Climate Change Reduces Radiation Risk of the “Komsomolets”
A recent study from December 2025 by the Norwegian Radiation Protection Authority examines how climate change affects the potential spread of radioactive substances from the sunken Soviet nuclear submarine “Komsomolets.” The submarine sank on April 7, 1989, southwest of Bear Island after a fire broke out on board. Of the 69 crew members, 42 died, while the others were rescued by fishing vessels. Since its sinking, the submarine has been lying at a depth of about 1,673 meters in the Norwegian Sea. On board are a nuclear reactor and two torpedoes with nuclear warheads.
As part of the study, scientists developed various computer simulations to analyze possible scenarios of radioactive leakage. Four variants were considered: continuous release from the seabed, continuous release throughout the entire water column, a one-time release from the seabed, and a one-time release throughout the water column. For each scenario, the spread of radioactive substances was calculated under both current conditions and future climate conditions.
The results show that climate change tends to reduce the risk of radioactive substances reaching the ocean surface. The reason is the increasing stratification of seawater due to rising temperatures and changing precipitation patterns. Warmer surface water mixes less with the colder deep layers where the wreck is located, making vertical transport of radioactive particles more difficult.
The strongest climate-related changes were observed between 1982 and 2001, when vertical mixing of water masses was particularly pronounced. Between 2002 and 2021, this mixing decreased, which also reduced the influence of climate change on the spread of radioactivity.
According to the model calculations, any leaking radioactivity would mainly spread within the Norwegian Sea and partly reach the Barents Sea and the Arctic Ocean. Along the Norwegian coast, especially in the regions of Lofoten, Tromsø, and Kirkenes, concentrations could increase over a period of about two decades, but would remain significantly lower than in a scenario without climate-related changes.
The study was conducted as part of Norway’s nuclear safety action plan. The scientists emphasize that their findings are based on model calculations and that there is currently no acute danger from the wreck. Measurements from 2019 show that the release of radioactive cesium-137 is about 0.1 gigabecquerels per year, a value several orders of magnitude lower than in the years immediately following the accident.
In summary, climate change in this specific case may have a mitigating effect on the spread of radioactive substances. Nevertheless, continuous monitoring of the wreck remains necessary to detect and assess potential risks at an early stage.
Heiner Kubny, PolarJournal
