The U.S. Environmental Protection Agency recently got in a rather public spat with the U.S. Department of State over the proposed Keystone XL pipeline project. Apart from the irregularity of one Cabinet agency attacking another, the episode was a boondoggle for the EPA, which came out looking both petty and unscientific.

In a letter to the State Department, the EPA contends that the State Department (which has the ultimate say in the whether or not the pipeline gets the green light) did not accurately assess the magnitude of the carbon dioxide emissions that would result from the burning of the 830,000 barrels of oil the pipeline would transport each day.

It’s important to point out that a barrel of oil extracted from Canada’s tar sands produces about 17 percent more carbon dioxide emissions than the average barrel of oil refined in the United States. However, that extra 17 percent does not come from the oil itself, but from the energy-intensive manner in which it is mined. This emissions premium will almost certainly shrink over time as new technologies are developed to more efficiently extract the oil.

The concern is how much of this extra carbon dioxide will find its way into the atmosphere because of the pipeline. The State Department concludes that the tar sands oil will come to market whether or not Keystone XL is ever built, meaning the pipeline would result in a minimal production of carbon dioxide that otherwise would not have occurred.

The EPA, on the other hand, argues that absent the pipeline, the oil will largely remain in the ground. Therefore, building the pipeline will cause the extraction of oil, with the end result being the emission of an extra 18.7 million metric tons of carbon dioxide per year.

That sounds like a lot. But herein lies the EPA’s prevarication. Typically, when gauging “climate impacts,” as the EPA claims is its “focus” in the letter, emissions are put into a computer model to determine how they would actually impact the climate. Taking that extra step isn’t hard. The EPA didn’t do it. In fact, climate models are designed precisely to provide information about how emissions affect the climate, and are the primary source of projections of future global warming resulting from the human carbon dioxide emissions.

So why did the EPA omit this critical step in determining the climate impacts of Keystone XL? Because even under the EPA’s highly pessimistic assumption, the extra 18.7 million metric tons of carbon dioxide annually results in less than 0.00001°C of warming per year. In English, that’s one one-hundred-thousandth of a degree. Needless to say, “18.7 million” sounds bigger.

Put another way, the extra emissions from the Keystone XL pipeline if it delivered oil at its maximum capacity for the next thousand years would be expected to raise the global average temperature by less than one hundredth of a degree. Even if climate modeling could be relied upon for its demonstrated accuracy over such a huge duration — which it most certainly cannot — that figure is obviously too infinitesimal to be included in any rational discussion of the issue.

After all, who would have taken the EPA seriously had it stated in its letter that the primary issue it had with the State Department analysis involved a calculation to the 5th decimal point? We all would have wondered why the EPA was wasting its time and taxpayer dollars on such triviality.

But the fact that the EPA circumvented what should be its normal procedures — running the carbon dioxide figure through climate modeling — is a damning bit of evidence. It is difficult not to conclude the EPA is trying to influence the discussion by confusing the public with large numbers of no real-world consequence.

The State Department is to be commended for considering copious amounts of evidence — including reams of environmental impact data — in its deliberations on the Keystone XL pipeline. The product of those deliberations is that the decidedly pro-environment Obama Administration is on the verge of approving the pipeline on its merits. For EPA bureaucrats to try to derail the process with underhanded tactics serves no one — not the president they work for, not the environment they are charged to protect, and certainly not the consumer public.