Economist: ONE of the bleakest scenes of man-made destruction is the strip mining of oil sands in the forests of Alberta, Canada. The sand is permeated with natural bitumen, a type of petroleum with the consistency of peanut butter. Once dug from the surface, the sand is hauled to an extraction plant where it is mixed with lots of hot water and chemicals to liberate the oil and make it flow into pipelines or be taken by tankers to refineries. Not all of the water can be recycled and what remains is a goopy...