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Heading: Environment Topic: Ocean
About 70.8 percent of the surface of the Earth is covered by salt water. This single ocean system united by currents and shared marine life is generally subdivided geographically into the Pacific, Atlantic, Indian, Southern and Arctic Oceans. The ocean plays an important role in regulating weather and climate, absorbing carbon dioxide and heat, hosting a major part of the planet's biodiversity, and providing resources for hundreds of millions of people. Climate change threatens the deep ocean currents that determine weather patterns, carbon storage and polar ice formation, one of the potentially irreversible tipping points. The thermal expansion of water and melting ice on land are raising the sea level, which will drown some small island countries, submerge coastal cities<, and displace at least 900 million people.
Coastal countries claim sovereignty over near-shore territorial waters, and a 200 mile Exclusive Economic Zone, beyond which the ocean is part of the global commons. The Law of the Sea provides a global legal framework for human activities, including an International Seabed Authority to regulate ocean mining, a variety of regional fisheries regimes, and a new convention on high seas biodiversity that has not yet entered into force.
Today there are many threats to the ocean from human activities. Global warming has raised the ocean temperature, threatening many species and the whole coral reef ecosystem. The water has become more acidic as carbon dioxide dissolves in it forming carbonic acid, which harms the calcification through which many marine animals including corals and shellfish make their skeletons. Most marine fisheries are overexploited. Whales have been hunted to near extinction. Many long-lived wastes and pollutants end up in the ocean, with plastics now an enormous threat. A plastics convention is under negotiation.
REFERENCES AND SOURCES
- UNEP. 1995. Global Programme of Action for the Protection of the Marine Environment from Land-based Activities. UNEP(OCA)/LBA/IG.2/7.
NEWS AND POSTS
Ocean agreements in force, September 2025
Southern Ocean circulation reversed, 1 July 2025
3rd UN Ocean Conference, Nice, France, 9-13 June 2025
UNOC3 Multi-faith Declaration, UN Ocean Conference (UNOC3), Nice, France, June 2025
Binding Global Climate Legislation, International Maritime Organization, 11 April 2025
Protecting the oceans from greenhouse gases, International Tribunal for the Law of the Sea, 21 May 2024
United Nations Ocean Conference 2022, Lisbon, Portugal, 27 June-1 July 2022
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Last updated 27 November 2025