Arctic News: Will 2026 El Nino cause Antarctic Blue Ocean Event?

Tuesday, October 20, 2026

Will 2026 El Nino cause Antarctic Blue Ocean Event?

The above image shows that the sea surface temperature in the Niño 3.4 region was 30.17°C on October 18, 2026, the highest temperature on record and 4.42°C higher than the 25.75°C recorded on January 9, 2025, while the anomaly versus 1982-2010 was +3.57°C on October 18, 2026, the highest anomaly on record.

The map (inset at the bottom of the above image) shows sea surface temperature anomalies versus 1991-2020 on October 18, 2026, around the globe, with the Niño 3.4 region highlighted.

Temperature anomalies in the Niño 3.4 region are indicative of El Niño's strength. The 2015/2016 El Niño reached its peak strength late 2015. Similarly, the 2023/2024 El Niño reached its peak strength late 2023, as indicated by the grey square on the thick grey line on the above image.

In the above image, issued by NOAA on October 19, 2026, the 2026/2027 El Niño doesn't show up yet.

[ image from earlier post ]

Strong melting of Antarctic sea ice occurs around the end of the year. On February 22, 2023, Antarctic sea ice area was 1.09 million km², very close to the 1 million km² threshold when a Blue Ocean Event could be called, and deviation from 1981-2010 of 3.03σ, as illustrated by the image below. The light blue shading in the image below indicates 3σ deviation.

Prospect of an Antarctic Blue Ocean Event

Importantly, there was no strong El Niño present when the Antarctic sea ice reached its minimum area in 2023. By contrast, the 2026 El Niño will be very strong, its peak strength will occur late 2026, and the El Niño is forecast to extend into early 2027.

The image below, from an earlier post, shows that on October 15, 2026, Antarctic sea ice area was 1.92 million km² lower than 1981-2010, the lowest anomaly on record for that day and a deviation of -5.31σ. The blue band in the middle indicates a deviation of 1σ from the 1981-2010 average.

Conclusion

The situation is dire and unacceptably dangerous, and the precautionary principle necessitates the danger to be acknowledged, while facilitating rapid, comprehensive and effective action to reduce the damage and to improve the outlook, where needed in combination with a Climate Emergency Declaration, as described in posts such as in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.