Last week, after three years of environmental review, public meetings, and public comment, President Obama postponed until first quarter 2013 a decision on whether or not to approve the Keystone XL Pipeline — the $7 billion, shovel-ready project to deliver up to 830,000 barrels a day of tar sands oil from Canada to U.S. Gulf Coast refineries. Obama’s punt, which Keystone opponents hope effectively kills the pipeline, is topic-of-the-week on National Journal’s Energy Experts Blog. So far, a dozen ”experts” have posted, including yours truly.

Now, if you’ve been paying attention at all over the past 40 years, you may suspect that most Keystone opponents want to kill the pipeline just because they hate oil and oil companies — even as they fill up their tanks to drive to the next demonstration. Bill McKibben, lead organizer of the anti-Keystone protest rallies outside the White House, lives in Vermont. On the Colbert Report, host Stephen Colbert asked McKibben: ”You’re from Vermont? Did you ride your bicycle down here? Or did you ride ox cart? How did you get down here? Or do you have a vehicle that runs on hypocrisy?”

If we take them at their word, McKibben and his climate guru, NASA scientist James Hansen, oppose Keystone because they believe it will contribute to global warming. How? The cutting-edge method for extracting oil from tar sands is a process called steam assisted gravity drainage. SAGD uses natural gas to heat and liquefy bitumen, a tar-like form of petroleum too viscous to be pumped by conventional wells, and burning natural gas emits carbon dioxide (CO2). So their gripe is that replacing conventional oil with tar sands oil will increase CO2 emissions from the U.S. transport sector. Maybe by only 1% annually,* but to hard-core warmists, any increase is intolerable.

Enter the Law of Unintended Consequences. If McKibben and Hansen succeed in killing the pipeline, petroleum-related CO2 emissions might actually increase!

Charles Drevna of the National Petrochemical & Refiners Association (NPRA) made this point on the aforementioned National Journal energy blog:

A study last year by Barr Engineering found that shipping more Canadian oil to Asia and shipping more oil from other parts of the world to the United States would increase greenhouse gas emissions, because of the long sea voyages. Barr Engineering called this the crude oil shuffle. So using more Canadian oil in the United States would reduce greenhouse gas emissions.

The Barr Engineering study analyzes the impacts on CO2 emissions of a low-carbon fuel standard (LCFS) that effectively bars U.S. imports of Canadian tar sands oil. Because global petroleum demand is growing, Canada would continue to produce tar sands oil even if the USA adopts an LCFS. However, instead of shipping the oil to the USA, Canada would ship the oil to China. At the same time, to meet U.S. demand that the LCFS does not allow Canada to fill, Middle East countries would ship oil to the USA that would otherwise go to China. The Canadian oil re-routed to China and Mideastern oil re-routed to the USA would travel by tankers, which burn fuel and emit CO2. Longer transport routes mean higher CO2 emissions. From the report:

Under the base case, crude is transported approximately 8,500 to 9,000 miles from Edmonton [Canada] to Chicago and from Basrah [Iraq] to Ningbo [China]. Under the crude shuffle case, total transport distance nearly triples, with crude transported approximately 22,300 to 22,700 miles from Basrah to Chicago and from Edmongton to Ningbo. Resulting GHG emissions are approximately twice as high on a total basis (for any of the crude displacement scenarios considered). . . .Under all scenarios considered, the crude shuffle results in emissions that are approximately twice as great as the emissions associatd with current base-case crude transport patterns.

The figure above shows U.S. petroleum-related greenhouse gas emissions in a “base case” and a “crude shuffle case.” PADD II refers to the Midwest petroleum market.

Although killing Keystone would not ban imports of Canadian tar sands oil, as would an LCFS, it would effectively block much of the forecast 830,000 daily barrels of tar sands from reaching U.S. refineries. That, in turn, would induce similar re-routing of international oil flows. Each barrel “shuffled” to more distant markets would have a bigger carbon footprint than a barrel of Canadian crude shipped via Keystone to the USA.

* The State Department estimates that full operation of the Keystone pipeline would produce incremental greenhouse gas emissions of 3 million to 21 million metric tons of CO2 annually (ES-15). For perspective, the U.S. transport sector in 2009 generated 1,854.5 million metric tons of CO2.