Canada’s wildfires are emitting CO2 like an industrialized country

Aug. 28 () –

Extreme wildfires of 2023 in Canadafueled by the hottest and driest conditions in decades, released around 640 million metric tons of carbon.

That figure is comparable in magnitude to the annual fossil fuel emissions of a major industrialized nation, NASA scientists have discovered as part of an ongoing mission to understand our changing planet.

The research team used satellite observations and advanced computing to quantify carbon emissions from the fires, which burned an area roughly the size of North Dakota between May and September 2023. The new study, published in the journal Naturewas led by scientists at the Jet Propulsion Laboratory (JPL).

They discovered that the Canadian fires released More carbon in five months than Russia or Japan emitted from fossil fuels in all of 2022 (about 480 million and 291 million metric tons, respectively).

While carbon dioxide (CO2) emitted by wildfires and fossil fuel burning causes additional warming immediately, there is an important distinction, the scientists noted. As the forest grows back, the amount of carbon emitted by the fires will be reabsorbed by Earth’s ecosystems. The CO2 emitted by burning fossil fuels is not easily offset by any natural process.

An ESA instrument designed to measure air pollution observed the fire plumes over Canada. The Tropospheric Monitoring Instrument, or TROPOMI, flies aboard the Sentinel 5P satellite, which has been orbiting Earth since 2017. TROPOMI has four spectrometers that measure and map trace gases and fine particles (aerosols) in the atmosphere.

The scientists started with the end result of the fires: the amount of carbon monoxide (CO) in the atmosphere during the fire season. They then “back-calculated” how large the emissions would have had to have been to produce that amount of CO. They were able to estimate how much CO2 was released based on the ratios of the two gases in the fire plumes.

“What we found was that the emissions from the fires were greater than anything else recorded in Canada,” he said. in a statement Brendan Byrne, a JPL scientist and lead author of the new study, said: “We wanted to understand why.”

Wildfires are essential to healthy forests, clearing brush and undergrowth and making way for new plant life. However, in recent decades, the number, severity and overall size of wildfires have increased, according to the U.S. Department of Agriculture. Contributing factors include prolonged drought, past fire management strategies, invasive species and the expansion of residential communities into previously less developed areas.

To explain why Canada’s fire season was so intense in 2023, the authors of the new study cited tinderbox conditions in its forests. Climate data revealed the warmest and driest fire season since at least 1980. Temperatures in the northwestern part of the country, where 61% of fire emissions occurred, were more than 2.6 degrees Celsius above average from May through September. Precipitation was also more than 8 centimeters below average for much of the year.

Fueled in large part by these conditions, many of the fires grew to enormous sizes. The fires were also unusually widespread, charring some 18 million hectares of forest from British Columbia in the west to Quebec and the Atlantic provinces in the east. The area of ​​land that burned was more than eight times the 40-year average and represented 5% of Canadian forests.

“Some climate models project that the temperatures we experienced last year will become the norm by the 2050s,” Byrne said. “Warming, coupled with a lack of moisture, is likely to trigger fire activity in the future.”

If events like the 2023 Canadian wildfires become more common, they could impact the global climate. That’s because Canada’s vast forests constitute one of the largest carbon sinks on the planet, meaning they absorb more CO2 from the atmosphere than they release. Scientists said it remains to be seen whether Canadian forests will continue to absorb carbon at a rapid rate or whether increased fire activity could offset some of the absorption, reducing the ability of forests to prevent global warming.