A study, published in the journal Nature Communications by an international
team of climate scientists and permafrost experts shows that, according to new
climate computer model simulations, global warming will accelerate permafrost
thawing and as a result lead to an abrupt intensification of wildfires in the
Subarctic and Arctic regions of northern Canada and Siberia.
Recent observational trends suggest that warm and unusually dry conditions have
already intensified wildfires in the Arctic region. To understand and simulate how
future anthropogenic warming will affect wildfire occurrences, it is important to
consider the role of accelerated permafrost thawing, because it strongly controls
the water content of the soil – a key factor in wildfire burning. Recent climate
models did not fully consider the interaction between global warming, northern
high latitude permafrost thawing, soil water and fires.
The new study uses permafrost and wildfire data generated by one of the most
comprehensive earth system models – the Community Earth System Model. It is
the first model of its kind, which captures the coupling between soil water,
permafrost and wildfires in an integrated way. To better separate the
anthropogenic effect of increasing greenhouse gas emissions from naturally
occurring variations in climate, the scientists used an ensemble of 50 past-tofuture simulations covering the period from 1850-2100 CE (SSP3-7.0 greenhouse
gas emission scenario), which was recently conducted by scientists from the IBS
Center for Climate Physics, Busan (South Korea) and the National Center for
Atmospheric Research in Boulder, Colorado (United States) on the IBS
supercomputer Aleph.
With this ensemble modelling approach, the team demonstrated that by the mid
to late 21st century anthropogenic permafrost thawing in the Subarctic and Arctic
regions will be quite extensive. In many areas, the excess soil water can drain
quickly, which leads to a sudden drop in soil moisture, subsequent surface
warming and atmospheric drying (Figure 1). “These conditions will intensify
wildfires,” says Dr. In-Won Kim, lead author of the study and postdoctoral
researcher at the IBS Center for Climate Physics in Busan, South Korea. “In the
second half of this century, our model simulations show an abrupt switch from
virtually no fires to very intensive fires within just a few years” she adds.
These future trends will be further exacerbated by the fact that vegetation
biomass is likely to increase in high latitude areas due to increasing atmospheric
CO2 concentrations. This so-called CO2 fertilization effect therefore provides extra
fire fuel.
“To better simulate the future degradation of the complex permafrost
landscape, it is necessary to further improve small-scale hydrological processes in
earth system models using extended observational datasets,” says Associate Prof.
Hanna Lee, co-author of the study at the Norwegian University of Science and
Technology, in Trondheim, Norway.
“Wildfires release carbon dioxide, and black and organic carbon into the
atmosphere, which can affect climate and feed back to the permafrost thawing
processes in the Arctic. However, interactions between fire emissions and the
atmospheric processes have not been fully integrated into earth system computer
models yet. Further consideration of this aspect would be the next step,” says
Prof. Axel Timmermann, co-author of the study and director of the ICCP and
Distinguished Professor at Pusan National University.
Figure 1. ARABIC 1. Schematic illustration showing the intensification of wildfires due to rapid permafrost thawing in a warmer climate. / Figure credit by In-Won Kim
Notes for editors
- References
Abrupt increase in Arctic-Subarctic wildfires caused by future permafrost thaw(2024) In-Won Kim, Axel Timmermann, Ji-Eun Kim, Keith B. Rodgers, Sun-Seon Lee, Hanna Lee, and William R. Wieder, Nature Communications, DOI: 10.1038/s41467-024-51471-x
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The IBS Center for Climate Physics (ICCP) expands the frontiers of earth system science by conducting cutting-edge research into climate dynamics and utilizing high-performance computer simulations to elucidate how climate has shaped
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