I’ve been a little baffled by the tar sands’ villainization in the climate literature for some time. While a few photographs can clearly show that the tar sands have dire impacts on the local environment (as a recent National Geographic special showed), I haven’t really understood why the tar sands have been singled out for so much venom in the climate literature. About two years ago, I first saw the stats: if you measure all emissions from extraction to the tailpipe (a “well-to-wheel” basis), the tar sands are between 15–40% worse than conventional oil. Why, then, is tar sands oil so much worse than—say—a vehicle with 15–40% poorer fuel efficiency? Here in Canada, the tar sands represent a lot of potential wealth and jobs; why should our oil get singled out relative to Saudi crude?
My reading recently took me past a figure that illuminated the problem for me in many ways. The figure below is adapted slightly from Farrell and Brandt, “Risks of the Oil Transition,” Environmental Research Letters 1(1), 2006, although I’m sure it can be found in many places in the literature.
The horizontal axis here represents the number of barrels of oil possible with each source, the vertical axis represents the greenhouse gas emissions per barrel, and the area of each bar is therefore the total emissions if all possible fuel of that type is extracted and used.
The black bar to the left of the axis represents the emissions from all oil burned to date. Everything to the right of the axis represents the potential emissions from conventional and unconventional oil, in order of price per barrel. The oil used to date is dwarfed but what remains in the ground and could be emitted in the future.
Coming back to the tar sands, a few points can be drawn from the figure:
Continue reading Emissions and the Tar Sands