## [The Boreal-Arctic Wetland and Lake Dataset](/resource/boreal-arctic-wetland-and-lake-dataset) Organization [University of Alberta (UofA)](/organization/university-alberta-uofa) [Stockholm University](/organization/stockholm-university) [Linköping University](/organization/linkoping-university) [WattIQ](/organization/wattiq) [Trinity College Dublin](/organization/trinity-college-dublin) [University of Alaska Fairbanks](/organization/university-alaska-fairbanks) [University of Toronto (UofT)](/organization/university-toronto-uoft) [Helmholtz Centre for Polar and Marine Research](/organization/helmholtz-centre-polar-and-marine-research) [University of Potsdam](/organization/university-potsdam) [Uppsala University](/organization/uppsala-university) [Dalhousie University](/organization/dalhousie-university) [University of Waterloo](/organization/university-waterloo) [University of Helsinki](/organization/university-helsinki) [University of Illinois](/organization/university-illinois) [Stanford University](/organization/stanford-university) [United States Geological Survey](/organization/united-states-geological-survey) [Woodwell Climate Research Centre](/organization/woodwell-climate-research-centre) [National Park Service](/organization/national-park-service) [University of Oslo](/organization/university-oslo) [Lund University](/organization/lund-university) [Northern Arizona University](/organization/northern-arizona-university) [University of Montreal](/organization/university-montreal) [University of New Hampshire](/organization/university-new-hampshire) [Ducks Unlimited Canada (DUC)](/organization/ducks-unlimited-canada-duc) Resource Type [Peer reviewed article](/taxonomy/term/37) Author(s) David Olefeldt Mikael Hovemyr McKenzie Kuhn David Bastviken Theodore Bohn John Connolly Patrick Crill Eugenie Euskirchen Sarah Finkelstein Hélène Genet Guido Grosse Lorna Harris Liam Heffernan Manuel Helbig Gustaf Hugelius Ryan Hutchins Sari Juutinen Mark Lara Avni Malhotra Kristen Manies David McGuire Susan Natali Jonathan O'Donnell Frans-Jan Parmentier Aleksi Räsänen Christina Schädel Oliver Sonnentag Maria Strack Suzanne Tank Claire Treat Ruth Varner Tarmo Virtanen Rebecca Warren Jennifer Watts Original Authors David Olefeldt Mikael Hovemyr McKenzie Kuhn David Bastviken Theodore Bohn John Connolly Patrick Crill Eugénie Euskirchen Sarah Finkelstein Hélène Genet Guido Grosse Lorna Harris Liam Heffernan Manuel Helbig Gustaf Hugelius Ryan Hutchins Sari Juutinen Mark Lara Avni Malhotra Kristen Manies David McGuire Susan Natali Jonathan O'Donnell Frans-Jan Parmentier Aleksi Räsänen Christina Schädel Oliver Sonnentag Maria Strack Suzanne Tank Claire Treat Ruth Varner Tarmo Virtanen Rebecca Warren Jennifer Watts Contacts [David Olefeldt](/contact/david-olefeldt) Resource Date: 2021 Page Length 40 Here we present the Boreal–Arctic Wetland and Lake Dataset (BAWLD), a land cover dataset based on an expert assessment, extrapolated using random forest modelling from available spatial datasets of climate, topography, soils, permafrost conditions, vegetation, wetlands, and surface water extents and dynamics. In BAWLD, we estimate the fractional coverage of five wetland, seven lake, and three river classes within 0.5 × 0.5∘ grid cells that cover the northern boreal and tundra biomes (17 % of the global land surface). Land cover classes were defined using criteria that ensured distinct methane emissions among classes, as indicated by a co-developed comprehensive dataset of methane flux observations. In BAWLD, wetlands occupied 3.2 × 106 km2 (14 % of domain) with a 95 % confidence interval between 2.8 and 3.8 × 106 km2. Bog, fen, and permafrost bog were the most abundant wetland classes, covering ∼ 28 % each of the total wetland area, while the highest-methane-emitting marsh and tundra wetland classes occupied 5 % and 12 %, respectively. Lakes, defined to include all lentic open-water ecosystems regardless of size, covered 1.4 × 106 km2 (6 % of domain). Low-methane-emitting large lakes (>10 km2) and glacial lakes jointly represented 78 % of the total lake area, while high-emitting peatland and yedoma lakes covered 18 % and 4 %, respectively. Small (<0.1 km2) glacial, peatland, and yedoma lakes combined covered 17 % of the total lake area but contributed disproportionally to the overall spatial uncertainty in lake area with a 95 % confidence interval between 0.15 and 0.38 × 106 km2. Rivers and streams were estimated to cover 0.12 × 106 km2 (0.5 % of domain), of which 8 % was associated with high-methane-emitting headwaters that drain organic-rich landscapes. Distinct combinations of spatially co-occurring wetland and lake classes were identified across the BAWLD domain, allowing for the mapping of “wetscapes” that have characteristic methane emission magnitudes and sensitivities to climate change at regional scales. With BAWLD, we provide a dataset which avoids double-accounting of wetland, lake, and river extents and which includes confidence intervals for each land cover class. As such, BAWLD will be suitable for many hydrological and biogeochemical modelling and upscaling efforts for the northern boreal and arctic region, in particular those aimed at improving assessments of current and future methane emissions. Data are freely available at (Olefeldt et al., 2021).