In the past 20 years, global climate change and human factors have led to more frequent and severe wildfires, resulting in historical highs for carbon dioxide emissions caused by forest fires. According to a report released by the Chinese Academy of Sciences, between 2001 and 2022, global wildfires have released a total of 33.9 billion tons of carbon dioxide. This figure means that the annual carbon dioxide emissions produced by wildfires have exceeded those of Japan, the world’s sixth-largest carbon emitter, through fossil fuel combustion.
The main reason for this surge in carbon emissions is the frequent occurrence of extreme wildfire events. Wenru Xu, a landscape ecologist from the Institute of Applied Ecology, Chinese Academy of Sciences in Shenyang, explained that “extreme wildfires” refer to those forest fire events with larger burnt areas, longer durations, and broader impact ranges. Xu Wenru and her colleagues found that the increased CO2 emissions were mainly driven by fires in tropical rainforest edge zones (5ºS to 20ºS) and high-latitude coniferous forest regions above 45ºN, particularly the rapidly growing trend of carbon emissions from northern forest fires.
Wenru Xu further pointed out that the increase in wildfire incidents is partly due to the frequent heatwaves and droughts caused by climate change. “On the other hand, the CO2 emissions produced by wildfires also exacerbate global warming, creating a cycle.” She also mentioned that human activities contribute to the increase in the frequency of wildfires, such as lighting fires for warmth, setting off fireworks, or discarding cigarette butts.
Tianjun Zhou, a meteorologist from the Institute of Atmospheric Physics, Chinese Academy of Sciences, was shocked by the report and emphasized that the average annual burnt area of forests from 2001 to 2022 reached 11 times the area of manmade afforestation in the same period. “Although afforestation is considered an effective way to increase carbon sinks, such high wildfire areas show that natural wildfires may be offsetting our efforts,” he said.
The report also lists ten extreme wildfire events that occurred between 2018 and 2023, each of which emitted more than 600 million tons of carbon dioxide into the atmosphere. These wildfires mainly occurred in countries with vast forests such as Russia, Brazil, Canada, Australia, and Indonesia. In the wildfires Canada faced in 2023, a record-breaking fire placed it at the top in terms of carbon emissions. Canada has 28% of the world’s northern coniferous forests, and in 2023, the number of wildfires exceeded 6,700, with a total burnt area reaching 18.5 million hectares, nearly half the size of Norway. As of October, the amount of carbon dioxide emitted from Canada’s wildfires in 2023 has exceeded 1.5 billion tons, more than the total for the country’s wildfires over the past 22 years.
Predictions point out that, in the coming decades, wildfires and other forms of wildland fires will have a more severe impact on the globe. Yuhang Wang, an atmospheric scientist and professor at Georgia Institute of Technology in the USA, stated that this prediction complements his research findings. His study found that, compared to the beginning of the 21st century, by the 2050s, the global burnt area is expected to increase by about 20%.
Professor Wang Yuhang further explained, “What is even more shocking is that the global carbon emissions from fires are expected to double, meaning that in the near future, fires will become a more significant source of carbon emissions.” Based on these data and predictions, Wang Yuhang said he agreed with the recommendations in the report that countries should include carbon emissions from forest fires in their national climate change plans and establish a rigorous system of monitoring, reporting, and verification.
Researcher Xu Wenru also stated that considering the emissions produced by forest fires, this has become an unavoidable source of CO2 emissions. Therefore, it is necessary for places around the world to pay attention and take action to mitigate the impact of fires on the climate and the environment. This data was detailed in a news piece with the title “Surge in extreme forest fires fuels global emissions” published in the journal Nature on December 20, 2023.
