Wednesday, September 24, 2025

Focus on Antarctica

The Antarctic sea ice area was 1.27 million km² below the 1981-2010 mean on September 23, 2025, a deviation from 1981-2010 of -3.05σ, as illustrated by the image below.


This is far below what the Antarctic sea ice area was in 1981-2010. If the situation gets worse over the next few months, an Antarctic Blue Ocean Event may well occur early 2026. In 2023, the Antarctic sea ice was very close to a Blue Ocean Event, with an area of only 1.09 million km² left on February 22, 2023, a deviation of -3.03σ, as illustrated by the image below.

[ image from earlier post, click to enlarge ]
The image below shows the Antarctic sea ice thickness on September 23, 2025. 


The image below shows the Antarctic sea ice concentration on September 23, 2025. 


Earth's energy imbalance keeps rising, due to high (and rising) greenhouse gas concentrations combined with a decrease in aerosol masking, which causes temperatures to rise and feedbacks to kick ion with increasing ferocity, including more water vapor in the atmosphere, less lower clouds, decline of the snow and ice cover and more extreme weather events.

Furthermore, a new El Niño may emerge soon. El Niño-Southern Oscillation (ENSO) is a climate pattern that fluctuates from El Niño to La Niña conditions and back. El Niño raises temperatures, whereas La Niña suppresses temperatures. This year, there have been neutral to borderline La Niña conditions, as illustrated by the image below, which shows the rises and falls of the sea surface temperature in Niño 3.4, an area in the Pacific (inset) that is critical to the development of El Niño.


[ image from earlier post ]
On September 24, 2025, the temperature reached an anomaly in this area of -0.55°C versus 1991-2020. The low temperatures in Niño 3.4 over the past few months indicate that La Niña conditions are likely to dominate late 2025, which means that global temperatures are suppressed. The inset on the above image shows the Niño 3.4 area and the sea surface temperature anomaly versus 1991-2020 that day.

The image on the right, adapted from ECMWF, shows an ENSO forecast for developments in Niño3.4 through August 2026, indicating that the next El Niño may emerge early 2026 and grow in strength in the course of 2026.

In conclusion, an Antarctic Blue Ocean Event may well occur early 2026 and this could be followed by an Arctic Blue Ocean Event 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 methane danger is also illustrated by the image below, adapted from an image issued by NOAA September 24, 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.


Links

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

• University of Bremen - sea ice concentration and thickness
https://seaice.uni-bremen.de/start

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

• Record high increase in carbon dioxide
https://arctic-news.blogspot.com/2025/04/record-high-increase-in-carbon-dioxide.html

• Double Blue Ocean Event 2026?
https://arctic-news.blogspot.com/2025/09/double-blue-ocean-event-2026.html

• Saltier water, less sea ice 




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