El Nino may trigger frequent extreme weather events from 2040s: Study

Researchers from the University of Exeter in the UK have concluded that drastic rainfall changes are on the cards starting in the 2040s.

El Nino and La Nina are the two alternating phases of sea-surface temperatures in the eastern Pacific Ocean, off the South American coast, in which the waters get unusually warm or cold.

In less than two decades from now, extreme weather events like intense heat waves and rainfall events triggered by El Nino are set to increase, a new study has shown.

El Nino is the unusual warming of ocean waters along the eastern equatorial Pacific Ocean. It is known to affect the monsoon and cause intense heat and droughts globally. In recent years, the 2015 El Nino event has significantly affected India’s rainfall, crop output and, thus, the overall economy.

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In this study, researchers from the University of Exeter, UK have tried to calculate the ‘time of emergence’ of changes along the tropical Pacific Ocean under four possible carbon emissions scenarios. They concluded that drastic rainfall changes were on the cards starting in the 2040s.

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“When looking at changes in El Nino rainfall patterns, the best estimate of the time of emergence of changes converges on 2040 in all of the four emissions scenarios considered,” the study published in the peer-reviewed scientific journal Nature Climate Change noted.

Normally, the India Meteorological Department (IMD) observes a weaker monsoon over India during El Nino years, even though the Met agency says that there is no one-on-one association between the two.

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During 1951 – 2021, 15 years have been dominated by El Nino, including 2015, 2009, 2004, 2002, 1997, 1991, 1987, 1982, 1972, 1969, 1965, 1963, 1957, 1953 and 1951. Of these, nine summer monsoon seasons over the country recorded deficient rain by more than 90 per cent (of the Long Period Average or LPA of 88cm for the country for June-September). During one of the strongest El Nino years in 1997, however, India’s seasonal rain was over 100 per cent of the LPA, the IMD data showed.

Earlier this month, the IMD said that a weak La Nina – the opposite phenomenon of El Nino when the equatorial Pacific remains cooler than normal – has been shown to favour Indian summer monsoons. As per the latest forecasts, the existing La Nina will turn the El Nino Southern Oscillation (ENSO) neutral sometime during the upcoming monsoon season.

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