Keeping the UK Secure in a Climate-Changed World

The UK’s new government has been quick to signal its commitment to improving the country’s security. Within weeks of his historic election victory, UK Prime Minister Keir Starmer hosted Ukrainian President Volodymyr Zelensky at a cabinet meeting, the first time a foreign leader has been invited in decades. This is because the ongoing conflict in Europe – together with those in the Middle East and elsewhere – is at the heart of the challenging security context facing the new government. 

Another factor, however, has received less attention: escalating climate change is making the world far more dangerous. Rising temperatures, combined with more extreme and less predictable weather patterns, are compounding traditional security stressors and contributing to new threats.

Climate Change is Becoming a Key Driver of Insecurity

Over the past year, more frequent and longer-lasting droughts have negatively affected agricultural production across Africa and Asia, weakening global food security. Water scarcity triggered violent protests in Algeria and disrupted hydropower in South America, prompting electricity rationing at a time of rising gang violence. A drop in rainfall disrupted global trade by causing unplanned operational downtime at maritime chokepoints – notably the Panama Canal – leading to shortages of goods and higher prices. 

Climate shocks have also complexified security dynamics in states affected by armed conflict. Russian military operations in Ukraine were reportedly disrupted by extreme winter weather in the Black Sea region, which scientists believe was made more likely due to climate change. In April, record-breaking temperatures in the Sahel region exacerbated hardship that has contributed to intercommunal violence, resource competition and radicalism. 

Responding to climate hazards is consuming more military bandwidth, too. Governments in at least 27 states deployed their armed forces to respond to climate shocks between January and July – including in Australia, China, Germany, India, Russia and the US – with some 80 such incidents recorded. This is almost double the total number of events recorded during the same period in 2023. 

The impact of climate change also goes beyond issues of hard security and defence, encompassing highly consequential impacts on human security. These include issues that were salient in the UK’s recent election, such as rising living costs. It is estimated that the impacts of extreme weather were responsible for up to a third of food price increases in the UK between 2022 and 2023. Inflation has also been driven by the main cause of climate change: fossil fuels. After Russia’s invasion of Ukraine, gas prices spiked. The UK was one of the worst impacted countries in Europe due to an over-reliance on gas. Altogether, the last few years have seen soaring pressure on the UK’s food, energy and economic security – and climate change has played a role.

Most indicators suggest that these trends – connecting climate change and multiple dimensions of insecurity – will gather pace over the coming decade as global temperatures continues to rise. As they do so, it is plausible that climate impacts will affect other areas of security, including nuclear safety, space power and cyber defence. The burden of having to respond to such challenges and the high potential for maladaptation also risks driving divisions between states and within security alliances, fuelling geopolitical tensions. Friction is already increasing as warmer temperatures make strategically important regions – such as the Arctic – more accessible, and because of the growing competition over the vast economic and geostrategic benefits of the clean energy transition.

Overall, climate change is no longer an ‘add-on’ for security strategies, or a tangential issue largely relating to the decarbonisation of militaries and the adaptation of equipment and operations to a changing climate. Rather, it is a fundamental condition of the security and geopolitical context – and, therefore, a core component of any defence and security strategy. 

The New Government is Not Starting from Scratch 

The UK has long recognised the importance of climate change as a global security issue. Over the past few years, it has worked to better understand how climate-related risks and opportunities affect the UK’s national interests. Examples of UK government engagement with academia abound, including commissioning research to identify climate-related dilemmas for defence and holding, in March, the UK’s first ever climate security war gaming exercise. 

Progress has been made in operationalising the government’s ambition to strengthen capacity to assess climate change’s security impacts and mainstream analysis into policymaking. This aim was set out in December 2023 at the UN’s climate change conference (COP28) by a cross-Whitehall delegation. Continuing efforts include a programme of international engagement led by the Ministry of Defence Directorate of Climate Change and Environment on matters relating to climate security. Beyond defence, energy security has been a key motivator for successive waves of energy and industrial policy in recent years.

These are all positive developments. But they are modest relative to the scale of the challenge, with a recent parliamentary inquiry hearing that previous governments have failed to put the climate crisis at the heart of national security. More action is required to ensure that climate change’s security consequences are not overlooked in the government’s assessments of the risks to security at home and abroad. Otherwise, the true nature, scale, origin, timing and potential impact of many looming threats to the UK’s security are likely to be underestimated. This raises the possibility that the government will be caught off guard and overwhelmed by future shocks, which now appear all but guaranteed. 

The Strategic Defence Review, launched by the prime minister on 16 July, affords a key opportunity. The Review should put climate change at the heart of the UK’s national security decision-making, creating a vision for how UK defence and the wider national security community can better face a future of worsening climate disruption and navigate these conditions to enhance national and human security.

Previous Reviews Underestimated Climate Risks

Previous reviews have acknowledged that climate change poses a threat. The UK’s 2021 Integrated Review and its subsequent 2023 Refresh identified climate change as an important multiplier of other global challenges, such as poverty and economic instability. It emphasised the need for the UK to work alongside other countries to tackle root causes. Earlier reviews, including in 2015 and 2010, similarly referred to climate change as an issue that could exacerbate existing security threats and drive instability overseas.

These concerns are valid. But simply citing climate change as an amplifier of instability is an incomplete diagnosis. These past reviews underappreciated the scale and pace of climate-related damages and the extent of their entanglement with (all) national security issues. They did not clearly state that climate risks present a fundamental challenge to the UK’s strategic interests. In turn, they failed to conclude that managing these issues should be considered a top national security priority, including establishing clear responsibilities and mechanisms for cross-departmental collaboration.

If the current defence review underestimates these challenges and climate risks go unchecked, the longer-term consequences for UK security and prosperity will be substantial. A plausible scenario is that the government’s ability to provide security and to pursue foreign, defence and development goals could be derailed amid growing climate pressures and greater demand to respond to them. This could produce a future in which spiralling conflict and humanitarian crises take the government by surprise and push the UK’s capabilities to the limit, endangering security at home and challenging the ability to maintain commitments abroad.

Climate Security is a Top Priority for NATO Member States

Neglecting climate change in the latest Strategic Defence Review would also cause the UK to fall further behind allies who are now prioritising climate security, diminishing the UK’s international leadership. This is particularly the case within NATO, where efforts to address the climate crisis continues apace. Although the UK helped lay the groundwork for NATO’s climate security agenda, others have now taken the lead. Germany released its military strategy on climate change in March, and Canada heads up the NATO Climate Change and Security Centre of Excellence, launched by Prime Minister Justin Trudeau on 9 July.

The US has also taken bold action. Within a week of his inauguration, President Joe Biden signed an Executive Order declaring climate considerations essential to US national security, recognising climate change as having evolved into a ‘profound’ crisis. Biden ordered the defence and security community to elevate the crisis as a core national security priority, integrating climate considerations into policies, strategies and partner engagements. Meanwhile, the US intelligence community was directed to complete a National Intelligence Estimate (NIE) on the security impacts of climate change within 120 days.

The inclusion of climate considerations at the highest level of US strategic planning in turn provided an impetus for the administration’s flagship policies. These include the CHIPS and Inflation Reduction acts, aimed at boosting US competitiveness in the green technology sector, enhancing energy security domestically and improving global security by contributing to climate change mitigation.

A Defence Review is an Opportunity for UK Leadership on Climate Change

The UK government has said the Strategic Defence Review will prioritise strengthening UK leadership within NATO and put personnel at the centre of responses to security threats. Providing a clear signal that tackling the security implications of climate change is a strategic priority for UK defence would certainly help to achieve the former. This should include mandating that climate considerations are included within all defence strategy, policy and planning activities, and major investment decisions. Building climate literacy across the national security workforce, including through enhanced training and skills development, would also contribute towards a more people-centred approach to defence. 

A defence review is unlikely to be sufficient on its own to bring about the transformational change needed to cohere a common effort across government on preventing climate-related insecurity. Defence should therefore demonstrate leadership within the wider UK national security community by driving efforts to strengthen interdepartmental understanding and coordination on climate security. Such an approach requires closer collaboration with climate policy departments, as well as those working on issues such as upstream conflict prevention, energy security and building supply chain resilience. The announcement of another review – of national resilience planning – provides a perfect opportunity to do so. The review comes in response to the UK Covid-19 Inquiry’s first report, which concluded that UK risk assessment and management structures have serious flaws and that non-hostile threats (like pandemics) should be treated in the ‘same way as we treat a threat from a hostile state’. The lessons for climate-induced security threats are clear. 

A key part of the effort to tackle climate security risks should be the initiation of a rapid national security risk assessment of climate change. This is needed to establish a full picture of the threats to UK security emanating from the climate crisis. Such an assessment should aim to complement and fill the gap between the existing Climate Change Risk Assessment and National Security Risk Assessment processes. A similar exercise was undertaken in Australia after the Labor Party came to power in 2022, as well in the US with its climate NIE. A national security climate risk assessment would signal the UK’s recognition of the shifting security context, while helping to surface future data requirements and identifying issues to prioritise with limited resources. 

The Ministry of Defence – with its sizeable intelligence apparatus – is also well placed to help create a cross-government capability to provide forward-looking assessments on climate change's geopolitical and security impacts and develop decision support tools. These would help policymakers across departments as they handle the escalating consequences of climate change and the significant challenges of accelerating decarbonisation. Without these, the UK risks failing to see the warning signs of future crises, increasing the potential for shocks – as has been the case with other security issues in recent years. 

The new government has so far shown a renewed commitment to addressing climate change during its first few weeks in office. To maintain strategic advantage amid a more volatile global security environment, such commitment must also extend to national security and defence. If not, the UK could be left more exposed to the impacts of climate-related disruption and its wider geopolitical and security consequences.

The views expressed in this Commentary are the authors’, and do not represent those of RUSI or any other institution.

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