Arctic News: Accelerating Temperature Rise

Monday, March 24, 2025

Accelerating Temperature Rise

The Northern Hemisphere temperature was 12.86°C on March 19, 2025, a record daily high and 1.65°C higher than 1979-2000.

Very high temperature anomalies are forecast over the Arctic Ocean for November 2025.

[ Nov 2025 temperature anomaly forecast ]

The image on the right shows the same forecast of temperature anomalies for November 2025, in this case with a Northern Hemisphere projection. Very high anomalies are visible over the Arctic Ocean, showing anomalies of 13°C, i.e. at the end of the scale, so anomalies may be even higher over some parts of the Arctic Ocean.

What makes such high temperatures possible is a combination of mechanisms speeding up the temperature rise, particularly in the Arctic.

Such mechanism include loss of sea ice, which comes with loss of albedo and loss of the latent heat buffer that previously consumed a lot of heat entering the Arctic Ocean from the Atlantic Ocean and the Pacific Ocean.

Loss of Arctic sea ice volume is illustrated by the image on the right.

Sea ice constitutes a Buffer that previously consumed much incoming ocean heat. As temperatures rise, sea ice thins and the Buffer disappears.

This disappearance occurs at the same time as increasingly larger amounts of ocean heat are entering the Arctic Ocean from the North Atlantic Ocean and the Pacific Ocean. As a result, the temperature of the water of the Arctic Ocean threatens to increase dramatically.

[ Arctic sea ice volume, click to enlarge ]

The image on the right illustrates the decline of Arctic sea ice volume over the years.

More heat in turn threatens to reach sediments at the seafloor of the Arctic Ocean and destabilize hydrates contained in the these sediments, resulting in eruptions of huge amounts of methane from hydrates as well as from methane stored in the form of free gas underneath these hydrates.

The image below illustrates these mechanisms and their interaction and amplification, i.e. the thinning of Arctic sea ice, the increase in ocean heat and the threat of methane eruptions.

[ The Buffer is gone ]

There are numerous feedbacks that can interact and amplify each other, such as the formation of a freshwater lid at the surface of the North Atlantic, as also illustrated by the images above and below.

[ formation of a freshwater lid at the surface of the North Atlantic ]

Further self-reinforcing feedback mechanisms accelerating the temperature rise in the Arctic include thawing of terrestrial permafrost, resulting in more emissions of carbon dioxide, methane and nitrous oxide.

There are further mechanisms driving up the temperature rise, such as sunspots, expected to reach their maximum in this cycle in July 2025, while the number of sunspots is also higher than predicted. For more on mechanisms behind a steep rise in temperature, see this earlier post.

Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.