Another Ice Age? Iceland declares potential AMOC collapse an ‘existential threat’

Iceland has designated the possible collapse of the Atlantic Meridional Overturning Circulation (AMOC) as a threat to national security and an existential threat, reported the news agency Reuters. AMOC brings warm waters from the tropical regions towards the Arctic region and makes the winters milder.

Even other climate change ministries and meteorological offices across North Europe are weighing the risks of a possible collapse in their climate adaptation plans, according to Reuters. 

“It is a direct threat to our national resilience and security,” climate minister of Iceland Johann Pall Johannsson told Reuters. “(This) is the first time a specific climate-related phenomenon has been formally brought before the National Security Council as a potential existential threat,” he added. 

AMOC is one of the climate tipping elements of Earth’s climate system, which means beyond a certain threshold or a tipping point, the changes happening within the system may become irreversible and lead to its complete collapse. 

According to the latest estimates from climate scientists, AMOC has already started weakening because of accelerated melting of ice sheets in Greenland and could possibly collapse at any time in the near to far future in the 21st century or beyond. Many uncertainties in understanding of this imminent collapse still remain. 

The complete collapse of AMOC could herald a modern day ice age in northern Europe, with severe cold temperatures, ice and snow. The last AMOC collapse was before the last ice age, just after which humans started agriculture and civilisation as we know it today began. 

The various ministries in Iceland shall now be preparing for the eventualities of the lack of warm water from the tropics and its far-reaching consequences. “The government is assessing what further research and policies are needed, with work underway on a disaster preparedness policy,” according to Reuters. The risks include food insecurity, energy generation and distribution and sea based transportation. 

“AMOC has only been monitored continuously since 2004 through combined measurements from moored instruments, induced electrical currents in submarine cables and satellite surface measurements”, according to a research paper published in the journal Nature Communications in July 2023.

The study also highlighted the slowing down of AMOC between 2004 and 2012, but warned that longer records are necessary for assessing the exact significance of the slowing down.

The paper assessed the slowdown based on the sea surface temperatures in the subpolar gyre in the North Atlantic, which show early warning signals for the shutdown of AMOC in their loss of resilience and slowing down.

The study analysed this fingerprint between 1870 and 2020 and found that early warning signals start around 1970 at which point the system started moving towards its tipping point with high probability, according to the paper. The paper further concluded the most likely time period for the transition of the AMOC to be 2037-2109. 

“The deep overturning in the northern Atlantic slows drastically by 2100 and completely shuts off thereafter in all high-emission scenarios, and even in some intermediate and low-emission scenarios. That shows the shutdown risk is more serious than many people realise,” said another report by the Potsdam Institute of Climate Impact Research in Germany, published on August 28, 2025. “The shutdown would cut the ocean’s northward heat supply, causing summer drying and severe winter extremes in northwestern Europe and shifts in tropical rainfall belts,” the authors of the report warned. 

Another research paper published in the journal Nature in February 2025 states that “better understanding and estimates of the Southern Ocean and Indo-Pacific circulations are urgently needed to accurately predict future AMOC change”. The paper also shows that the AMOC is more resilient than other analyses show us making the complete shut down not imminent though it talks about the weakening of the AMOC which could have its own impacts on the weather and near term climate of Europe and many regions around the world. 

Whatever the instance of the AMOC collapse countries in Europe are already worried about it and Iceland has already brought this into its national policy. The environment ministry in Norway said it was “seeking to deepen our understanding of the issue through new research” before determining whether to classify AMOC as a security risk, according to Reuters.