A potentially historic El Niño is developing in the Pacific Ocean, with a 69 per cent chance of becoming stronger than any event recorded since 1950, according to the US National Oceanic and Atmospheric Administration (NOAA).
NOAA said there is a 90 per cent probability of a strong El Niño during the Northern Hemisphere winter. The phenomenon is expected to intensify through the end of the year and peak between October and December 2026.
El Niño can influence weather patterns far beyond the Pacific, increasing the risk of extreme heat, drought and below-normal rainfall in several regions.
Possible impact on India
El Niño years have historically been associated with below-normal southwest monsoon rainfall in India. However, the relationship is not direct, as the monsoon is also influenced by several other oceanic and atmospheric factors.
India has already recorded below-normal rainfall this monsoon. The country received 491.8 mm of rain between June 1 and August 13, which was 12 per cent below the normal level. Rainfall in June was 35.4 per cent below normal, while July rainfall was close to normal.
The India Meteorological Department has forecast below-normal rainfall for August and the remaining part of the monsoon season.
However, the developing El Niño may have a limited effect on the current monsoon because its influence generally reaches the Indian Ocean and areas around India after a delay of about 40 to 45 days. By then, the southwest monsoon will be close to its official withdrawal date of September 30.
The India Meteorological Department has also said that the current monsoon has not been affected by El Niño so far.
The Indian Ocean Dipole (IOD), the Indian Ocean counterpart of El Niño-Southern Oscillation (ENSO), could partly offset El Niño’s impact. The IOD is currently neutral, but the IMD expects it to turn positive towards the end of the monsoon season.
A positive IOD can reduce some of the adverse effects of El Niño on the Indian monsoon.
What is El Niño?
El Niño is the warm phase of the El Niño-Southern Oscillation, or ENSO, a natural climate pattern caused by changes in sea-surface temperatures and atmospheric conditions across the tropical Pacific.
ENSO has three phases: El Niño, neutral and La Niña. El Niño is declared when the relevant three-month average sea-surface temperature anomaly in the equatorial Pacific crosses a prescribed threshold.
While the possible record-strength El Niño is unlikely to have a major effect on the current monsoon because of its timing, it could influence temperatures, rainfall patterns and drought risks in India and other parts of the world later this year and during the following months.