Seaborne transportation is considered one of the most environmentally sound ways for transporting goods and people. For many years, shipping has steadily been increasing and the Baltic Sea has some of the busiest shipping routes in the world. According to HELCOM, around 2000 ships are normally at sea at any time on the Baltic Sea. Cargo and container traffic is expected to triple and oil transportation is estimated to increase by 40 percent by 2017. The large number of islands, narrow straits, routes that are difficult to navigate and ice covered in the winter, makes the Baltic Sea a high risk area for accidents.
The Baltic Sea with its unique flora and fauna has a very slow exchange of water which makes the sea sensitive to changes in the environment caused by pollution. An accident in the Baltic Sea could therefore have devastating impacts on the sea environment.
Seaborne transportation contributes to one and a half to three percent of the total emissions of carbon dioxide. Fuel consumption in shipping also contributes considerably to global emissions of nitrogen oxides and sulphur oxides. In 2005 the European Commission reported, that nitrogen and sulphur oxide emissions from international shipping around Europe will by 2020 have surpassed the emissions from all land-based sources in the EU. Nitrogen oxides and sulphur oxides are proven to have an acidifying effect on soil and water. As shipping is one of the main contributors to nitrogen oxide deposition in the Baltic Sea, it is thereby a huge contributor to eutrophication.
Maritime transport uses up to five billion tons of ballast water each year. The ballast water stabilizes and balances the ship. However, the water also contains alien species which are transported from one ecosystem to another. This may have serious consequences as foreign organisms can cause devastating harm to the existing ecosystem. It is estimated that approximately 8000 species are in transit in this manner. Over 120 non-native aquatic species have been recorded in the Baltic Sea to date, and around 80 of these have become established in our sea.
TBT (Tributyltin oxide) or organic tin compounds have long been used as an additive in bottom coating to prevent algae and sea tulips to grow on the hull of boats. The organic tin compounds are among the most toxic substances as they are toxic even in small concentrations. In 1999, a total ban on TBT-based paints was introduced in the EU. Since January 2008 no boat or ship whose hull is painted with TBT-based paints is allowed to dock in European ports, unless the coat is sealed. However, it will take a very long time before the existing levels of organic tin compounds are removed from the sediment of the Baltic Sea.
It has been generally acknowledged that not enough has been done in order to reduce the environmental impacts of shipping. In 2005 the UN International Maritime Organization (IMO) classified the Baltic Sea as a Particularly Sensitive Sea Area (PSSA). A PSSA designation, which requires ships to take special care when navigating, can be used to protect a variety of marine and coastal habitats. Despite conventions and regulations, continuous discharges to sea from ships cleaning their tanks, sludge and oily bilge water, still occur. These discharges have devastating and long lasting effects on the vulnerable Baltic Sea environment and its wildlife.