It's silly to include climate change related impacts on a pipeline project.  The pipeline is merely a vehicle for transporting the crude.  Climate change related impacts come into play when the crude is processed at the refineries.  And we're  dealing with refineries which are already processing oil from other sources.

Whether the crude is going to Canadian refineries or US refineries, it will get processed at its final destination.  Why aren't we supporting our own markets with domestic supplies first??  If oil prices are all based on global pricing and we have a surplus of oil, it makes no sense to import oil from countries on another continent.  Where are all the climate change related impacts from the pollution generated by those oil tankers?

Let's not hamstring one of our economic drivers while other countries aren't playing by the same rules.