The oil and gas sector produces more greenhouse gas (GHG) emissions than any other sector of the Canadian economy. Even without considering their end use for things like heating fuels or gasoline, the extraction, transportation, and refining of oil and gas contributes more than a quarter of Canada’s total emissions.
Beyond the volume of these emissions, we must also consider their carbon intensity – that is, the GHGs emitted for each unit of oil or gas produced.
Oil sands vs. conventional oil
Of the 192 million tonnes of GHG emissions produced each year by the oil and gas sector, a full 35% (68 million tonnes) come from the oil sands. By comparison, just 19% (36 million tonnes) comes from conventional oil.
The per-barrel GHG emissions of the oil sands are much higher than those from the production of conventional crude. Estimates vary widely on the relative intensity of oil sands emissions, but some studies suggest that 3.2 to 4.5 times more emissions are produced per-barrel.
This is mainly because a lot of energy goes into extracting crude from the oil sands. Electricity, natural gas, and diesel are all required. In fact, as much as 20% of the natural gas produced in Canada goes into converting bitumen into oil.
Fracking vs. conventional natural gas
Next up is natural gas, which contributes 30% of Canada’s oil and gas GHG emissions, or 57 million tonnes.
Natural gas is often touted as a cleaner, less carbon intensive, transition fuel in the move away from oil and coal. It is true that the burning of natural gas produces fewer emissions than other fossil fuels, but this isn’t the whole story.
Shale and tight gas have increasingly become a part of the natural gas mix, and now make up more than half of Canada’s natural gas supply. These are both forms of “unconventional” natural gas obtained using hydraulic fracturing (fracking). And the fracking process – which “involves drilling into shale [and other rock] formations and injecting water, sand, ceramic and about 750 chemicals … under high pressure” – releases high levels of methane, a highly potent GHG and significant contributor to climate change.
This means that the production emissions per unit of fracked gas are significantly higher than those of conventionally-sourced natural gas.
How we produce our energy matters
Canada has committed to transition to a low-carbon future, and has taken some important first steps.
As we move forward, it is imperative that we understand and acknowledge the implications of our energy choices. Not all oil and gas is created equal: the carbon intensity of GHG emissions varies significantly between conventional and unconventional extraction methods.
Currently, over half of Canadian oil and gas emissions are the result of carbon intense extraction methods – despite the many traditional and renewable energy options available.
It’s time to make a change.
 Based on this estimate (rounded to 3.85 times), the same volume of oil that produced 68 million tonnes of GHG emissions from the oil sands in 2014 would have led to only 18 million tonnes of emissions from conventional crude.
 Gordon Laxer, After the Sands: Energy and Ecological Security for Canadians, 2015. p. 32.