Saturday, October 25, 2025

Antarctic sea ice area reaches record daily low


Antarctic sea ice area was 12.43 million km² on October 23, 2025, a record low for that day and a deviation from 1981-2010 of -3.62σ.

On February 24, 2023, Antarctic sea ice reached a record low area of 1.09 million km², close to a Blue Ocean Event and deviation of -2.86σ.

High temperature anomalies over Antarctica and high sea surface temperatures are behind the low sea ice area. The image below shows the September 2025 temperature anomaly compared to 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, Antarctic temperature anomalies were high in September 2025 (see the above image) and the Antarctic temperature anomaly recently was as high as +4.22°C compared to 1979-2000 (on October 14, 2025).

The record low Antarctic sea ice area and the high temperatures over Antarctica are remarkable given the absence of El Niño conditions. Record high daily temperatures over Antarctica were reached on each consecutive day over the period from 12 through 17 October 2025, as illustrated by the image below. The inset shows high polar temperature anomalies versus 1991-2020 on October 17, 2025.

[ from earlier post, click on images to enlarge ]

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.

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.




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