Antarctic sea ice area reaches record daily low

Antarctic sea ice area remained at a record daily low on October 24, 2025, following a record daily low on October 23, 2025. Antarctic sea ice area was 12.40 million km² on October 24, 2025, a deviation from 1981-2010 of -3.57σ, as illustrated by the image below.

The above image also shows that Antarctic sea ice reached a record low area of 1.09 million km² on February 24, 2023, close to a Blue Ocean Event and corresponding with a deviation of -2.86σ, i.e. smaller than the deviation of -3.57σ reached recently (on October 23, 2025).

Low sea ice means that less sunlight gets reflected back into space and instead gets absorbed by the sea surface, resulting in high sea surface temperatures. Currently, sea ice is low at both poles. Low global sea ice over the coming months spells bad news for Antarctic sea ice, which typically reaches its minimum in February. 

The image below shows that the standard deviation from 1981-2010 of the global sea ice extent was -6.48σ on October 28, 2025. 

Low sea ice and polar amplification of the temperature rise contribute to high air temperatures at both poles. The image below shows the September 2025 temperature anomaly compared to 1951-1980.

[ from earlier post ]

The low sea ice and the high temperatures are even more remarkable given the absence of El Niño conditions.

[ click on images to enlarge ]

While little sunlight is yet reaching the South Pole at this time of year and temperatures over Antarctica are still well below zero °C, they are rising fast. Antarctic temperature anomalies were high in September 2025 (see the above image). 

The image on the right, adapted from NOAA, shows the ENSO outlook (CFSv2 ensemble mean, black dashed line) favors La Niña persisting into the early Northern Hemisphere winter 2025-26. 

[ image from earlier post ]

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

Record high daily temperatures over Antarctica were reached on each consecutive day of the week from 12 through 18 October 2025, and on October 23, 2025. The Antarctic temperature anomaly was +4.22°C vs 1979-2000 on October 14, 2025. The temperature reached a record daily high on October 24, 2025, and an anomaly of +3.82°C vs 1979-2000. The inset on the image below shows high temperature anomalies at both poles vs 1991-2020 on October 24, 2025.

High temperature anomalies at the poles occurred on October 25, 2025, as illustrated by the image below. 

High temperatures come with Jet Stream distortion on October 25, 2025, as illustrated by the image below that shows the Jet Stream (at 500 hPa) moving deep over Antarctica. 

This came with high precipitable water anomalies over Antarctica, as illustrated by the image below. 

This came with snowfall over Antarctica, as illustrated by the image below. 

The danger has been discussed in earlier posts such as this one. The increased snowfall thickens the snow on Antarctica with only little freshwater returning to the ocean. As a result, the Southern Ocean surface is getting more salty, and as also discussed in an earlier post, saltier surface waters sink more readily, allowing heat from the deep to rise, which can melt Antarctic sea ice from below, even during winter, making it harder for ice to reform. This vertical circulation also draws up more salt from deeper layers, reinforcing the cycle.

This leads to a loss of sea ice (and thus loss of albedo and latent heat buffer), as well as less heat getting transferred from the atmosphere into the Southern ocean, while more heat can be transferred from the Southern Ocean to the atmosphere. 

Arctic sea ice volume

Meanwhile, 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 October 28, 2025.

Global temperature

Global temperature anomalies have been rising over the past few months, and reached a record daily high of 15.04°C, an anomaly of +0.93°C versus 1991-2020, on October 25, 2025, as illustrated by the image below.

The following day, on October 26, 2025, the temperature reached another daily high. The image below shows temperature anomalies in red from January 1, 2023, through October 26, 2025, with a non-linear (polynomial) trend added in blue. 

Note that the anomalies on the above images are calculated from 1991-2020. When calculated from pre-industrial, the anomalies will be much higher, as discussed in earlier post such as this one. 

The situation is dire. 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, as the next El Niño is strengthening, which comes with a huge danger of massive amounts of methane erupting from the seafloor. 

The methane danger

The methane danger is illustrated by the image below, adapted from an image issued by NOAA October 29, 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

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

• Climate Reanalyzer
https://www.climatereanalyzer.org

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

• Copernicus
https://pulse.climate.copernicus.eu

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

• Focus on Antarctica
https://arctic-news.blogspot.com/2025/09/focus-on-antarctica.html

• Antarctic sea ice in danger
https://arctic-news.blogspot.com/2025/10/antarctic-sea-ice-in-danger.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

Antarctic sea ice in danger

The Antarctic sea ice area was 12.54 million km² on October 17, 2025, the second lowest daily area (behind 2023) and a deviation from 1981-2010 of -4.15σ.

This low Antarctic sea ice area is alarming. Antarctic sea ice typically reaches its annual low in February. The record low of 1.09 million km² that was reached on February 24, 2023, was very close to a Blue Ocean Event, yet the deviation then was only -2.86σ.

High temperature anomalies over Antarctica and high sea temperatures are behind the low sea ice area. The image below shows how much higher the September 2025 temperature was than it was in 1951-1980.

[ from earlier post ]

At this time of year, little sunlight is reaching the South Pole yet, so temperatures over Antarctica are still well below zero °C. Nevertheless, temperature anomalies were high in September 2025 and anomalies were as high as +4.22°C compared to 1979-2000 on October 14, 2025, which is remarkable given the absence of El Niño conditions. Record high daily temperatures were reached on each day of the period from 12 to 17 October 2025. The inset shows high polar temperature anomalies versus 1991-2020 on October 17, 2025.

[ click on images to enlarge ]

Meanwhile, Arctic sea ice volume remains at a record daily low, as it has been for more than a year, as illustrated by the image below. This contributes to low global sea ice, as this causes less sunlight to be reflected and instead more sunlight to be absorbed by the ocean surface. 

The global sea ice area was 3.45 million km² lower than 1981-2010 on October 17, 2025, a deviation from 1981-2010 of -4.47σ, as illustrated by the image below.

The image below shows Antarctic sea ice concentration on October 17, 2025.

The image below shows Antarctic sea ice thickness on October 17, 2025.

The situation is dire. An Antarctic Blue Ocean Event (sea ice approaching a low of one million km²) could occur in February 2026, triggering an Arctic Blue Ocean Event later in 2026.   

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.

Transform Society with the Climate Plan

[ image from this 2019 post, text discussed in earlier posts such as this 2022 one and links below ]

The Climate Plan calls for Transformation of Society in at least four sectors, as follows:

1. Energy - Generate clean, renewable energy with solar panels, turbines and batteries.

2. Food - Produce vegan-organic food and pursue synthetic food, solar food and precision fermentation.

3. Waste management - Pyrolyze organic waste with the biochar added to the soil.

4. Construction and Activities - Transition to online work, ordering, education and health diagnosis, using wood and green steel to construct buildings, vessels, bridges and water storage, while adding olivine sand to footpaths, bikeways, paths, gardens, beaches, forests and water bodies, and while letting eVTOL air taxis add extra mobility, battery exchange and mobile communications, in support of microgrids, WiFi, microwave and laser links.

The above transitions will help increase forests, as discussed in posts such as this one. Reforestation and afforestation efforts work best when including restoration of wildlife and creation of food forests as discussed in this post and in this post. A recent study led by Evan Fricke finds that with healthy populations of animals that disperse seeds, tropical forests can absorb up to four times more carbon. A 2024 study led by Maddi Artamendi finds a notable negative impact of reduced pollinator species diversity on plant reproductive success measures, such as seed set, fruit set and fruit weight. 

The images below illustrate the decline over time of wild mammals and birds, compared to humans, livestock and poultry. 

Further Links

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

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

• Climate Reanalyzer

https://www.climatereanalyzer.org

• Focus on Antarctica
https://arctic-news.blogspot.com/2025/09/focus-on-antarctica.html

• Emissions and Temperature Rise
https://arctic-news.blogspot.com/2025/10/emissions-and-temperature-rise.html

• Seed dispersal disruption limits tropical forest regrowth - by Evan Fricke et al. (2025) https://www.pnas.org/doi/10.1073/pnas.2500951122

and
• Loss of pollinator diversity consistently reduces reproductive success for wild and cultivated plants - by Maddi Artamendi et al. (2024)
https://www.nature.com/articles/s41559-024-02595-2
discussed on Facebook at: 
https://www.facebook.com/groups/climateplan/posts/25746278341642263

• Wild mammals make up only a few percent of the world’s mammal biomass - by Hannah Ritchie (2022)

https://ourworldindata.org/wild-mammals-birds-biomass

• 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

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. This is much lower than the record Arctic sea ice area minimum of 2.24 million km² reached on September 12, 2012, as illustrated by the combination image below.

Sea ice loss results in Albedo loss, i.e. less sunlight getting reflected back into space and instead getting absorbed by the ocean and the impact of Antarctic sea ice loss is even stronger than Arctic sea ice loss, since Antarctic sea ice is located closer to the Equator. A warmer Southern Ocean also comes with fewer bright clouds, further reducing albedo. 

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

Temperatures keep rising as Earth's energy imbalance keeps rising, which results from a combination of high (and rising) levels of pollution (including concentrations of greenhouse gases, other gases and warming aerosols) and loss of Earth's albedo (reflectivity). Furthermore, rising temperatures come with feedbacks that can speed up acceleration of the temperature rise. 

The image below, by Eliot Jacobson, shows Earth's Energy Imbalance through July 2025 (12-month running mean). 

The image below, by Leon Simons, shows the Energy Imbalance in the Northern Hemisphere (left) and the Southern Hemisphere (right). The image is also discussed on facebook. 

Albedo loss over the years is illustrated by the graph below, by Eliot Jacobson (based on data through July 2025, 36-month running average). 

Albedo loss results from a decrease in cooling aerosols and from certain feedbacks that are kicking in with increasing ferocity as temperatures rise, including less lower clouds and decline of the snow and ice cover. With the temperature rise also come further feedbacks such as more water vapor in the atmosphere and more extreme weather events that can cause deforestation and associated reductions in cooling aerosols, as illustrated by the Danger Diagram below. 

Many feedbacks are self-amplifying and can also amplify other feedbacks, further speeding up acceleration of the temperature rise, as illustrated by the image below. 

[ from earlier post ]

El Niño 2026 prospect

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. 

On September 27, 2025, the temperature reached an anomaly in this area of -0.67°C versus 1991-2020. The inset on the above image shows the Niño 3.4 area and the sea surface temperature anomaly versus 1991-2020 that day. The low temperatures in Niño 3.4 over the past few months indicate that La Niña conditions will likely dominate in the remainder of 2025, which implies suppression of the 2025 global temperatures.

A strong La Niña could spell bad news for Antarctic sea ice. A recent study led by Shaoyin Wang shows that the triple-dip La Niña event during 2021–2023 played a major role in record low February Antarctic sea ice extent reached in 2022 and 2023, while the Antarctic ice sheet experienced a transient mass gain rebound.

As also described in earlier posts such as this one and this one, more water evaporates from the Southern Ocean and part of it falls on the Antarctic ice sheet, thickening the snow layer. As a result, the Southern Ocean surface is getting more salty. Saltier surface waters sink more readily, allowing heat from the deep to rise, which can melt Antarctic sea ice from below, even during winter, making it harder for ice to reform. This vertical circulation also draws up more salt from deeper layers, reinforcing the cycle.

[ image from earlier post ]

On the other hand, a new El Niño may emerge soon. 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 in 2026 and grow in strength in the course of 2026.

In conclusion, an Antarctic Blue Ocean Event may occur early 2026 and this could be followed by an Arctic Blue Ocean Event later in 2026, in particular if a strong El Niño will emerge in the course of 2026 and further feedbacks are triggered, such as seafloor methane eruptions. 

Why a Blue Ocean Event is so dangerous

[ from earlier post ]

PIOMAS estimates that 16,400 km³ of ice is lost every year (1979-2010 average) from April to September, consuming an amount of energy of 5 x 10²¹ Joules (the image on the right shows calculations, click on this link or on the image to enlarge).

Once the latent heat buffer is lost, further heat must go elsewhere. During the phase change from ice to water, the temperature doesn't rise, i.e. all the energy goes into the process of changing ice into water. Once all ice has melted, further heat will raise the temperature of the water. The amount of energy that is consumed in the process of melting the ice is as much as it takes to heat an equivalent mass of water from zero°C to 80°C. 

Decline of the snow and ice cover comes with numerous feedbacks, the loss of the latent heat buffer (feedback #14 on the feedbacks page) is only one of them. Further feedbacks include the loss of albedo (feedback #1), increases in emissions (feedback #2), loss of emissivity (feedback #23), while there are also changes to the Jet Stream (feedback #14) and changes to clouds and water vapor (feedback #20), and there are mechanisms and circumstances aggravating the danger, such as the slowdown of AMOC and further changes to ocean currents.

[ The Buffer is gone, from Accelerating Temperature Rise ]

Sea ice constitutes a buffer that previously consumed much incoming ocean heat (left); as sea ice thins, the buffer disappears while more heat also enters the Arctic Ocean (right). Further heat entering the Arctic Ocean from the Atlantic Ocean and the Pacific Ocean threatens to destabilize sediments that contain methane, causing eruption of huge amounts of methane.

Eruption of methane from the seafloor of the Arctic Ocean (feedback #16) is one of the most dangerous feedbacks. As the seafloor of the Arctic Ocean heats up, heat can penetrate sediments and cause destabilization of hydrates, resulting in eruption of methane. As the seas in the Arctic Ocean can be very shallow, the methane can erupt with force in the form of plumes, with little opportunity for the methane to get decomposed in the water. Furthermore, there is very little hydroxyl in the air over the Arctic, which extends the lifetime of methane over the Arctic.

Ominously, the sea surface temperature anomaly versus 1951-1980 in the north mid latitudes (inset) reached a record monthly high of 1.657°C in August 2025, as illustrated by the image below.

Meanwhile, the Arctic sea ice remains at a record low daily volume, as it has been for more than a year.  

The methane danger is also illustrated by the image below, adapted from an image issued by NOAA September 29, 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. 

The image below shows methane concentrations as high as 2622 parts per billion (ppb) recorded by the NOAA 20 satellite on September 30, 2025 am, at 399.1 mb. Note the high methane concentrations over the Arctic, over Antarctica and over the Antarctic sea ice.

While the Antarctic methane danger has been described before, such as in this April 2013 post, the main focus of the Arctic-news blog has long been on the Arctic, in particular on the East Siberian Arctic Shelf (ESAS). However, recent research highlights the dire situation in Antarctica, justifying an additional wider focus on global developments, as discussed on facebook.

The above image, from Ted Scambos et al. (2017), illustrates the dangerous situation in Antarctica. The danger is that progressively stronger intrusion of warm and salty water underneath Antarctic glaciers can destabilize methane hydrates and cause eruption of huge amounts of methane held in and underneath such hydrates, as also discussed here on facebook.

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

• 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

• Strong impact of the rare three-year La Niña event on Antarctic surface climate changes in 2021–2023 - by Shaoyin Wang et al.
https://www.nature.com/articles/s41612-025-01066-0

• Extreme Heat Risk
https://arctic-news.blogspot.com/2025/08/extreme-heat-risk.html

• Saltier water, less sea ice 

https://arctic-news.blogspot.com/2025/07/saltier-water-less-sea-ice.html

• How much, how fast?: A science review and outlook for research on the instability of Antarctica's Thwaites Glacier in the 21st century - by Ted Scambos et al. (2017)
https://www.sciencedirect.com/science/article/pii/S092181811630491X

• Antarctic seep emergence and discovery in the shallow coastal environment - by Sarah Seabrook et al. 

https://www.nature.com/articles/s41467-025-63404-3

• 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

Double Blue Ocean Event 2026? (update)

Arctic sea ice looks set to continue to be at record low daily volume, as it has been for more than a year. The image below shows Arctic sea ice volume through September 22, 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 (as also discussed in comments on facebook). 

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 21, 2025, when the global sea ice area was 2.48 million km² below the 1981-2010 mean, a deviation from 1981-2010 of -3.72σ. Critically, the global sea ice anomaly has been very low in 2025 (in blue) and this occurred in the absence of an El Niño.

Antarctic sea ice 

Ominously, the Antarctic sea ice area anomaly is very low. The image below shows the 2025 anomaly (in black) from April through September 22, 2025, when the Antarctic sea ice area was 1.30 million km² below the 1981-2010 mean, a deviation from 1981-2010 of -3.24σ. Note that, during the period shown on the image, very little sunlight has reached the Southern Hemisphere. 

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 22, 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

• 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

• 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

• 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