President Obama's decision to reject the Keystone XL pipeline won big cheers from environmental advocates, as well as some international green cred for his upcoming visit to the Paris climate talks in December. But will the decision have much of an impact on actual climate emissions?
Experts point out that the even though the source of the Canadian crude oil was from a "dirty" source, the tar sands of Alberta, the amount of carbon emissions would have been less than 1 percent of U.S. greenhouse gas emissions.
"It's a symbolic gesture and a symbolic victory," said Steve Cohen, director of Columbia University's Earth Institute. "But the reality is that the American and world economy is addicted to fossil fuels and we need to get on with the business of development of alternatives."
In 2011, according to EPA figures, the global economy spewed out 32.6 billion metric tons of carbon pollution. The United States put out 5.5 billion, second behind China. U.S. power plants produced 2.8 billion tons, while cars, trucks and other vehicles produced 1.9 billion tons.
In comparison, the additional carbon produced by shipping oil from Canada through the United States via the Keystone pipeline was only 18.7 million metric tons. While it seems like a lot, it's less than 1 percent of the U.S. total, according to an analysis by the New York Times.
President Obama himself noted the diminishing impact of the Keystone pipeline for both pro-jobs and pro-environment advocates.
"This pipeline would neither be a silver bullet for the economy, nor the express lane to climate disaster," Obama said during his Friday announcement at the White House.
The president noted that gas prices are currently low, and that the United States has also continued to reduce carbon emissions, mainly by switching to burning more natural gas. The administration is also proposing to further stiffen emissions from existing coal-burning utilities.
"America is leading on climate change with new rules on power plants," Obama said. "Approving this project would undercut this global leadership. If we are going to prevent large parts of the earth from becoming uninhabitable, we are going to have to keep some fossil fuels in the ground rather than burn them."
Doug Vine, senior energy fellow C2ES (formerly the Pew Center on Climate Change), said that the State Department found that, well to wheels, oil from the Canadian oil sands is 17 percent more carbon-intensive than the average oil consumed in the United States. Vine said a better idea is to use a carbon tax to reduce the use of fossil fuels.
"For long-term reductions of greenhouse gases, we need to focus on strategies, including carbon pricing, to reduce the global demand for oil," Vine said.
Still, the president's decision on Keystone may not be final. The project took seven years of review by agencies of the U.S. government, but all GOP presidential candidates say they support construction of the pipeline.
Pipeline operator TransCanada said in a statement that it "would review all of its options in light of a permit denial for Keystone XL," including the possibility of filing a new permit application.
"TransCanada and its shippers remain absolutely committed to building this important energy infrastructure project," TransCanada CEO Russ Girling said in a statement.