ISRO Satellite Spots Strong Signals of a Powerful El Nino Developing

An Indian Earth-observation satellite is providing scientists with an early view of major changes taking place in the tropical Pacific, raising concerns that a potentially powerful El Nino could strengthen in the coming months.

Orbiting around 741 kilometres above Earth, ISRO's EOS-06, also known as Oceansat-3, has detected significant changes in both ocean biology and surface winds across the equatorial Pacific. Scientists say these signals are consistent with the development and strengthening of El Nino conditions.

The satellite observations come alongside the latest assessment from the World Meteorological Organization (WMO). In its June 2026 update, the WMO had estimated an around 80% likelihood of El Nino conditions developing during June-August. By late July, the organisation said the phenomenon was gaining strength and could intensify further between August and October.

Falling chlorophyll levels raise alarm

One of the most notable changes detected by EOS-06 is a decline in chlorophyll-a, a pigment found in phytoplankton — microscopic organisms that form the base of the marine food chain.

Analysis by ISRO's National Remote Sensing Centre (NRSC) in Hyderabad found a significant reduction in surface chlorophyll-a over parts of the tropical Pacific in June 2026 compared with the same period in 2024 and 2025, when ENSO conditions were largely neutral.

The decline is important because phytoplankton depend heavily on nutrient-rich waters brought to the surface through ocean upwelling. As El Nino develops, warmer surface waters move eastward and suppress this natural upwelling, reducing the supply of nutrients and consequently lowering phytoplankton growth.

According to NRSC Director Prakash Chauhan, the biological response in the ocean can therefore provide an additional indication of El Nino's development alongside conventional measurements such as sea surface temperatures.

Satellite also catches reversal in winds

EOS-06 has detected another classic El Nino signal — a shift in equatorial Pacific surface winds.

Under normal conditions, trade winds generally blow from east to west, pushing warm surface water towards the western Pacific. During El Nino, these winds weaken and can reverse direction, allowing warm water to spread towards the central and eastern Pacific.

The Scatterometer onboard EOS-06 can monitor these changes in surface winds, while its Ocean Colour Monitor tracks variations in marine productivity.

The combination allows scientists to study both the physical and biological response of the Pacific Ocean from space.

Chauhan said that changes in phytoplankton levels, when assessed alongside sea surface temperatures, can provide a clearer picture of the status of El Nino and its effects on the Pacific Ocean.

Why the development matters for India

El Nino is the warm phase of the El Nino-Southern Oscillation (ENSO), a major climate pattern capable of influencing weather across large parts of the world.

During an El Nino event, changes in Pacific Ocean temperatures and atmospheric circulation can affect rainfall patterns, temperatures and the frequency or intensity of extreme weather in different regions.

India watches the phenomenon particularly closely because El Nino has historically been associated with weaker southwest monsoons. However, the relationship is not absolute, and an El Nino does not automatically result in a drought over India.

A stronger event can nevertheless increase the risk of below-normal rainfall, affecting agriculture, soil moisture and water availability.

The India Meteorological Department has also reported moderate El Nino conditions over the equatorial Pacific, with sea surface temperatures remaining above average across the central and eastern parts of the region. Forecast models have indicated the possibility of further strengthening during the southwest monsoon season.

Could this become a 'Godzilla El Nino'?

The possibility of a particularly intense El Nino has attracted growing attention because of the potential global consequences.

Some comparisons have invoked the term "Godzilla El Nino", a phrase previously used to describe exceptionally powerful events. However, the eventual strength and duration of the current episode remain uncertain and will depend on how ocean temperatures, winds, upwelling and atmospheric circulation evolve.

Scientists will continue monitoring several indicators, including sea surface temperatures, thermocline depth, sea level variations and ocean circulation, rather than relying on chlorophyll levels alone.

The concern is heightened by already elevated global temperatures. A strong El Nino developing against this background could contribute to additional heat extremes and amplify weather disruptions in different parts of the world.

EOS-06 offers an early window into ocean changes

Launched aboard the PSLV on November 22, 2022, EOS-06 was designed to observe the oceans and study interactions between the ocean and atmosphere.

Its ability to simultaneously monitor ocean colour, marine productivity and surface winds gives researchers a broader picture of how the Pacific is responding to the developing El Nino.

The latest observations do not, by themselves, establish how strong the event will ultimately become. But the combination of declining chlorophyll and changing wind patterns provides a significant signal that the Pacific is undergoing a major shift.

From hundreds of kilometres above Earth, EOS-06 is effectively capturing the early fingerprints of a climate phenomenon that could influence weather far beyond the Pacific — including the Indian monsoon and global temperatures — over the months ahead.