Study shows why the Russian Arctic is burning | Polarjournal
Over the past three years, massive fires in parts from Siberia to the Arctic coast have made broad headlines. A now-published study shows that they are not simply due to warmer temperatures, but a number of factors have caused and driven the fires. Photo: NASA

Anyone who has followed the news from the Arctic in recent years has almost regularly come across news about massive bush and tundra fires that have been reported in almost all regions of the Arctic. Especially in large parts of Russia’s central and eastern regions, commonly known as Siberia, flames blazed for most of the summer. A study has looked at the reasons for these long-standing recurring fires and their extent, and has come across a number of factors.

A northward shift of the polar jet stream (also known as the Arctic Front), coupled with an increasingly early snowmelt and stronger and northward-shifted lightning activity are the reasons why fires had been so frequent and severe in the eastern and central parts of Russia over the past twenty years. This is the result of the study by PhD student Rebecca Scholten and Professor Sander Veraverberke of the Free University of Amsterdam, who, together with other team members, had investigated the causes and factors behind the fires. The work was published in the journal Science.

Most of the fires have occurred in the tree-covered regions of the Russian taiga. But in the tundra, too, there have been more frequent and more severe fires in recent years. This also releases greenhouse gases, which in turn changes the climate toward more fires. Image: Dr Michael Wenger

The research team studied fires in the eastern part of Russia in the period between 2001 and 2021. According to the results, the fires that affected the region in recent years were the most severe, accounting for about 41 percent of the total area burned over the 20-year period. They were mostly driven by the northward shifting polar jet stream, which was responsible for higher than average temperatures and drought in the areas. These occurred because the air masses had not moved properly due to the shift in the airflow, and the snow still lying in Siberia thawed faster and earlier. Thus, the soil underneath was exposed to sunlight longer and was more susceptible to fire. The fires, some caused naturally by lightning strikes and some human-caused, had not only been devastating to the region’s plant life, but had also re-released large amounts of greenhouse gases stored in the soil. Furthermore, they also affected the permafrost, which remains thawed in the long term and no longer serves as a CO2 sink, but becomes a source of greenhouse gases through degradation processes.

It is not only the plants that suffer from the fires. Animals also migrate further north, displaced by the fires, and encounter the Arctic inhabitants, for whom they represent competition for food and space. Picture: Annina Egli

Other studies have also shown that fires have a major impact on more than just the plant life and the few people who live there. Wildlife is also threatened by the increasing number of fires. This is because especially large and mobile species such as bears, reindeer or wolves evade the fires to the north (also favored by the warming of these regions) and thus encounter Arctic species. This encourages competition for food and space, and is an additional stressor for warming animals.

Overall, the researchers believe the region will face even more frequent intense fires in the future

Dr Michael Wenger, PolarJournal

Link to study: Scholten et al (2022) Science 378 (6623) Early snowmelt and polar jet dynamics co-influence recent extreme Siberian fire seasons; DOI: 10.1126/science.abn4419

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