A record carbon dioxide emissions

A study reveals a record number of carbon dioxide emissions from fires in the boreal regions in 2021.

Boreal fires, which typically account for 10% of global carbon dioxide emissions from all fires, contributed 23% in 2021, a new study reports.

“The boreal forests could be a ticking time bomb for carbon, and the recent increases in wildfire emissions we’re seeing make me fear the clock is ticking,” said Steven Davis, co-author of the study.

Forest fires of an extreme nature (which affect the climate through the carbon dioxide they emit) have become more frequent. Forest fires in tropical forests have received considerable attention due to their emissions, while fires in boreal forests have attracted much less attention. And this despite the fact that boreal forests are the largest terrestrial biome in the world and fires in these regions release between 10 and 20 times more carbon per unit area burned than other ecosystems. Therefore, monitoring emissions from fires in these high-carbon-density ecosystems is critical to understanding Earth’s temperature and risks to climate change mitigation efforts.

Satellite methods for monitoring carbon dioxide emissions from fires may not detect emissions from small fires, while bottom-up modeling methods may not detect smoldering ground fires.

Likewise, carbon dioxide is difficult to specifically attribute to fires; it can remain in the atmosphere for hundreds of years, which means that background carbon dioxide concentrations are quite high compared to carbon dioxide emissions released by small fires. To better monitor emissions from fires, and in the boreal regions in particular, Davis, Bo Zheng and their colleagues used a new approach to indirectly track carbon dioxide emissions from fires.

This approach consisted of monitoring carbon monoxide, whose lifetime in the atmosphere is much shorter than that of carbon dioxide. The study authors used satellite data from MOPITT (Measurements Of Pollution In The Troposphere), the satellite instrument with the longest continuous time series of carbon dioxide measurements to date, to calculate weekly global emissions of carbon monoxide. carbon and carbon dioxide from fires in the boreal regions using an atmospheric inversion system. This revealed a two-decade trend of expansion of summer fires in boreal forests since 2000 and a record of emissions from boreal forest fires in 2021, coinciding with a severe heat wave, drought and high water deficit in the boreal regions in that year.

A moment during the work of extinction of a forest fire. (Photo: Michael Gue/NPS)

“Our data analysis implies a link between extensive boreal fires and climatic factors (especially temperature rises and heat waves),” they stated. They argue that boreal ecosystems could become in the future the regions that will produce more intensive fires and more carbon emissions from fires.

They also state that the method they have developed to monitor estimates of fire emissions will be useful for developing a more integrated system capable of monitoring and evaluating global and regional carbon balances produced by fires, land use flows after the fires and the net impact of fire emissions on atmospheric carbon dioxide.

The study is titled “Record-high CO2 emissions from boreal fires in 2021”. And it has been published in the academic journal Science. (Source: AAAS)