In the eye of the storm: Why Iceland treats the collapse of ocean currents as a national security issue

National security usually brings to mind warfare, cyberattacks and conflict: the defence of a nation against unwelcome interference by other states or groups. That is national security in the narrow sense. But national security is equally about ensuring that our society can withstand shocks that could disrupt its basic foundations.

Icelanders know this well. We live with natural hazards in our backyard, and few find it remarkable that the National Security Council (þjóðaröryggisráð) discusses the volcanic eruptions on the Reykjanes Peninsula or risk assessments for natural hazards.

In September 2025 the Government of Iceland took a step that, as far as is known, no other state had taken. On my proposal, the government referred the risk of a weakening or collapse of the Atlantic Meridional Overturning Circulation (AMOC) to the National Security Council. The decision drew considerable attention around the world, and it is the subject I have discussed most often with foreign media. It caused less surprise in Iceland, since it is closely tied to natural hazards that the council has dealt with before.

The decision was not taken lightly. A weakening or collapse of the AMOC could disrupt the foundations of living conditions in Iceland. The risk of weakening or collapse rises with global warming, and greater and faster warming means greater risk for Iceland.

Stable ocean currents are the foundation of life in Iceland

The AMOC is a large circulation system in the Atlantic that carries heat from southern latitudes northward. It is a complex system linking surface and deep-water currents: warm, salty surface water flows north, cools and sinks, which keeps the circulation going. The Gulf Stream, familiar to most people, is part of this system.

The circulation governs the climate of the North Atlantic and so fundamentally shapes living conditions in Iceland and elsewhere in Europe. Iceland’s climate is far milder than at comparable latitudes that the circulation does not reach.

Climate change can upset this balance. A warmer climate and more fresh water from the melting Greenland ice sheet can, among other things, alter the physical conditions that drive the circulation and reduce its strength, so that it weakens or, in the worst case, collapses. The distinction matters: weakening is not the same as collapse.

Scientists have long studied whether the circulation could weaken and reach a so-called tipping point. Climate tipping points can be thought of as thresholds at which Earth systems shift irreversibly from one state to another. Much of the danger lies in the fact that a tipping point may be crossed some time before the consequences appear, when the trend can no longer be reversed. It is therefore impossible to know whether a tipping point has been crossed until it is too late, which is why it matters to act while there is still room to prevent serious consequences. The AMOC has been studied extensively in recent years. There are numerous indications that the circulation is already losing stability and weakening. A collapse of the AMOC would have far-reaching and profound consequences worldwide. Research indicates that land suitable for growing key crops could shrink substantially across the world, and studies point to a serious prospect of prolonged drought in Europe.

Model studies show alarming results for a possible collapse of the AMOC given the trajectory of greenhouse gas emissions, and the findings indicate that the effects depend, among other things, on how fast warming proceeds. The UN Environment Programme (UNEP) recently confirmed that the 1.5°C goal of the Paris Agreement is slipping out of reach. The thinking behind the 1.5°C goal was to spare humanity and ecosystems the worst effects of climate change, including tipping points such as the AMOC. It is therefore increasingly important to treat climate change as a security issue, as the Icelandic government has done in the case of the AMOC.

Although scientific knowledge is advancing, considerable uncertainty remains. We do not know exactly, for example, what combination of warming, fresh water and other factors would push the system past a tipping point, or when that could happen. This uncertainty must not become an excuse for inaction. It should instead give us reason for foresight and swift action.

Why this is a national security issue

The reason is simple. Changes to the AMOC could seriously affect the pillars of Icelandic society. In the most severe scenarios, adaptation will be impossible for Icelandic society. The issue is therefore the scale of the possible consequences, not only the likelihood or timing of the event. Iceland’s National Security Policy also states explicitly that one of its 12 priorities is to counter disruption to living conditions and settlement caused by climate change. The National Security Council’s reports on implementing the policy accordingly include whole chapters on climate.

Start with food security.

Fisheries are one of Iceland’s main export industries, and fish stocks depend on conditions in the ocean. Changes in temperature, currents, nutrients and ecosystems can alter the distribution and behaviour of fish stocks, and with them the basis of a vital industry.

Changes in climate, precipitation patterns and water resources can affect agriculture and food production, while current-driven changes elsewhere in the world can affect international food trade and supply chains.

Then there is energy security.

Iceland’s electricity system relies largely on hydropower. Changes in precipitation, snow accumulation, melt and water resources can therefore affect the basis of the energy system. If Iceland’s climate becomes colder or more volatile at times, demand for heating may also change.

Transport and infrastructure are another factor.

We depend on ports, shipping and aviation. Changing weather, more turbulence, changes in sea level or more sea ice in certain areas could affect infrastructure and transport. Telecommunications and supply chains likewise depend on infrastructure that must be able to withstand shocks.

Then there are the economic effects.

If the natural conditions on which industries depend change, businesses, jobs, public finances and asset values can all be affected. Insurance markets and financial systems will also have to handle risk that grows as uncertainty and volatility increase.

Changes to the AMOC could also have wide-ranging effects in Europe, threatening supply chains for Iceland, which depends heavily on imports.

Major disruption of the AMOC could affect agriculture, water supply and food security in many parts of the world. The consequences could include increased migration, greater need for humanitarian aid, disrupted international trade and greater geopolitical instability.

These risks are linked and can amplify one another.

By taking the issue to the National Security Council, we are not predicting a collapse of the AMOC. We are recognising that the risk exists, that it is multifaceted and systemic, and that the authorities need to monitor it and prepare a response.

That is responsible governance and foresight. We are building awareness across government and preparing the ground for decisions on a risk that threatens the security of society.

A targeted response to serious warning signs

In 2024 a group of leading climate scientists wrote an open letter to the Nordic Council of Ministers warning of the risks of major disruption to the AMOC. Since then, the number of published studies on the AMOC has risen considerably, as noted above, and knowledge of the circulation keeps advancing. In August 2025 I therefore asked experts at the ministry and the Icelandic Met Office (Veðurstofa Íslands) for a memorandum on the state of scientific knowledge and on the effects a disruption or collapse of the AMOC could have on Iceland. I presented it to the government, which agreed to refer the matter to the National Security Council.

I then set up an interdisciplinary working group on climate tipping points, with a focus on the AMOC. Its tasks include following developments in scientific knowledge, identifying knowledge gaps, reviewing the state of ocean monitoring and research, and proposing how the authorities can respond.

These were necessary steps to connect key actors across government and to ensure a coordinated response to a new and serious risk to Icelandic society.

In this context, the ministry is now preparing a scenario exercise on a possible weakening or collapse of the AMOC. The exercise is part of an international project run by the Strategic Climate Risks Initiative, the University of Exeter and the Climate Action Unit at University College London.

The exercise aims to bring together senior officials from government and public agencies to examine the possible effects of this type of systemic risk, and to practise assessment, preparation and response to complex climate-related challenges to the security of society. The purpose is to deepen the government’s understanding of the possible effects of a weakening or collapse of the AMOC, and of its options for response and adaptation. The exercise draws on future scenarios, some of them developed by the Icelandic Met Office. We are not trying to predict the future, but to find weaknesses in governance and decision-making before they are put to the test.

Alongside analysis and exercises, robust monitoring must be secured. We need to use ocean research, satellites and observing systems to follow changes in the North Atlantic more closely. We also need to continue work on early-warning systems, so that we can respond in time and do not miss the signs of serious change.

This summer I accepted an invitation from Costas Kadis, the European Commissioner for Fisheries and Oceans, for Iceland to become a key partner in the EU OceanEye International Alliance. OceanEye covers ocean research and monitoring and the use of artificial intelligence models to forecast changes in the ocean, and it is part of the EU’s ocean package, the European Ocean Pact. I pointed out in a letter to Commissioner Kadis that such research and monitoring infrastructure could be decisive for the security of societies when there are signs that the stability of ocean currents such as the AMOC is under threat, and that OceanEye could serve as monitoring infrastructure for a weakening or collapse of the circulation.

Beyond monitoring, we need Icelandic and Nordic risk and vulnerability assessments. We need an even clearer picture of the consequences this risk could bring. What would a major change in the AMOC mean for Iceland? Which industries are most vulnerable? Which infrastructure is most at risk? Where are the weakest links in our supply chains? We need analysis, and we need more than one scenario. Talking about a single possible “AMOC collapse” is not enough. We need to examine slower weakening, severe weakening, faster transitions and what happens if the effects appear in many areas at once.

International cooperation is essential

Preparation at home is necessary, but it is not enough on its own. Climate change drives the instability of the AMOC, and climate change is by nature a global problem that requires cooperation among all the world’s states.

We need to revive the sense that climate action is urgent and cannot wait. One way to do so is to speak more plainly about what is at stake: the security of societies, people’s living conditions and the resilience of states. This is a security issue. By putting the AMOC on the agenda of the National Security Council, Iceland took a step in that direction. We gained a measure of agenda-setting power internationally, which I believe we have a duty to use. Not because Iceland has all the answers or the greatest capacity to tackle the problem, but because we are in the eye of the storm. We also hold a strong and credible position in international cooperation on the ocean and climate, and we can connect different regions: the Nordic countries, Europe and North America.

On that basis, my national statement at COP30 in Belém in November 2025 focused on the AMOC and security. Early in 2026, Dr Johan Rockström, director of the Potsdam Institute for Climate Impact Research, and I joined forces to write about why climate risk is a security threat. We will also appear together at the Arctic Circle Assembly this October to discuss the AMOC, climate risk and security. I also asked the Nordic Council of Ministers to put the AMOC on the agenda of its meeting of environment ministers in May 2026. The issue was well received, and my colleagues all agreed on its seriousness, on the need to secure monitoring, and that the Nordic Council of Ministers was the right channel for addressing this threat. In a closely related step, ocean monitoring and research were on the agenda again when we met in the Faroe Islands in late September.

Political leaders in Europe are also placing growing emphasis on climate change as an international security issue.

When Ed Miliband took office as UK Foreign Secretary in July 2026, one of his first acts was to meet his Spanish counterpart, José Manuel Albares Bueno, and sign a joint statement declaring that “climate change was now a national security emergency facing Europe and threatening our way of life.” The UK has for some time committed substantial funding to research on climate tipping points. Defence analyses in France and analyses by the Finnish government examine the effects of the circulation, and senior officials in Ireland call the AMOC the greatest climate risk Ireland faces, to name a few examples. Climate has often been linked to security before, for instance at the Munich Security Conference and within NATO. It is fair to say, though, that individual ministers and government representatives in Europe have rarely pressed the issue and spoken out the way they do now.

Cutting emissions is the first line of defence

We must not, however, lose sight of what matters most.

The best way to prepare for this danger is to reduce the likelihood that it materialises. Cutting emissions is therefore the first line of defence.

The goal of limiting global warming to 1.5°C is slipping out of reach, but that is no reason to give up. On the contrary, it is all the more important to keep warming as close to 1.5°C as possible and to avoid prolonged overshoot. Every tenth of a degree matters.

There is also reason for optimism. The global energy transition is moving fast, and economics is driving it. In 2025, renewables generated more of the world’s electricity than coal for the first time in a century, and clean energy met all growth in global electricity demand. In China, the world’s largest annual emitter, carbon dioxide emissions have been flat or falling since early 2024, not least because of an unprecedented build-out of solar power. The International Renewable Energy Agency (IRENA) describes renewable energy as a shock absorber against international crises.

Optimism is justified, yet climate politics is entering a new and harder phase.

Even as science shows ever more clearly how destructive climate change is for ecosystems and societies, the political and economic conditions for a response have in many ways become harder. Among the factors are armed conflict, trade and tariff wars, rising debt and shrinking fiscal space, the erosion of international rules and the rise of nationalist populism.

Adequate emission cuts require policy measures for which politicians in many places can find it hard to win support. Today’s politics and economic policy in fact reveal a fundamental tension between the goals of ever-rising prosperity, social cohesion and rapid cuts in greenhouse gas emissions.

Iceland and the other Nordic countries have an advantage in breaking out of such tensions and trade-offs. We have already shown that renewable energy can make society stronger, richer and more equal. In Iceland, electricity comes almost entirely from hydropower and geothermal energy, and most homes are heated with geothermal water. As we replace oil with domestic energy in transport and industry, we will cut emissions, save foreign currency, reduce the need for imported fuel and strengthen our economic security and resilience. That is how we break out of the tension: by making climate action a visible and tangible source of better living standards, greater competitiveness and economic independence.

Imported fossil fuels still account for about 15% of Iceland’s energy use, at a cost of about ISK 160 billion a year (roughly €1.1 billion). The conflict in the Strait of Hormuz was also a sharp reminder that ending our reliance on imported fossil fuels is a security issue.

This is the climate policy I believe in: one that strengthens competitiveness, energy security and resilience. A climate policy built on opportunity rather than sacrifice, one that brings people together and strengthens our society.

Above all, we must rely on the latest and best science. We must not let the threat blind us or lead us astray. We must face up to the risk and make sound decisions based on the best available information and science. A comprehensive, more security-focused approach to climate risk is more urgent now than ever.