In Canada, activists with the environmental group Greenpeace have shut down production at a large oil sands mine in northern Alberta. On Tuesday, the activists locked themselves to a massive dump truck and mining shovel, forcing owners to suspend operations. The oil giant Royal Dutch Shell has majority ownership in the mine, while Chevron holds a minor stake. Greenpeace says it took action to protest what it calls “the climate crimes of tar sands development — rising energy intensity, greenhouse gas emissions, and boreal forest destruction.” Tar sand oil extraction is said to generate up to five times the greenhouse gas pollution of conventional oil.