A1 Journal article (refereed)
Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw (2020)

Hugelius, G., Loisel, J., Chadburn, S., Jackson, R. B., Jones, M., MacDonald, G., Marushchak, M., Olefeldt, D., Packalen, M., Siewert, M. B., Treat, C., Turetsky, M., Voigt, C., & Yu, Z. (2020). Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw. Proceedings of the National Academy of Sciences of the United States of America, 117(34), 20438-20446. https://doi.org/10.1073/pnas.1916387117

JYU authors or editors

Publication details

All authors or editors: Hugelius, Gustaf; Loisel, Julie; Chadburn, Sarah; Jackson, Robert B.; Jones, Miriam; MacDonald, Glen; Marushchak, Maija; Olefeldt,David; Packalen, Maara; Siewert, Matthias B.; et al.

Journal or series: Proceedings of the National Academy of Sciences of the United States of America

ISSN: 0027-8424

eISSN: 1091-6490

Publication year: 2020

Publication date: 10/08/2020

Volume: 117

Issue number: 34

Pages range: 20438-20446

Publisher: National Academy of Sciences

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1073/pnas.1916387117

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/73873

Abstract

Northern peatlands have accumulated large stocks of organic carbon (C) and nitrogen (N), but their spatial distribution and vulnerability to climate warming remain uncertain. Here, we used machine-learning techniques with extensive peat core data (n > 7,000) to create observation-based maps of northern peatland C and N stocks, and to assess their response to warming and permafrost thaw. We estimate that northern peatlands cover 3.7 ± 0.5 million km2 and store 415 ± 150 Pg C and 10 ± 7 Pg N. Nearly half of the peatland area and peat C stocks are permafrost affected. Using modeled global warming stabilization scenarios (from 1.5 to 6 °C warming), we project that the current sink of atmospheric C (0.10 ± 0.02 Pg C⋅y−1) in northern peatlands will shift to a C source as 0.8 to 1.9 million km2 of permafrost-affected peatlands thaw. The projected thaw would cause peatland greenhouse gas emissions equal to ∼1% of anthropogenic radiative forcing in this century. The main forcing is from methane emissions (0.7 to 3 Pg cumulative CH4-C) with smaller carbon dioxide forcing (1 to 2 Pg CO2-C) and minor nitrous oxide losses. We project that initial CO2-C losses reverse after ∼200 y, as warming strengthens peatland C-sinks. We project substantial, but highly uncertain, additional losses of peat into fluvial systems of 10 to 30 Pg C and 0.4 to 0.9 Pg N. The combined gaseous and fluvial peatland C loss estimated here adds 30 to 50% onto previous estimates of permafrost-thaw C losses, with southern permafrost regions being the most vulnerable.

Keywords: peatlands; carbon; nitrogen; greenhouse gases; permafrost; climate changes

Free keywords: northern peatlands; carbon stocks; nitrogen stocks; greenhouse gas fluxes; permafrost thaw

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 3