Maritime transport is essential to the global economy, providing the most cost-effective means of transporting bulk goods over great distances compared to road or rail. Over 80% of the volume of international trade in goods – including everything from food and fuel to construction materials, chemicals and household items – is carried by sea, with more than 90,000 commercial ships sailing the world’s oceans, with a combined tonnage of 1.86 billion dead weight tonnes (UNCTAD, 2017). World trade and maritime transport are fundamental to sustaining economic growth and spreading prosperity throughout the world, thereby fulfilling a critical social as well as an economic function. However, the sheer scale of the international shipping industry in comparison to other modes of transport means that overall emissions from ships remain a concern, having negative impacts on local port and coastal air quality and hence on human health, and contributing to regional acidification and global climate change. According to the Third IMO GHG Study 2014, maritime transport emits around 1 billion tonnes of carbon dioxide annually and is responsible for approximately 3% of global greenhouse gas emissions from fuel combustion. Shipping is forecast to grow as international trade grows. According to projections, by 2050, depending on future economic growth and energy developments, greenhouse gas emissions from shipping may increase by between 50% and 250%. Annually, international shipping is also responsible for approximately 13% and 12% of global nitrogen oxides (NOx) and sulphur oxides (SOx) emissions respectively.