korea. Notably, this is approximately 7.5 times the total area affected by forest fires in China over a span of two decades from 2000 to 2021.
With the widespread fires comes an ominous cloud of carbon emissions. Researchers at the Institute of Applied Ecology (IAE) of the Chinese Academy of Sciences estimate that the Canadian fires have released one billion tons of carbon dioxide.
“The greenhouse gases emitted from these fires, such as carbon dioxide, methane, and nitrous oxide, have an undeniable impact on global climate warming, which has become a global environmental event,” said Dr. LIU Zhihua, a renowned forest fire expert at IAE.
The escalating numbers were calculated using remote sensing technology, an effective approach for gauging carbon emissions from large-scale wildfires. With this method, carbon emission intensity is evaluated in conjunction with the area of land burned, as observed from satellite imagery.
Factoring in the emissions of methane and nitrous oxide, which have a greenhouse effect equivalent to 110 million tons of carbon dioxide, the total greenhouse gas emissions from the ongoing Canadian fires is equivalent to approximately 1.11 billion tons of CO2.
A fraction of these wildfires, approximately one-eighth, has impacted permafrost areas, leading to the release of methane trapped in the frozen soil.
Beyond the climate implications, the fires are precipitating a cascade of environmental and health repercussions. The flames have released an array of pollutants into the atmosphere, including particulate matter (PM2.5, PM10), organic aerosols, and black carbon.
The wildfire smoke plumes have also crossed national borders during four periods this year – May 17-26, June 6-19, June 23-30, and July 15-20 – significantly deteriorating air quality in the United States.
For example, New York City experienced its worst air pollution since 1960 due to the second smoke episode. Meanwhile, Chicago’s air quality index during the third episode exceeded standard levels by a staggering 5.6 times on June 27.
The pollutant particulates are also being swept across continents by the westerly winds, impacting regions as far off as Europe, North Africa, and Asia. During one such atmospheric transport event from June 27-30, PM2.5 levels in Europe increased by over 5 μg/m3. The transport also contributed 1-2 μg/m3 to PM2.5 concentrations in western China.
Furthermore, the wildfires are wreaking havoc on forest ecosystems. The uncontrolled flames rapidly consume vegetation, destroying habitats, and depleting food sources for wildlife. The aftermath of wildfires often exposes the soil surface, triggering secondary disasters like soil erosion, sediment runoff, and landslides.
These occurrences highlight how wildfires are no longer merely a traditional ecological disturbance but have morphed into an environmental catastrophe.
These severe forest fires deplete carbon reserves in the vegetation and soil, disrupt the natural succession of forests, and degrade ecosystems. The result is a shift from forests to shrubland or grassland, with a consequent reduction in the carbon sequestration capacity of the ecosystem.
The worsening wildfire situation is not exclusive to Canada. Recent years have seen the Amazon Rainforest burning over 90,000 square kilometers in just 10 months in 2019, and the Australian bushfires devouring more than 243,000 square kilometers in 2019-2020.
With the wildfire season in Canada typically lasting until October, there is a growing concern that the scale of the disaster could escalate further.
In the wake of these disastrous events, China, with its extensive forest area of approximately 2.31 million square kilometers (about two-thirds of Canada’s forest area), has implemented a comprehensive strategy for forest fire prevention. The Chinese government has adhered to the policy of “Combining prevention and control, with prevention as the primary focus.”
These collective efforts have considerably curtailed the occurrence of forest fires, mitigating the disaster losses and notably improving the nation’s fire prevention and control capability.
In the past two decades, carbon dioxide emissions from forest fires in China have averaged about 15 million tons per year, constituting only about 0.2% of the CO2 emissions from global wildfires.