Introduction
In November, the world came together at COP29 in Baku. For a brief period, the world’s media ran yet more stories about ice caps and polar bears. Some went further and highlighted risks to food production, deforestation and biodiversity loss. Few said, ‘Climate change is a clear, present, and escalating danger to global security’. Yet it is.
The risks
Climate change is already impacting global food security. Desertification, drought, and floods, alongside new vectors for pests and expanding disease zones, are throwing global agriculture out of kilter. These stressors exacerbate pre-existing tensions between groups as economic vulnerabilities and the struggles for productive land increase. When overlaid with economic inequality and fragile governance, the result is invariably conflict.
More than all this: the changing climate is also having a deleterious impact on military capabilities and has been limiting operational outcomes.
The case of Somalia
In Somalia, flooding linked to climate change increasingly blocks many of the main access roads into southern parts of the country. This impedes the operations of security forces to degrade al-Shabaab. During droughts, al-Shabaab has denied access to aid agencies in those areas it controls. It has also seized aid and distributed it itself to win hearts and minds.
Somalia is not an exception. Climate change is adding burdens, costs, and complications to security operations around the world. It is easy to forget that the military’s primary role is deterrence and warfighting. Yet when military capabilities—both personnel and equipment—are deployed in support of humanitarian assistance, they are not available to train for or deliver that primary objective.
The global problem
In October 2024 alone, there were 48 separate occasions in 11 countries, including India, Mexico, the Philippines, Spain and the United States, that required their respective militaries to assist with the aftermaths of severe storms, floods and wildfires.
Extreme weather has also struck direct strategic blows to military installations. In 2018, Hurricane Michael wreaked £3.74 billion of damage to aircraft hangars and F-22 Raptors at Tyndall Air Force Base in Florida. The US Air Force has yet to finish the repairs. A wildfire resulting from extreme heat in the summer of 2023 triggered explosions at a military ammunition depot in Nea Anchialos in central Greece and, in turn, the urgent evacuation of Greek Air Force F-16 jets from their bases.
It is perhaps unsurprising that, in March of this year, leaked Canadian documents indicated that only 58% of the country’s armed forces could respond if called upon by NATO – highlighting how climate risks are compounding low levels of combat readiness. In the UK, we need to be clear how our own capacity may similarly have been eroded. The use of service personnel to support civil authorities is, of course, an established UK policy, but a greater tempo of such activity must be anticipated.
The impact on UK Defence – people
The UK is not immune to these trends in other ways either. Climate change is disrupting the vital work our armed forces and other agencies do in the defence of the nation. In July, HMS Trent, an offshore naval patrol vessel, was diverted from her mission to intercept maritime drug trafficking in order to provide humanitarian assistance in the Caribbean after Hurricane Beryl. With the hurricane season lasting longer and involving a greater tempo of storms, such demands are only set to amplify. Sadly, we know that criminal networks tend to flourish in the aftermath of natural disasters, and so the operational harm is also magnified.
Rising temperatures and the duration of extreme heat episodes are another factor that puts armed forces at risk. Each year the British armed forces lose training days due to heat. This is not just at overseas bases, such as Brunei, Cyprus and Kenya, but also at home. In 2022, for example, dozens of soldiers were pulled from training exercises to fight wildfires on Salisbury Plain.
(Cpl Rob Travis RAF, Credit: UK Ministry of Defence 2019. Copyright: UK MOD © Crown copyright 2019)
The impact on UK Defence – estate and infrastructure
Climate change also impacts infrastructure, causing operational harm. Two summers ago, the RAF had to suspend flights from Brize Norton, Britain’s largest air base, because the runway had melted in the extreme (for Britain!) heat. The full cost of maintaining operational effectiveness in the face of rising sea levels on Britain’s coastal installations and weapon ranges remains unclear. HM Naval Base Clyde (Faslane) is the home of the UK’s submarine service and the nation’s nuclear deterrent. Combatting sea level rise at the United States Naval Station Norfolk provides a salutary lesson for the UK in the cost of climate change to our military capability.
And on the topic of submarines, melting polar ice has operational implications. Less pack ice equates to less surface cover to hide beneath, just as more slush ice has implications for engines and communications. The receding Arctic ice will also permit an ‘over the top’ shipping, via the Northern Sea Route, facilitating increasing access to military and commercial vessels. The implications are many, including prospects for economic and trade disruption as well as untold environmental damage and, where adversaries are concerned, risks relating to proximity and reach.
The UK response
What should Britain do to respond? The security implications of climate change are cross-party issues. Enhancing operational outcomes should remain an ongoing military priority, and this includes maintaining preparedness and resilience. That begins with targeted policy, and specific climate and security training that supports effective decision-making by military personnel. For example, gaining an understanding of how climate-induced scarcity escalates sectarian violence, shapes sentiment towards authorities and security forces, drives civil unrest, and exacerbates displacement (internal and cross-border) in conflict zones around the world.
Improving civilian-military cooperation is key. Gaps in provision undermine an effective response. Better integrated planning across in-theatre military, police, and civilian actors is essential. Attention also needs to be afforded to how operations – joint or otherwise – in climate change-impacted environments amplify the requirement for specialist equipment that is designed specifically for temperature and weather extremes.
Commanders must also be mindful that increased temperatures also cause fatigue in service personnel (and service animals) more quickly, necessitating not only greater logistical support but also a re-evaluation of expectations for deployed troops in terms of the distances they can cover, tasks they can undertake and the duration they can perform them. This was a lesson that UK forces learnt in Iraq and Afghanistan but may have been forgotten since combat operations ceased. Given climate trajectories, impacts will be greater going forward.
The issue of migration…
Then there is the issue of migration. When food and water are scarce, lands become uninhabitable, or conflict breaks out, and movement often becomes the only viable means of adaptation. Criminal gangs soon take the chance to exploit systems and migrants. Here, enhancing upstream capacity with community and environmental resilience is key to reducing displacement. But the UK and others must follow through on their funding and capacity commitments as the failure to deliver risks not only reputational and diplomatic damage but also leaves vulnerable countries without the finances to prepare and adapt.
Conclusion
The new government in the UK must understand the urgent need for cross-party and interdepartmental climate security policy. It must be delivered at scale and at pace. A unitary focus on net zero initiatives is not enough. The UK must also maintain effective defence and crisis management capabilities in a climate-changed world. The defence, development and diplomatic agendas must work together to ensure preparedness and situational foresight. Only with such climate security cooperation and integration across a wider ‘whole of system’ approach will the government have a coherent set of policies that are adequate to face the inevitable climate security shocks to global food security, supply chain failures, economic instability and mass migration. The climate is shaping national security, and the UK must act to adapt now in order to be prepared.
Main picture – Reserve Soldiers of 7 Battalion The Rifles assist the Berkshire Fire Brigade to dam a breach in the Kennet Canal that had threatened an electrical sub-station near Burghfield, south of Reading during flooding in February 2014. (© Crown Copyright 2014. Defence Images UK. Photographer: Cpl Richard Cave LBPPA)
Tim Clack
Tim Clack is an Associate Professor at the University of Oxford and Director of the Climate Change & (In)Security Project. He is Editor of the Routledge Advances in Defence Studies (RAiDS) book series.
Barry Gardiner MP
Barry Gardiner is the Labour Member of Parliament for Brent North and Chair of the All-Party Parliamentary Group for Climate, Nature and Security.
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Barry Gardiner MP#molongui-disabled-link
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Barry Gardiner MP#molongui-disabled-link
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Barry Gardiner MP#molongui-disabled-link
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Barry Gardiner MP#molongui-disabled-link
