The Canadian wildfires of 2023 have set a new record for the largest area burned in the country’s history. These fires not only devastated vast regions within Canada but also significantly impacted air quality across the Northern Hemisphere, extending as far as Europe and China.
A recent study led by Zhe Wang from the Institute of Atmospheric Physics (IAP) provides a detailed analysis of this global environmental crisis.
“There were photographs from New York City in July in news outlets around the world that showed the city trapped in an almost unbreathable orange haze like something out of a dystopian movie,” said Wang.
“But what we know about long-range transport of particulate matter means that the fires likely impacted Europe and Asia as well. We just didn’t know to what extent.”
The researchers used the Aerosol and Atmospheric Chemistry Model (IAP-AACM), a module of the Chinese Academy of Sciences Earth System Model (CAS-ESM), to simulate the dispersal of pollutants.
The findings revealed a marked deterioration of air quality across almost the entire Northern Hemisphere due to the Canadian wildfires.
Six major episodes of widespread air pollution were identified during Canada’s wildfire season, severely affecting air quality in both Canada and the United States, and even reaching Europe and Asia.
These episodes resulted in unprecedented levels of PM2.5, fine particulate matter with diameters of 2.5 microns or less, known to be particularly harmful to health.
For example, on June 7, New York City experienced the worst air quality in over 50 years, with PM2.5 concentrations exceeding the World Health Organization’s air-quality guidelines.
The study also revealed significant increases in PM2.5 levels in Europe, western, central, and east Asia, and even the Arctic region, due to the northward movement of the fires.
Beyond the immediate impact on air quality, the wildfires also had a profound effect on greenhouse gas emissions. The researchers found that the CO2 levels due to the wildfires were substantially high, not only over North America but also over Europe and northwestern Asia.
This surge in greenhouse gases is particularly alarming as it effectively nullifies Canada’s plan for reducing human-caused greenhouse gases.
“Canada’s 2030 Emissions Reduction Plan has been wiped out by a single year of wildfires,” said study co-author Zifa Wang.
The Canadian wildfires wreaked havoc on forest ecosystems. The uncontrolled flames rapidly consumed vegetation, destroying habitats, and depleting food sources for wildlife.
Furthermore, 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.
Severe forest fires deplete carbon reserves in the vegetation and soil and disrupt the natural succession of forests. 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.
Ultimately, the 2023 Canadian wildfires highlight the interconnectedness of environmental issues. The far-reaching impact on air quality and greenhouse gas emissions underscores the need for global awareness and action in addressing climate change.
“Aside from the direct emissions from forest fires, the peat fires beneath the surface might smolder for several months or even longer and release substantial amounts of CO2. The substantial amounts of greenhouse gases from forest and peat fires might contribute to the positive feedback to the climate, potentially accelerating global warming,” wrote the researchers.
“To better understand the comprehensive environmental effects of wildfires and their interactions with the climate system, more detailed research based on advanced observations and Earth System Models is essential.”
The study is published in the journal Advances in Atmospheric Sciences.
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