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The writer is director of the climate change and risk programme at the Stockholm International Peace Research Institute
President Donald Trump’s push to acquire Greenland earlier this year sparked alarm in European capitals. Yet while leaders focused on Washington’s dubious territorial claims in the Arctic, they ignored the water rising around their ankles.
Political debates assume that national security and climate change occupy separate domains. This is a strategic fiction. Climate change is actively altering the physics on which strategic stability in the region depends.
Consider the changing acoustics of the north Atlantic. Anti-submarine warfare relies on certain assumptions about the way sound propagates underwater. Arctic warming is disrupting these assumptions.
As fresh water from melting ice mixes with saltwater, it creates new thermal layers and density gradients. This creates what Nato scientists describe as degraded acoustic environments. Acoustic detection could become more unpredictable in critical operational zones. When oceanographic conditions change faster than detection systems can adapt, neither side can confidently predict whether their assumptions about underwater warfare still hold.
The infrastructure challenge is equally acute on land. Melting permafrost is destabilising the runways and radar stations that provide early warning in the High North. Russia’s own environment ministry acknowledged in 2021 that over 40 per cent of its Arctic infrastructure has suffered climate-related damage. These impacts increase the risk to military installations on the Kola Peninsula housing critical naval assets.
Some will argue that militaries have always adapted to changing environments. But the nuclear domain is different. It depends on predictability. Nuclear stability between the US and Russia requires that both sides maintain confidence in their systems.
The collision between environmental physics and nuclear stability creates an investment paradox. Global military expenditure reached $2.7tn in 2024, the steepest sustained increase since the cold war. Yet countries are systematically underinvesting in protection against environmental forces that degrade the capabilities of their defence assets. When a fighter jet is grounded because permafrost melt has buckled the runway, that is not an environmental issue; it is a loss of defence capability. The solutions cannot come from procurement alone.
Some exceptions exist: Spain has earmarked roughly €1.75bn of its military budget for climate-responsive capabilities. But such approaches remain rare. Most European defence ministries still treat climate adaptation as an inconvenience.
The timing is perilous. The New Start treaty, which limits the number of operational nuclear missiles and warheads for the US and Russia, expired this month. The diplomatic window is closing just as the environmental one fogs up. If Russian or US early-warning radars fail because their foundations have thawed, then the risk of a false alarm — or at worst, an accidental launch — rises.
To adapt, we need to incorporate environmental realities into arms control agreements and introduce a mechanism to share global data on environmental disruptions.
Currently, we are making 21st-century security decisions with 20th-century climate assumptions. Nuclear deterrence is inherently fragile and climate change is an additional destabilising factor.
Focusing diplomatic energy on territorial disputes in Greenland while the physical conditions supporting deterrence degrade is strategically shortsighted. The physics of the Arctic are changing. Our security architecture must acknowledge this reality.