Shipping regulators plan to cut greenhouse-gas emissions

SHIPPING IS AIMOIMO dirty business. Since the late 19th century, when steam replaced wind as the main means of propulsion, ships have relied on filthy fossil fuels. Coal-fired steam has given way to internal-combustion engines. But these still burn stuff that is so gunky as to be almost solid unless heated. Like coal, these refinery dregs, known as bunker fuel, release a lot of carbon dioxide—perhaps 3% of global emissions of this greenhouse gas. Cleaning up ship exhausts is therefore a good idea if the world is to get anywhere near the goal, enshrined in the Paris climate agreement, of keeping global warming “well below” 2°C relative to pre-industrial times. Ironically, the matter is made more urgent by the decision of the International Maritime Organisation (), the United Nations body responsible for the world’s shipping, to reduce the amount of sulphur allowed in bunker fuel from 3.5% to 0.5% by 2020. Sulphur is nasty stuff. When burned, it forms sulphates, which cause acid rain and pollute the air. A paper published last February in , by Mikhail Sofiev of the Finnish Meteorological Institute, found that the ’s new rule could stop between 139,000 and 396,000 premature deaths a year.