Oiling the oceans
The Torrey Canyon disaster – a wake-up callThe global oil industry often exacts a heavy toll from the environment. Onshore, there is the problem of soil contamination by oil from leaking pipelines. Offshore, oil spilled from damaged tankers poisons marine life, coats and clings to the feathers of seabirds, and pollutes coastlines. The problems associated with the production and transportation of crude oil became all too apparent in the 1960s and 1970s, when the first supertankers came into service, increasing the potential threat to the environment. It was then that the world witnessed its first major oil spills, often affecting many thousands of people. The first of these disasters occurred in 1967, when the tanker Torrey Canyon, which was carrying 119,000 tonnes of crude oil, hit rocks and was wrecked near the Isles of Scilly off southwest England. The oil formed a slick measuring some 1000 square kilometres and caused massive pollution of coastlines around Cornwall, Guernsey in the Channel Islands, and France.
- 1.30 > In March 1967, the Torrey Canyon hit rocks off the south coast of England. The oil from the stricken tanker caused massive pollution along the coast of southern England, and within three weeks had drifted as far as Brittany and Normandy in France. 1.31 > The Royal Air Force dropped bombs in an attempt to sink the vessel and its remaining cargo, igniting the oil slick. The pall of smoke from the burning oil was visible more than 60 miles away.
Oil pollution – an insidious threatTanker disasters and oil rig explosions still occur from time to time; one example was the Deepwater Horizon incident in spring 2010, in which a vast quantity of oil was released into the environment in a very short period of time. Yet in reality, this kind of spectacular disaster accounts for only a small percentage of global marine oil pollution. Most of the oil travels along less obvious pathways. Of the estimated one million tonnes of oil entering the marine environment annually, around 5 per cent comes from natural sources. In the Gulf of Mexico, for example, crude oil seeps naturally out of underground fissures and cracks and rises from the reservoirs to the ocean floor. Elsewhere, as in the Caspian region, large amounts of crude oil erupt from underground reservoirs into the water via mud volcanoes. These are not true volcanoes but mounds on the seabed. They contain watery sediment which heats up deep underground, causing it to rise. In some cases, it transports oil from nearby reservoirs upwards as well. Oil tanker disasters account for around 10 per cent of global marine oil pollution. Around 35 per cent comes from regular shipping operations; this includes oil released during incidents involving all other types of vessel, as well as oil from illegal tank cleaning. The largest share, amounting to 45 per cent, comes from inputs from municipal and industrial effluents and from routine oil rig operations, together with a small amount from volatile oil constituents which are emitted into the atmosphere during various types of onshore burning processes and then enter the water. A further 5 per cent comes from undefined sources. This includes smaller inputs into the sea by polluters who go undetected. These percentages naturally do not apply to 2010 and other years in which major oil spills have occurred. The Deepwater Horizon disaster alone released around 700,000 tonnes of oil into the sea – more than two-thirds the amount that would normally enter the marine environment over the course of an entire year.
Progress on combating pollutionThe good news is that the number of oil spills from tanker incidents or caused by technical failures or explosions on tankers has fallen dramatically in recent decades, despite steady growth in the seaborne oil trade. In the 1970s, there were between 50 and 100 large oil spills a year, compared with fewer than 20 a year since the start of the millennium. The statistics cover oil spills above seven tonnes; there is no systematic collection of data on smaller incidents. Consistent with the reduction in the number of oil spills from tankers, the volume of oil spilled has also gradually decreased. Of the total volume of oil spilled from tankers between 1970 and 2009, only around 3.7 per cent was spilled after 2000. The largest amount of oil entered the marine environment in the 1970s – around 15 times more than in 2000 to 2009. According to experts, this decrease is primarily due to the international conventions and regulations to protect the marine environment, which were progressively introduced after the various oil disasters. One of the most important is the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78), which since 1983 has formed the basis for the designation of marine protected areas where tanker traffic is wholly or partly restricted. The Convention brought the number of oil tanker disasters down during the 1980s. MARPOL 73/78 also paved the way for the introduction of double hull tankers. It is now mandatory for all new tankers to be fitted with a double hull, so that if a vessel is involved in a collision which penetrates the outer hull, the tanks inside generally remain intact.
- 1.33 > Although seaborne oil trade has increased since the 1970s, the number of tanker spills has decreased. The statistics cover oil spills above seven tonnes.
- 1.40 > The Deepwater Horizon explosion is the largest oil spill in the oil industry’s history. The map shows the location of the world’s 10 largest oil spills and other incidents.
- 1.41 > Of the total volume of oil lost as a result of tanker incidents around the world from 1970 to 2009, the largest amount was spilled in the 1970s and the smallest during the period 2000 to 2009.
- Another milestone was the adoption of the Oil Pollution Act (OPA) in the United States, which was signed into law in 1990 – one year after the Exxon Valdez ran aground in Prince William Sound in the Gulf of Alaska in March 1989, spilling crude oil along a 2000 kilometres stretch of coastline which included several bird sanctuaries and nature reserves. Even today, some areas are still contaminated with oil residues, which have biodegraded very slowly in Alaska’s cold temperatures. As a result of this disaster, the US took the initiative on the protection of the marine environment and adopted legislation – the OPA – to protect its territorial waters, ahead of other countries. Under the legislation, ships entering US waters are regularly inspected, primarily to ensure that they comply with safety standards and regulations pertaining to the adequacy of qualifications and training of crew members. The OPA also established a double hull requirement for tanker vessels operating in US waters. Much of the OPA’s content has been incorporated into international regulations as well, including provisions on reliable radio technology for onboard communication and a vessel identification system to enable shipping control authorities to check a ship’s course and position at any time. Following a comprehensive analysis of the tanker incidents that occurred in the 1980s, the International Maritime Organization (IMO) in London adopted the International Management Code for the Safe Operation of Ships and for Pollution Prevention (International Safety Management Code, or ISM Code) in 1994. The development of the ISM Code was based on the recognition that a number of serious incidents had manifestly been caused by human errors by crew members. The primary objective of the ISM Code is therefore to ensure the safe operation of vessels and thus protect persons on board ships and avoid damage to the environment. According to the ISM Code, entities responsible for the operation of ships must ensure, among other things, that each ship is manned with qualified, certified and medically fit seafarers, who must undergo regular training to prepare them for emergencies, the aim being to prevent incidents in future. >