Contrary to what one might think, maritime transport has never been overtaken by the faster and more “modern” air transport.
Maritime traffic still accounts for almost 90% of all international trade. It has even increased substantially, in line with the increase in international trade and globalisation. This is reflected in the fact that, while 500 million tons of goods were traded by sea in 1950, a total of 8 billion tons are currently transported across the oceans every year. Every day, almost 50,000 ships travel along international shipping routes, maritime motorways consisting of straits, ports and canals.
It is, in fact, only the maritime transportation of people that has declined. For centuries, boats were the only means of crossing the oceans, carrying settlers, migrants, slaves, etc. Today, they are only used for short distances – small stretches of water, islands near the mainland and archipelagos – or by the poorest refugees and clandestine migrants. Leisure cruises have to be added to the list, a significant and booming activity, with several million people embarking every year on the 500 cruise ships operating worldwide.
THE CONTAINER REVOLUTION
In the 1960s, the maritime transportation of goods underwent a revolution with the invention of container transport, which substantially simplified the handling of goods and their storage on board ships, while at the same time protecting them. In 2010, 12 million containers navigated the world’s seas. A new class of ship, the container ship, had made its appearance. One of the largest of them, the Emma Mærsk, launched in 2006 and, 369 metres long, sails between Asia and Europe, loaded with more than 11,000 of these large crates on every voyage.
Ocean freight enables goods to be transported across the world at low cost, making it cheaper to import products than to manufacture them. One of the significant consequences of this form of globalisation is the deindustrialisation of the West: the asymmetry of the trade flow means that nearly 50% of containers from Asia are empty on their return journey from Europe and the USA.
However, not all goods are transported in containers. Some are placed directly into the holds of specialist ships: minerals, grain, liquids, gas, etc. Tankers (designed to transport liquid fuels) now account for 35% of global maritime transport.
WHAT IS THE ENVIRONMENTAL IMPACT OF MARITIME TRANSPORT?
Whether they run aground or sink, tankers are responsible for oil slicks, which are among the most tragic and highly publicised marine pollution factors. However, such shipwrecks have decreased due to the advances made in the safety of ships (such as the progressive use of double hulls), the introduction of inspections and procedures established by the International Marpol Convention and, finally, national regulatory systems such as those implemented in the USA after the Exxon Valdez disaster (40,000 tonnes of oil in Alaska in 1989) and in Europe after the Erika disaster (30,000 tonnes of oil off the coast of Brittany in 1999). Nowadays, major disasters account for only a small share of the oil discharged into the ocean, a long way behind the illegal degassing of storage tanks.
These discharges aside, maritime transport is often presented as a low-risk pollution activity. Indeed, ships have the advantage of transporting large quantities of freight, which enables them to be less polluting, ton for ton, than road or air transport. Maritime transport now accounts for only 3% of CO2 emissions of human origin. However, the fuel used at sea has a very high sulphur level, around 27,000 parts per million, and the engines consequently emit sulphur dioxide, a greenhouse gas and a harmful pollutant.