Most dominant climate models do not include increasing rates of fire activity registered in the Earth’s Boreal Forests. Instead, these models tend to assume that the activity of fires, and associated emissions would remain at the levels registered in the late 2010 decade.
In an article in the magazine Proceedings of the National Academy of Sciences In early June, three researchers studied what would happen to climate projections if new models were used more accurately the severity of the fires time Boreal forests of recent years and in the future.
According to, what they discovered seems Contraintuitive. According to the new models, the smoke from all fires could actually mitigate global warming by about 12%.
Dargan Friersonatmospheric scientist and co -author of the article, says it was “waiting for the opposite.”
To calculate the impact of increasing fires activity on climate change, Frierson and his colleagues used Global Fire Emissions Databasewhich records the levels of smoke, soot and CO2 emitted by the fires In a given year.
Then analyzed the relationship between fire activity, related emissions and global temperatures Between 1997 and 2023and inserted these variables into existing climate change models.
“Forest fires affect the climate in many ways”Explains Frierson. These fires release smoke, carbon dioxide, methane and all kinds of pollutants – including sometimes toxic substances.
Much of this mixture has a heating effect on the planeteither by adding more greenhouse gases to the atmosphere or by darken the surface of snow and ice, causing greater heat retention and faster defrost.
But the models of Frierson and colleagues indicated that this heating is more than compensated for the Net Cooling Effect that smoke and other aerosols cause by illuminating the clouds and prevents part of the sun’s heat from reaching the surface.
This helps even preserve some maritime ice in the Arcticcausing ice to last longer and stay thicker during the summer and fall than it would happen otherwise, which causes even more cooling during the winter compared to what most climatic models suggest.
Still, although Frierson and his team can affirm with some confidence that the increase in the activity of the fires may Reduce global warming by 12% and 38% in Arctic.
Hamish Gordonatmospheric scientist at Carnegie-Mellon University, says that “accurate numbers are extremely uncertain.”
Gordon does not say this to call into question the study, which even pleased him, but because the authors have had to make a lot of assumptions and because there are many uncertainties inherent in climate modeling, especially when it comes to aerosols such as fires, which remain one of the biggest challenges for climate scientists.
Aerosols, tiny particles suspended in the atmosphere, behave in complex ways: Some disperse the light, others absorb heat, some do both; and they all illuminate the clouds by multiplying the drops of water, sometimes causing even spontaneous precipitation.
Frierson says that “ Numbers should not be taken too seriously right now.”
The article was not intended to determine the precise and definitive effect of increasing fires in the global climate, but rather highlight the importance of accounting Correctly these emissions in future climate models, especially with the preparation of intergovernmental panel reports for climate change in their seventh evaluation cycle.
But even if future analyzes reinforce the conclusions of Frierson and their employees and indicate that a large amount of smoke may have a pronounced cooling effect on the planet and the Arctic, this It does not mean that these fires are benign or benevolent.
How The faucetFire Ecologist at the University of Nevada Reno. “Changes in the fire regime in the boreal regions are an ecological, environmental and human health disaster.”
Teresa Oliveira Campos, Zap //
