# 2026-2027 El Niño phenomenon intensification

> Live situation record from CLSTR: https://clstr.news/situations/2026-2027-el-nio-phenomenon-intensification
> Updated: 2026-08-18T06:03:33.000Z. Sources: 45. Developments: 3.

The 2026-2027 El Niño phenomenon is intensifying, with sea surface temperature anomalies in the Niño 3.4 region approaching the “very strong” threshold of +2°C. In the Niño 1+2 region near Peru, anomalies have hit 3.3°C. This warming has led to a decline in chlorophyll-a concentrations in the central equatorial Pacific, threatening marine food webs. Scientists warn that the interaction between natural cycles and anthropogenic warming makes the global impact increasingly unpredictable, with the event potentially lasting until autumn 2027.

Meteorological agencies report significant intensification. NOAA has raised the probability of a “very strong” event to 95% for the October-December 2026 period, with a median sea surface temperature anomaly forecast at +2.66°C. There is a 97% chance the phenomenon will persist until the spring of 2027. Some projections suggest a 69% chance that this could become the most intense event recorded since 1950.

Environmental risks are escalating. An analysis by Amazon Conservation highlights a historical correlation between strong El Niño events and subsequent wildfire crises, noting that the 2023 event preceded record forest losses in 2024. Researchers warn the upcoming cycle could trigger similar or more severe primary forest losses in the Amazon basin. 

Regional concerns persist across South America. In Peru, the ENFEN commission has warned of a potential “extraordinary” El Niño Costero. In Brazil, authorities report intense rainfall and extreme winds in the south and southeast, while the Amazon and northeast face drought. In Bolivia, the climate crisis has already caused a 20% drop in milk production in the La Paz department. In Europe, concerns remain regarding temperature increases and persistent weather patterns.

## Claims

- The probability of a very strong El Niño during October–December 2026 is 95%. (single source)
- There is a 97% probability that El Niño will persist until the beginning of spring 2027. (single source)
- Stronger El Niño events are consistently followed by more severe fire seasons and greater primary forest loss in the following year. (single source)
- The median sea surface temperature anomaly for October–December 2026 is forecasted at +2.66°C. (single source)
- The 2015 El Niño resulted in 4.35 million acres of primary forest loss in 2016. (single source)
- The 2023 El Niño led to the worst fire season on record in 2024, with 6.89 million acres of forest lost. (single source)

## Timeline

### 2026-08-18: El Niño forecast indicates very strong event for late 2026

A very strong El Niño is forecasted for late 2026, with a 95% probability of high intensity and a 97% chance of persisting into spring 2027, raising significant global wildfire and climate risks.

7 sources. https://clstr.news/cluster/el-nio-intensifies-with-potential-for-extreme-impact-through-2027

### 2026-08-13: Amazon leaders prepare for intense 2026 El Niño

Amazonian leaders are leveraging past experiences with extreme droughts and wildfires to prepare communities for a potentially intense El Niño phenomenon predicted for 2026.

6 sources. https://clstr.news/cluster/amazon-leaders-prepare-for-intense-2026-el-nio

### 2026-08-10: El Niño 2026 intensifies as Pacific sea temperatures rise

The 2026-2027 El Niño is approaching “very strong” intensity, with NASA observing declining marine productivity in the Pacific. Scientists warn of unpredictable global impacts and rising extreme heat risks.

31 sources. https://clstr.news/cluster/argentina-weather-alert-storms-and-extreme-cold-forecast

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Cite as: 2026-2027 El Niño phenomenon intensification. CLSTR, https://clstr.news/situations/2026-2027-el-nio-phenomenon-intensification