Double Blue Ocean Event 2026? (update)

Arctic sea ice looks set to continue to be at record daily volume, as it has been for more than a year. The image below shows Arctic sea ice volume through September 19, 2025. 

While Arctic sea ice volume continues to be at record daily low levels, its decline since its maximum in April through to its minimum in September has been relatively slim this year, which can be the result of natural variability (including of wind patterns), of an increase of freshwater and of slowing down of AMOC. 

At the same time, sea surface temperatures have kept rising, with huge amounts of ocean heat accumulating at higher latitudes north recently, as illustrated by the image below that shows sea surface temperature anomalies at 30°N-90°N. 

[ image from earlier post, click to enlarge ]

High (and rising) greenhouse gas concentrations combined with a decrease in aerosol masking are causing Earth's energy imbalance to keep rising, which comes with feedbacks including more water vapor in the atmosphere, a decrease in lower clouds and decline of the snow and ice cover. The decline of sea ice is illustrated by the image below that shows the global sea ice area anomaly through September 18, 2025. 

Ominously, the Antarctic sea ice area anomaly has been very low this year. The image below shows the 2025 anomaly (in black) from April through September 18, 2025, a period during which very little sunlight has reached the Southern Hemisphere. Furthermore, the low anomaly has been reached in the absence of an El Niño.

This spells bad news for Antarctic sea ice, which almost crossed the threshold for a Blue Ocean Event on February 22, 2023, as illustrated by the image below. 

[ image from earlier post, click to enlarge ]

In conclusion, a Blue Ocean Event could occur in the Southern Hemisphere in early 2026. This could be followed by a Blue Ocean Event in the Northern Hemisphere later in 2026, in particular if a new El Niño will emerge in the course of 2026 and further feedbacks are triggered, such as seafloor methane eruptions. 

The danger is also illustrated by the image below, adapted from an image issued by NOAA September 19, 2025, showing hourly methane averages recorded at the Barrow Atmospheric Baseline Observatory (BRW), a NOAA facility located near Utqiaġvik (formerly Barrow), Alaska, at 71.32 degrees North.

Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group. </ div>

Links

• Kevin Pluck - Sea ice visuals
https://seaice.visuals.earth

• Danish Meteorological Institute - Arctic sea ice thickness and volume
https://ocean.dmi.dk/arctic/icethickness/thk.uk.php

• NOAA - Global Monitoring Laboratory - Data Visualisation - flask and station methane measurements
https://gml.noaa.gov/dv/iadv

• Double Blue Ocean Event 2026?

https://arctic-news.blogspot.com/2025/09/double-blue-ocean-event-2026.html

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html