Benguela Current

THE BENGUELA CURRENT is located in the southern part of the Atlantic Ocean and moves northward from the western coast of South Africa, Namibia, and [Page 117]Angola, merging into the Southern Equatorial Current. It takes its name from the Angolan port of Benguela, which was founded by the Portuguese in 1617. The current was quickly noticed by European seafarers, who initially had trouble navigating the region.

While the Benguela Current is cold, generated by water from the very deepest parts of the ocean moving in line with the rotation of the Earth, the Southern Equatorial Current is warm. The effect of the two merging is the subject of much research, starting with the English geographer James Rennell (1742–1830), whose book Currents of the Atlantic Ocean was published posthumously in 1832. From work by subsequent geographers, it has been found that the Benguela Current also includes subtropical water from the Indian Ocean. About 124–186 mi. (200–300 km.) wide in coastal regions, it becomes much wider as it reaches the tropics, and the cold current is responsible for some of the trade winds in the South Atlantic because there is a certain level of displacement of some of the waters on the surface of the ocean.

The problem facing the Benguela Current from global warming and climate change comes from a rise in the temperature of the water in the oceans, which has led to a rise in the temperature of the waters of the Benguela Current. A Benguela El Nino effect has already been detected. Not only has there been a rise in water temperature as far south as 25 degrees S, but the water has also become increasingly saline. This change may be generated by anomalous atmospheric conditions that have been seen in the western part of the tropical Atlantic Ocean.

Although each year some warm water from Angola has impacted the northern part of the Benguela Current, El Nino has caused this to happen further south. Although this may have occurred throughout history, there are accurate records of it taking place in 1934, in 1963, and in 1984. In 1963 the resultant temperatures off the Namibian coast were some 2–4 degrees higher than normal. The water pressure was also higher. Research by L.V. Shannon suggests that the problem is less frequent, and also has a lower intensity than the similar phenomenon in the Pacific Ocean.

The result of these changes from the Benguela El Nino is expected to have a serious effect on some of the lands in southern Africa, with a dramatic effect on marine life, on the southwest coast of Africa, and also on the trade winds, which are likely to affect marine life and shipping in the southern Atlantic.

Although the impact of the Benguela El Nino is not, at this moment, noticeable south of the Namibian port of Lüderitz, if the trend continues, it would have a major effect in the region off the Cape of Good Hope where the south-flowing Agulhas Current meets the Benguela Current. Throughout history, this has resulted in turbulence and storms on the surface of the sea off the southwest coast of South Africa, and the creation of a very rich marine ecosystem underwater. Off the coast of southwestern Africa, there has already been a fall in the catch of the fishing industry, including jack mackerel, sardines, and, off the coast of Angola, anchovies. Whether this is a result of over-fishing in the last two centuries or of less fish spawning because of the rising temperature has not been firmly established, although both are likely to be major contributory causes.

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