Thirteen studies of GHG emissions associated with oil sands operations are reviewed. The production of synthetic crude oil (SCO) through surface mining and upgrading (SM&Up) or in situ and upgrading (IS&Up) processes is reported to result in emissions ranging from 62 to 164 and 99 to 176 kgCO2eq/bbl SCO, respectively (or 9.2–26.5 and 16.2–28.7 gCO2eq MJ−1 SCO, respectively), compared to 27–58 kgCO2eq/bbl (4.5–9.6 gCO2eq MJ−1) of crude for conventional oil production.

The difference in emissions intensity between SCO and conventional crude production is primarily due to higher energy requirements for extracting bitumen and upgrading it into SCO. On a 'well-to-wheel' basis, GHG emissions associated with producing reformulated gasoline from oil sands with current SM&Up, IS&Up, and in situ (without upgrading) technologies are 260–320, 320–350, and 270–340 gCO2eq km−1, respectively, compared to 250–280 gCO2eq km−1 for production from conventional oil. Some variation between studies is expected due to differences in methods, technologies studied, and operating choices.

However, the magnitude of the differences presented suggests that a consensus on the characterization of life cycle emissions of the oil sands industry has yet to be reached in the public literature. Recommendations are given for future studies for informing industry and government decision making.

This forms the abstract of an article published in Environmental Research Letters. The full article is available here.