South China Sea
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What is the South China Sea?
The South China Sea is an arm of the western Pacific Ocean that borders Southeast Asia. It connects to the East China Sea via the Taiwan Strait and is bounded by Taiwan and the Philippines to the east; Borneo, the Gulf of Thailand's southern limit, and the Malay Peninsula's east coast to the southeast and south; and the Asian mainland to the west and north.
It covers about 1,423,000 square miles (3,685,000 square km), with a mean depth of 3,976 feet (1,212 meters). This sea is a vital shipping route and is rich in marine life, providing a key source of protein for the region's dense population. It also holds large reserves of oil and natural gas under its floor.
Overlapping territorial claims have led to conflicts, particularly involving China, which asserts economic and military rights over much of the sea. These disputes involve Vietnam, the Philippines, Malaysia, and Brunei, and have drawn in external stakeholders like the United States.
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Where is the South China Sea located?
The South China Sea is an arm of the western Pacific Ocean that borders the Southeast Asian mainland. It is bounded by Southeast Asia to the west, China to the north, Taiwan and the Taiwan Strait to the northeast, the Philippines to the east, and the Indonesian archipelago to the south. The South China Sea connects to the East China Sea through the Taiwan Strait. It is the largest marginal sea of the western Pacific.
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Which countries border the South China Sea?
The South China Sea is bordered by several countries. To the West, it is bordered by the Southeast Asian mainland; to the North, by China; to the Northeast, by Taiwan; to the East, by the Philippines; and to the Southeast and South, by Borneo, the southern limit of the Gulf of Thailand, and the east coast of the Malay Peninsula.
Territorial disputes have arisen from overlapping claims in the South China Sea, with primary claimants including China, Taiwan, the Philippines, Vietnam, and Malaysia. While not a claimant, Indonesia has struggled with Chinese incursions into its exclusive economic zone. Brunei also has claims in the region.
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Why is the South China Sea important for shipping and trade?
The South China Sea is vital for shipping and trade due to its strategic location and busy sea lanes. It connects the Pacific and Indian Oceans through the Strait of Malacca, serving as the main route between them. In 2016, approximately $3.4 trillion in trade, about one-fifth of global trade, passed through its waters. Oil and minerals generally move north, while food and manufactured goods move south through the sea.
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What natural resources are found in the South China Sea?
The South China Sea possesses significant natural resources, including an abundance of marine life, such as tuna, mackerel, croaker, anchovy, shrimp, and shellfish, which serve as a primary protein source for the Southeast Asian region. Additionally, large reserves of oil and natural gas have been discovered beneath the sea floor, particularly north of Borneo, east of the Malay Peninsula, and northwest of Palawan. These resources are located in strategically vital shipping lanes that facilitate a significant portion of global trade.
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Why are there disputes between countries over the South China Sea?
The disputes between countries over the South China Sea arise from overlapping territorial claims. China's claim, represented by the "9-dash line," asserts economic and military rights over approximately 90% of the sea, conflicting with the United Nations Convention on the Law of the Sea (UNCLOS).
These claims and actions have led to increased tensions, especially between China and the Philippines, with maritime confrontations on the rise. China has also engaged in land reclamation, constructing military infrastructure on reclaimed land, and employing tactics such as sending fishing fleets into other countries' Exclusive Economic Zones (EEZ).
Other claimants like Vietnam, the Philippines, Malaysia, and Brunei have asserted their rights through various means, including military build-ups and international legal challenges. The United States, despite officially remaining neutral, has increased its involvement to check Chinese ambitions, supporting allies and regional security mechanisms.
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News •
South China Sea, arm of the western Pacific Ocean that borders the Southeast Asian mainland. It is bounded on the northeast by the Taiwan Strait (by which it is connected to the East China Sea); on the east by Taiwan and the Philippines; on the southeast and south by Borneo, the southern limit of the Gulf of Thailand, and the east coast of the Malay Peninsula; and on the west and north by the Asian mainland. The South China Sea and the East China Sea together form the China Sea. The southern boundary of the South China Sea is a rise in the seabed between Sumatra and Borneo, and the northern boundary stretches from the northernmost point of Taiwan to the coast of Fujian province, China, in the Taiwan Strait. It embraces an area of about 1,423,000 square miles (3,685,000 square km), with a mean depth of 3,976 feet (1,212 meters).
For a full treatment of geopolitical tensions in this region, see territorial disputes in the South China Sea.
Physical features
Physiography
The sea’s major feature is a deep rhombus-shaped basin in the eastern part, with reef-studded shoals rising up steeply within the basin to the south (Reed and Tizard banks and the Nanshan Island area) and northwest (Paracel Islands and Macclesfield banks). The deep portion, called the China Sea Basin, has a maximum depth of 16,457 feet (5,016 metres) and an abyssal plain with a mean depth of some 14,100 feet (4,300 metres).
Along the eastern side of the basin, the continental shelf falls off sharply near the Philippine islands of Luzon and Palawan and forms the Palawan Trough near the latter island. Along the northwest side of the basin toward the mainland is a broad, shallow shelf as wide as 150 miles (240 km). This shelf includes the Gulf of Tonkin and the Taiwan Strait and the large islands of Hainan and Taiwan.
To the south, off Vietnam, the shelf narrows and connects with the Sunda Shelf, one of the largest in the world, which covers the area between Borneo, Sumatra, and the Malay Peninsula and includes the southern part of the South China Sea, the Gulf of Thailand, and the Java Sea. This broad trough is about 130 feet (40 metres) deep at its periphery and up to 330 feet (100 metres) in its central part. On the bottom of the shelf is a network of submerged river valleys that converge into the Sunda Depression and then into the China Sea Basin.
The Sunda Shelf is covered with littoral sediments contributed by submerged valleys. The inner zone of mud is characteristic of the continental shelf near the Mekong and Red river deltas, while the sediment of the deeper parts of the South China Sea is mainly composed of clay. A characteristic part of the sediments in both deep and shallow water is volcanic ash. This is found in layers, derived from large volcanic eruptions in the East Indies, notably the enormous eruption of Krakatoa in 1883, during which ash was transported through the entire area by both wind and currents.
The South China Sea has connecting channels. The Taiwan Strait on the north is about 100 miles (160 km) wide, with a depth of about 230 feet (70 metres). The Luzon Strait, the main deep channel connecting the South China Sea with the Pacific Ocean, lies between Taiwan and the Philippines and has a depth of about 8,500 feet (2,600 metres). Shallow channels are found on the east along the Philippine island chain and on the south between Borneo and Sumatra. The western connection to the Indian Ocean is the long Strait of Malacca. At its narrowest it is 19 miles (31 km) wide and about 100 feet (30 metres) deep.
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The South China Sea is the largest marginal sea of the western Pacific. Some 1 million to 60 million years ago, it rifted and then collapsed as a result of seafloor spreading. The China Sea Basin is believed to have dropped 2.5 miles (4 km), leaving residual plateaus studded with numerous coral reefs, islets, and banks, some of which are drowned atolls.
Climate
Weather in the sea is tropical and largely controlled by monsoons. In summer, monsoonal winds blow predominantly from the southwest; in winter, winds blow from the northeast. Annual rainfall varies from about 80 inches (2,000 mm) to more than 120 inches (3,000 mm) around the southern basin. Summer typhoons are frequent.
Hydrology
Monsoons control the sea-surface currents as well as the exchange of water between the South China Sea and adjacent bodies of water. In August the surface flow into the South China Sea is from the south from the Java Sea through the Karimata and Gelasa (Gasper) straits. Near the mainland the general flow is northeasterly, passing out through the Taiwan and Luzon straits. There is a weak countercurrent on the eastern side of the sea. In February the flow is generally to the southwest; the strongest flow occurs in summer along the bulging part of Vietnam, with speeds of up to 3.5 miles (5.6 km) per hour generated by the strong southwestern monsoon.
The near-surface waters are relatively warm (about 84 °F [29 °C] in the summer) because of the low latitude and a tendency for the equatorial current to feed warm water into the area. In early summer, wind from the southwest not only moves the surface water to the northeast but causes it to be displaced off the coast. As a result, upwelling areas having colder surface temperatures and higher nutrient content are found off central Vietnam. In winter the general surface temperature is cooler, ranging from about 70 °F (21 °C) in the north to 81 °F (27 °C) in the south.
The major rivers draining into the South China Sea are the tributaries of the Pearl (Zhu) River Delta south of Guangzhou (Canton), China, including the Xi River; the Red River at Haiphong, Viet.; and the Mekong River, near Ho Chi Minh City (Saigon), Viet. The wet summer season causes the Mekong to triple its annual average flow, and it causes an even greater relative change in the flow of the Red River.