Climate models predict wildfires in the north will suddenly intensify as permafrost thaws

A study, It was published in the magazine Nature Communications Global warming will accelerate permafrost melting, leading to a sudden intensification of wildfires in the subarctic and arctic regions of northern Canada and Siberia, according to new climate computer model simulations by an international team of climate scientists and permafrost experts.

Recent observational trends suggest that warm and unusually dry conditions are already intensifying wildfires in the Arctic. To understand and simulate how future anthropogenic warming will affect forest fire Considering the frequency of events, it is important to consider the role of accelerated thawing of permafrost, as this strongly controls the water content of the soil, which is an important factor in extinguishing forest fires.

Recent climate models have not fully considered the interactions between global warming, thawing of northern high latitude permafrost, soil water, and fires.

The new study uses permafrost and wildfire data generated by the Community Earth System Model, one of the most comprehensive Earth system models. It is the first model of its kind to capture the connection between soil water, permafrost, and wildfires in an integrated way.

To better separate the increasing anthropogenic impact greenhouse gas emissions The scientists used an ensemble of 50 past-future simulations, spanning the period 1850-2100 (SSP3-7.0 greenhouse gas emission scenario), starting with naturally occurring changes in climate. This simulation was recently run on the IBS supercomputer Aleph by scientists from the IBS Center for Climate Physics in Busan, South Korea, and the National Center for Atmospheric Research in Boulder, Colorado, USA.

With this ensemble modelling approach, the team showed that anthropogenic permafrost thaw in the Subarctic and Arctic regions will be quite extensive by the mid-to-late 21st century. In many areas, extreme soil water It can dry out quickly, causing a sudden drop in soil moisture, resulting in surface heating and drying of the atmosphere.

“These conditions will intensify wildfires,” says Dr. In-Won Kim, a postdoctoral researcher at the IBS Center for Climate Physics in Busan, South Korea, and lead author of the study. “In the second half of this century, our model simulations show a sudden transition from almost no fires to very intense fires within a few years,” he adds.

These future trends will be exacerbated by the possibility of increased vegetation biomass in high latitude areas due to increasing atmospheric CO2.₂ concentrations. These so-called CO₂ It provides extra fire fuel due to its fertilizing effect.

“To better simulate future degradation of the complex permafrost landscape, it is necessary to further improve small-scale hydrological processes in Earth system models using expanded observational datasets,” says Associate Professor Hanna Lee, co-author of the study at the Norwegian University of Science and Technology in Trondheim, Norway.

“Forest fires unleash carbon dioxideand black and organic carbon may mix with the atmosphere and affect climate and give feedback frozen ground “Thawing processes in the Arctic,” says Prof. Axel Timmermann, co-author of the study, director of the ICCP and Distinguished Professor at Pusan ​​National University.

“However, the interactions between fire emissions and atmospheric processes have not yet been fully integrated into Earth system computer models. Further evaluation of this aspect would be the next step.”