Record-high CO2 emissions from boreal fires in 2021
Emission emergency
Carbon dioxide emissions from boreal forest fires have been increasing since at least the year 2000, reaching a new high in 2021, Zheng et al. report. Although boreal fires typically produce about 10% of global carbon dioxide emissions from wildfires, in 2021 they produced nearly one quarter of the total. This abnormally high total resulted from the concurrence of water deficits in North America and Eurasia, which was an unusual situation. The increasing number of extreme wildfires that is accompanying global warming presents a real challenge to global climate change mitigation efforts. —HJS
Abstract
Extreme wildfires are becoming more common and increasingly affecting Earth’s climate. Wildfires in boreal forests have attracted much less attention than those in tropical forests, although boreal forests are one of the most extensive biomes on Earth and are experiencing the fastest warming. We used a satellite-based atmospheric inversion system to monitor fire emissions in boreal forests. Wildfires are rapidly expanding into boreal forests with emerging warmer and drier fire seasons. Boreal fires, typically accounting for 10% of global fire carbon dioxide emissions, contributed 23% (0.48 billion metric tons of carbon) in 2021, by far the highest fraction since 2000. 2021 was an abnormal year because North American and Eurasian boreal forests synchronously experienced their greatest water deficit. Increasing numbers of extreme boreal fires and stronger climate–fire feedbacks challenge climate mitigation efforts.
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Volume 379 | Issue 6635
3 March 2023
3 March 2023
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Copyright © 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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Received: 23 July 2022
Accepted: 19 January 2023
Published in print: 3 March 2023
Acknowledgments
Funding: This work was supported by the Young Elite Scientists Sponsorship Program by CAST grant YESS20200135 (B.Z.), National Natural Science Foundation of China grant 41921005 (Q.Z.), and Scientific Research Start-up Funds from Tsinghua Shenzhen International Graduate School grant QD2021024C (B.Z.). H.Y. was supported by grant 50EE1904 funded by the German Federal Ministry of Economics and Technology.
Author contributions: Conceptualization: B.Z. and Q.Z. Methodology: B.Z., P.C., and F.C. Investigation: B.Z., P.C., H.Y., J.G.C., Y.C., and X.L. Visualization: B.Z. Funding acquisition: B.Z. and Q.Z. Project administration: B.Z. Supervision: B.Z., Q.Z., and K.H. Writing – original draft: B.Z. Writing – review and editing: B.Z., P.C., F.C., J.G.C., Y.C., E.C., M.D., C.H., Y.K., Ha.L., Hu.L., I.R.v.d.V., I.A., S.J.D., and Q.Z.
Competing interests: The authors declare that they have no competing interests.
Data and materials availability: The MOPITT Version 9 products are available from NASA through the Earthdata portal (https://earthdata.nasa.gov/) or directly from the ASDC archive (https://asdc.larc.nasa.gov/data/MOPITT/). The GFED 4.1s fire emissions data can be derived from https://www.geo.vu.nl/~gwerf/GFED/GFED4/. The CEDS anthropogenic emissions data files can be accessed through https://data.pnnl.gov/dataset/CEDS-4-21-21. The country- and sector-level CO2 emission growth rates are derived from the Carbon Monitor project (https://carbonmonitor.org/). The ERA5 reanalysis data can be derived from https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-v5. The inversion-based global gridded fire CO2 emissions data are available from (43). The global atmospheric inversion system used in this study can be accessed through http://community-inversion.eu/installation.html#getting-the-code. License information: Copyright © 2023 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original US government works. https://www.science.org/about/science-licenses-journal-article-reuse
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Young Elite Scientists Sponsorship Program by CAST: YESS20200135
Scientific Research Start-up Funds from Tsinghua Shenzhen International Graduate School: QD2021024C
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