Using Repeated Aerial Methane Measurements to Assess Inventory Protocols and Track Year-over-year Trends in Emissions

Measurement-based inventories combining source-resolved aerial LiDAR measurements with bottom-up emission and activity data have provided unprecedented insight into the origins and magnitudes of oil and gas sector methane emissions and, in Canada, are now being used to inform methane estimates used in official national greenhouse gas inventory reporting.  However, the protocols for creating measurement-based inventories are new and continue to be refined as both measurement technology and scientific understanding of the oil and gas sector improve.  In this study, we examine independent, measurement-based inventory estimates derived from aerial survey data collected during 2020, 2021, 2023, and 2024 in the Canadian province of Saskatchewan; 2021, 2023, and 2024 in the province of British Columbia; and 2021 and 2023 in the province of Alberta.  Data for each province are used to quantify region-specific sample size requirements, providing important insights into how prescribed sample sizes may need to vary depending on the characteristics of the production basin.  Year-over-year emission trends are also examined in detail, which reveal varying degrees of success in reducing emissions in regions with distinct regulatory frameworks while highlighting key remaining sources to target for mitigation.