10 - managing ocean pollution ✅ Flashcards
what are sources of ocean pollution
- Surface runoff (waste from urban streets + landfill sites)
- Waste disposal (directly or indirectly into oceans)
- Oil spills (washing out of ship’s tanks and tanker crashes)
- Chemical runoff (agricultural fertilisers can runoff and cause eutrophication in oceanic areas)
- Plastic (bags, bottles, packaging, waste)
- Ocean currents (transfers pollution to areas of oceanic circulation, where accumulation may occur, such as the Great Pacific Garbage Patch)
how much plastic is produced
- In 2014, 311 million tonnes of plastics were produced worldwide and more plastic was produced between 2000-2010 than the entire C20th.
- The production is set to rise to 1100 million tonnes by 2050.
reasons for growth in plastics
- Use of plastics in everyday life, toothbrushes, credit cards, mobile phones, Lego bricks, biros etc
- Cheap consumer products, ‘make do and mend’ no longer applies to the consumer middle classes in HICs or NEE.
- A boom in bottled water and other drinks. 2 million plastic bottles are thrown away every 5 minutes in the USA. This use is often driven by ‘lifestyle’ advertising.
how much plastic is in the ocean
- Plastic accounts for 90% of all rubbish floating in the oceans.
- The UN estimates that every 1 mile2 contains 46000 pieces of plastic.
- These concentrate in ‘ocean garbage patches’.
where is the great pacific garbage patch
- spans waters from the West Coast of North America to Japan.
- The patch is comprised of the Western Garbage Patch, located near Japan, and the Eastern Garbage Patch, located between the U.S. states of Hawaii and California.
what connects the garbage areas
- These areas of spinning debris are linked together by the North Pacific Subtropical Convergence Zone, located a few hundred kms north of Hawaii.
- This convergence zone is where warm water from the South Pacific meets up with cooler water from the Arctic. The zone acts like a highway that moves debris from one patch to another.
what is the great pacific garbage patch bounded by
bounded by the North Pacific Subtropical Gyre.
The North Pacific Subtropical Gyre is created by the interaction of the California, North Equatorial, The Great Pacific Garbage Patch and North Pacific currents.
These four currents move in a clockwise direction around an area of 20 million2 kms.
what is an ocean gyre
An ocean gyre is a system of circular ocean currents formed by the Earth’s wind patterns and the forces created by the rotation of the planet.
The area in the centre of a gyre tends to be very calm and stable. The circular motion of the gyre draws debris into this stable centre, where it becomes trapped.
what is the impact of the garbage patch
- 95% of fulmars washed up on Scottish beaches have plastic debris in their gut.
- 260 species of marine birds and mammals are known to ingest or become tangled in plastic waste.
what is eutrophication
Eutrophication is the process where excessive nutrients are added to a body of water. Nitrate fertilisers often get carried by surface runoff from farmland.
what are marine dead zones
An explosion of algae uses up oxygen and species of fish and crustaceans suffocate.
20 major marine dead zones have been identified.
These include the North Sea, where lobster populations have plummeted. The Gulf of Mexico is another example where large amounts of nitrates are added to the ocean from agribusiness in the Southern States of the US.
what is a wicked problem
A ‘wicked problem’ is a term used to describe an issue that is too big to be tackled by a single action or organisation.
Other examples include; climate change, the refugee crisis and the illegal drug trade.
what is the effect of UNCLOS
States bound by UNCLOS rules are prohibited from dumping waste deliberately at sea.
Landfill sites have to be used, but much plastic still enters the oceans via heavy rainfall that washes plastics into rivers and estuaries that then makes its way to the oceans.
what is another example of global governance of the oceans
The EU Marine Directive is another example of how global governance is being used to reduce pollution.
Its aim is to ensure a ‘good environmental status’ of EU marine waters that maximises biodiversity.
what is the effect of plastic bags
In 2014 over 7.6 billion single-use plastic bags were given to customers by major supermarkets in England.
They take longer than other bags to degrade in the environment, can damage wildlife, and are extremely visible when littered in our towns, parks and the countryside.
