This op-ed is part of a Special Series on the 4th Montreal Climate Security Summit (8-9 October 2025), co-hosted by the CDA Institute and the NATO Climate Change and Security Centre of Excellence (CCASCOE). The series features written reflections from Summit speakers, bringing key insights from this invitation-only event.
With oceans covering nearly 70% of the Earth’s surface, the world’s navies will play a central role in addressing the security challenges that arise from climate change. Militaries across the globe cannot afford to overlook this reality, particularly as many NATO Allies and partners operate naval forces and infrastructure along strategic coastlines – as do their principal adversaries. The roundtable discussion at the 4th Montreal Climate Security Summit in October 2025, “Resilience of Military Infrastructure and Equipment in the Maritime Domain”, explored how navies can plan, operate, and maintain their prowess as climate changes alter the marine environment. The panel included security scholars and practitioners from both sides of the Atlantic.
Climate change planning for navies demands more than resilience alone. It is a necessary part of maintaining strategic and tactical advantage. Climate change will alter some of the basic physical conditions that underpin naval operations. Navies that are unaware of climate change’s impact on the world’s oceans could find themselves in a position of weakness, while those who understand and prepare for it will hold a decisive advantage.
From Climate Impacts to Naval Physics
Changing climate conditions are already forcing navies to rethink the ships they build and operate. Many naval vessels and merchant ships currently rely on sea water to cool their engines and mechanical systems. As global ocean temperatures rise, this capacity could be reduced. Left unprepared, a ship’s captain may be forced to reduce travel speeds to prevent engines from overheating, potentially delaying response time in a crisis. This climate impact could be particularly consequential in the Red Sea and the Persian Gulf, which harbor some of the warmest waters on earth with sea surface temperatures reaching 30oC to 35oC. These seas have also been the site of numerous conflicts and geostrategic tensions, including the two Gulf wars and recent attacks on shipping by Yemen’s Houthi groups. Vessel commanders in the Middle East and other tropical and subtropical waterways would be wise to watch how climate change affects water temperatures and vessel cooling systems.
Climate change is also impacting the art of submarine cloaking and detection, a key part of strategic deterrence. Warming waters, along with changes to the ocean’s salinity and density, impact how sound travels through water, and sonars are a key part of tracking submarines. Changing water temperatures and salinities will impact where and when submarines can conceal themselves. The savvy submariner must, therefore, consider climate change’s impacts on ocean acoustics when planning routes, missions, and hiding spots.
Building Naval Resilience
Sea level rise is another reason why climate planning is crucial for naval operations, as naval bases operate at or near sea level. Global sea level has, on average, risen by about 23 centimeters since 1900, and will likely rise by another 28 to 101 centimeters by 2100. There is also an unlikely, but nonetheless possible, scenario of up to a 2.5 meter rise should a major ice sheet collapse. Sea level rise, particularly when combined with increasingly intense storms – another manifestation of climate change – can damage port infrastructure and flood critical buildings at naval bases. If runways at coastal airports flood due to sea level rise, that would also prevent planes from taking off and landing, reducing the access and mobility of military patrols and other security operations. Sea level rise, therefore, has the potential to degrade readiness – a situation which an adversary could take advantage of by attacking during flooding conditions.
Increasingly extreme weather events, such as rapidly intensifying hurricanes, are an additional concern. Consider Hurricane Melissa, a 2025 storm that intensely impacted Jamaica, Cuba, and several other Caribbean islands. Melissa’s wind speed doubled in less than a day, increasing from 110 kilometers per hour to 230 kilometers per hour in 18 hours. Navies classically prepare for such extreme storms by sending their ships to sea, where they are less vulnerable to destructive coastal waves. At the 4th Montreal Climate Security Summit, experts speaking on the maritime domain panel wondered whether navies would be able to respond in time as extreme storms intensify. While this risk is most acute for countries operating naval assets in tropical and subtropical regions, where hurricanes and typhoons are most common, northern countries like Canada should also remain alert. As climate change drives an increase in Atlantic hurricanes, more storms are tracking northward, affecting eastern Canada and raising the potential for impacts on key naval hubs such as Halifax.
Building resilience to extreme-weather events is feasible but can be expensive. For coastal floods and sea level rise, resilience often involves constructing levees, seawalls and jetties, elevating critical equipment, adjusting operational planning, and improving regional water management. Naval bases preparation for rising sea levels and extreme weather will impact their ability to function for decades to come. The most lethal navies may well be the most resilient ones.
The Arctic: A Rapidly Changing Maritime and Security Landscape
Naval operations in the Arctic and High North are changing significantly as the planet warms and polar ice melts. Canada, along with other NATO allies with Arctic presence, is closely monitoring this strategic region, as are Russia, China, and several non-Arctic nations. Rising temperatures have the potential to drive increased resource exploration for oil, gas, and critical minerals, leading to an increase in maritime activity and a greater need for naval patrols. Over the long term, sea ice melt is also likely to extend navigability along Arctic shipping routes, further contributing to increased activity in the region. Shipping is already increasing along the Northern Sea Route, along Russia’s Arctic coast, particularly for liquified natural gas (LNG) exports from Russia’s Yamal and Arctic-2 facilities. While Western sanctions have constrained parts of Russia’s energy sector, Arctic LNG shipments have persisted and continue to generate significant state revenue. These revenues contribute to Russia’s overall fiscal capacity, illustrating how climate-driven changes in the Arctic can have far-reaching security implications well beyond the region, including in the context of the war in Ukraine.
Climate change’s physical impacts will also transform how vessels operate in the Arctic. Surface vessels, such as aircraft carriers, destroyers, and frigates, may have an easier time operating at higher speed as obstructions from sea ice melt, and could find new activity in the region’s expanded areas of open ocean. Conversely, as sea ice retreats, submarines may lose a key layer of concealment, increasing exposure to surveillance and detection. At the same time, warming temperatures, changes in salinity, and the cracking of sea ice are altering ocean acoustics, reshaping how sound propagates underwater and complicating both undersea stealthing and detection in the region. Changes to stealth and detection can, in turn, impact geostrategic calculations, such as maintaining the prowess of nuclear-armed submarines.
Despite widespread melting, sea ice will remain present in the Arctic, particularly in the winter months, early spring, and late autumn. The melting of Greenland’s ice sheet could create more icebergs, amplifying an existing challenge for northern mariners. The increase in open water may even allow icebergs to move more rapidly, creating an increased need for icebreakers. Icebreakers serve both military and civilian roles; they allow ships carrying energy products, mined ores, and other cargoes to leave or transit the Arctic. They can also make frozen waters passable for military vessels. It is, therefore, not surprising that countries are expanding their icebreaker fleet as climate warms.
Climate Science: Information To Guide Action
Climate science can play an instrumental role in helping countries manage and reduce risks in the maritime domain. Organizations such as the Intergovernmental Panel on Climate Change (IPCC) and the European Union’s Copernicus Climate Service provide robust estimates of how the world’s oceans will continue to change. Research hubs such as NATO’s Centre for Maritime Research and Experimentation are turning climate projections into security insights. Projections include maps showing expected shifts in salinity, temperature, sea ice, winds, waves, and sea level in the years ahead, and are presented across different scenarios based on warming rates and greenhouse gas concentrations in the atmosphere. The sea level rise projections described earlier in this paper are one example of actionable climate data. Studies of winds and waves are also used by scientists to assess how naval operations may be affected by climate change.
While unexpected storms and rogue waves will always occur, marine science can reduce uncertainty about long-term trends. In this sense, climate science offers a nautical chart, guiding navies toward resilience and capability in a changing future. Navies that incorporate climate projections into their planning will be better positioned to gain strategic and tactical advantages in the years ahead. Ultimately, the most climate-resilient navies will also be the strongest.
Alexander S. Kolker directs the Coastal Climates Institute. He recently served as a fellow with NATO’s Energy Security Centre of Excellence and NATO’s Climate Change And Security Centre of Excellence.
The views expressed in this op-ed are the author’s/authors’ own and do not necessarily represent those of the Institute or its staff.
