EL NINO & ITS IMPACTS (Syllabus: GS Paper 3 – Env and Eco)

Context: A new study has shown that the southern hemisphere has been drying out more than the northern hemisphere over the past two decades (2001-2020). 

• The authors suggest the principal cause is the weather phenomenon known as El Nino, which occurs every few years when ocean water in the eastern Pacific is warmer than usual.

Key Point of Study

• The new analysis reveals a strong decrease in water availability in South America, most of Africa, and central and northwestern Australia. 
• However, some regions such as the southern part of South America will have more water available.
• South America includes the Amazon rainforest, which is a key regulator for the climate, as well as a globally important habitat for species and home to many Indigenous communities.
• Drying of the rainforest would reduce vegetation and increase the risk of fire. This would be bad news for humans and animals that live in the forest, and has the potential to release billions of tons of carbon currently locked into forest vegetation and soils.
• The experts suggest the principal cause is the weather phenomenon known as El Nino, which occurs every few years when ocean water in the eastern Pacific is warmer than usual.

El Nino

• About: It is the name given to the occasional development of warm ocean surface waters along the coast of Ecuador and Peru.
• Frequency: El Niño events occur irregularly at intervals of 2–7 years, although the average is about once every 3-4 years.
• Impact of El Nino across the globe: El Nino impacts ocean temperatures, the speed and strength of ocean currents, the health of coastal fisheries, and local weather.

o South America: El Niño can bring heavy rainfall to the west coast of South America, particularly in countries like Peru and Ecuador. In the eastern part of South America, including parts of Brazil and Argentina, El Niño is often associated with drier conditions.

o Asia: El Niño tends to bring drier and warmer conditions to parts of Indonesia and Southeast Asia including India.

o Africa: It result in reduced rainfall in eastern and southern Africa, but parts of West Africa may experience increased rainfall and flooding during El Niño events, which can disrupt communities and agriculture.

o Pacific Islands: Many Pacific Island nations experience rising sea levels and increased storm activity during El Niño, which can lead to coastal erosion and damage to infrastructure.