A new NASA-funded study brings into sharp focus how climate change is gaining momentum. It reports that extreme wildfires, which swept through Canada in 2023, released a record amount of carbon into the atmosphere. Fueled by the country’s warmest and driest conditions in decades, the fires spewed out about 640 million metric tons of carbon. This also is equal to the annual emission of fossil fuel from a big industrialized nation and shows the large contribution of wild fires to global levels of carbon.
Unprecedented Carbon Emissions
Results from the study, led by scientists at NASA’s Jet Propulsion Laboratory in Southern California, were published in Nature on August 28, 2023. “Using satellite observations and advanced computing, the research team has quantified the carbon emissions from the fires between May and September 2023, which burned an area roughly the size of North Dakota.
That’s more carbon than the combined total from fossil fuel combustion in countries such as Russia and Japan, which came in at 480 million and 291 million metric tons, respectively, in 2022 alone. Brendan Byrne, the lead author of the study from JPL, emphasized how massive this scale was for these emissions. “What we found was that the fire emissions were bigger than anything in the record for Canada,” he said.
Climate Conditions Play a Role
An extremely dry and warm climate in Canada can be blamed for the severity of the 2023 wildfire season. The new study underlines how this year’s fire season was the hottest and driest on record for Canada since at least 1980. For the northwest of the country, where most of the fire-related emissions occurred-61 percent of it-temperatures ran over 4.5 degrees Fahrenheit above average from May through September. Precipitation was also below average for the month with over 3 inches below average in some locations.
These factors together created a textbook perfect storm in the forests of Canada, feeding large-scale wildfires spreading across the country-from British Columbia in the far west to Quebec and the Atlantic provinces. The total area on fire was more than eight times the average of the last 40 years and reflects about 5% of the area under forest cover in Canada.
Implication of Climate Change
The heavy output of carbon from the 2023 wildfires has raised concerns over possible long-term implications for global climate. Large forests in Canada have traditionally been among the important carbon sinks, absorbing more carbon dioxide from the atmosphere than what is usually emitted. However, the magnitude of the 2023 fires places in question the role of such forests in climate change mitigation into the future.
Though both emit CO2 in wildfires and the combustion of fossil fuel, there is one important distinction in their long-term effects: the carbon that emits from the fires can eventually be taken up again by regrowth of forests, balancing carbon over long time periods. In contrast, CO2 from fossil fuel combustion in the atmosphere builds up and feeds long-term warming with no natural offset.
The findings are based on data from the TROPOspheric Monitoring Instrument, an ESA product flying on its Sentinel 5P satellite in orbit around Earth since 2017. This instrument was generally intended to measure air pollution, but it has become important for observing the fire plumes over Canada. They had first inferred the atmospheric CO during the fire season and then they had done back-calculation of the size of emission required to give that amount of CO. From these, they estimated the amount of CO2 released.
Outlook Ahead
These findings serve as a warning that the future may hold more frequent and intense wildfire seasons. According to some climate models, temperatures from the 2023 fire season could become the norm in the 2050s. In such a scenario, the potential is there for increased fire activity to greatly reduce the capacity of Canada’s forests to act as a carbon sink, fuelling global warming.
As those authors concluded in this study, it was longer-term monitoring and research that would be required to determine just how the future climate might alter that balance and, by extension, the carbon balance of the world’s forests. Again, this study tries to outline comprehensive strategies needed for management and mitigation with respect to the risks of extreme wildfires in Canada and indeed globally.
In a continuing warming world, climate change and the interactions with wildfire activity are likely to be an increasingly important area of study with major implications not only for global carbon dynamics but also for general climate policy.
Source: NASA’s Jet Propulsion Laboratory, JPL, and Nature Journal