El Nino to peak during Oct-Dec this year, says US climate agency

Why in the News

The current El Nino event will enter its peak phase during October to December this year and will prevail through the winter season. The National Oceanic and Atmospheric Administration (NOAA) puts the chance of the event intensifying further into the “very strong” category at greater than 90 per cent. Sea surface temperatures in the key Nino regions continued to rise through August and clocked readings of 1.8 to 3 degrees Celsius. On that trajectory the 2026 El Nino would be a historic event, the strongest ever recorded since 1950. The consequence is that a year of below normal rainfall and above normal temperature is now being forecast with confidence rather than flagged as a possibility.

What is El Nino?

1. El Nino: El Nino is a naturally occurring ocean and atmospheric phenomenon in which abnormal warming is recorded along the equatorial and central Pacific Ocean waters.
2. What drives the warming: The easterly trade winds that normally push warm surface water towards the western Pacific weaken, so warm water spreads back eastward and suppresses the cold upwelling off South America.
3. Global weather effects: El Nino conditions are linked to extreme weather across the globe, in the form of higher than average temperatures, rainfall or droughts.
4. El Nino Southern Oscillation cycle: It is the warm phase of the El Nino Southern Oscillation, whose cool phase is La Nina, and the cycle recurs irregularly rather than on a fixed calendar.

What does the latest assessment actually record?

1. The temperatures kept climbing: Sea surface temperatures continued to rise in August, and the key Nino regions clocked readings of 1.8 to 3 degrees Celsius.
2. The index confirms acceleration: The latest Nino index, covering June through August, rose by 0.4 degrees Celsius over the May to July value, confirming a rapidly intensifying event.
3. The category is expected to move up: NOAA puts the chance of intensification into the “very strong” category at greater than 90 per cent.
4. The duration is not short: The event is expected to prevail through the winter season, beyond the October to December peak.
5. Strongest event since 1950: The 2026 event would be the strongest recorded since 1950, which is the start of the comparable record.

Challenges posed by a very strong El Nino

1. The Indian monsoon weakens in most El Nino years: A warm eastern Pacific shifts the rising limb of the Walker circulation away from the Indian Ocean, which suppresses monsoon rainfall over India. Eg. The very strong event of 2015 and 2016 followed consecutive deficient monsoons in India in 2014 and 2015.
   The Fix: Trigger the contingency crop plans of the Indian Council of Agricultural Research at the forecast stage rather than after a rainfall deficit is confirmed, so short duration and drought tolerant seed reaches districts before sowing.
2. Reservoir and groundwater stress follows the deficit by months: A weak monsoon empties storage that the following summer depends on, so the damage peaks long after the event is over. Eg. Southern States drawing on hydropower face the shortfall in the dry season that follows a deficient monsoon.
   The Fix: Set reservoir drawdown limits for the post monsoon season on the forecast rather than on the current storage level, so carryover is protected.
3. Food price inflation moves with a small production shortfall: A modest fall in output of pulses, oilseeds and vegetables translates into a disproportionate price rise because those crops have thin buffer stocks. Eg. Pulses and edible oils are already import dependent, so a domestic shortfall is met at world prices.
   The Fix: Pre position import contracts for pulses and edible oils in the peak forecast window, so procurement is not made in a market that has already moved.
4. Marine fisheries are disrupted by the same warming: Suppressed upwelling cuts nutrient supply and moves fish stocks, which hits coastal livelihoods that carry no crop insurance equivalent. Eg. The collapse of the Peruvian anchoveta catch is the classic documented El Nino fishery effect.
   The Fix: Extend forecast linked advisories and lean season support to registered marine fishers on the same basis as agricultural advisories.
5. A strong event raises the global temperature record itself: El Nino releases ocean heat into the atmosphere, so the warmest years on record cluster in El Nino years and compound the underlying warming trend. Eg. Heat released during a strong event is added on top of the long term rise rather than substituting for it.
   The Fix: Issue heat action plan activation thresholds for the following summer at the time of the peak forecast, so city level preparation runs on the seasonal outlook rather than on the first heatwave.

Conclusion

The forecast has moved from probability to expectation, since the agency now attaches a greater than 90 per cent chance to further intensification and expects the event to hold through the winter. That gives India a lead time of several months between the warning and the season in which the consequences land, which is the interval in which seed, storage and import decisions are actually made. The status is that the event is intensifying and unbroken, and the next milestone is the peak window itself, when the category will either be confirmed or fall short of it.

Back2Basics: The Nino regions and the Nino index

1. What the regions are: The Nino regions are fixed boxes in the equatorial Pacific, numbered 1+2, 3, 3.4 and 4, running from the South American coast westward.
2. Nino 3.4 as the standard region: Nino 3.4, in the central equatorial Pacific, is the region used for standard El Nino Southern Oscillation monitoring.
3. What the index measures: The index tracks the sea surface temperature anomaly, meaning the departure from the long period average for that region, rather than the absolute temperature.
4. How an event is classified: Sustained positive anomalies of half a degree Celsius or more mark an El Nino, and anomalies of about 2 degrees Celsius and above place it in the “very strong” category.

Matching Previous Year Question

“[2017] With reference to ‘Indian Ocean Dipole (IOD)’ sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? 1. IOD phenomenon is characterized by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean. 2. An IOD phenomenon can influence an El Nino’s impact on the monsoon. Select the correct answer using the code given below: (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 ANSWER: (b)”