Sometimes, we like to make people aware that producing a barrel of synthetic crude oil from tar sands causes around three to five times the carbon dioxide emissions of producing a barrel of conventional crude oil. That’s pretty terrible. And unfortunately, it’s true. It’s based on data from GREET, NRCan's GHGenius v. 3.13, and the EPA.

But what the industry comes back with is: This three-to-five times number is misleading. The lifecycle emissions are what you have to look at, and those are only [and let me repeat, this is an industry-proclaimed number] 10% greater than conventional oil. Canada is friendly, so we should definitely use this oil. (There are a lot of other arguments made around other issues, but this is one of the big ones around greenhouse gases – that the emissions are just not that bad.)

This is a poor assessment on several levels. First, while some of the most efficient surface mining methods of extracting tar sands cause lifecycle greenhouse gas emissions 10% greater than conventional oil, many of the in-situ operations—where the ground is heated with steam for several years in order to melt the tar-like oil enough so that it can flow out—cause lifecycle emissions that are 30% greater. Currently, about half of the tar sands production is from mining, and half in-situ; the trend is towards using more in-situ. So on average, tar sands have lifecycle greenhouse gas emissions that are closer to 20% greater than conventional oil; simply reporting the best value (10%) against the worst conventional crude oil emissions is misleading PR—not scientific.

Okay, so 20% still doesn’t sound like so much to you? If you do the math, it turns out that replacing 3 million barrels per day (mbd)* of conventional oil with tar sands oil would cause 120 million metric tons of greenhouse gas emissions per year.**

Sounds like a lot? That’s because it is. According to GREET, the average car travelling 12,000 miles per year contributes 5.8 metric tons of global warming pollution to the atmosphere. So adding 120 million metric tons of greenhouse gas emissions per year is equivalent to adding over 20 million cars to the road – and that’s a low-end estimate. For some context, this is approximately the number of automobiles in California and over double the number of cars in Texas, which has the second highest number of cars in any U.S. state.

There are many other reasons not to develop and import tar sands oil that you can read about in my colleagues’ blogs: The destruction of migratory bird habitat in the Boreal Forest that it causes, the increases in air and water pollution tar sands refining will cause, and the fact that it will force us to continue our reliance on expensive fossil fuels to name a few. But even that aside, the climate implications are NOT negligible.

So next time somebody says, “well, tar sands isn’t that bad because it’s only 20% more carbon dioxide emissions than conventional oil,” ask them if they’d be comfortable saying the following sentence: “It’s only like adding 20 million cars to the roads, eh?”

* If the TransCanada Keystone XL pipeline gets permitted by the Department of State to bring 900,000 barrels per day (bpd) of tar sands oil to the United States, we would have the capacity to be importing 3 mbd of tar sands oil (According to Pembina Institute analysis, current imports = 800,000 bpd. Keystone capacity will ultimately be 590,000 bpd. Enbridge Alberta Clipper plans to have an ultimate capacity of 800,000 bpd. And TransCanada has requested a permit for 900,000 bpd for Keystone XL. Add that all up, and you get just over 3 mbd.).

** For all you numerically inclined people out there, here are my calculations to get to 120 million metric tons of CO2e per year: Conventional gasoline, according to GREET, causes 91 grams of carbon dioxide equivalent greenhouse gases for every megajoule of energy (91g CO2e/MJ). Tar sands, on average, causes 111g CO2e/MJ. So the difference in global warming pollution between tar sands and conventional oil is 20g CO2e/MJ. There are around 5840 MJ of energy in every barrel of gasoline.

How much greenhouse gas pollution does this amount to if we replace 3 million bpd of conventional oil with tar sands oil?

20g CO2e/MJ * 5840 MJ/bbl * 3,000,000 bbl/day * 365 days/yr * 1 metric ton/1,000,000g = 127,896,000 metric tons CO2e/year.

I’m going to be conservative, round down, and call this 120 million metric tons of CO2e per year from replacing 3 mbd of conventional oil with tar sands.