What a ‘super’ El Niño would mean for India’s monsoon

The United States’ National Oceanic and Atmospheric Administration (NOAA) confirmed this month that an El Niño has formed in the equatorial Pacific, and placed the odds at about 63% that it will strengthen into a “very strong” — colloquially, a “super” — event by the northern winter. India’s June rainfall, until 16th June, is roughly 35% below normal. The combination has revived a question that returns with every El Niño year: how reliably do the strongest of these events translate into a failed Indian monsoon?

An El Niño is the periodic warming of the central and eastern equatorial Pacific that tends to weaken the South Asian monsoon and whose potency is measured by how far sea-surface temperatures in a reference patch of the Pacific climb above their long-term average. D.S. Pai, Chief Forecaster at the India Meteorological Department’s (IMD) Regional Meteorological Centre in Chennai, sets out the gradations: a departure of 0.5 to 1 degree Celsius is classed as ‘weak,’ 1 to 1.5 as ‘moderate,’ 1.5 to 2 as ‘strong’, and anything beyond 2 degrees as ‘very strong.’ “People call that very strong … as you wish, super,” he told The Hindu, adding that some forecasts suggest the current event could approach a record of around 2.5 degrees.

Following a calendar