Oceans
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"El Niño." Earth, Oceans, Q-files Encyclopedia, 4 Aug. 2023.
https://www.q-files.com/earth/oceans/el-nio.
Accessed 19 Mar. 2024.
El Niño 2023. Earth, Oceans. Retrieved 19 March 2024, from
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Earth, Oceans, s.v. "El Niño," accessed March 19, 2024.
https://www.q-files.com/earth/oceans/el-nio
El Niño
El Niño is Spanish for "the child" and refers to the infant Jesus, because the occasional warming in the Pacific Ocean off South America peaks around Christmas time. Every 3-5 years, ocean currents in the Pacific Ocean are reversed. No one knows why this occurs. Warm water, which normally pools near Indonesia and the Philippines, moves eastwards towards northwestern South America. The event usually lasts up to a year, often starting in spring, climaxing in December and January, then easing off by May the following year. The storms that accompany the warming of the ocean waters also shift eastwards. This shift causes the weather to change all over the planet.
Effects of El Niño
The warmer than usual waters of the tropical Pacific Ocean off South America release so much energy into the atmosphere that weather patterns across the Earth are dramatically affected. Typhoons in some parts of the Pacific become more active, while rainfall is much higher in western South America.
Fish catches offshore in Peru and Ecuador are lower than normal because marine life, which is usually abundant due to the upwelling of cooler, nutrient-rich waters from the ocean depths, tends to migrate to colder waters either to the north or south. El Niño-caused droughts may affect southern Africa, India, Southeast Asia, Australia, the Pacific Islands and the Canadian prairies.
Flooding
El Niño causes heavy rainfall along the coast of Peru, whose coast the current meets. This often leads to flooding. The warmer water causes many fish native to Peruvian waters to die, or disappear in search of cooler waters. During the 1998 El Niño, Peru’s fishing industry was devastated: floods destroyed boats and jetties, and catches of fish fell by 80%.
Coral bleaching
El Niños cause above-average warming of Pacific surface waters for prolonged periods. This has devastating effects on coral reefs, not only in the Pacific but in the Indian and Atlantic oceans too. Corals cannot survive such extreme fluctuations in water temperature, on top of the rapid rise due to global warming.
If the waters around the corals become too warm, they expel the algae that they rely on for their food. Since the algae are responsible for their brilliant colours, the corals turn white without them. This is called coral bleaching. If the algae do not return to the reef within a few weeks, the corals starve and die. Even though they cover only 0.1% of the sea bed, coral reefs, often called the “rainforests” of the ocean, are home to 25% of ocean species, which rely on them for their food.
The last great bleaching event was in 1998, when 11% of the world’s coral reefs died. The Maldives lost about 90% of its reefs. Many experts think the 2014–16 event was worse in a number of regions. For example, in 2016 between a third and a half of coral on Australia’s Great Barrier Reef was killed. Scientists fear that if action is not taken, the world may lose all its coral by 2050 because of bleaching.
Drought
The 2015–16 El Niño, considered the strongest for 35 years, triggered the worst global food crisis of the last 25 years. Much of India, Latin America and parts of Southeast Asia suffered intense heatwaves and devastating droughts. India recently broke its national record, with a temperature of 51°C (124°F) recorded in Rajasthan. But the worst effects of El Niño were felt in southern Africa, where several countries declared national emergencies or disasters.
In India, vast tracts of farmland were scorched, with rice, maize, sugar cane and oilseed crops badly damaged. Rivers, lakes and dams have dried up in some areas, while heatwaves led to power cuts in the cities after excessive demand for air conditioning overloaded electricity supplies. Because of low water in the Mekong river in Vietnam, saltwater spread up to 30 kilometres (nearly 20 miles) further inland than normal, destroying rice fields and coffee plantations. Large areas of Cambodia were ravaged by wildfires.
La Niña
Often, but not always, an El Niño is often followed by what is known as a La Niña. From the Spanish, meaning “The Girl”, it is the opposite of an El Niño. Whereas El Niño brings unusually warm ocean temperatures to the Pacific equatorial waters off South America, La Niña produces significantly colder-than-normal temperatures (by between 3 and 5°C) in the same area. The consequences are heavy rains, floods and much cooler temperatures in the same regions affected by El Niño. La Niña may even trigger more severe hurricanes in the Atlantic Ocean.
Consultant: Ian Fairchild