A. Britta K. Sannel


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Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems
Heather Kropp, M. M. Loranty, Susan M. Natali, Alexander Kholodov, A. V. Rocha, Isla H. Myers‐Smith, Benjamin W Abbot, Jakob Abermann, E. Blanc‐Betes, Daan Blok, Gesche Blume‐Werry, Julia Boike, A. L. Breen, Sean M. P. Cahoon, Casper T. Christiansen, Thomas A. Douglas, Howard E. Epstein, G. V. Frost, Mathias Goeckede, Toke T. Høye, Steven D. Mamet, J. A. O’Donnell, David Olefeldt, Gareth K. Phoenix, V. G. Salmon, A. Britta K. Sannel, Sharon L. Smith, Oliver Sonnentag, Lydia Smith Vaughn, Mathew Williams, Bo Elberling, Laura Gough, Jan Hjort, Peter M. Lafleur, Eugénie Euskirchen, M.M.P.D. Heijmans, Elyn Humphreys, Hiroyasu Iwata, Benjamin M. Jones, M. Torre Jorgenson, Inge Grünberg, Yongwon Kim, James A. Laundre, Marguerite Mauritz, Anders Michelsen, Gabriela Schaepman‐Strub, Ken D. Tape, Masahito Ueyama, Bang-Yong Lee, Kirsty Langley, Magnus Lund
Environmental Research Letters, Volume 16, Issue 1

Abstract Soils are warming as air temperatures rise across the Arctic and Boreal region concurrent with the expansion of tall-statured shrubs and trees in the tundra. Changes in vegetation structure and function are expected to alter soil thermal regimes, thereby modifying climate feedbacks related to permafrost thaw and carbon cycling. However, current understanding of vegetation impacts on soil temperature is limited to local or regional scales and lacks the generality necessary to predict soil warming and permafrost stability on a pan-Arctic scale. Here we synthesize shallow soil and air temperature observations with broad spatial and temporal coverage collected across 106 sites representing nine different vegetation types in the permafrost region. We showed ecosystems with tall-statured shrubs and trees (>40 cm) have warmer shallow soils than those with short-statured tundra vegetation when normalized to a constant air temperature. In tree and tall shrub vegetation types, cooler temperatures in the warm season do not lead to cooler mean annual soil temperature indicating that ground thermal regimes in the cold-season rather than the warm-season are most critical for predicting soil warming in ecosystems underlain by permafrost. Our results suggest that the expansion of tall shrubs and trees into tundra regions can amplify shallow soil warming, and could increase the potential for increased seasonal thaw depth and increase soil carbon cycling rates and lead to increased carbon dioxide loss and further permafrost thaw.

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Expert assessment of future vulnerability of the global peatland carbon sink
Julie Loisel, Angela Gallego‐Sala, Matthew J. Amesbury, Gabriel Magnan, Gusti Z. Anshari, David W. Beilman, Juan C. Benavides, Jerome Blewett, Philip Camill, Dan J. Charman, Sakonvan Chawchai, A. Hedgpeth, Thomas Kleinen, Atte Korhola, David J. Large, Claudia A Mansilla, Jurek Müller, Simon van Bellen, Jason B. West, Zicheng Yu, Jill L. Bubier, Michelle Garneau, Tim R. Moore, A. Britta K. Sannel, Susan Page, Minna Vӓliranta, Michel Bechtold, Victor Brovkin, Lydia E.S. Cole, Jeffrey P. Chanton, Torben R. Christensen, Marissa A. Davies, François De Vleeschouwer, Sarah A. Finkelstein, Steve Frolking, Mariusz Gałka, Laure Gandois, Nicholas T. Girkin, Lorna I. Harris, Andreas Heinemeyer, Alison M. Hoyt, Miriam C. Jones, Fortunat Joos, Sari Juutinen, Karl Kaiser, Terri Lacourse, Mariusz Lamentowicz, Tuula Larmola, Jens Leifeld, Annalea Lohila, Alice M. Milner, Kari Minkkinen, Patrick Moss, B. David A. Naafs, J. E. Nichols, J. A. O’Donnell, Richard J. Payne, Michael Philben, Sanna Piilo, Anne Quillet, Amila Sandaruwan Ratnayake, Thomas P. Roland, Sofie Sjögersten, Oliver Sonnentag, Graeme T. Swindles, Ward Swinnen, Julie Talbot, Claire C. Treat, Amy Valach, Jiequn Wu
Nature Climate Change, Volume 11, Issue 1

The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland–carbon–climate nexus. Peatlands are impacted by climate and land-use changes, with feedback to warming by acting as either sources or sinks of carbon. Expert elicitation combined with literature review reveals key drivers of change that alter peatland carbon dynamics, with implications for improving models.

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Carbon release through abrupt permafrost thaw
M. R. Turetsky, Benjamin W. Abbott, Miriam C. Jones, K. M. Walter Anthony, David Olefeldt, Edward A. G. Schuur, Guido Grosse, Peter Kuhry, Gustaf Hugelius, Charles D. Koven, David M. Lawrence, Carolyn Gibson, A. Britta K. Sannel, A. David McGuire
Nature Geoscience, Volume 13, Issue 2


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Permafrost collapse is accelerating carbon release
M. R. Turetsky, Benjamin W. Abbott, Miriam C. Jones, K. M. Walter Anthony, David Olefeldt, Edward A. G. Schuur, C. Koven, A. D. McGuire, Guido Grosse, Peter Kuhry, Gustaf Hugelius, David M. Lawrence, Carolyn Gibson, A. Britta K. Sannel
Nature, Volume 569, Issue 7754

The sudden collapse of thawing soils in the Arctic might double the warming from greenhouse gases released from tundra, warn Merritt R. Turetsky and colleagues. The sudden collapse of thawing soils in the Arctic might double the warming from greenhouse gases released from tundra, warn Merritt R. Turetsky and colleagues.