On heavy oil from other article of that blog: Cargo ships are significant sources of air pollution globally, and their fuel oil is largely responsible. Pitch black and thick as molasses, “bunker” fuel is made from the dregs of the refining process. It’s also loaded with sulfur — the chemical that, when burned, produces noxious gases and fine particles that can harm human health and the environment, especially along highly trafficked areas. wasn't there an effort to release sulfur burning products to reduce global temperature?