Catastrophic wildfires in Canada last year, driven by warming temperatures, released more heat-trapping carbon dioxide into the atmosphere than India’s 4 times fossil fuel emissions, affecting an area larger than West Virginia, according to new research. Scientists at the World Resources Institute and the University of Maryland assessed the impacts of the 2023 Canadian fires, finding they emitted 3.28 billion tons (2.98 metric tons) of carbon dioxide, as reported in a Global Change Biology study update. This update is not peer-reviewed, though the original study was.
These fires emitted nearly four times the carbon of annual airplane emissions, comparable to the emissions from 647 million cars, based on US Environmental Protection Agency data. Forests typically absorb carbon and store it in their biomass, but when they burn, this carbon is released back into the atmosphere, explained lead author James MacCarthy, a research associate with WRI’s Global Forest Watch. Although regrowth can eventually recapture some of this carbon, the fires have a significant short-term impact on global emissions.
The research calculated that the fires burned 29,951 square miles (77,574 square kilometers) of forest, six times the average from 2001 to 2022. These fires accounted for 27% of global tree cover loss last year, compared to the usual 6%, according to MacCarthy’s data. Co-author Alexandra Tyukavina, a geography professor at the University of Maryland, emphasized that this tree cover loss is a major issue.
Syracuse University geography professor Jacob Bendix, who was not part of the study, noted that while forests will eventually regrow and sequester carbon, this process will take decades, resulting in a substantial lag between the initial carbon release and its eventual recapture. Consequently, the fires contribute significantly to climate warming in the interim.
Beyond increasing greenhouse gases and deforestation, the fires also had health repercussions, affecting air quality in populated areas. Tyukavina cited the smog-filled summer in New York City and the evacuation of over 200 communities with around 232,000 residents, as reported in another study by Canadian forest and fire experts, which has yet to be published or peer-reviewed. Fire expert Mike Flannigan at Thompson Rivers University, who was not involved in the WRI study, estimated the burned area to be twice as large as MacCarthy and Tyukavina’s figures.
Flannigan, Bendix, Tyukavina, and MacCarthy all agreed that climate change contributed to the severity of the fires. A warmer climate leads to longer fire seasons, more lightning-caused fires, and drier vegetation prone to burning. Flannigan’s research indicated that the average temperature in Canada from May to October last year was almost 4 degrees Fahrenheit (2.2 degrees Celsius) above normal, with some areas experiencing temperatures 14 to 18 degrees Fahrenheit (8 to 10 degrees Celsius) higher than average in May and June.
