On March 24, 1989, an oil tanker called Exxon Valdez struck a reef shortly past midnight at William Sound, Alaska, and spilled about 42 million litres of crude oil. The spill, then considered the largest in the history of the United States, threatened more than a million migratory shore birds and waterfowl, hundreds of sea otters, harbor porpoises, sea lions, several varieties of whales and other species.
And even though the cleanup began swiftly, the environmental protection agency notes that “wildlife rescue was slow,” and “through direct contact with oil or because of a loss of food resources, many birds and mammals died.”
On April 20, 2010, a mobile offshore drilling unit Deepwater Horizon in Mexico exploded, burned, sank and killed 11 workers, and spilled about 508 million litres of oil. The spill took over as the largest in US history, and impacted bottlenose dolphins in Mississippi and Northern Gulf. The welfare of the dolphins, says EPA, “will require long-term monitoring.”
Now, 13 years later, marine animals, which have also been under constant threat from plastic pollution, climate change, overfishing and illegal fishing methods risk severe health challenges from about 23 billion litres of oil should abandoned sunken ships break apart. This is according to the International Union for Conservation of Nature.
The report shows that the leaks are likely to originate from over 8,500 ship wrecks, classified as “potentially polluting wrecks.”
“There are an estimated 3 million sunken and abandoned vessels in the ocean, over 8,500 of which are classified as ‘potentially polluting wrecks."
The majority of these wrecks date back to World War I and II and contain harmful chemical pollutants, unexploded munitions and an estimated 23 billion litres (6 billion gallons” of heavy fuel oil. This is 545 times more oil than the Exxon Valdez leak in 1989 and 30 times that of the Deepwater Horizon spill in 2010, both of which had severe and long-lasting environmental consequences,” says IUCN.
“Severe weather events resulting from climate change are likely to speed up the process of wrecks breaking apart. After more than 75 years of corrosion, leaks from sunken vessels are expected to reach their highest levels within ten years but scientists do not yet have enough data to forecast when or where individual leaks will occur,” adds IUCN.
IUCN also notes that pollution from wrecks can lead to death of marine animals, damage to mangroves and coral reefs which act as habitats for fish. This, by extension, threatens the food security of communities that depend on them to earn livelihoods. The communities also risk their health from possible explosions of munitions and eating fish exposed to chemicals that may be toxic and carcinogenic.
The task of cleaning up the ocean is however hinder by the expensive cost, especially for developing nations, and the fact that the country’s responsible for the cost remain unclear. This is because most countries “most affected were not participants in WWI and WWII, and ships sunk in war remain owned by the country they sailed for under the principle of sovereign immunity.”
Lack of sufficient data and international cooperation on how to manage pollution from wrecks also hinders governments from actively ensuring that leaks are prevented.
The report recommends development of a new International Standard that will classify sunken vessels according to the danger they pose to the environment, social life and economy. Countries also need to conduct more research to address individual wrecks, impacts on the local area affected and factors that contribute to wreckages breaking apart.
“Existing research programmes should be extended to combine historical data, local biodiversity and economic assessments, and analysis of weather patterns, currents, water salinity and temperature, seismic activity and detailed mapping of the seafloor,” says the report.
“Collaboration is particularly important between neighboring governments to manage cross-border impacts, and between ‘flag states’ (which maintain sovereignty over sunken vessels) and coastal states in whose territorial waters wrecks lie,” it adds.
Governments are advised to include wrecks into their marine contingency plans, ensure that they safely retrieve oil from wreckages to prevent leaks, financially support affected communities affected by pollution, and restore ecosystems damaged by pollutions.
