Jennifer D. Watts Stefano Potter Brendan M. Rogers Sarah M. Ludwig Anne-Katrin Selbmann Patrick F. Sullivan Benjamin W. Abbott Kyle A. Arndt Leah Birch Mats P. Bjorkman Anthony Bloom Gerardo Celis Torben R. Christiensen Casper T. Christiansen Roisin Commane Elisabeth J. Cooper Patrick Crill Claudia Czimczik Sergey Davydov Jinyang Du Jocelyn E. Egan Bo Elberling Eugenie S. Euskirchen Thomas Friborg Helene Genet Mathias Gockede Jordan P. Goodrich Paul Grogan Manuel Helbig Elchin E. Jafarov Julie Jastrow Aram Kalhori Yongwon Kim John S Kimball Lars Kutzbach Mark J. Lara Klaus S. Larsen Michael M Loranty Magnus Lund Massimo Lupascu Nima Madani Avni Malhorta Jack McFarland David A. McGuire Anders Michelson Christina Minions Walter C. Oechel David Olefeldt Frans-Jan Parmentier Norbert Pirk Benjamin Poulter William L. Quinton Fereidoun Rezanezhad David Risk Torsten Sachs Kevin Schaefer Neils M. Schmidt Edward A. Schuur Philipp R. Semenchuk Gaius Shaver Oliver Sonnentag Gregory Starr Claire C. Treat Mark P. Waldrop Yihui Wang Jeffrey Welker Christian Wille Xiaofeng Xu Zhen Zhang Qianlai Zhuang Donatella Zona Susan M Natali 2019 <p><span>Recent warming in the Arctic, which has been amplified during the winter</span>^{<a id="ref-link-section-d35506e2410" title="Huang, J. Recently amplified Arctic warming has contributed to a continual global warming trend. Nat. Clim. Change 7, 875–879 (2017)." href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" data-mce-href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR1">1</a>,<a id="ref-link-section-d35506e2410_1" title="Koenigk, T. et al. Arctic Climate Change in 21st century CMIP5 simulations with EC-Earth. Clim. Dynam. 40, 2719–2743 (2013)." href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR2" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" data-mce-href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR2">2</a>,<a id="ref-link-section-d35506e2413" title="Cohen, J. et al. Recent Arctic amplification and extreme mid-latitude weather. Nat. Geosci. 7, 627–637 (2014)." href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR3" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" data-mce-href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR3">3</a>}<span>, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO</span>₂<span>)</span>^{<a id="ref-link-section-d35506e2419" title="Schadel, C. et al. Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils. Nat. Clim. Change 6, 950–953 (2016)." href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR4" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" data-mce-href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR4">4</a>}<span>. However, the amount of CO</span>₂<span>&nbsp;released in winter is not known and has not been well represented by ecosystem models or empirically based estimates</span>^{<a id="ref-link-section-d35506e2425" title="Fisher, J. B. et al. Carbon cycle uncertainty in the Alaskan Arctic. Biogeosciences 11, 4271–4288 (2014)." href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 5" data-mce-href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR5">5</a>,<a id="ref-link-section-d35506e2428" title="Commane, R. et al. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra. Proc. Natl Acad. Sci. USA 114, 5361–5366 (2017)." href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR6" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 6" data-mce-href="https://www.nature.com/articles/s41558-019-0592-8#ref-CR6">6</a>}<span>. Here we synthesize regional in situ observations of CO</span>₂<span>&nbsp;flux from Arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1,662 TgC per year from the permafrost region during the winter season (October–April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (−1,032 TgC per year). Extending model predictions to warmer conditions up to 2100 indicates that winter CO</span>₂<span>&nbsp;emissions will increase 17% under a moderate mitigation scenario—Representative Concentration Pathway 4.5—and 41% under business-as-usual emissions scenario—Representative Concentration Pathway 8.5. Our results provide a baseline for winter CO</span>₂<span>&nbsp;emissions from northern terrestrial regions and indicate that enhanced soil CO</span>₂<span>&nbsp;loss due to winter warming may offset growing season carbon uptake under future climatic conditions.</span></p> application/pdf 10.1038/s41558-019-0592-8 en Nature Publishing Group Large loss of CO2 in winter observed across pan-arctic permafrost region article