In President Obama's original rejection of the Keystone project, on 18 January 2012 (after Hillary Clinton's first draft EIS, which had been done by another firm chosen by TransCanada), he said "I have determined ... that the Keystone XL pipeline project, as presented and analyzed at this time, would not serve the national interest." He did not mention global warming as a reason for rejecting it.
On 7 October 2011, The New York Times had already raised public concerns when they headlined "Pipeline Review Is Faced With Question of Conflict," and reported that Hillary Clinton's first draft EIS on Keystone was prepared by Cardno Entrix, the first firm that had been selected by TransCanada. If President Obama was rejecting the pipeline now because that choice had been untrustworthy, then the subsequent Clinton-State-Department-produced draft EIS, from ERM, was no better. Unfortunately, the third and final one, from Secretary of State John Kerry's State Department, is not much better than Clinton's were.
However, buried on page 64 of "Appendix W" in Secretary Clinton's second draft version was an admission that the prior scientific studies of the impact of the proposed Keystone XL Pipeline had estimated that there would be something on the order of an additional half-billion metric tons of carbon dioxide added to this planet's atmosphere if the pipeline is built and used, as compared to if it's not built and used. If President Obama really cares about global warming (such as his public rhetoric has indicated), then he can simply trash the reports from his State Department, and reject this project with finality, because it will add considerably to the heating-up of this planet. On the other hand, why would he do such a thing, since he is trying to force the European Union to weaken their anti-global-warming regulations so as to enable them to import Alberta Canada's tar-sands oil, half of which is owned by the Koch brothers, David and Charles, plus, according to Tim Dickenson in Rolling Stone, Bill Koch, who has his own separate company eagerly awaiting approval of Keystone XL.
Investigative historian Eric Zuesse is the author, most recently, of They're Not Even Close: The Democratic vs. Republican Economic Records, 1910-2010, and of CHRIST'S VENTRILOQUISTS: The Event that Created Christianity .