In recent weeks, wildfires have ravaged large swathes of Canada. The fires have burned millions of hectares of land, displaced tens of thousands of people and disrupted the lives of millions.

Smoke from wildfires in the Canadian province of Quebec has blown across the United States, turning the New York skyline orange. This unprecedented episode of air pollution has drawn global attention to the wildfires.

But Canada has already had over 2,000 wildfires this year. More than 400 are currently crossing many parts of British Columbia and Alberta in the west of the country, as well as Nova Scotia, Quebec and parts of Ontario in the east. About a third of these fires are burning in the east of the country, a region unaccustomed to handling large fires.

It also affects the total burned area. An area larger than the Netherlands has already burned this year (more than 5 million hectares), prompting Canadian officials to say this summer’s fire season is set to become the worst on record.

Experts warn that climate change and human activities are likely to make fire seasons like this normal in the future.

A satellite image showing fires burning across Quebec.
June 13, 2023: Fires across Quebec.
Lauren Dauphin/NASA Earth Observatory, CC BY-NC-ND

Unusual times, size and location

In Western Canada, wildfires are a natural and common part of the forest ecosystem. They clear debris and undergrowth from the forest floor, open the forest canopy to sunlight, kill tree-damaging insects and diseases, and add valuable nutrients to the soil. Tree species including lodgepole and jack pines grow rapidly after a fire.

But this year’s fire season is unique because it’s not isolated to any particular province. Eastern provinces such as Nova Scotia, New Brunswick and Quebec, which typically have wetter and colder climates than Canada’s west, are seeing significantly more wildfires than in previous years. In Quebec alone, more than 400 fires were reported this year, double the historical average.

The size and timing of the fires also broke all previous records. The area of ​​land burned by wildfires over the past seven weeks has already reached the 10-year average for the full season (April to October). This amount of burn is usually only reached much later in the year.

A graph showing the total area of ​​land burned in Canada this year.
The total area of ​​land burned by wildfires since the start of the 2023 season in Canada compared to the 10-year average.
Natural Resources Canada, CC BY-NC-ND

What is causing the fires?

A particularly hot and dry spring across much of Canada set the stage for the current wildfire situation. Many of the country’s provinces are deeply affected by drought. In May of this year, parts of Nova Scotia experienced less than 50% of their average monthly rainfall.

May was also one of the warmest on record in Canada. Heatwaves have pushed temperatures well above normal for this time of year in British Columbia and Nova Scotia. In Squamish (a city north of Vancouver), a temperature of 32.4 on May 13 surpassed the city’s previous record of 29.6 set in May 2018.

Heatwaves like this were seen in Siberia in 2020, where wildfires burned an estimated 62,000 square miles. At the time, the Siberian fires were larger than all the fires raging around the world combined.

Hot, dry conditions reduce humidity levels. This dries out vegetation such as trees, grass and peat (which act as fuel for fires), creating the perfect conditions for fires to start and burn more easily.

The role of climate change

There is no doubt that climate change has played a big part in wildfires across Canada. Extreme heat is made much more likely by climate change, and since the mid-20th century, temperatures in Canada have been rising faster than in many other parts of the world.

Between 1948 and 2022, the average annual temperature in Canada increased by 1.9. This is about double the increase observed for the Earth as a whole.

As the country warms, the possibility of prolonged droughts and stronger heatwaves will increase. This will create even better conditions for fires to start and spread, potentially leading to longer and more intense fire seasons in the future.

Lightning also occurs more frequently in warmer weather. Research estimates that for every degree increase in global average air temperature, the number of lightning strikes will increase by about 12%. Lightning is a common ignition source for wildfires in many parts of Canada.

However, these more intense fires are not entirely the fault of climate change. How humans now use forests also plays a role.

Regular controlled burns have been used by Indigenous groups in Canada for thousands of years. It has proven to be an effective way to manage forests and reduce the accumulation of debris and brushwood in the understory.

A forest on fire.
Controlled forest fires in Sodermanland, Sweden.

But over the past century, fire suppression has been the norm in many parts of Canada. Bypassing fire in some areas has disrupted the natural cycle of fire. In addition, commercial planting of less fire-tolerant tree species, such as balsam fir and white fir, has further contributed to increased fire risk.

Some provinces, including British Columbia, are now starting to embrace traditional controlled burn practices as a means of forest management. But challenges remain. The exclusion of fire for so long, coupled with increasingly extreme heat, has led to the emergence of extreme fire seasons like the one we are seeing in Canada today.

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By Admin

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