The environmental impact of shipping includes air pollution, water pollution, acoustic, and oil pollution. Ships are responsible for a significant amount of air pollutants, including greenhouse gas emissions.
Although ships release the majority of their pollution far from land, they are thought to be responsible for over 60,000 deaths every year. With the recent focus on diesel car pollution, very little is heard of a worse source of diesel particulate pollution, the shipping industry. A large contributor to their high ranking as top polluter is the use of the world’s dirtiest diesel fuel, bunker fuel. Bunker fuel is a cheap alternative, tar-like sludge that contains almost 4,000 times more sulphur than the diesel used for cars.
By recent estimates, trans-ocean shipping is responsible for almost 15% of the annual sulphur oxide emissions worldwide. Although upcoming global shipping rules are expected to call for shipping to cut sulphur pollution, the sulphur content of shipping diesel fuel could still be over 500 times higher than auto diesel. Regardless, some global leaders, including the United Kingdom, require that ships in their national waters use the more costly low-sulphur fuel.
Shipping also contributes over 15% of the global NOx emissions, and 3% of CO2 emissions. This pollution goes mostly unnoticed as it happens at sea far from land. Regardless, ships in seaports, generally closer to populated areas, have become major pollution hazards. According to a study in 2007, diesel particulates emitted from ships were estimated to cause 60,000 deaths each year worldwide.
Shipping is the only sector not subject to cutting greenhouse gas emissions in the UN’s recent Paris accord and the industry says no worldwide targets should be set until they have done more monitoring of emissions - this will not last long with increased awareness of the impact of the contribution to global pollution.