Caution in the case of Keystone XL is about potential spills, not the actual pumping of the oil. It's okay that oil is being pumped there, if the economic engine so demands. It's good that it's being transported by rail, because it's less likely to create an (additional) environmental catastrophe.
You might say it's dirtier to move the oil by train, I'd say it's responsible and a price worth paying to protect sensitive ecologies from inevitable pipeline leaks. You say externalities are higher, I say your worst case summed externalities are lower.
You might say it's dirtier to move the oil by train, I'd say it's responsible and a price worth paying to protect sensitive ecologies from inevitable pipeline leaks. You say externalities are higher, I say your worst case summed externalities are lower.