The media heralded a report in early 2014, which claimed that building the controversial Keystone XL pipeline would not have a significant impact on climate change. Since then, multiple studies have found that same report to be flawed, but most mainstream media outlets have refused to give these studies coverage.

President Obama has stated that he would not approve construction of the Keystone XL pipeline, which would transport tar sands crude from Canada through the United States, if it “significantly exacerbate[s] the problem of carbon pollution.” So when the U.S. State Department released its environmental impact statement concluding that the Keystone XL would not have a significant impact on climate change, the media touted State's findings as justification for the contentious pipeline's approval.

However, various studies have since called the State Department's report into question, finding specifically that their climate impact analysis is likely inaccurate. The agency's conclusion rests on the assumption that if the Keystone XL is not approved, the oil sands will simply be transported by rail instead. This may not be the case. According to Reuters, the State Department's predictions of increased rail capacity have been consistently wrong. Reuters broke the news in March that State's latest estimates of tar sands being transported by rail were overestimated by over 400 percent. But no* other major mainstream outlet reported on these findings, which undermined the claim that Keystone XL won't affect the climate - a meme many of these same outlets previously had amplified.

More recently, a study published in Nature Climate Change found that approving the Keystone XL could lead to carbon dioxide emissions four times greater than the State Department's highest estimates. Again, the findings were mostly ignored by top U.S. media outlets** -- with one notable exception. The Los Angeles Times amplified the study and its findings that State's analysis didn't account for the pipeline's impact on the global oil market, which would lead to far greater greenhouse gas emissions. The study authors projected that the pipeline will increase carbon emissions by up to 110 million metric tons due to increased global consumption, far overshooting State's projection of 1.3 to 27.4 million metric tons. The oil industry has dismissed this study based on the faulty argument that the oil will be shipped by rail anyways, which Associated Press reported -- without mentioning Reuters' contradictory findings.

The authors previously concluded in a similar study that approving the Keystone XL could “potentially counteract some of the flagship emission reduction policies of the U.S. government.” How many more studies and reports need to be issued before the mainstream media corrects themselves on the climate impact of approving the Keystone XL pipeline?

*According to a LexisNexis search for “keystone” from March 5 to March 8 for The New York Times, The Washington Post, Los Angeles Times, USA TODAY, ABC, CBS, NBC, CNN, MSNBC and Fox News, and a Factiva search with the same parameters for The Wall Street Journal.

**According to a search of LexisNexis and internal video archives for “keystone” from August 8 to August 11 for The New York Times, The Washington Post, Los Angeles Times, USA TODAY, ABC, CBS, NBC, CNN, MSNBC and Fox News, and a Factiva search with the same parameters for The Wall Street Journal.

Image at the top of an oil sands site from Flickr user Pembina Institute with a Creative Commons license.