The danger of abrupt eruptions of seafloor methane

Arctic

Vast amounts of methane are held in sediments at the seafloor of oceans, in the form of hydrates and in the form of free gas held underneath hydrates. Heat penetrating these sediments can destabilize hydrates and cause huge amounts of methane to erupt abruptly and enter the atmosphere. 

The danger has been described many times, e.g. at the threat of seafloor methane eruptions and in the video below, by International Cryosphere Climate Initiative. 

The danger is large during the Northern Summer when Arctic sea ice reaches its minimum extent and more sunlight is heating up its shallow waters. As described below, the danger is also large outside this period. 

At this time of year, Arctic sea ice is expanding rapidly, resulting in much of the Arctic Ocean getting covered with sea ice, as illustrated by the image on the right that shows Arctic sea ice concentration on November 24, 2025. 

A thin layer of sea ice has sealed off the East Siberian Sea and the Laptev Sea from the atmosphere, resulting in less heat getting transferred from these seas to the atmosphere, so more heat remains in the water. This keeps the temperature of the water high, so the danger of methane eruptions remains high. 

Furthermore, the temperature rise is hitting the Arctic stronger than elsewhere, resulting in more extreme weather events occurring in the Northern Hemisphere such as strong wind over the North Atlantic abruptly pushing much ocean heat from the North Atlantic into the Arctic Ocean, which can trigger destabilization of sediments at the seafloor of the Arctic Ocean at times when the ocean surface is sealed off by sea ice, reducing the ocean heat that can get transferred to the atmosphere. 

Such an event occurred in February 2017 when strong wind was forecast to cause above-freezing temperatures at the North Pole, as described in an earlier post that also features the above map, indicating ocean heat getting carried along the path of the Gulf Stream into the Arctic ocean.  

The image on the right shows sea surface temperatures as high as 31.2°C in the North Atlantic on November 25, 2025, while the Gulf Stream continues to push heat north toward the Arctic Ocean.

Arctic sea ice volume remains at a record daily low, as it has been for more than a year. This implies that Arctic sea ice is very thin. The image below shows Arctic sea ice volume through November 30, 2025. 

Ocean heat flowing into the Arctic Ocean causes Arctic sea ice to lose thickness and volume, reducing 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, which also points at the danger of a freshwater lid forming at the surface of the North Atlantic, further reducing transfer of ocean heat to the atmosphere.

[ screenshot from earlier post ]

Arctic sea ice extent was 9.27 million km² on November 30, 2025, a record low for this time of year, which is even more significant since this daily record low extent was reached in the absence of El Niño conditions elevating the temperature. The image below was created with a screenshot from the Japanese National Institute of Polar Research. 

[ click on images to enlarge ]

The image below shows the anomaly. Arctic sea ice extent was 9.35 million km² on November 26, 2026, a record daily low and 1.97 million km² lower than 1981-2020 on November 26, 2025, a deviation from 1981-2010 of -3.42σ. 

The image below shows that the global sea ice extent was 3.49 million km² lower than 1981-2020 on November 26, 2025, a deviation from 1981-2010 of -5.34σ. 

Antarctica

Sea ice extent is currently 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.

The image on the right shows Antarctic snow cover and sea ice concentration on November 24, 2025.

An Antarctic Blue Ocean Event (sea ice approaching a low of one million km²) threatens to occur in February 2026, in turn triggering an Arctic Blue Ocean Event later in 2026.

The image below shows the Antarctic sea ice concentration (left) and thickness (right) thickness on November 27, 2025.

The image below shows that the Antarctic temperature was at a record daily high on November 25, 2025, 3.53°C above 1979-2020. The inset shows temperature anomalies that day, highlighting Antarctica.  

The image below shows the rise of the Antarctic temperature anomaly (versus 1951-1980) for the 12-month period from November through October over the years. The inset shows Antarctica from 60°S.

Higher temperatures result in decline of the snow and ice cover, which means that less sunlight gets reflected back into space and instead gets absorbed by the sea surface, resulting in higher temperatures, in a self-amplifying feedback loop.

Less Antarctic sea ice contributes strongly to lower albedo (reflectivity), due to the size of Antarctic sea ice and its proximity to the Equator. The image below, by Eliot Jacobson, shows that the 36-month running average for the Earth albedo just hit yet another new record low, at 28.693%.

Huge temperature rise

The image below shows global surface daily air temperature anomalies in °C versus 1991-2020 (ERA5 data through November 22, 2025). The added trend warns about a 10°C rise in 2026. The inset shows the rise 2023-2025. 

The image below shows that the temperature was at a record daily high on November 23, 2025. 

[ click on images to enlarge ]

What could contribute to a huge rise in temperature is methane erupting from the seafloor, triggered by higher temperatures and more wild weather swings as El Niño emerges and strengthens, which in itself could make a difference of as much as 0.5°C, as discussed in an earlier post. The image on the right shows an update of temperatures in the Niño-3.4 region.

NOAA considers La Niña conditions 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). 

Also, there must be an expectation that the 3-month Oceanic Niño Index (ONI) threshold will be met, and an atmospheric response typically associated with La Niña is observed over the equatorial Pacific Ocean. These anomalies must also be forecasted to persist for 3 consecutive months.

The image on the right features a graph using CDAS (Climate Data Assimilation System) data that show an anomaly of -1.24°C on Nov 26, 2025.

The image on the right, adapted from ECMWF and from an earlier post, shows the ENSO anomaly and forecast for developments in Niño3.4 through November 2026, indicating the next El Niño will emerge and strengthen in the course of 2026.

The CDAS analysis below shows very low sea surface temperature anomalies (in blue) in the Niño3.4 area in the Central Pacific on November 26, 2025. Moving from the depth of a La Niña to the peak of a strong El Niño can make a difference in the global temperature of more than 0.5°C, as discussed in an earlier post.

Methane

The methane danger is further illustrated by the images below. The image directly below shows methane as high as 2601 parts per billion (ppb) recorded by the NOAA 21 satellite at 399.1 mb on November 21, 2025 PM.

The image below shows hourly in situ methane measurements well above 2400 ppb. The image is adapted from an image issued by NOAA November 23, 2025, showing methane hourly 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

• Permafrost Thaw is Warming the Global Climate and Impacts Communities, Health, and Oceans - by International Cryosphere Climate Initiative 

https://www.youtube.com/watch?v=0uAcPf6-9-Q

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

• Warning of mass extinction of species, including humans, within one decade 
https://arctic-news.blogspot.com/2017/02/warning-of-mass-extinction-of-species-including-humans-within-one-decade.html

• Japanese National Institute of Polar Research

https://ads.nipr.ac.jp/vishop

• NOAA - sea surface temperatures

https://www.ospo.noaa.gov/products/ocean/sst/contour/index.html

• Cold freshwater lid on North Atlantic

https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

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

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

• Climate Reanalyzer
https://climatereanalyzer.org

• 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 - HEAP/NUCAPS, NOAA-20 and NOAA-21 satellite recordings 
https://www.ospo.noaa.gov/products/atmosphere/soundings/heap/nucaps/new/nucaps_products.html

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

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

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

Earth losing her sea ice

Earth is losing her sea ice. Arctic sea ice was at record low extent for the time of the year on March 24, 2017, as illustrated by the image below.

As the image below shows, on March 24, 2017, Arctic sea ice featured many cracks (top of Greenland is bottom left and Svalbard is on the right).

The poor state of Arctic sea ice is also reflected by the sea ice volume, as depicted by the image below, by Wipneus, showing PIOMAS anomalies up to March 2017.

On March 24, 2017, Antarctic sea ice extent was also much lower than it used to be at this time of year, as illustrated by the image below.

Altogether, global sea ice extent has now been at a record low for many months, as illustrated by the graph by Wipneus below. This means that a huge amount of additional sunlight has been absorbed over these months, instead of getting reflected back into space as before.

As Earth loses her sea ice, tipping point look set to be crossed that could result in rapid acceleration of Earth's temperature, as discussed at the extinction page, which warns that surface temperatures of the atmosphere could rise by some 10°C or 18°F within a decade, i.e. by 2026.

The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.


Links

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

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

• How much warming have humans caused?
http://arctic-news.blogspot.com/2016/05/how-much-warming-have-humans-caused.html

• Warning of mass extinction of species, including humans, within one decade
http://arctic-news.blogspot.com/2017/02/warning-of-mass-extinction-of-species-including-humans-within-one-decade.html

Low sea ice extent contributes to high methane levels at both poles

[ click on images to enlarge ]

On March 2, 2017, Antarctic sea ice extent was at a record low since satellite readings started.

As the image on the right shows, sea ice extent in 2017 (light blue) around Antarctica has been more than 1 million km² lower than the 1981-2010 median.

At the same time, Arctic sea ice extent was at a record low for the time of the year since 1979.

As the image underneath on the right shows, Arctic sea ice extent in 2017 has also been more than than 1 million km² lower than the 1981-2010 median.

[ click on images to enlarge ]

For about half a year now, global sea ice extent has been more than 2 million km² lower than it used to be, not too long ago, as illustrated by the image below, by Wipneus.

This means that a lot of sunlight that was previously reflected back into space, has been absorbed instead by Earth, contributing to global warming, especially at the poles.

Greater warming at the poles has also caused more extreme weather, resulting in stronger winds and waves and in wild weather swings, further accelerating the decline of the sea ice.

The combination of rising ocean heat and stronger winds looks set to devastate the sea ice around Antarctica. Ocean heat is increasing particularly in the top layer (see image on the right).

Warming water is increasingly reaching the coast of Antarctica. The image below illustrates how much sea ice melt has occurred close to the coast of Antarctic over the past few months, while much sea ice has drifted away from the coast due to strong currents and wind.

As said, less sea ice means that a lot of sunlight is no longer reflected back into space, but is instead further warming up the poles. As a result, methane levels can be very high at both poles. The combination image below shows methane levels as high as 2560 ppb on March 1, 2017. The image in the panel on the left shows high methane levels over Antarctica in an area with much grey, indicating that it was hard to get a good reading there. On the image in the panel on the right, high methane levels do show up clearly in that area.

[ click on images to enlarge ]

As discussed before, methane hydrates can be present both on Greenland and on Antarctica underneath thick layers of snow and ice. Due to global warming, wild weather swings are now common at the poles, as illustrated by the image below. This can cause sequences of rapid and extreme expansion, compacting and fracturing of snow and ice, resulting in destabilization of methane hydrates contained in the permafrost.

The image below shows methane levels as high as 2562 ppb, with solid magenta-colored areas showing up over the Laptev Sea on March 4, 2017.

The image below shows that sea surface temperatures in the Arctic Ocean were as high as 12.7°C or 54.9°F on March 3, 2017 (at the location marked by the green circle), i.e. 12°C or 21.6°F warmer than in 1981-2011.

Below is the same image, but in a different projection and showing sea surface temperatures, rather than anomalies. In 1981-2011, the temperature of the water at a spot near Svalbard (green circle) was 0.7°C (33.3°F.). On March 3, 2017, it was 12°C (21.6°F) warmer on that spot.

The danger is that self-reinforcing feedback loops such as albedo decline and methane releases will further accelerate warming and will, in combination with further warming elements, cause a temperature rise as high as 10°C or 18°F by the year 2026, as described at the extinction page.

The situation is dire and calls for comprehensive and effective action as described in the Climate Plan.


Links

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

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

• Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

• Earthquakes in the Arctic Ocean
http://arctic-news.blogspot.com/2014/04/earthquakes-in-the-arctic-ocean.html

Sea ice is shrinking

Arctic sea ice extent fell 0.16 million km² from November 16 to November 19, 2016, as illustrated by above ads.nipr.ac.jp/vishop image. The image below, based on NSIDC data, shows the Arctic sea ice shrinking 49,000 km² in four days.

This is happening at a time when there is little or no sunlight reaching the Arctic, as illustrated by the image below.

The image below was created by Torstein Viddal and earlier posted at the Arctic Sea Ice Collapse blog.

This recent fall in extent is partly due to strong winds, as illustrated by the image on the right.

Mostly, though, the lack of sea ice over the Arctic Ocean is caused by very warm water that is now arriving in the Arctic Ocean.

During the northern summer, water off the coast of North America warms up and gets pushed by the Coriolis force toward the Arctic Ocean. It takes several months for the water to travel along the Gulf Stream through the North Atlantic.

It has taken until now for the Arctic Ocean to bear the brunt of this heat.

As the image below shows, record sea surface anomalies showed up near Svalbard on October 31, 2016, when this heat first arrived in the Arctic.

On October 31, 2016, the Arctic Ocean was as warm as 17°C or 62.7°F (green circle near Svalbard), or 13.9°C or 25°F warmer than 1981-2011. This indicates how much warmer the water is beneath the surface, as it arrives in the Arctic Ocean from the Atlantic Ocean.

Moreover, Antarctic sea ice is also falling, reflecting the warming of oceans globally. For some time now, Antarctic sea ice extent has been at a record low for the time of the year.  On November 19, 2016, the combined extent of Arctic and Antarctic sea ice was 22.423 million km², as the image below shows.

This constitutes a fall in global sea ice extent of 1.085 million km² (418,900 square miles) since November 12, 2016, when global sea ice extent was 23.508 million km².

Let's look at those figures again. On Saturday November 12, 2016, global sea ice extent was 23.508 million km². On Saturday November 19, 2016, global sea ice extent was 22.423 million km². That's a fall of more than one million km² in one week.

By comparison, that's more than the combined size of ten European nations (such as Switzerland, Austria, Hungary, Germany, Denmark, the Netherlands, Belgium, Luxembourg, the United Kingdom and Ireland).

Or, it's more than the combined size of seventeen States of the United States (such as Ohio, Virginia, Tennessee, Kentucky, Indiana, Maine, South Carolina, West Virginia, Maryland, Hawaii, Massachusetts, Vermont, New Hampshire, New Jersey, Connecticut, Delaware and Rhode Island).

How much additional energy does Earth retain, due to such an albedo change? If it was a total albedo flip, it would be some 0.68 W/m². A conservative estimate would be a 50% albedo flip, as the image below illustrates, so this would mean that Earth now retains some 0.34 W/m² extra energy.

Thick sea ice covered with snow can reflect as much as 90% of the incoming solar radiation. After the snow begins to melt, and because shallow melt ponds have an albedo (or reflectivity) of approximately 0.2 to 0.4, the surface albedo drops to about 0.75. As melt ponds grow and deepen, the surface albedo can drop to 0.15, while the ocean reflects only 6% of the incoming solar radiation and absorbs the rest.



So, this one-week fall in sea ice extent means there now is an additional warming of some 0.34 W/m². By comparison, the warming impact relative to the year 1750 of all carbon dioxide emitted by people was 1.68 W/m² in the most recent IPCC assessment report (AR5).

There's more! As sea ice declines, there is not only albedo loss due to a fall in extent, but there is also albedo loss over the remaining sea ice, which turns darker as it melts.

The image below shows the fall in extent of Antarctic sea ice up to November 20, 2016. On November 20, 2016, Antarctic sea ice extent was 2.523 million km² less than its extent was at the same time of the year in 2015.

How much more energy is now retained by Earth than in 2015? Assuming a 50% albedo flip for this extent loss and a similar albedo loss that's taking place over the remaining ice, this means that Earth is now retaining an extra amount of energy (compared to 2015) that is equal to all the warming relative to pre-industrial due to carbon dioxide emitted by people.

Above image shows how the difference between 2016 and 2015 Antarctic sea ice extent grew between November 4 and November 23. On November 23, 2016, Antarctic sea ice extent was 2.615 million km² smaller than on November 23, 2015.

That means that a huge amount of sunlight is now absorbed by the ocean, rather than reflected back into space.

The animation on the right (added later) shows the decline of the sea ice around Antarctica over the period from November 16, 2016, to January 4, 2017. For comparison, the blue line shows the 1979-2000 average.

The situation is dire and calls for comprehensive and effective action as described in the Climate Plan.