The ongoing El Nino event in the equatorial Pacific Ocean may continue into April 2024 and peak between November and January, according to the latest El Nino Southern Oscillation (ENSO) update from the World Meteorological Organization (WMO).
This could cause further rise in global average temperatures and fuel more extreme weather events such as heatwaves, wildfires and droughts. For India, it could mean a warmer-than-normal winter season in most of India and also a stormier-than-normal pre-monsoon season for north-west India.
El Nino is the warmer-than-normal phase of ENSO, when the sea-surface temperatures in the eastern and central equatorial Pacific Ocean are warmer than the average by more than 0.5 degrees Celsius. El Nino is generally known to bring warmer-than-normal temperatures to many regions around the world and disrupt other major weather systems, such as the Indian summer monsoon.
The world has experienced warmer than normal temperatures throughout 2023 and the year is well on its way to becoming the warmest year since pre-industrial times. It may also be the first year when the global average annual temperature temporarily breaches the 1.5°C mark set as a target in the 2015 Paris Agreement.
The breach has already happened in July, August, September and October. The margins by which these months have broken previous records have alarmed scientists. This has happened when the El Nino has not really been at its peak.
The current El Nino developed pretty quickly during July-August 2023 and reached moderate levels by September. “Based on historical patterns and current long-range predictions, it is anticipated that it will gradually diminish during the forthcoming boreal spring,” said the WMO update. The update combines forecasts and expert guidance from around the world.
El Nino’s peak may bring above-normal rainfall to the Greater Horn of Africa, Parana / La Plata basin in South America, Southeast North America and parts of central and eastern Asia, according to the update. It may also cause above-average rainfall in a narrow band along and just north of the equator in the Pacific.
Regions such as northern South America, Australia, Indonesia, Borneo, Papua New Guinea and the Philippines may experience below-normal rainfall. The same could be true for the Pacific Islands south of 30 degrees N latitude and regions immediately north of the wet band.
“El Ninos typically mature during December-January-February anyway and the annual spring warming arrives in March-April-May in the eastern tropical Pacific. So everything is on track,” said Raghu Murtugudde, climate scientist at the Indian Institute of Technology, Bombay and emeritus professor at the University of Maryland.
“El Nino impacts on global temperature typically play out in the year after its development, in this case in 2024. But as a result of record high land and sea-surface temperatures since June, the year 2023 is now on track to be the warmest year on record,” said Petteri Taalas, secretary general of the WMO.
“Next year may be even warmer. This is clearly and unequivocally due to the contribution of the increasing concentrations of heat-trapping greenhouse gases from human activities,” he added.
“During an El Nino, the winter cold tends to be trapped to the northwest and central India. But this year’s El Nino is warmer than expected in the western Pacific and the Arabian Sea is warm. I am hoping that some of the western disturbances will bring more precipitation than usual,” said Murtugudde.
As for the next year’s monsoon, we must wait to see if this El Nino transitions to a La Nina and how strong it may be. “We may have normal to excess monsoon if the Pacific goes into a La Nina,” he added.