Showing posts with label Arctic-Antarctic. Show all posts
Showing posts with label Arctic-Antarctic. Show all posts

Sunday, November 2, 2025

The threat of seafloor methane eruptions

Arctic sea ice volume

Arctic sea ice volume remains at a record daily low, as it has been for more than a year. The image below shows Arctic sea ice volume through November 2, 2025.


The image below shows monthly Arctic sea ice volume in the past 25 years. Markers show April (blue) and September (red) volume, corresponding with the year's maximum and minimum. In 2025, Arctic sea ice reached a record low maximum volume as well as a record low minimum volume.

[ from earlier post ]
Warmer water flowing into the Arctic Ocean causes Arctic sea ice to lose thickness and thus volume, diminishing its capacity to act as a buffer that consumes ocean heat entering the Arctic Ocean from the North Atlantic. This means that - as sea ice thickness decreases - a lot of incoming ocean heat can no longer be consumed by melting the sea ice from below, and the heat will therefore contribute to higher temperatures of the water of the Arctic Ocean. The danger of this is described in the screenshot below.

[ screenshot from earlier post ]
Global sea ice extent

The image below shows that the standard deviation from 1981-2010 of the global sea ice extent was -7.02σ on November 1, 2025, which is remarkable given the absence of El Niño conditions in 2025.

Low sea ice extent means that less sunlight gets reflected back into space and instead gets absorbed by the sea surface, resulting in higher sea surface temperatures. 

Sea surface temperature

The image below shows monthly sea surface temperature anomalies from 1951-1980 through September 2025, when the anomaly was 0.74°C. The image also shows that the anomaly in September 2023 was 0.901°C. 


The image below shows the standard deviation from 1951-1980 of the monthly sea surface temperature through September 2025, when it was 8.045σ. The image also shows that the standard deviation in August 2023 was 10.148σ. 


In statistics, the empirical rule states that in a normal distribution, 68% of the observed data will occur within one standard deviation (1σ), 95% within two standard deviations (2σ), and 99.7% within three standard deviations (3σ) of the mean. A 4σ event indicates that the observed result is 4 standard deviations (4σ) away from the expected mean. In a normal distribution, 99.993666% of data points would fall within this range. The chance for data to fall outside of 4σ is thus infinitesimally small.

Currently, sea ice is low at both poles. The low global sea ice extent at this time of year combined with high sea surface temperatures spells bad news for Antarctic sea ice, which typically reaches its minimum extent in February.

An Antarctic Blue Ocean Event (sea ice approaching a low of one million km²) threatens to occur in February 2026, triggering an Arctic Blue Ocean Event later in 2026 while the upcoming El Niño is strengthening. All this increases the danger that massive amounts of methane will erupt from the seafloor in 2026, further accelerating the temperature rise.

The methane danger


The methane danger is further illustrated by the images above (hourly methane) and below (monthly methane), adapted from images issued by NOAA November 2, 2025, showing methane averages recorded at the Barrow Atmospheric Baseline Observatory (BRW), a NOAA facility located near Utqiaġvik (formerly Barrow), Alaska, at 71.32 degrees North latitude.


Climate Emergency Declaration

UN secretary-general António Guterres recently spoke about the need for “a credible global response plan to get us on track” regarding the international goal of limiting the global temperature rise. “The science demands action, the law commands it,” Guterres said, in reference to a recent international court of justice ruling. “The economics compel it and people are calling for it.”

What could be added is that the situation is dire and unacceptably dangerous, and the precautionary principle necessitates 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 this 2022 post and this one and as discussed in the Climate Plan group.



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

• Feedbacks in the Arctic
https://arctic-news.blogspot.com/p/feedbacks.html

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

• Focus on Antarctica


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