WOW!  What unbelievably faulty logic and lack of knowledge from these  "professors".
Pray tell, what are the upstream GHG emissions from crude imported into Canada from from the Middle East, North Africa, East Africa, etc.?  These "professors" totally ignore comparing upstream GHG emissions of Canadian crude vs imported crude, or Canadin crude exported to compete in foreign markets against foreign crude.
In fact, GHG emissions from the average barrel of crude produced in Canada compares very well with, or is lower than, any of those sources, while GHG emssions intensity, CO2 per bbl, in the oil sands is trending down year after year.
If you want to reduce global GHG emissions, produce oil in Canada - don't import oil from abroad!
It's not rocket science - and those professors should be disciplined by their faculties for incompetence.