india

Updated: Mar 27, 2019 23:06 IST

Monsoon rainfall and summer temperatures in India this year may be perceptibly affected by El Nino, a weather phenomenon characterised by warm ocean temperatures in the equatorial Pacific Ocean that is sometimes associated with drought in the subcontinent, weather officials have said.

According to officials, an El Niño condition has formed, and while it is predicted to weaken in the following months, its effect could be more serious if it strengthens instead.

“El Nino has already formed. There are predictions for a weak El Niño. During El Niño years, monsoon is usually weak, though there have been many El Niño years when there was no drought or effect on a normal monsoon. We can have a clearer picture in April when we will also issue our monsoon forecast,” said M Rajeevan, secretary, ministry of earth sciences (MoES).

The India Meteorological Department (IMD) recently predicted borderline El Niño conditions.

If the phenomenon is stronger, it is likely to sap the monsoon system and lead to more episodes of heat waves.

A weaker monsoon will have consequences for India’s agriculture, which is mostly dependant on rains for irrigation.

The World Meteorological Organisation (WMO) last month said “there is a 50-60% chance of El Niño developing by May 2019, although it is not expected to be a strong event. Sea surface temperatures in the tropical Pacific were at or slightly below El Niño thresholds in January and early February 2019. Some El Niño-like atmospheric patterns also emerged around late January.

According to KJ Ramesh, director general of meteorology, IMD, El Niño affects atmospheric circulation — impacting the heating and cooling processes which disrupt the Indian monsoon.

“Warm ocean surface temperatures over the equatorial Pacific region leads to large amount of warm air rising and moving horizontally towards the Indian region, causing subsidence during the monsoon season and weakening of monsoon. This causes low rainfall. More episodes of heat wave or above normal temperatures are also likely in El Nino years,” said DS Pai, senior scientist at IMD, Pune.

He added that there was a lot of variability in forecasts with some models predicting a weakening, while a few others show the phenomenon strengthening.

“WMO recently confirmed 2015, 2016, 2017 and 2018 as the four warmest years on record. But even a weak El Nino is likely to make 2019 warmer than 2018,” said Maxx Dilley, director of WMO’s Climate Prediction and Adaptation branch.