A gridded inventory of Canada’s anthropogenic methane emissions

Abstract

Canada's anthropogenic methane emissions are reported annually to the United Nations Framework Convention on Climate Change (UNFCCC) through Canada's National Inventory Report (NIR). Evaluation of this policy-relevant inventory using observations of atmospheric methane requires prior information on the spatial distribution of emissions but that information is lacking in the NIR. Here we spatially allocate the NIR methane emissions for 2018 on a 0.1º x 0.1º grid (≈ 10 km x 10 km) for individual source sectors and subsectors, with further resolution by source type for the oil/gas sector, using an ensemble of national and provincial geospatial datasets and including facility-level information from Canada's Greenhouse Gas Reporting Program. The highest emissions are from oil/gas production and livestock in western Canada, and landfills in eastern Canada. We find 11 hotspots emitting more than 1 metric ton h-1 on the 0.1º x 0.1º grid. Oil sands mines in northeast Alberta contribute 3 of these hotspots even though oil sands contribute only 4% of national oil/gas emissions. Our gridded inventory shows large spatial differences with the EDGAR v5 inventory commonly used for inversions of atmospheric methane observations, which may reflect EDGAR's reliance on global geospatial datasets. Comparison of our spatially resolved inventory to atmospheric measurements in oil/gas production fields suggests that the NIR underestimates these emissions. We also find strong spatial overlap between oil/gas, livestock, and wetland emissions in western Canada that may complicate source attribution in inversions of atmospheric data.

Effectiveness of the National Pollutant Release Inventory as a Policy Tool to Curb Atmospheric Industrial Emissions in Canada

“…None of the three reported substances used for this study (e.g., sulfur dioxide, carbon monoxide, and nitrogen dioxide) are reported under the Canadian Greenhouse Gas Reporting Program (GHGRP) [26]. Therefore, this study only focused on the limitations of the NPRI tool.…”

Satellite quantification of oil and natural gas methane emissions in the US and Canada including contributions from individual basins

“…Fig. 1b shows the bottom-up O/G methane emissions from the US and Canada in 2018 based on the gridded versions of the EPA and ECCC national inventories (Maasakkers et al, 2016;Scarpelli et al, 2021), which are used as prior estimates in our inversion framework.…”

“…We conduct inversions of TROPOMI observations for 22 months (May 2018 -February 2020) in the five rectangular domains of Fig. 1a, which encompass over 98% of total O/G emissions, 97% of oil production and 99% of gas production in the continental US and Canada (Enverus DrillingInfo, 2020; Maasakkers et al, 2016;Scarpelli et al, 2021), and include all 19 major O/G production basins shown in Fig. 1b (see Fig.…”

“…recent gridded versions of the EPA and ECCC inventories as prior estimates (Maasakkers et al, 2016;Scarpelli et al, 2021).…”

Supplementary material to "Satellite quantification of oil and natural gas methane emissions in the US and Canada including contributions from individual basins"

“…We use the anthropogenic emissions inventory for the US from Maasakkers et al (2016) for 2012, and the O/G emissions are updated to the year 2018 based on activity data in the Enverus DrillingInfo database (Enverus DrillingInfo, 2020). For Canada, we use anthropogenic emissions from Scarpelli et al ( 2021) based on the Environment and Climate Change Canada's (ECCC) inventory for 2018 (ECCC, 2020). The optimal value of g can be selected when…”