The wildfire season last year (2021) set new records throughout the world, charring terrain from California to Siberia. The fire risk is increasing, and the UN research released last month predicted that wildfires will increase by 50% in 2050. As they burn, these flames damage homes, plant life and animals, but the danger does not end there.
Image Credit: Shutterstock.com/ Christian Roberts-Olsen
On March 18th, 2022, researchers published a paper in the journal One Earth detailing how brown carbon produced by burning biomass in the northern hemisphere is hastening Arctic warming and warning that this might lead to even more wildfires in the future.
Large plumes of brown smoke, mainly composed of granules of brown carbon floating in the air, accompany blazing wildfires. This smoke is hazardous to one’s health and may even block out the light during the summer, and scientists believe it is contributing to global warming.
The Chinese icebreaker Xue Long set out for the Arctic Ocean in 2017 to investigate how aerosols were drifting around in the clear Arctic air and to determine their sources.
The researchers on board were especially interested in learning how brown carbon released by wildfires affected the climate and how its warming effects compare to those of denser black carbon produced by high-temperature fossil fuel combustion, which is the second most influential warming agent after carbon dioxide.
Brown carbon contributed to warming more than initially expected, according to their findings.
To our surprise, observational analyses and numerical simulations show that the warming effect of brown carbon aerosols over the Arctic is up to about 30% of that of black carbon.
Pingqing Fu, Study Senior Author and Atmospheric Chemist, Tianjin University
Over the last 50 years, the Arctic has risen at a rate three times that of the rest of the world, and wildfires appear to be contributing to this disparity. Brown carbon from biomass burning was determined to be responsible for nearly twice as much heat as brown carbon from fossil fuel combustion, according to the researchers.
Brown carbon, like black and carbon dioxide, heats the globe by absorbing solar energy. This creates a positive feedback loop because rising temperatures have been related to an increase in wildfires in recent years.
The increase in brown carbon aerosols will lead to global or regional warming, which increases the probability and frequency of wildfires. Increased wildfire events will emit more brown carbon aerosols, further heating the earth, thus making wildfires more frequent.
Pingqing Fu, Study Senior Author and Atmospheric Chemist, Tianjin University
Fu and his collaborators aim to look into how wildfires change the composition of aerosols from resources other than brown carbon in the future. They are particularly interested in how fires affect bioaerosols, which come from animals and plants and can include live creatures such as diseases. Meanwhile, Fu recommends that attention be paid to wildfire mitigation. “Our findings highlight just how important it is to control wildfires,” Fu concludes.
The National Natural Science Foundation of China funded this research.
Journal Reference:
Yue, S., et al. (2022) Brown carbon from biomass burning imposes strong circum-Arctic warming. One Earth. doi.org/10.1016/j.oneear.2022.02.006.