Unconventional maritime challenges: Naval forces in a world of strategic flux
The Memorandum | No. 43.2025
Russia’s full-scale invasion of Ukraine and the military buildup of the People’s Republic of China (PRC) have given fresh impetus to strategic studies. Yet, beneath this dominant narrative lies a more intricate and urgent reality: today’s naval forces are navigating a sea of unconventional, intertwined and rapidly evolving challenges.
From covert operations and nuclear cooperation to organised crime, humanitarian crises, climate-induced disasters and mass migration, the maritime domain is now a polycrisis theatre. These challenges defy conventional military boundaries and demand serious reflection on sea power as a multifunctional force capable of responding to these challenges.
In this contested maritime environment, navies must adapt not only in strategy and capability, but also in mindset, balancing core defence roles with an increasing number of unconventional responsibilities which stretch across diplomacy, disaster response and global governance. This transformation carries profound implications for resources, personnel and operational priorities, especially as governments face mounting economic pressures and geopolitical instability. Understanding these challenges is crucial to answering the question of how navies need to evolve in order to address them.
Covert and nuclear activities in the maritime domain: Cold War 2.0 or new opportunities?
Russia’s aggression towards Ukraine has underscored both the limitations and the evolving adaptability of naval power in the 21st century. The conventional performance of the Russian Navy, particularly in the Black Sea – where it has lost one third of its fleet – has been marked by notable setbacks. Yet, the Kremlin has recalibrated its maritime strategy, shifting towards less visible, but nonetheless valuable, roles for naval assets in less conventional maritime activities.
Chief among these is the deployment of a ‘shadow fleet’ of oil tankers, operating under obscure ownership and employing evasive tactics to conceal their movements and cargoes, and bypass international sanctions, including the Group of Seven (G7) oil price cap. This covert logistical network not only sustains Russia’s energy revenues, but also undermines the efficacy of economic pressure from free and open nations.
The maritime domain has become crucial to sub-threshold warfare, and is likely to pose significant challenges to European security for the foreseeable future…
Concurrently, Russia has expanded its capacity for maritime sabotage, targeting critical European infrastructure such as undersea cables and gas pipelines. For example, a vessel belonging to Russia’s shadow fleet was suspected of severing a power cable between Finland and Estonia on 25th December 2024, in what was the latest in a series of suspected attacks on critical undersea infrastructure. These actions blur the boundaries between military and civilian domains, complicating attribution, deterrence and response.
The maritime domain has become crucial to sub-threshold warfare, and is likely to pose significant challenges to European security for the foreseeable future, as evidenced by the deployment of an Estonian patrol vessel to monitor the remaining power link and the North Atlantic Treaty Organisation (NATO) bolstering its naval presence in the Baltic Sea.
This strategic recalibration is mirrored in efforts to reinforce deterrence and collaboration. The Northwood Declaration, signed between the United Kingdom (UK) and France in July 2025, represents a significant deepening of bilateral nuclear cooperation as a strategic response to growing threats in the European security environment, particularly considering Russia’s aggression and concerns about the reliability of the United States’ (US) nuclear umbrella.
The Northwood Declaration commits both nuclear powers to coordinate across nuclear policy, capabilities and operations, while maintaining independent control over their respective arsenals. It reaffirms that an extreme threat to European allies and partners would prompt a joint response from Britain and France.
Such intentions, however, need to be credible. Their credibility in part rests on capabilities and operations. In the absence of significant changes in these, the Northwood Declaration would leave both countries worse off because their joint commitment would lack credibility. Given the centrality of both nations’ navies to their respective nuclear deterrents, their role is crucial not only as platforms for strategic weapons, but also as instruments of assurance and operational readiness against extreme threats and capabilities.
Understanding global health, refugee movements and climate change as maritime security challenges
Beyond deterrence and covert operations, navies are increasingly drawn into humanitarian spaces. During the Covid-19 pandemic, for example, over 95% of affected states used military elements in their response. The World Health Organisation (WHO) has acknowledged that most states lack sufficient civilian capacity to manage major disease outbreaks, and are therefore reliant on militaries to supplement civilian resources.
Yet, the presence of militaries in a civilian/humanitarian space remains controversial, especially from a public health and Non-Governmental Organisation (NGO) perspective. There are also important distinctions between international and national responses to emergencies, as well as between health emergencies, such as disease outbreaks, and public health issues arising from natural disasters, such as earthquakes and tsunamis.
The presence of militaries, including naval forces, can raise concerns about the militarisation of aid, and provoke resistance from both NGOs and affected populations, while practice suggests that the use of militaries is often less effective than was hoped for. Navies, therefore, must balance the demand from governments to contribute to major health emergencies – when civilian capacity is overwhelmed – with the practical and perceived limitations and complications of their involvement.
The response to migration further illustrates these practical and ethical tensions. Since 2018, more than 180,000 people have crossed the English Channel in small boats, hoping to claim asylum in the UK. In April 2022, the Royal Navy was tasked to lead efforts to deter small boat migrant crossings through the short-lived Operation ISOTROPE, which ended in January 2023. While aiming to deter and reduce small boat crossings, the principle of saving lives at sea was a key priority, with the Coastal Forces Squadron receiving the Firmin Sword of Peace – the highest collective award in the British Armed Forces for humanitarian and lifesaving efforts.
However, political and media narratives have increasingly reframed these crossings as security threats, obscuring the humanitarian dimension as well as legal and ethical protections afforded to asylum seekers under international law. Indeed, a former senior Royal Navy officer criticised the operation for reducing the deterrent element by potentially making crossings ‘safer’ via the presence of naval and other vessels being in the vicinity of disasters, and their duty to save lives at sea.
A Defence Committee report also highlighted that such operations would take scarce naval resources and potentially cause reputational damage. With 68% of small boat arrivals ultimately being granted status to remain, the ethical dilemma for navies and border forces is clear: how can maritime (border) security be reconciled with humanitarian principles, and how can navies continue to respond to increasing demands for similar operations while resources remain relatively limited?
Navies can expect to encounter major change in the types of resources they use and protect, the geographies in which they operate, and the practices they uphold and sustain.
Perhaps the most profound unconventional threat facing naval forces is climate change. It has traditionally been viewed as an external challenge and potential distraction, managed through well-established institutional modalities centred on four areas: greening, hardening, fighting and aiding.
While this view is not incorrect, it misses the true consequences of climate change for the employment of sea power. These emerge from the deeper social, political, economic and technological changes which societies are undergoing in response to climate change.
Navies can expect to encounter major change in the types of resources they use and protect, the geographies in which they operate, and the practices they uphold and sustain. Rising sea levels, shifting resource geographies and changing patterns of human activity are altering the strategic landscape in which navies operate. Missions will increasingly involve protecting climate-sensitive infrastructure, responding to environmental disasters and engaging in resource competition in newly accessible regions, such as the Arctic.
The social and political consequences of climate change, displacement, conflict over water and food, and economic instability will drive new forms of maritime insecurity. Depending on how these combine, naval forces can expect significant change to their mission and rationale as the 21st century warms.
Conclusion: Navigating complexity in maritime security
The unconventional and evolving nature of maritime threats demands a rethinking of naval roles and capabilities. From covert logistics and nuclear deterrence to humanitarian response and climate adaptation, naval forces are navigating a complex and contested maritime security environment. This transformation challenges traditional boundaries between war and peace, military and civilian, and national and global.
Maritime security research must keep pace, bridging strategic theory and operational practice. As unconventional threats increasingly shape and reshape the maritime domain, navies will play a critical role, not only in defending national interests, but also in ensuring security for a wider range of actors and objects – from those traversing the seas in fear of their lives to the subsea critical infrastructure and the health of people and the planet.
Dr Alistair Shepherd is Senior Lecturer in European Security at Aberystwyth University and Head of Department. His research focuses on European and international security, in particular the evolving nature of security challenges and their implications for security governance and capabilities, and the role of strategic culture in shaping responses to defence and security challenges. He focuses on national and regional security actors in Europe including the UK, NATO and the European Union.
This article is published in association with Aberystwyth University as part of the International Sea Power Conference 2025.
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A fascinating overview of the diverse challenges and upcoming potential changes in the maritime sector! Will be interesting to see how the UK continues to tackle and adapt to the challenges and developments.
This is a really sharp piece. It actually echoes a point Mahan made in his own time, that sea power isn’t only about fleet combat, but about safeguarding the wider economic and infrastructural system a nation relies on. The “polycrisis” roles you outline feel like a modern extension of that logic. The challenge that you hint at nicely is doing that without hollowing out the core deterrent function navies still need.