Bill... please stop posting on this board because you are using your computer or phone to consume electricity that is generated by burning coal (and don't tell me you live in a tepee with a windmill that is generating your electricity). Stop ruining the world for others.
Let's compare the harm caused by mining Canadian tar sands to that caused by importing oil from regions of the world in which the proceeds have found their way into the hands of corrupt dictators and genocidal terrorists.
Bill, The total canadian tar sands operation emits less polution than just the coal fired plants in wyoming. The pipeline will be run. Not because it will create any jobs (because it's a long term job killer eliminating railway and trucking jobs) but because it is cleaner ( because of the pollution from railways and trucks) in the long run.