El Nino scare looms over Monsoon 2023, climate change to aggravate situation

The meteorological change from La Niña to El Niño is not good news for the upcoming monsoon season - as in the past it has led to severe droughts during the El Niño years, according to scientists and meteorologists.

The four-month-long southwest monsoon contributes close to 75 per cent of the annual rainfall in India and irrigates over half of India’s agricultural land.

According to the National Oceanic and Atmospheric Administration of the United States, a transition from La Niña to ENSO-neutral will occur mostly during the February-April 2023 season. This is the first triple-dip La Niña of the 21st century, which is also likely to be the longest on record.

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A note compiled by Climate Trends explained that El Niño is invariably linked with poor monsoon performance and has been considered a threat.

According to statistics, about 60 per cent of the time there will be a probability of drought in the country during an El Niño year. The chances of below-normal rain will be 30 per cent, while the prospect of normal rain remains very rare at 10 per cent.

“During a La Niña, the tropical Pacific soaks up heat like a sponge and builds up the warm water volume. This is the warm water that spills across from the western Pacific to the eastern Pacific during an El Niño. Three consecutive years of La Niña means that the warm water volume is fully loaded and it is likely that the system is ready to give birth to an El Niño. Will it be a strong El Niño like the one during 2015-16? We may get some indications in spring itself,” said Raghu Murtugudde, Visiting Professor, Earth System Scientist at IITB and Emeritus Professor at the University of Maryland.

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“As for the monsoon itself, if an El Niño state does emerge by summer, then we are more than likely to see a deficit monsoon. A transition from a La Niña winter (which we are in now) to a summer El Niño state tends to produce the largest deficit in the monsoon – of the order of 15 per cent. This implies that the pre-monsoon and monsoon circulations tend to be weaker,” added Dr Murtugudde.

“El Nino forecast is available for the next 9 months. However, model accuracy for lead times greater than 4 months is generally low at this time. Yet, the record of El Niño indicated around this time, is a testimony of spoiled southwest monsoon. ENSO forecasts for December 2013 and December 2017 were akin to December 2022. Both these years witnessed sub-par southwest monsoon rainfall leading to moderate drought in 2014 and near drought in 2018. Earlier, similar patterns in 2003 and 2008 also proved dreadful, defacing Indian monsoon 2004 and 2009, both drought years,” said GP Sharma, President of Meteorology and Climate Change, Skymet Weather.

Several researchers have already raised an alarm citing an increase in the frequency of extreme El Niño and La Niña events from about one every 20 years to one every 10 years by the end of the 21st century under aggressive greenhouse gas emission scenarios.