"Environmental groups are pushing Obama to seek restrictions on tar sands oil, a dirtier form of oil that contributes about half of the oil imported into the United States from Canada.
Canadians point out that processing the tar sands oil produces half as much carbon emissions as does the coal-fired plants that are common across the United States.
In an interview with the Canadian Broadcasting Corp., Obama said he thinks the oil sands create "a big carbon footprint" and said that is part of a broader dilemma facing the United States about how to get the energy it needs without contributing to climate change.
But he expressed optimism that the two countries can find ways to use technology to lessen the environmental impact from the sand oil. Canada is the leading provider of U.S. imported oil, accounting for about 20 percent, slightly more than Saudi Arabia."