Oil and gas industry emissions in Saskatchewan, Canada: a case study in uncertain reduction trends

The province of Saskatchewan, Canada, came under new oil and gas industry emission regulations in 2020 to meet Canada’s methane emission reduction target for 2025. Although the province reportedly met its reduction target only two years into a five-year commitment, this finding was based on a bottom-up inventory whose operator-reported data had not been public until very recently. With these data made public for the first time, we recreated the federal government inventory for Saskatchewan (2012-2022) to better understand where and how emissions have changed in response to new regulations. Not only will this shed light on the regulations themselves (an updated version of which will be under review for Canada’s longer-term targets), but this inventory will also permit more detailed comparisons with forthcoming top-down measurements.

Since new measurements are expected to be included in this inventory structure, we also used recently published aerial LiDAR measurements to update the inventory. Importantly, while the unmodified inventory confirms the significant emission reduction reported by the Saskatchewan Government (~45% reduction), the inclusion of aerial measurement data suggests that emissions may have actually increased over the same time period. We discuss how the manner in which new measurements are included can influence the emission reductions relative to an uncertain baseline year, and we discuss whether a trend can be calculated reliably. Careful consideration will therefore be needed when including new measurement data into existing inventories.