September 24 () –
Global warming will accelerate the thawing of permafrost and, as a result, sharply intensify wildfires in the subarctic and arctic regions of Canada and Siberia.
This is according to new computer simulations of climate models, in a study published in the journal Nature Communications by an international team of climate scientists and permafrost experts.
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 occurrence, 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 forest fire burningAccording to the authors, recent climate models have not fully considered the interaction between global warming, permafrost thawing at high northern latitudes, 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. This is the first model of its kind to capture in an integrated way the coupling between soil water, permafrost and wildfires.
To better separate the anthropogenic effect of increased greenhouse gas emissions from natural climate variations, the scientists used a set of 50 past-to-future simulations spanning the period from 1850 to 2100 AD (greenhouse gas emissions scenario SSP3-7.0), which were recently run by scientists at the Institute for Basic Science (IBS) Climate Physics Center in South Korea and the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, on the Institute for Basic Science (IBS) Aleph supercomputer.
Using this ensemble modeling approach, the team showed that by the mid- to late 21st century, anthropogenic permafrost thawing in the subarctic and Arctic regions will be quite extensive. In many areas, excess soil water can drain rapidly, which causes a sudden drop in soil moisture, consequent heating of the surface and atmospheric drying..
“These conditions will intensify forest fires,” he says. in a statement Dr In-Won Kim, lead author of the study and a postdoctoral researcher at the IBS Climate Physics Centre in Busan, South Korea, said: “In the second half of this century, our model simulations show an abrupt change from virtually no fires to very intense fires in just a few years.”
These future trends will be further exacerbated by the fact that plant biomass is likely to increase in high latitude areas due to rising atmospheric CO2 concentrations. This so-called CO2 fertilization effect therefore provides additional fuel for the fires.
“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 data sets,” says Associate Professor Hanna Lee, co-author of the study at the Norwegian University of Science and Technology.
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