Explained | Why India is watching the El Niño forecast with bated breath Premium

While India has benefitted from three consecutive La Niña years, an El Niño in 2023 could knock the wind out of its monsoon sails.

India is experiencing a colder than normal winter thanks to the north-south winter flow set up by the weather phenomenon known as La Niña (pronounced “la ninya”). The La Niña itself is going on for a record-breaking third consecutive year. Now, forecasts for the 2023 fall and winter are predicting that its companion phenomenon – the El Niño (“el ninyo”) – will occur with more than a 50% probability.

At this juncture, what outlook can we develop on the cyclone season and the Indian monsoon? As the saying goes, predicting is very difficult, especially the future. But we can use scientific knowledge to give it a shot.

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El Niño refers to a band of warmer water spreading from  west to east in the equatorial Pacific Ocean. Years in which an El Niño occurs are simply called ‘El Niño years’, and global weather patterns in that year tend to be anomalous in certain ways. Similarly, a La Niña occurs when the band of water spreads east-west and is cooler.

Both phenomena affect the weather worldwide and can have drastic effects on economies that depend on rainfall. Together, El Niño and La Niña make up a cyclical process called the El Niño Southern Oscillation (or ENSO).

The first thing to note is that El Niño forecasts before spring tend to be notoriously unreliable due to a so-called ‘spring predictability barrier’. The climate system is quite noisy in spring as the Sun transitions across the equator, from one hemisphere to the other. This complicates El Niño predictions before the spring.

Second, and perhaps more importantly, in a La Niña year, the tropical Pacific Ocean soaks up heat like a sponge and builds up its volume of warm water. During the El Niño, this warm water spills from the western part of the Pacific Ocean to the eastern part. But the earth has had three straight La Niña years, which means the Pacific’s warm-water volume is fully loaded and is likely to birth an El Niño soon. The question is: Will this be a strong El Niño, like the one in 2015-2016?