25 Apr 2022
25 Apr 2022
Status: this preprint is currently under review for the journal TC.

Significant underestimation of peatland permafrost along the Labrador Sea coastline

Yifeng Wang1, Robert G. Way1, Jordan Beer1, Anika Forget1, Rosamond Tutton1,2, and Meredith C. Purcell3 Yifeng Wang et al.
  • 1Northern Environmental Geoscience Laboratory, Department of Geography and Planning, Kingston, K7L 3N6, Canada
  • 2Global Water Futures, Wilfrid Laurier University, Yellowknife, X1A 2P8, Canada
  • 3Torngat Wildlife, Plants, and Fisheries Secretariat, Happy Valley-Goose Bay, A0P 1E0, Canada

Abstract. Northern peatlands cover approximately four million km2, and about half of these peatlands are estimated to contain permafrost and periglacial landforms, like palsas and peat plateaux. In northeastern Canada, peatland permafrost is predicted to be spatially concentrated in the western interior of Labrador and largely absent along the Labrador Sea and Gulf of St. Lawrence coastline. However, the paucity of observations of peatland permafrost in the interior coupled with ongoing use of perennially frozen peatlands along the coast by Labrador Inuit and Innu cast doubt on the reliability of existing maps of peatland permafrost distribution in the region. In this study, we develop a multi-stage consensus-based inventory of peatland permafrost complexes in coastal Labrador and adjacent parts of Quebec using high-resolution satellite imagery and validate it with extensive field visits and low-altitude aerial photography and videography. A total of 1885 wetland complexes were inventoried, of which 1023 were interpreted as likely containing peatland permafrost. Likely peatland permafrost complexes were mostly found in lowlands within 40 km of the coastline where mean annual air temperatures of up to +1.2 °C are recorded. Evaluation of the geographic distribution of peatland permafrost complexes reveals a clear gradient from the outer coasts, where peatland permafrost is more abundant, to inland peatlands, where permafrost is generally absent. This coastal gradient may be attributed to a combination of climatic and geomorphological influences which lead to lower insolation, thinner snowpacks, and more frost-susceptible materials along the coast. The results of this study also suggest that existing maps of permafrost distribution for southeastern Labrador require adjustment to better reflect the abundance of peatland permafrost complexes which are located to the south of the regional sporadic discontinuous permafrost limit. This study constitutes the first dedicated peatland permafrost inventory for Labrador, and our results provide an important baseline for future mapping, modelling, and climate change adaptation strategy development in the region.

Yifeng Wang et al.

Status: open (until 20 Jun 2022)

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Yifeng Wang et al.

Yifeng Wang et al.


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Latest update: 24 May 2022
Short summary
Peatland permafrost in northeastern Canada has been misrepresented by models, resulting in significant underestimates of peatland permafrost and permafrost distribution along the Labrador Sea coastline. Our multi-mapper, consensus-based, multi-stage mapping and review process, supported by extensive validation efforts, identifies peatland permafrost complexes all along the coastline. The highest density of complexes is found to the south of the current sporadic discontinuous permafrost zone.