Last year’s Canadian wildfires, which blanketed much of the eastern U.S. in smog, released more carbon emissions than all but three countries worldwide, according to research published Wednesday.
Not only did the fires burn nearly 4 percent of the country’s forests, but they also generated 647 million metric tons in carbon emissions, quadruple that of the emissions from fossil fuel consumption the same year.
The study, published in the journal Nature, found that only China, the U.S. and India produced more carbon emissions than the fires in 2023. Those three countries are the three leaders in carbon emissions worldwide. Canada is the No. 10 emitter, producing just under 2 percent of worldwide emissions.
Large boreal forests like those affected by the Canadian fires have long been considered a major carbon sink, or a location that absorbs more carbon than it emits, but the data in the study suggests that if a fire is big enough, the forests may not reliably absorb the damage. Canada is the site of nearly 9 percent of forestland worldwide.
Last year was also the hottest year on record worldwide, creating conditions like extreme heat, early snow melt and dry conditions that made it easier for forest fires to rage out of control in the first place, potentially contributing to a feedback loop, the study noted.
“Climate models project that the temperatures of 2023 will become normal by the 2050s. Such changes are likely to increase fire activity, risking the carbon uptake potential of Canadian forests,” the study authors wrote. “This will impact allowable emissions for reaching warming targets, as reduced carbon sequestration by ecosystems must be compensated for by adjusting anthropogenic emissions reductions.”
The results are more ominous than those reached by the European Union’s Copernicus Atmosphere Monitoring Service in December, which used different methodologies to estimate the fires generated about 480 megatons’ worth of emissions.