Specifically, that the tar sands projects around Fort MacMurray are stressing the Athabasca River. From now on:
All oil sands operators - whether new or existing - will have to work together to share water within prescribed limits. Companies are working closely with Alberta Environment and the Department of Fisheries and Oceans to ensure they meet these new limits to water withdrawals.
Sucking up twice the water required to feed Calgary so you can run your oil extraction machinery is pretty obviously an unsustainable energy/environmental policy. Of course, if someone like Dion or Suzuki had suggested restrictions like those noted above, they would have been run out of the province.
h/t to Civitatensis.