Arctic News: Antarctica

Antarctica

The image below shows a forecast for August 15, 2026, with high temperature anomalies showing up over Antarctica. What are the circumstances that can lead to such high anomalies and what consequences could that have?

On August 15, 2026, the global surface air temperature was 17.05°C, the highest temperature on record for this day of the year.

The globe (inset above image) shows the global temperature anomaly vs 1991-2020 on August 15, 2026, with anomalies showing up higher than 12°C and with Antarctica and sea ice around Antarctica getting hit by very high (as well as low) temperature anomalies.

Sea surface temperatures are also high. The nullschool.net image below shows the Jet Stream at 250 hPa and sea surface temperature anomalies as high as 10°C or 17.9°F south of South Africa on August 4, 2026. Very high anomalies are also visible in the Equatorial Pacific, indicating that the 2026 El Niño is on track to become the strongest on record.

[ click on images to enlarge ]

It is winter in the Southern Hemisphere and on August 15, 2026, the average temperature was 11.78°C or 53.2°F, the highest temperature on record for that day and an anomaly of +1.01°C calculated from 1979-2000 (not pre-industrial), as illustrated by the image below. This situation has developed while the 2026 El Niño is strengthening, with a peak expected at the end of 2026 that could devastate Antarctic sea ice.

Strong Jet Stream in Southern Hemisphere

The image below, from an earlier post, shows record high temperatures in the Tropics for the time of year. The image below shows sea surface temperatures in the Tropics through September 4, 2026, when the temperature in the Tropics was 26.27°C or 79.29°F, an anomaly of 1.33°C or 2.39°F versus 1979-2000. The globe (inset bottom right) shows sea surface temperature anomalies versus 1991-2020 on September 4, 2026 with the Tropics highlighted. Keep in mind that neither of those base periods is a pre-industrial base.

[ -70°C near South Pole ]

In winter in the Southern Hemisphere, the temperature can be -70°C or even lower near the South Pole and over East Antarctica, as illustrated by the image on the right.

Given the above record high temperatures in the Tropics, the temperature difference between the Equator and the South Pole can therefore be very large, which strengthens the Jet Stream in the Southern Hemisphere.

The image below shows the Jet Stream on August 24, 2026. At the location marked by the green circle, wind at 250 hPa reaches a speed of 351 km/h, while Instantaneous Wind Power Density is 178.9 kW/m².

The above image also shows the Polar Jet Stream moving over Antarctica, which can increase temperatures, especially in West Antarctica, in a self-amplifying feedback loop, as described below.

[ snowfall over Antarctica, forecast for August 2, 2026 ]

At times, the Jet Stream can move over parts of Antarctica, enabling warm, moist air to move from the Southern Ocean and reach Antarctica.

Warm, moist air can travel in the form of atmospheric rivers toward Antarctica, and this can result in snowfall over Antarctica, as illustrated by the forecast on the right.

High temperatures anomalies

As a result, there can be very high temperatures anomalies over Antarctica and over the sea ice around Antarctica. The image below shows a forecast with areas over Antarctica reaching temperature anomalies of about +30°C on July 18, 2026, i.e. winter heatwave conditions in some areas in and around Antarctica, while other areas experience very low temperatures.

The image below also shows a forecast with some areas over Antarctica reaching temperature anomalies of about +30°C, this time on August 3, 2026.

The image below shows a forecast for August 23, 2026, with the manicule pointing at areas on Antarctica with temperatures about 30°C or 54°F higher than 1979-2000. At the same time, very low temperature anomalies are recorded at some other locations over and around Antarctica.

The amount of snow falling on Antarctica can be significant. The image below, from the Antarctica page, shows a 3-hour precipitation accumulation of 16.9 kg/m² on August 25, 2026.

The combination image below shows the Jet Stream moving over West Antarctica and atmospheric rivers of moisture moving toward Antarctica, coming with snowfall and relative humidity as high as 100% on Antarctica on August 1, 2026.

[ click on images to enlarge ]

The two images below, from an earlier post, show wind pushing warm, moist air over West Antarctica resulting in high temperature anomalies and snowfall. The image below shows an air temperature of 0.0°C or 32.1°F over the sea surface near Antarctica on August 22, 2026, at the location marked by the green circle.

The image below shows that an air temperature of 4.1°C or 39.3°F was recorded over Antarctica at 1000 hPa on August 22, 2026, at the location marked by the green circle.

Antarctic sea ice

The image below shows a forecast for August 21, 2026, of precipitable water anomalies.

[ 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 of the extra snowfall over Antarctica, the Southern Ocean surface is getting more salty. In salty water, sea ice can start melting when the temperature rises to about -2°C (28.4°F), while freshwater remains frozen as long as the temperature remains below 0°C (32°F).

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 this self-amplifying feedback loop.

The above mechanism was discussed in earlier posts such as this one. The dramatic decrease in sea ice around Antarctica in 2023 therefore looks set to continue long-term, due to the compound impact of feedbacks that are self-amplified and/or that amplify each other through albedo loss, lower emissivity, loss of the sea ice's latent heat buffer, ocean current changes, salinity changes, ocean stratification, etc.

On August 13, 2026, Antarctic sea ice area was 2 million km² lower than 1981-2010, the second lowest on record for that day and a deviation of -4.44σ, as illustrated by the image below from an earlier post. The year 2026 is highlighted in black, the year 2023 is highlighted in blue and the year 2016 is highlighted in purple.

The image below, from an earlier post, shows a sea surface temperature forecast for January 2027, indicating that there will be dramatic Antarctic sea ice loss.

The danger is that a Double Blue Ocean Event will occur, in the Arctic in 2026, and subsequently in the Antarctic in early 2027, triggering numerous additional feedbacks, including eruption of methane from the seafloor and release of ocean heat into the atmosphere.

The image below, from Berkeley Earth Temperature Report for 2024, illustrates the importance of Antarctic Sea ice loss in accelerating the temperature rise in 2020-2023 compared to 2010-2019.

[ image from earlier post ]

Colored in red on the above image is an area with an extra radiative forcing of +2.1 W/m², which is primarily the result of loss of Antarctic sea ice. While this extra forcing of +2.1 W/m² applied only to parts of Antarctica and the Southern Ocean, it is a big deal, considering that all carbon dioxide released by people from 1750 to 2019 amounted to an extra radiative forcing of +2.16 W/m² globally, as discussed in an earlier post.

The image below, from an earlier post, shows Antarctic sea ice concentration on September 5, 2026, by the University of Bremen (left) and the National Snow and Ice Data Center (right). Low concentration of the sea ice and of the snow and ice cover on land lowers albedo, resulting in more sunlight getting absorbed by Antarctica and by the sea ice around Antarctica.

On September 5, 2026, Antarctic sea ice area was 1.27 million km² lower than 1981-2010, the lowest on record for that day and a deviation of -3.39σ, as illustrated by the image below, from an earlier post. The year 2026 is highlighted in black, the year 2023 is highlighted in blue and the years 2016, 2024 and 2025 are highlighted in purple.

Both 2016 and 2023 were strong El Niño years and the 2026 El Niño is on track to become even stronger. Antarctic sea ice typically reaches its annual minimum in February, but this time most sea ice may be gone earlier, as the 2026 El Niño is on track to increase in strength in the course of 2026 and become the strongest El Niño on record, which could devastate the sea ice over the coming months. The image below, from an earlier post, shows ECMWF El Niño forecast plumes in three regions dated September 1, 2026.

Methane danger

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.

More generally, the danger has been described in many posts, such as this one and this one.

Conclusion

The image below shows an increase in annual maximum daily precipitation change as temperatures versus 1850-1900 rise by 1.5°C, 2°C, and 4°C, from the IPCC AR6, which looks set to increase snowfall over Antarctica.

The situation looks set to deteriorate further. More water vapor causes more warming, since water vapor is a potent greenhouse gas. As more snow falls over Antarctica, the sea surface of the Southern Ocean increases in salinity, which speeds up melting of sea ice. The extra water vapor and increased melting of sea ice can both strongly accelerate the temperature rise, while water vapor that reaches the stratosphere also causes damage to the ozone layer.

The situation is dire and unacceptably dangerous, and the precautionary principle necessitates the danger to be acknowledged, while facilitating 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.