Increase in forest fires in the Arctic due to global warming

According to a new study, global warming is creating conditions that are likely to cause dramatic increases in Arctic wildfires over the next several decades, potentially releasing large stores of organic carbon from burned peatlands into the atmosphere.

The study has been carried out by a team that includes Adrià Descals from the Center for Ecological Research and Forestry Applications (CREAF), at the Autonomous University of Barcelona.

Using satellite data, Descals and colleagues show that land fires in the Siberian Arctic burned almost 4.7 million hectares in 2019 and 2020, which represented 44% of the total area burned in this region during almost the last 40 years. .

The study’s authors argue that temperatures in the Arctic region — one of the world’s fastest-warming areas — could be moving toward a threshold where small increases in temperature are capable of producing exponential increases in area burned.

Arctic soils store large amounts of organic carbon, much of which is in the form of peat bogs. Although peatland soils are often frozen or flooded, a warming climate thaws and dries out these soils, increasing the likelihood of large wildfires in Arctic lands.

Burning these carbon-rich soils releases this carbon into the atmosphere as carbon dioxide, fueling a feedback loop of continued warming, subsequent burning, and carbon dioxide (CO2) emission.

In Alaska, global warming is melting near-surface subsurface ice that has been permanent since time immemorial. As a more visible consequence of this, trees and bushes lose their grip on the ground and lean or even fall. (Photo: Miriam Jones, USGS)

Descals and colleagues used six satellite-derived maps to assess the annual burned area in the Siberian Arctic during 1982-2020 and combined it with an analysis of 10 climatic factors associated with fire probability, including temperature and rainfall. The researchers found that fires saw their highest rates in 2019 and 2020 and accounted for 44% of the entire area burned during their nearly 40-year study period, releasing almost 150 million tons of carbon into the atmosphere. 2019 and 2020 were also the warmest years in the entire study.

According to the study authors, the findings suggest an exponential relationship between fire associated with rising temperatures and annual burned area: the Siberian Arctic has already doubled the long-term average of burned area in just the last three years of its history. analysis. This could indicate a profound change in the region’s fire regimes caused by accelerating global warming.

The study is titled “Unprecedented fire activity above the Arctic Circle linked to rising temperatures.” And it has been published in the academic journal Science. (Source: AAAS)