Sources and impacts of ocean pollution

Ocean pollution is a significant environmental challenge, arising from both marine and land-based activities.

Major sources of ocean pollution

• Marine-based activities - These include operations from the fishing industry, shipping for transport, tourism, and recreational purposes, offshore mining and extraction, illegal dumping at sea, and discarded fishing gear.
• Land-based activities - Key contributors are discharges from stormwater drains, industrial outfalls, untreated municipal sewerage, littering on beaches and rivers, and waste from landfills.

Case studies on major pollution incidents

Several high-profile incidents highlight the devastating effects of ocean pollution.

Deepwater Horizon oil spill (2010)

• Method - In April 2010, an explosion on the Deepwater Horizon oil rig in the Gulf of Mexico led to a catastrophic collapse.
• Results - Approximately 4.2 million barrels of oil were released, impacting over 160 km of coastline, damaging marine habitats like oyster beds and shrimp farms, and affecting land-based ecosystems.

Fukushima Daiichi radioactive waste (2011)

• Method - Following a nuclear power station explosion in Japan in 2011, radioactive waste was released into the Pacific Ocean.
• Results - The waste spread across the northern Pacific towards North America, with radiation levels tracked over 24 to 48 hours.
• Evaluation - Radioactive materials can remain hazardous for decades.

The issue of plastic and oil pollution in oceans

Plastic and oil are two of the most pervasive pollutants in the oceans.

Plastic pollution in marine environments

• Scale of the problem - Estimates suggest that in 2006, each square kilometre of ocean contained around 18,000 pieces of floating plastic, with massive accumulations like the Great Pacific Garbage Patch.
• Impact on wildlife - Marine animals such as turtles, seals, and birds often ingest plastic, mistaking it for food. A study in the North Sea found that 95% of 560 sampled fulmars had plastic in their stomachs.
• Decomposition challenges - Plastic can take hundreds of years to break down.

Oil pollution from shipping

• Primary source - Shipping activities contribute significantly through the use of bunker oil, a heavy fuel linked to approximately 60,000 annual deaths from respiratory and lung diseases, particularly near coastal areas in Europe and Asia.
• Reduction in spills - Since the global ban on single-hulled ships in 2010, major oil spills have become less frequent.

International actions to manage ocean pollution

Efforts to combat ocean pollution have seen some success through global agreements and public advocacy.

Key international frameworks and successes

• United Nations Convention on the Law of the Sea (UNCLOS) - Established in 1982 and effective from 1994, this treaty provides a legal framework for ocean governance, including rules for deep-sea mining and economic exclusion zones extending 200 nautical miles around coastal nations.
• European regulations - A series of laws have eliminated the discharge of toxic materials, such as radioactive waste and sewage sludge, into European waters, alongside reducing air pollution from incinerator ships.
• Public pressure and policy change - In the mid-1990s, international outcry prevented a major oil company from sinking the Brent Spar oil structure in deep waters off Scotland. Subsequent European agreements mandate the removal of oil platforms and structures at the end of their operational life where feasible.

Geopolitical conflicts over ocean resources in the South China Sea

Oceans are not only environmental resources but also arenas for geopolitical tension, particularly in areas rich in economic and strategic value like the South China Sea.

Overview of the South China Sea conflict

• Economic importance - This region handles around 30% of global trade, valued at over £3 trillion annually, and is rich in oil and gas.
• Territorial disputes - China claims nearly the entire South China Sea, overlapping with claims by Vietnam, Taiwan, the Philippines, Brunei, and Malaysia. Key areas of contention include the Paracel and Spratly Islands.
• Military developments - China has reportedly placed surface-to-air missile batteries on Woody Island in the Paracels and constructed over 4 km² of artificial land in the Spratlys, including a 3000 m runway for potential military use.
• Legal status of islands - Under UNCLOS, features like Itu Aba in the Spratlys are classified as rocks unable to sustain human life, entitled to only 12 nautical miles of territorial waters rather than a 200-mile exclusive economic zone.

Approaches to managing the conflict

• Legal measures - The Philippines has challenged China's historical claims through UNCLOS, arguing they lack legal basis.
• Military deterrence - Despite increased defence spending in the region, the United States remains the primary power capable of countering China's actions.