Scientists have uncovered a previously overlooked factor that could significantly strengthen one of the planet’s most disruptive climate events -- El Niño. The findings carry particular importance for India, one of the world’s most climate-vulnerable nations, as early projections hint at the possibility of another El Niño developing in 2026.

Researchers at Duke University’s Nicholas School of the Environment have found that variations in ocean salinity or how salty seawater is can play a crucial role in determining the strength of an El Niño event. Their study, published in Geophysical Research Letters, suggests that specific salt distribution patterns in the Pacific Ocean can boost the intensity of El Niño by nearly 20 per cent and potentially double the likelihood of an extreme episode.

The conclusions are based on an analysis of 65 years of ocean observations combined with advanced climate modelling. Scientists say incorporating salinity patterns into forecasting systems could improve early warning mechanisms worldwide.

Why El Niño Matters for India

El Niño is a recurring climate phenomenon that typically appears every two to seven years. It occurs when surface waters in the eastern Pacific Ocean become unusually warm. This warming disrupts global wind systems and often diverts rain-bearing clouds away from South Asia, weakening India’s crucial monsoon season.

Historically, about half of all El Niño years have been associated with below-average monsoon rainfall in India. In particularly strong events, the probability of drought conditions somewhere in the country rises to around 60 per cent.

For India, already grappling with prolonged heatwaves, erratic rainfall and water shortages, the consequences can be severe. Agriculture, food supply and rural livelihoods are especially vulnerable. The 2023 El Niño, ranked among the five strongest on record, led to India’s driest August since 2018 and contributed to food grain shortages and rising inflation.

With climate indicators now pointing to the potential emergence of another El Niño in the latter half of 2026, researchers say understanding the forces that shape its intensity has become increasingly urgent.

The Role of Ocean Salinity

The ocean is not uniform in composition; its waters vary in salt concentration depending on rainfall, evaporation and currents. According to Shineng Hu, assistant professor of climate dynamics at Duke and the study’s lead author, these salinity differences can influence how ocean currents behave and in turn affect major climate systems.

The research team found that during spring, when fresher water accumulates along the western Pacific equator and saltier water is positioned farther away, the contrast can drive warm surface waters eastward. That eastward shift of warm water is a key mechanism behind the formation and strengthening of El Niño.

By highlighting the impact of salinity patterns, scientists believe their work could pave the way for more precise predictions of future El Niño events, a development that could help vulnerable regions like India prepare better for extreme weather swings.