Oil storage tanks at the Chevron Burnaby Oil Refinery on the shores of Burrard Inlet, east of Vancouver, B.C.
Credit Andy Clark / Reuters/Landov
President Obama is feeling election-year pressure on the pending decision over the Keystone XL pipeline. Republicans say the Canadian project would provide the U.S. with oil and new jobs, but environmentalists want him to block it. They say Alberta's oil sands generate more greenhouse gases than other kinds of oil, and Americans must not become dependent on such a dirty source of energy. But it may already be too late to change that.