The Truth About Dirty Oil: Is CCS the Answer?

The rapid expansion of oil sands production in northern Alberta is under scrutiny worldwide due to concerns about its environmental, social, and economic impacts. Environmental concerns include climate change impacts from CO₂ emissions along with more local environmental impacts such as dead birds, cancer clusters, and destruction of boreal forests. Within Canada, oil sands have become an important driver of economic growth, so producers and governments are under simultaneous pressure to reduce environmental impacts while maintaining their economic competitiveness. The environmental footprint of oil sands production is hotly contested; here we aim to clarify divergent claims about CO₂ emissions by exploring how various choices about the scale of analysis (i.e., system boundaries) determine the emissions estimates, the technologies available to reduce emissions, and perspectives and strategies of stakeholders (Table 1). We pay particular attention to carbon capture and storage (CCS), showing how divergent views about its cost-effectiveness emerge from divergent choices about the scale of analysis. Debate about the future of oil sands development is so contentious that even the name of the resource is disputed: proponents typically use oil sands while opponents use tar sands. We use oil sands not to express our views on the debate, but because tar is technically incorrect because tars are products of biomass combustion and are chemically distinct from bitumen. The source material is neither oil nor tar but bitumen, but is most generally described as an example of ultraheavy oil.