Researchers are increasingly worried that an Atlantic Ocean current could disappear, ushering northern Europe into the next ice age.
As in most of Europe, 2025 was Iceland's hottest year on record, as greenhouse gases continue to warm the planet. According to the Icelandic Meteorological Office, the country's average temperature last year was 5.2°C, which is 1.1°C above the average for the period from 1991 to 2020 and the highest since records began.
In almost every month, and especially in spring, temperatures were "significantly above average". In mid-May a 10-day heatwave swept the country, with the temperature at Egilsstaðir airport reaching +26.6°C.
Annual rainfall over the past 10 years has been below average across most of the country, though in many places it still exceeded the 1991-2020 average. For every 1°C rise in air temperature, the atmosphere can hold roughly seven per cent more moisture, which can lead to more intense and heavier rainfall. Despite the rising temperatures, scientists are worried that global warming could ultimately have the opposite effect in northern Europe.
The threat of an *AMOC slowdown
Concern about a sharp cooling centres on the AMOC, a system of ocean currents that moves water around the Atlantic, carrying warm water north and cold water south. As higher temperatures accelerate the melting of Arctic ice and send meltwater from Greenland's ice into the ocean, the current's flow can be disrupted. If that happened, scientists warn, northern Europe could enter a "modern ice age", bringing a new period of cold to Iceland as well. The AMOC has already collapsed once before, prior to the last ice age, which ended some 12,000 years ago.
In September 2025, Iceland's National Security Council formally recognised a possible AMOC collapse as a security risk.
Will Iceland turn into a "giant glacier"?
A new report, published on the Nordic Council's website on 5 February, warns that in the Nordic countries a collapse of the AMOC could have "extreme consequences" that differ from — and in part run counter to — those brought about by global climate change. Climate models suggest that winter temperatures in Iceland could fall as low as -45°C, with the result that, for the first time since the Viking age, frozen sea could surround the entire country.
Speaking to the Washington Post, the director general of the Icelandic Meteorological Office, Hildigunnur Thorsteinsson, said: "In such a case, Iceland would become a giant glacier." That is, of course, only one of many scenarios, but scientists warn that it can no longer be dismissed as pessimistic fantasy. "The AMOC is a key component of the Nordic climate system. Although the future of the AMOC is uncertain, the possibility of a rapid weakening or collapse is a risk to be taken seriously," stresses Aleksi Nummelin, research professor at the Finnish Meteorological Institute.
How can Iceland be saved from freezing over?
The report calls for "vigorous measures" to meet decarbonisation and net-negative emissions targets, warning that the longer global temperatures remain above 1.5°C over pre-industrial levels, the greater the risk of triggering an AMOC tipping point. The researchers urge that long-term funding be secured and that an AMOC early warning system be set up that "combines Earth observations with model simulations".
"This early warning system should be embedded in policymaking processes in order to create rapid knowledge and response capabilities," the report states. "The new European Union Ocean Act offers opportunities to coordinate these efforts." The study was carried out on the basis of a 2024 letter from climate scientists which noted that the risk of an AMOC collapse may have been previously overlooked.
*The AMOC (Atlantic Meridional Overturning Circulation) is a vast system of ocean currents that acts as the planet's "conveyor belt", transporting heat from the tropics northwards. How it works: warm, salty surface waters (including the Gulf Stream) flow north, where they cool, become denser and sink into the ocean depths to flow back southwards.