Over the past decade, major oil companies, under pressure from investors and environmentalists, have been fleeing Canada's oil sands, the fourth-largest oil reserve in the world, while investment in existing projects has stalled. A lack of pipelines and heavy emissions have weighed on the Canadian heavy crude sector for years, with some companies exiting after coming under pressure to invest in projects with lower emissions. According to research firm Rystad Energy, oil sands production in Alberta generates ~160 pounds of carbon per barrel,…