The bosses of four of Canada's biggest oilsands producers shared the stage with Alberta Premier Rachel Notley as she unveiled the province's sweeping new climate policy, but a fifth big player is still mulling over the details. Canadian Natural Resources , Suncor Energy , Cenovus Energy and Shell Canada all sang the praises of a plan that aims to cap oilsands emissions at 100 megatonnes annually - about 30 megatonnes more than the industry now emits.