Developing the Alberta oil-sands will lead to carbon emissions that in turn result in global warming. Our paper calculates the amount of warming the oil-sands could potentially cause. We also consider how oil-sands carbon emissions relate to the effort to keep global mean temperatures from exceeding 2°C above pre-industrial levels, as agreed to in the Copenhagen Accord. Finally, we compare the potential for warming of the Alberta oil-sands with the potential for warming of other global fossil-fuel resources.