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The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape.
Glob Chang Biol 2017; 23(6):2413-2427GC

Abstract

At the southern margin of permafrost in North America, climate change causes widespread permafrost thaw. In boreal lowlands, thawing forested permafrost peat plateaus ('forest') lead to expansion of permafrost-free wetlands ('wetland'). Expanding wetland area with saturated and warmer organic soils is expected to increase landscape methane (CH4) emissions. Here, we quantify the thaw-induced increase in CH4 emissions for a boreal forest-wetland landscape in the southern Taiga Plains, Canada, and evaluate its impact on net radiative forcing relative to potential long-term net carbon dioxide (CO2) exchange. Using nested wetland and landscape eddy covariance net CH4 flux measurements in combination with flux footprint modeling, we find that landscape CH4 emissions increase with increasing wetland-to-forest ratio. Landscape CH4 emissions are most sensitive to this ratio during peak emission periods, when wetland soils are up to 10 °C warmer than forest soils. The cumulative growing season (May-October) wetland CH4 emission of ~13 g CH4 m-2 is the dominating contribution to the landscape CH4 emission of ~7 g CH4 m-2 . In contrast, forest contributions to landscape CH4 emissions appear to be negligible. The rapid wetland expansion of 0.26 ± 0.05% yr-1 in this region causes an estimated growing season increase of 0.034 ± 0.007 g CH4 m-2 yr-1 in landscape CH4 emissions. A long-term net CO2 uptake of >200 g CO2 m-2 yr-1 is required to offset the positive radiative forcing of increasing CH4 emissions until the end of the 21st century as indicated by an atmospheric CH4 and CO2 concentration model. However, long-term apparent carbon accumulation rates in similar boreal forest-wetland landscapes and eddy covariance landscape net CO2 flux measurements suggest a long-term net CO2 uptake between 49 and 157 g CO2 m-2 yr-1 . Thus, thaw-induced CH4 emission increases likely exert a positive net radiative greenhouse gas forcing through the 21st century.

Authors+Show Affiliations

Département de Géographie, Université de Montréal & Centre d'études nordiques, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada.Department of Geography, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.Department of Geography, Swansea University, Singleton Park, Swansea, SA28PP, UK.Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada.Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA. U.S. Geological Survey, Menlo Park, CA, 94025, USA.Département de Géographie, Université de Montréal & Centre d'études nordiques, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27689625

Citation

Helbig, Manuel, et al. "The Positive Net Radiative Greenhouse Gas Forcing of Increasing Methane Emissions From a Thawing Boreal Forest-wetland Landscape." Global Change Biology, vol. 23, no. 6, 2017, pp. 2413-2427.
Helbig M, Chasmer LE, Kljun N, et al. The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape. Glob Chang Biol. 2017;23(6):2413-2427.
Helbig, M., Chasmer, L. E., Kljun, N., Quinton, W. L., Treat, C. C., & Sonnentag, O. (2017). The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape. Global Change Biology, 23(6), pp. 2413-2427. doi:10.1111/gcb.13520.
Helbig M, et al. The Positive Net Radiative Greenhouse Gas Forcing of Increasing Methane Emissions From a Thawing Boreal Forest-wetland Landscape. Glob Chang Biol. 2017;23(6):2413-2427. PubMed PMID: 27689625.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape. AU - Helbig,Manuel, AU - Chasmer,Laura E, AU - Kljun,NatasCha, AU - Quinton,William L, AU - Treat,Claire C, AU - Sonnentag,Oliver, Y1 - 2016/10/26/ PY - 2016/08/11/received PY - 2016/09/20/accepted PY - 2016/10/27/pubmed PY - 2017/10/24/medline PY - 2016/10/1/entrez KW - boreal forest KW - carbon dioxide KW - climate change KW - eddy covariance KW - methane KW - radiative forcing KW - wetland SP - 2413 EP - 2427 JF - Global change biology JO - Glob Chang Biol VL - 23 IS - 6 N2 - At the southern margin of permafrost in North America, climate change causes widespread permafrost thaw. In boreal lowlands, thawing forested permafrost peat plateaus ('forest') lead to expansion of permafrost-free wetlands ('wetland'). Expanding wetland area with saturated and warmer organic soils is expected to increase landscape methane (CH4) emissions. Here, we quantify the thaw-induced increase in CH4 emissions for a boreal forest-wetland landscape in the southern Taiga Plains, Canada, and evaluate its impact on net radiative forcing relative to potential long-term net carbon dioxide (CO2) exchange. Using nested wetland and landscape eddy covariance net CH4 flux measurements in combination with flux footprint modeling, we find that landscape CH4 emissions increase with increasing wetland-to-forest ratio. Landscape CH4 emissions are most sensitive to this ratio during peak emission periods, when wetland soils are up to 10 °C warmer than forest soils. The cumulative growing season (May-October) wetland CH4 emission of ~13 g CH4 m-2 is the dominating contribution to the landscape CH4 emission of ~7 g CH4 m-2 . In contrast, forest contributions to landscape CH4 emissions appear to be negligible. The rapid wetland expansion of 0.26 ± 0.05% yr-1 in this region causes an estimated growing season increase of 0.034 ± 0.007 g CH4 m-2 yr-1 in landscape CH4 emissions. A long-term net CO2 uptake of >200 g CO2 m-2 yr-1 is required to offset the positive radiative forcing of increasing CH4 emissions until the end of the 21st century as indicated by an atmospheric CH4 and CO2 concentration model. However, long-term apparent carbon accumulation rates in similar boreal forest-wetland landscapes and eddy covariance landscape net CO2 flux measurements suggest a long-term net CO2 uptake between 49 and 157 g CO2 m-2 yr-1 . Thus, thaw-induced CH4 emission increases likely exert a positive net radiative greenhouse gas forcing through the 21st century. SN - 1365-2486 UR - https://www.unboundmedicine.com/medline/citation/27689625/The_positive_net_radiative_greenhouse_gas_forcing_of_increasing_methane_emissions_from_a_thawing_boreal_forest_wetland_landscape_ L2 - https://doi.org/10.1111/gcb.13520 DB - PRIME DP - Unbound Medicine ER -