Emissions from Ships

Air emissions from ships have not been adequately evaluated for their scientific or policy importance. Current international policy initiatives by the International Maritime Organization (IMO) to reduce emissions from ship propulsion systems (NOand SO, primarily) mark the first efforts to define a framework to address this issue. Corbett and Fischbeck estimate ship emissions on a global scale, updating current emission inventories. Global annual nitrogen and sulfur emissions from ships are estimated to be 10.12 Tg (1012 grams) and 8.48 Tg, respectively, showing that ship emissions represent more than 14 percent of nitrogen emissions from global fuel combustion sources and more than 16 percent of sulfur emissions from world petroleum use. The policy implications of ship emissions are discussed.