The oil sands industry is in the throes of a major expansion, powered by C$20 billion ($19 billion) a year in investments. Companies including Syncrude Canada Ltd., Royal Dutch Shell Plc and Exxon Mobil Corp. affiliate Imperial Oil Ltd. are running out of room to store the contaminated water that is a byproduct of the process used to turn bitumen — a highly viscous form of petroleum — into diesel and other fuels.
By 2022 they will be producing so much of the stuff that a month’s output of wastewater could turn an area the size of New York’s Central Park into a toxic reservoir 11 feet (3.4 meters) deep, according to the Pembina Institute, a nonprofit in Calgary that promotes sustainable energy.
To tackle the problem, energy companies have drawn up plans that would transform northern Alberta into the largest man-made lake district on Earth. Several firms have obtained permission from provincial authorities to flood abandoned tar sand mines with a mix of tailings and fresh water.
One big concern surrounding end-pit lakes is that the contaminated water will spread through the boreal ecosystem, the tract of trees and marshland that stretches around the top of the world from Canada to Russia and Scandinavia. Boreal forests store almost twice as much carbon as tropical forests.