Earth has two poles, the North Pole (Arctic) and the South Pole (Antarctic), and there are some important differences between them.
The South Pole is dominated by Antarctica, a huge landmass. By contract, at the center of the North Pole is open water, the Arctic Ocean.
Furthermore, while warm water surrounds Antarctica, the Antarctic Circumpolar Current (ACC) acts as a barrier, keeping ocean heat away from the Antarctic coasts and the sea ice. By contrast, the flow of water in the Atlantic Ocean is dominated by the Atlantic Meridional Overturning Circulation (AMOC). Water in the North Atlantic Ocean is funneled through a passage in between North America and Europe that aligns with prevailing winds from the Equator towards the North Pole and the deflection caused by the Coriolis Effect, created by the rotation of Earth, thus strengthening the flow of ocean heat into the Arctic Ocean underneath the sea ice.
Arctic
Ocean heat is mainly moving from the North Atlantic through the Fram Strait into the Arctic Ocean and - to a lesser extent - from the North Pacific through the Bering Strait into the Arctic Ocean.
The image below, from an earlier post, shows sea surface temperatures as high as 33.3°C (or 91.94°F) around North America on August 2, 2026. The image also illustrates geographic conditions facilitating the Gulf Stream to push ocean heat north in the Atlantic Ocean toward the Arctic.
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| [ Sea surface temperatures as high as 33.3°C, click on images to enlarge ] |
While wind strengthens as temperatures rise, polar amplification of global warming is narrowing the temperature difference between the Equator and the Poles, and this can slow down and distort wind patterns such as the Jet Stream and ocean currents such as the Atlantic Meridional Overturning Circulation (AMOC) and the Southern Meriodinal Ocean Circulation (SMOC). Slowing down of AMOC can result in less heat arriving in the Arctic ocean.
Distortion of the Jet Stream can cause extreme weather events to become more extreme. Heatwaves and storms over land can result in increasingly larger amounts of freshwater getting added to the surface of the Arctic Ocean in the form of water from rivers and from runoff from land. Furthermore, a cold freshwater lid is forming at the surface of the North Atlantic, due to ocean stratification, meltwater and increased precipitation falling down the path of the Gulf Stream, as described at this page.
Slowing down of AMOC can result in less salty, warm water arriving in the Arctic ocean. This may temporarily slow down the melting of Arctic sea ice. However, the heat does not disappear and is instead accumulating in the Atlantic Ocean. A single cyclone may suffice to abruptly move huge parts of the accumulated ocean heat into the Arctic Ocean. The freshwater lid at the surface of the North Atlantic further enables warm water to be carried underneath this freshwater lid into the Arctic Ocean.
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| [ Saltier water, less sea ice, from earlier post ] |
Freshening of the sea surface can slow down the melting of sea ice by making a maximum difference of 2°C (as depicted by the image on the right). The less salt the water contains, the higher 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).
As said, the increase in freshwater can hold back Arctic sea ice decline, but as temperatures keep rising, this can only be temporary.
Given the speed at which the temperature of the water of the Arctic Ocean keeps rising, a slowdown looks set to be overwhelmed soon and huge melting of sea ice looks set to return abruptly as sea surface temperatures keep rising in line with the 2026 El Niño. More ocean heat entering the Arctic Ocean subsequently threatens to cause abrupt destabilization of sediments containing huge amounts of methane.
How much slowing down could freshening of the water of the Arctic Ocean cause for the melting of Arctic sea ice? The above image shows that salt content could theoretically make a maximum difference of 2°C, but that would be going from one extreme end to the opposite end. In practice, the difference will be less than 1°C. If the temperature of the global ocean surface kept rising at the current pace, how long would it take for the rise to overwhelm the potential freshening effect of the Arctic Ocean? The image below shows an extension of a 5-year Lowess smoothing trend of NASA data, illustrating how long it may take for a difference of 1°C to eventuate.
There are large seasonal variations that also have an impact. In October, sea ice will have sealed off the water of the Arctic Ocean from precipitation, so no more fresh water will be added to the Arctic Ocean due to rain falling or snow melting on the water. In October, temperatures on land around the Arctic Ocean will have fallen below freezing point, so less fresh water will flow from glaciers and from melting snow and ice from land into the Arctic Ocean. At that time of year, melting of sea ice has stopped, so no more fresh water from melting sea ice gets added to the Arctic Ocean.
Furthermore, as the sea ice seals off the Arctic Ocean, there will be less transfer of Ocean heat to the atmosphere over the Arctic Ocean, which can result in further heating up of the water of the Arctic Ocean, which is very shallow in many places, making it easy for Ocean heat to reach and penetrate sediments at the seafloor.
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| Pingos and conduits. Hovland et al. (2006) |
The image on the right, from a study by Hovland et al., featured in an earlier post. Hydrates can be present at the end of conduits leading to Pingos that were formed in the sediment where methane did escape from hydrates in the past. Heat can travel down such conduits relatively fast, warming up the ice in the Pingos and conduits, destabilizing hydrates and resulting in huge abrupt releases of methane from the hydrates, as well as from methane held in the form of free gas underneath such hydrates.
Antarctic
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| [ Precipitable water anomalies over Antarctica ] |
In the Southern Hemisphere, water evaporates from the Southern Ocean and part of the resulting precipitation falls on the Antarctic ice sheet, thickening the snow layer, as illustrated by the image on the right, from an earlier post and showing a forecast of high precipitable water anomalies over Antarctica on August 20, 2025.
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, as discussed in earlier posts such as this one.
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, as discussed in earlier posts such as this one.
The dramatic decrease in sea ice around Antarctica looks set to continue long-term, as a feedback that is amplified by albedo loss, lower emissivity, loss of the sea ice's latent heat buffer, ocean current changes and salinity changes.
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, research published in 2025 highlights the dire situation in Antarctica, justifying an additional wider focus on global developments, as discussed on facebook.
Conclusion
In conclusion, geographic differences result in different precipitation outcomes and this can in turn result in salinity differences that are behind different melting patterns. In both cases, there is a huge threat that methane will erupt in enormous volumes.
Links
• Extreme heat danger
• The 2026 El Niño
• Cold freshwater lid on North Atlantic
• Saltier water, less sea ice
• Will humans go extinct soon?
• Extreme Heat Risk
• Focus on Antarctica
