Showing posts with label feedbacks. Show all posts
Showing posts with label feedbacks. Show all posts

Friday, May 1, 2026

Arctic and Antarctic sea ice may be gone within ten months

Both Arctic and Antarctic sea ice may be gone within ten months. On April 24, 2026, Arctic sea ice was lowest for the time of year in extent, in area and in volume, as highlighted in an earlier post. The post warns that the upcoming El Niño could cause all Arctic sea ice to disappear in September 2026, resulting in albedo loss, transfer of ocean heat to the atmosphere and additional emissions that could jointly increase global temperatures and subsequently also cause all Antarctic sea to disappear in a matter of months.

Forecasts indicate that the upcoming El Niño threatens to become a monster within months.


The above image, adapted from NOAA, shows an anomaly forecast dated May 6, 2026, for the Niño3.4 region (which is indicative for El Niño development), with forecasts exceeding 4°C for part of one forecast member and exceeding 3°C part of the forecast for the Coupled Forecast System version 2 (CFS.v2) ensemble mean (black dashed line). The image below shows an anomaly forecast for the Niño3 region dated May 6, 2026, with forecasts exceeding 4°C for parts of several forecast members. 


Forecasts of sea surface temperature anomalies in El Niño regions partly exceeding 3°C indicate that the 2026-2027 El Niño may be even stronger than the 2015-16 El Niño, as illustrated by the image below, adapted from ClimateReanalyzer and with a potential 2026-27 El Niño anomaly of more than 3°C added (red dashed line on the right). 


The image below shows the sea surface temperature (SST) in the Nino 3.4 region over the years from the start of the year to June. On April 30, the 2026 SST (red line) was higher than the 2016 SST (thick grey line). From January 9, 2026, through April 30, 2026, the sea surface temperature in the Nino3.4 region has risen by 3.15°C.


The image below shows a May 1, 2026, ECMWF forecast for the Niño3.4 region on the right, with a map of the El Niño regions on the left. 


Forecasts for each of the four NINO regions are added in the combination image below. 

[ click on images to enlarge ]

Arctic sea ice

The image below, adapted from the Danish Meteorological Institute, shows that the daily Arctic sea ice volume was at a record low for the time of year on May 6, 2026, as it has been for years. 


The April 2026 Arctic sea ice volume was about 18,500 km³ (as illustrated by the image on the right), which is very close to the magenta bar which stands for strong melting (18,000 km³) from the annual maximum volume. 

The image below shows Arctic sea ice volume through April 2026, with the strength of the melting between the annual maximum (blue circle) and the annual minimum (red circle) highlighted by colored bars, magenta for strong melting (18,000 km³) and green for little melting (15,000 km³). 

Last year, only about 15,000 km³ of sea ice melted away from the maximum in 2025 to the minimum in September 2025, and this relatively little melting can be attributed in part to La Niña conditions.

The April 2026 volume was about 18,500 km³, so if strong melting (18,000 km³) will take place over the next few months (dashed magenta line), as can be expected due to El Niño, a Blue Ocean Event will occur and virtually all Arctic sea ice volume will be gone in September 2026. 


Feedbacks, thresholds and tipping points

Sea ice loss comes many feedbacks and there is interaction between feedbacks. As an example, sea ice decline comes with both loss of albedo (Feedback #1) and loss of the latent heat buffer (Feedback #14), each of which will accelerate the temperature rise of the water of the Arctic Ocean, thus contributing to the threat that hydrates contained in sediments at the seafloor of the Arctic Ocean will be destabilized, which in turn threatens to cause eruption of huge amounts of methane (Feedback #16), which will further drive up the temperature in the Arctic and cause stronger melting of terrestrial permafrost.

A further danger lies in changes occurring to wind and ocean current patterns; the temperature rise will cause stronger wind, waves and storms, as well as deformation of the Jet Stream (Feedback #19). In addition, the temperature rise causes loss of reflectivity of clouds (Feedback #25) and more ocean stratification (Feedback #29), exacerbated by more freshwater accumulating at the surface of oceans, due to stronger ice melting, due to heavier runoff from land and rivers and due to changes in wind patterns and ocean currents and circulation. In the North Atlantic, there is the additional danger that formation of a freshwater lid (Feedback #28) will cause huge amounts of ocean heat to be pushed into the Arctic Ocean and enter the atmosphere as sea ice disappears.

Higher temperatures come with feedbacks, as illustrated by the image below, from an earlier post. The image illustrates the mechanism of multiple feedbacks increasing and accelerating the temperature rise (the yellow horizontal bar), and of thresholds and tipping points causing the temperature rise to jump up a step when crossed.

[ the temperature in the atmosphere can keep rising, even in the absence of further emissions ]
Feedback numbers correspond with the list at the feedbacks page. Some of them are discussed below.

Feedback #1: albedo loss (loss of reflectivity) as sea ice melts due to rising temperatures and due to the ice getting covered by soot, dust, algae, meltpools and rainwater pools;

Feedback #14: loss of the latent heat buffer - as sea ice disappears, heat can no longer be consumed by the process of melting, and the heat will instead go into increasing the temperature;

Feedback #19: distortion of the Jet Stream as the temperature difference narrows between the Arctic and the Tropics, in turn causing further feedbacks to kick in stronger, such as hot air moving into the Arctic and cold air moving out, and more extreme weather events bringing heavier rain and more intense heatwaves, droughts and forest fires that cause black carbon to settle on the sea ice;

Feedback #23: open oceans hold more far-infrared energy than sea ice, resulting in warmer oceans, stronger melting of sea ice, with a study showing a 2°C rise in the polar climate after a 25-year run;

Feedback #25: extra water vapor feedback - rising temperatures will result in more water vapor in the atmosphere (7% more water vapor for every 1°C warming), further amplifying the temperature rise, since water vapor is a potent greenhouse gas;

Feedback #28: freshwater lid on the North Atlantic - melting of sea ice and glaciers and thawing of the permafrost results in meltwater accumulating at the surface of the North Atlantic Ocean, where it forms a cold freshwater lid on top of the water; this lid grows further due to more rain falling on top of this lid. This results in less evaporation and transfer of heat from the North Atlantic to the atmosphere, and more ocean heat getting carried by the Gulf Stream underneath the sea surface into the Arctic Ocean;

Feedback #30: The clouds feedback reduces the reflectivity of lower clouds and comes with a tipping point at 1200 CO₂e that, when crossed, causes the temperature rise to increase by an abrupt 8°C. Such a high CO₂e could be reached due to eruption of methane from the seafloor, as discussed in an earlier post and below

Feedback #16: eruptions of seafloor methane - as more heat reaches the seafloor of the Arctic Ocean, sediments and hydrates contained in them destabilize, resulting in methane releases. Vast amounts of methane are held in hydrates at the seafloor of the Arctic Ocean. Miesner et al. (2023) warn that 2822 Gt of organic carbon is stored in subsea Arctic shelf permafrost and Huang et al. (2024) warn that the top two meters of soil globally holds about 2300 Gt of inorganic carbon, which has been left out of environmental models, and 23 Gt of this carbon may be released over the next 30 years. By comparison, the atmosphere contains about 5 Gt of methane. The image below, from an earlier post, illustrates the threat of thinning of Arctic sea ice resulting in increased ocean heat and methane eruptions.
[ The Buffer is gone ]
Ominously, the forecast for August 2026 below shows very high sea surface temperature anomalies for the Arctic Ocean, which spells bad news for Arctic sea ice, which typically reaches its annual minimum in September. 


Antarctic sea ice

Could an Antarctic Blue Ocean Event occur in early 2027? Antarctic sea ice typically reaches its annual minimum in February. As illustrated by the image below, Antarctic sea ice area was only 1.09 million km² on February 22, 2023, very close to the 1 million km² threshold when a Blue Ocean Event could be called.

   [ Saltier water, less sea ice - from earlier post ]
What caused the 2023 Antarctic sea ice decline? Until 2015, rising temperatures resulted in melting of ice and enhanced precipitation that freshened the surface of the Southern Ocean, exacerbated by increasing stratification that prevented mixing. The temperature rise over the years also caused winds to be stronger, at the time causing the sea ice to spread out wider.

The higher the water's salt content, the lower its melting point. Seawater typically has a salinity of about 3.5% (35 grams of salt per liter of water). Sea ice starts melting when the temperature rises to about -2°C (28.4°F). By contrast, freshwater remains frozen as long as the temperature remains below 0°C (32°F).

A recent study led by Theo Spira finds that, in 2015, anomalously strong winds enhanced mixing across the thin Winter Water layer, entraining warm and salty subsurface waters, which broke down upper-ocean stratification. Another recent study led by Earle Wilson find that in 2015, intensified wind-driven upwelling reversed the freshening trends, releasing years of accumulated ocean heat that contributed to unprecedented sea ice loss.

[ image from: 10°C or 18°F warmer by 2021? ]
An earlier post discusses a study led by Alessandro Silvano that finds how, around 2015, surface salinity in the Southern Ocean began rising sharply – just as sea ice extent started to crash.

The post describes that higher temperatures come with feedbacks such as stronger wind and stronger evaporation, resulting in increased water vapor in the atmosphere. Much of the water vapor will return to the surface in the form of precipitation such as rain and snow, but part of this precipitation will fall over Antarctica, with the net result of an increase in salinity of surface of the Southern Ocean. 

The post also points at the danger that heat, previously stored in the deep ocean by sinking circumpolar waters, will instead remain at the surface and cause atmospheric temperatures to rise, as illustrated by the above image.

A recent study warns that Antarctic regions (60°S − 90°S) may warm by around 6°C due to the collapse of the Atlantic meridional overturning circulation (AMOC).

Ominously, the forecast below for January 2027 shows very high sea surface temperatures anomalies around Antarctica, which spells bad news for Antarctic sea ice, which typically reaches its annual minimum in February, as mentioned above. 


Temperature rise

On May 6, 2026, a record high sea surface temperature was recorded for that day, tiered with May 6, 2024, as illustrated by the image below. 


The image below, from an earlier post, uses NASA monthly data through March 2023. Data are first adjusted from NASA's default 1951-1980 base to an earlier 30-year base, i.e. a 1886-1915 base, and then further adjusted by 0.99°C to reflect ocean air temperatures, higher polar anomalies and a pre-industral base.


The image below is a 2025 update, the same adjustments are made to data through April 2025.


The image below is a 2026 update, the same adjustments are made to data through March 2026.


While the above images indicate that we have dodged a few bullets, we keep playing Russian roulette and keep pulling the same clathrate gun's trigger until one day the bullet will be in the chamber. Note also that we've been in a La Niña and a monster El Niño is on the way.

How the 0.99°C adjustment in the above images is calculated is shown in the bright yellow inset of the image below.

[ from April 2024 post, click on images to enlarge ]
The images show that, when adjusting the data and using a genuinely pre-industrial base, the temperature rise may have already crossed both the 1.5°C and the 2°C thresholds that politicians at the 2015 Paris Agreement pledged shouldn't and wouldn't be crossed.

Human extinction

In 2022, the IPCC said that limiting warming to 2°C would require global greenhouse gas emissions to peak before 2025 at the latest. As discussed in an earlier post, it looks like we have missed the target of limiting the temperature rise to 2°C, while humans are likely to go extinct with a 3°C rise in temperature, yet the IPCC refuses to warn people about the dire situation.

The screenshot below describes the existential danger for humans.
The screenshot below adds:

Conclusion

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 in this 2022 post and this 2025 post, and as discussed in the Climate Plan group.



Links

• NOAA - Seasonal climate forecast from CFSv2
https://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2_body.html

• NOAA - ENSO: Recent Evolution, Current Status and Predictions - Update issued May 4, 2026
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• ECMWF - The European Centre for Medium-Range Weather Forecasts
https://charts.ecmwf.int

• Climate Reanalyzer
https://climatereanalyzer.org

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

• Tropicaltidbits.com
https://www.tropicaltidbits.com

• NASA - GISS Surface Temperature Analysis - custom plots
https://data.giss.nasa.gov/gistemp/graphs_v4/customize.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






Monday, December 29, 2025

Huge temperature rise in 2026?

[ image from 1991 poster ]
The image on the right was included in a poster featuring at the AGU Fall Meeting in 1991. The image warned about an escalating temperature rise in the Arctic, pointing at a 10°C rise in the Arctic by 2036. The poster warns that this rise threatens to trigger seafloor methane releases resulting in runaway global warming. 

Over time, further contributors to the temperature rise have been highlighted with the warning that they could jointly trigger a total potential global temperature rise of 10°C as early as 2026. 

A huge temperature rise threatens to unfold and it could do so as early as next year (2026), as illustrated by the image on the right. Altogether, the temperature rise from pre-industrial could be more than 18.44°C by the end of 2026. 

[ see the Extinction page ]
The barchart on the right conceptually dates back to 2016, when a strong El Niño came with a strong temperature rise. When expressed by means of a polynomial trend that was extended by a decade, the trend pointed at a 10°C rise by 2026.

The barchart has basically remained the same over the past ten years, be it that the historic temperature rise from pre-industrial has turned out to be larger (pink) and that the cloud feedback could add a further 8°C to the rise (grey). Also, for clarity, aerosols have been split up into on the one hand sulfates (green) and on the other hand carbon monoxide, black & brown carbon and non-methane volatile organic carbon (brown).  

Importantly, posts have over time pointed out that humans are likely to go extinct with a rise of 3°C and most life on Earth will disappear with a 5°C rise, as illustrated by the image below, from an analysis discussed in an earlier post.

With the year 2026 approaching fast, it is time to have another look at how fast and by how much temperatures could rise. The danger of a strong El Niño emerging in 2026 is highlighted below and this could come at a time when emissions are high, Earth's albedo is low and both land and ocean sinks are losing their capacity to take up carbon dioxide and heat. 
[ from earlier post ]
The image below shows how, over the course of the year, temperature anomalies in 2023, 2024 and 2025 each have at times reached the highest daily records, even though 2025 wasn't an El Niño year. The image shows temperature anomalies from 1940 through to December 29, 2025, compared to 1991-2020, which isn't pre-industrial.

[ click on images to enlarge ]
The image below, from an earlier post, shows NASA Land Only monthly temperature anomalies (black squares) with respect to 1880-1890 (not pre-industrial) through November 2025 and shows the 1.5°C threshold crossed for all months since 2022. The Lowess 3-year smoothing trend (red line) indicates that the 2°C threshold was crossed in 2022 and that 3°C may get crossed in 2028 if this trend continues (dashed extension). The picture could look even worse when a genuinely pre-industrial base was used and a polynomial trend was applied and extended.
[ Potential Land-only rise, from earlier post ]
As said, the image at the top shows very high temperatures in 2025, even though 2025 wasn't an El Niño year. In other words, current temperatures are suppressed. Moving from the bottom of a La Niña to the peak of a strong El Niño can in itself make a difference of more than 0.5°C. This is illustrated by the image below, from an earlier post, that shows a temperature rise of more than 0.5°C from November 2022 to March 2023, when the last El Niño had not yet even started.

[ Temperature rise due to El Niño from earlier post ]
How deep into La Niña conditions are we at the moment? Sea surface temperatures in the Niño-3.4 region of the equatorial Pacific Ocean (5°N-5°S, 120°W-170°W) are indicative for El Niño/La Niña conditions. The image below shows the location of that region (square on the globe, inset) and graphs with the sea surface temperatures in the Niño-3.4 region for each of the days of the years from 1981 through December 27, 2025. 


The image below shows a graph with temperature anomalies in the Niño-3.4 region from 1950 through November 2025, when the anomaly was -0.68°C.


[ click on images to enlarge ]
The image on the right shows a NOAA update of Niño-3.4 region temperature anomalies and forecasts. 

NOAA considers a La Niña event to occur when a one-month negative sea surface temperature anomaly of -0.5° C or less is observed in the Niño-3.4 region of the equatorial Pacific Ocean (5°N-5°S, 120°W-170°W) and is forecasted to persist for three consecutive months, while an atmospheric response typically associated with La Niña must also be observed over the equatorial Pacific Ocean.

[ from an earlier post ]
The image on the right, adapted from NOAA, shows ENSO (El Niño-Southern Oscillation) probabilities, with El Niño (red bar) emerging in the course of 2026.

The graph below, adapted from tropicaltidbits, uses CDAS (Climate Data Assimilation System) data showing an anomaly of -1.272°C on Dec 28, 2025. The graph gives another idea as to how deep we have descended into La Niña conditions.


The CDAS analysis below shows very low sea surface temperature anomalies (in blue) in the Niño3.4 region in the Central Pacific on December 28, 2025.


The image below, adapted from ECMWF, shows the ENSO anomalies and forecasts for developments through November 2026 in Niño3.4 (left panel) and in Niño1+2 (right panel), indicating that the next El Niño will emerge and strengthen in the course of 2026.

[ from earlier post ]

How large could the temperatures rise be?

Sea ice is low at both poles. The image below shows Antarctic sea ice on December 31, 2025. Massive loss of albedo amplifies the decline of Antarctic sea ice and the decline of the snow and ice cover over Antarctica, resulting in elevated global temperatures that could persist through September 2026, when Arctic sea ice typically reaches its minimum extent. 


As discussed above, moving from the depth of a La Niña to the peak of a strong El Niño in itself could make a difference in the global temperature of more than 0.5°C. Add up feedbacks and the combined impact could trigger a huge temperature rise, since the rise is already accelerating, due to the self-amplifying nature of feedbacks such as albedo loss and more water vapor in the atmosphere, and due to further feedbacks that come with the temperature rise itself such as ocean stratification.
[ image from earlier post ]

[ from earlier post ]
Oceans are still absorbing an estimated 91% of the excess heat energy trapped in the Earth's climate system due to human-caused global warming. If just a small part of that heat instead remains in the atmosphere, this could constitute a huge rise in air temperature. Heat already stored in the deeper layers of the ocean could also rise up and commit Earth to further additional surface warming in the future.

The image on the right illustrates how the temperature rise can cause oceans to take up less heat, resulting in more heat remaining in the atmosphere. 

[ from earlier post ]
The above image shows very high temperature anomalies forecast around Antarctica and over the Arctic Ocean for September 2026, at a time when Arctic sea ice volume is expected to be very low. Arctic sea ice volume is at a record low for the time of year, it has been at a record daily low for well over a year. The image below shows Arctic sea ice volume through December 30, 2025.


There is a huge danger that seafloor methane and methane from thawing terrestrial permafrost will add strongly and abruptly to the temperature rise, as discussed in many earlier posts such as this one and as illustrated by the screenshot below.
[ screenshot from earlier post ]
The methane danger is further illustrated by the image below that shows hourly average in situ methane measurements well above 2400 ppb (parts per billion). The image is adapted from an image issued by NOAA December 31, 2025. The image shows methane recorded over the past few years 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

• AGU poster

• Climate Reanalyzer
https://climatereanalyzer.org

• NSIDC - Sea Ice Today
https://nsidc.org/sea-ice-today

• Tropicaltidbits.com
https://www.tropicaltidbits.com


• NOAA - ENSO: Recent Evolution, Current Status and Predictions

• NOAA - ENSO sea surface temperatures
https://www.ncei.noaa.gov/access/monitoring/enso/sst

• ECMWF
https://charts.ecmwf.int/products/seasonal_system5_nino_annual_plumes

• The threat of seafloor methane eruptions
https://arctic-news.blogspot.com/2025/11/the-threat-of-seafloor-methane-eruptions.html

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

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

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

• When Will We Die?
https://arctic-news.blogspot.com/2019/06/when-will-we-die.html

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.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




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. 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.