Tar sands oil is the world's most harmful fossil fuel, emitting 3 to 5 times the greenhouse gas emissions of conventional oil production. Tar sands extraction also requires significant amounts of water and is destroying huge swaths of Canadian Boreal Forest. In 2008, the U.S. imported 780,000 barrels of tar sand oil from Canada every day. USCAN urges the U.S. administration to not exclude tar sand oil production from any potential greenhouse gas reduction agreement with Canada.

USCAN and CAN Canada sent the president a letter on February 18, 2009 just before the president's first international trip to Canada. The letter criticizes the Canadian federal government on emission reduction targets and urges Obama not to accept an agreement that would exclude tar sand oil from any greenhouse gas reduction agreement.