Workers leave the Suncor oil sands extra

Workers leave the Suncor oil sands extraction facility near the town of Fort McMurray in Alberta Province, Canada on October 25, 2009. Greenpeace is calling for an end to oil sands mining in the region due to their greenhouse gas emissions and have recently staged sit-ins which briefly halted production at several mines. At an estimated 175 billion barrels, Alberta's oil sands are the second largest oil reserve in the world behind Saudi Arabia, but they were neglected for years, except by local companies, because of high extraction costs. Since 2000, skyrocketing crude oil prices and improved extraction methods have made exploitation more economical, and have lured several multinational oil companies to mine the sands. AFP PHOTO/Mark RALSTON (Photo credit should read MARK RALSTON/AFP via Getty Images)