Arctic News: The next El Nino

Monday, December 1, 2025

The next El Nino

Arctic sea ice volume is at a record daily low. It has been at a record daily low for well over a year. The image below shows Arctic sea ice volume through December 1, 2025.

Loss of Arctic sea ice volume can contribute to a huge rise in temperature as a result of methane erupting from the seafloor of the Arctic Ocean. As Arctic sea ice shrinks in volume, its capacity shrinks to act as a buffer that consumes ocean heat entering the Arctic Ocean from the Atlantic Ocean. As the buffer disappears, the temperature of the water can rise strongly and abruptly, causing heat to penetrate sediments that contain huge amounts of methane in the form of hydrates and free gas underneath hydrates. Heat penetrating such sediments can destabilize such hydrates, resulting in huge eruptions of methane.

Such an event could be triggered by wild weather swings resulting from higher temperatures that come with the next El Niño that may emerge and strengthen in the course of the year 2026.

The next El Niño

[ click on images to enlarge ]

The image on the right shows a NOAA update of temperature anomalies and forecasts 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 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.

Moving from the depth of a La Niña to the peak of a strong El Niño in itself 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 discussed in many earlier posts such as this one and 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 1, 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.