The Impact of Climate Change on Security: Is the UK in Need of a Nationwide Review?

In 2008, the CIA was ordered to carry out the first ever US National Intelligence Assessment (NIA) on the national security implications of climate change. The findings from the assessment predicted that over the next twenty years, global climate change will affect a wide range of security interests.

Crucially, only some of the impacts on national security were expected to be the result of physical changes in the environment. In the short to medium term, the NIA found that the greatest security challenges will stem from political, social and economic issues associated with mitigation and adaptation strategies, most of which are designed to reduce exposure to climate change, and capitalise on potential gains.[1]

Demand for ‘climate intelligence’ continues to grow in the US and elsewhere largely because there is increasing awareness of the potential impacts of climate change. Extreme weather events such as Hurricane Katrina are becoming more frequent, and the consequences are worsening. The director of national intelligence, Dennis C Blair, recognised the significance of climate change in the annual threat assessment published in February 2009.[2] More recently, the CIA opened The Center on Climate Change and National Security to assess how environmental factors will potentially affect political, economic and social stability overseas. In December, the Pentagon announced that the impact of climate change will be addressed in the next Quadrennial Defense Review, which updates Pentagon priorities every four years. These moves reflect a serious commitment by intelligence agencies to further their understanding of how climate change is likely to affect US national security.

Climate Change and Security in the UK

The impacts of climate change on UK security will be similar to those identified in the US. In the coming years, the UK government will have to decide how it will protect its citizens and pursue its interests in a rapidly changing environmental context. The Institute of Public Policy Research (IPPR) Commission on National Security in the Twenty-first Century has specifically warned that ‘there are no scenarios in which unchecked climate change is good for either international or national security’.[3] Last year, the former secretary of defence, John Reid, suggested that we should expect to see environmental security ‘at the heart’ of everything that UK governments will do for years to come.[4]

The Ministry of Defence (MoD) identified a number of potential threats to national security in its Climate Change Strategy, published in 2008.[5] Elsewhere, in its National Security Strategy, the Cabinet Office has consistently declared the need for a full review of how climate change is likely to affect security both at home and abroad.[6] Nevertheless, an assessment comparable to the US NIA has not been carried out. Instead, government decision-makers continue to direct intelligence resources primarily towards the conflict in Afghanistan and the wider fight against terrorism. Meanwhile, broader security policy is still being developed around the need to deliver hard security.

Although this situation is perhaps understandable given the immediate security context, Nick Mabey, Chief Executive of E3G, has rightly warned that the singular focus is contributing towards the marginalisation and weakening of the UK’s ‘ability to anticipate, prevent and respond to more complex and long-term security challenges’ such as climate change.[7] To help address this deficit in security policy, the security implications of our changing climate need to be assessed. Doing so will give us a better chance to avoid becoming embroiled in social unrest and volatile conflicts, both domestically and abroad.

Our Changing Climate

Despite the uncertainty that surrounds climate modelling, the British climate will change in a number of ways. Summer heat waves will increasingly threaten health and put pressure on energy and water supplies. An overall decrease in rainfall will add further stress to water resources, particularly in major cities. At the same time, shorter but heavier periods of rainfall will cause widespread flooding. Sea level rises (of up to 80 cm in some parts of the UK by 2100, according to the IPCC Third Assessment Report) will inundate eastern coastal regions as well as some key naval bases, such as Portsmouth and Devonport, and is likely to be accompanied by dangerous storm surges.[8] Left unchecked, the economic cost to the UK will be substantial. In 2006, the Stern Review showed that annual flood losses alone could increase from 0.1 to 0.2-0.4 per cent of GDP if the global average temperature rises by 3-4°C as predicted.[9]

The domestic challenges outlined above are compounded by the UK’s intricate connection to the rest of the world through global networks of trade, diplomacy, military alliance, transport, communication and aid. These networks operate beyond our control and are vulnerable to the types of disruption that climate change will cause. As the IPPR Commission predicted last year, the UK will therefore almost certainly be influenced indirectly by the wider consequences of increased state failure, violent conflict, humanitarian disaster and forced movement of people that are likely to accompany climate change elsewhere in the world.[10] Commonwealth countries in the tropics and subtropics may be especially badly affected.

Past emissions of greenhouse gases will continue to drive climate change over the next century, regardless of how effective mitigation measures prove to be. The debate that surrounds climate change therefore no longer focuses on whether the climate is changing, but rather the extent of this change, the frequency of extreme events and their likely consequences. Although the exact nature of impacts depends on the mitigation and adaptation strategies that are deployed, we can expect that they will negatively affect key energy and transport infrastructure, food production, water supplies and defensive capabilities – systems that have all been designed around the expectation that the environment is, and will remain, a relatively stable variable. This, in turn, will affect where, when and how the security and defence communities operate.[11] Combined with other pressures such as resource scarcity and overpopulation, even small changes in the climate are increasingly likely to have negative impacts on the social, political and economic institutions that underpin security, be it locally, nationally or globally. In particular, climate change threatens to drive political and social conflict over issues of responsibility, accountability, fairness and justice.

From a defence perspective, there is a danger that the military will be ill-equipped, under-resourced and under-prepared. Decisions made over a decade ago about the types of helicopters that would be required have had considerable knock-on effects for the current conflict in Afghanistan. This is because weapons, vehicles and delivery systems can take ten years to develop and are typically expected to be in service for twenty to thirty years – a deeply worrying state of affairs given the potential for rapidly altering climatic conditions (such as higher temperatures and flooding) that could disrupt the effectiveness of military equipment and infrastructure.[12]

Climate Change Policy

Under the Climate Change Act of 2008 the government is legally committed to publish a full risk assessment of climate change impacts in the UK by 2011. The most recent National Security Strategy states that understanding security risks is ‘integral’ to this work.[13] However, despite the emergence of a distinct climate security discourse, the government’s national response to climate change continues to be, for the most part, developed in non-security departments (DECC, DfID, DEFRA).

The evidence base for climate change impacts on the UK expands through research at the MET Office, UK universities and research institutes. However, not enough is being done to develop our understanding about how to ensure the safety of UK citizens, protect key strategic assets and maintain access to vital resources in an environment that is changing physically, politically and socially.

One exception to this is the Integrated Climate Programme (ICP). The ICP started in 2007 when the MET Office, DEFRA and MoD agreed to collaborate on a five-year programme to identify where conflict and security threats might emerge as a consequence of climate change. However, the outward focus of the programme means that impacts on domestic security are not of primary concern.

A Nationwide Review of Security Impacts

The precise impacts of climate change on the UK will depend on the resilience of our systems and on the mitigation and adaptation strategies that are adopted locally, nationally and internationally. As the NIA noted, mitigation and adaptation strategies are themselves likely to have considerably greater implications for national and international security than the physical impacts of climate change. Moreover, the UK has little control over global efforts to mitigate climate change unilaterally as we contribute only around 2 per cent of CO2 emissions.[14]

The UK may be in a better position than most states as the worst physical impacts of climate change are not expected to be felt here for many years, but this will not insulate the country from political, social and economic upheaval both domestically and abroad. Identifying where and how climate change is likely to contribute to such upheaval should therefore be a key strategic goal. What is ultimately required is continual reassessment of the security implications of both the physical impacts of climate change, and the political, social and economic consequences of adaptation, mitigation and overall resilience-building. The MoD has already identified the need for further research to develop our understanding of what climate security means, the security implications of climate change for UK defence, how climate change could affect our interests, and how it is likely to interact with other issues such as energy security and migration. However, the main focus of the MoD is to defend the UK from overseas threats. It is the Home Office, with its mandate to protect the public, which should be responsible for ensuring that a nationwide assessment of climate change’s impact on security is carried out.

A review would also be valuable in a broader security context. With UK security policy currently weighted heavily towards counter-terrorism, there is a risk that climate change will not be positioned high enough up on the agenda when the next Strategic Defence Review takes place later this year. A review of climate change impacts on UK security is therefore essential to help ensure the right balance between short- and long-term security planning.

Internationally, it is important to recognise that the UK will inevitably be restricted by European and global efforts to address climate change. We live in an interdependent world and the development of effective mitigation measures, as well as strategies for adaptation, are liable to be influenced or controlled by multilateral institutions and international regimes. This will inevitably restrict autonomous policy options available to the UK to act on climate change. A nationwide review of climate change impacts would help us to understand how UK interests are likely to be affected, and show us where they are most vulnerable. This will reduce the risk of entering into international agreements over adaptation and mitigation that in the long term prove detrimental to our national security.

Consolidating the Response

The need for us to understand the future strategic context for defence was expressed in the Strategic Defence Review in 1998. This document ‘confirmed the long-term nature of Defence Planning and the need for a wide-ranging understanding of the complex strategic context, including environmental security’.[15] Much of this message has since been dwarfed by the scale of the response to international terrorism which has come to dominate the strategic agenda in the UK.

Nevertheless, the call from the Secretary of Defence, Robert Ainsworth, for a full Strategic Defence Review to be carried out after the next general election represents an opportune moment to redress the apparent imbalance in security policy between short- and long-term strategic goals. A nationwide review of climate change impacts on security would help the government to meet this challenge. Some of this work has already begun – all government departments are working on high-level adaptation plans which will provide the basis for the government’s National Adaptation Programme due in 2012. However, it is vital that the security community is involved in the development of this programme in order to assess how different mitigation and adaptation strategies are likely to impact on national security.

One agency should be responsible for consolidating the UK’s response to climate change. As the ministry responsible for protecting the public and maintaining domestic security, the Home Office should do so in collaboration with other departments such as DEFRA, DECC and the MoD, to prevent the doubling-up of efforts. For the review to have a meaningful impact on security policy, structures and institutions will need to be put in place to enable the regular assessment of the security implications of climate change impacts, both domestically and abroad. Because there is no single endpoint to aim for, whatever climate change strategy is implemented must be able to evolve as our understanding of the phenomenon and its political, social and economic impacts becomes clearer through emerging science. Regular assessments will ensure that ‘climate security’ issues remain at the forefront of the government’s broader security strategy.

Duncan Depledge
Climate Change Programme


[1] National Intelligence Council, ‘National Intelligence Assessment on the National Security Implications of Global Change: Statement for the Record of Dr. Thomas Fingar’, 2008.

[2] Dennis C Blair, ‘Annual Threat Assessment of the Intelligence Community for the Senate Select Committee on Intelligence’, 2009.

[3] IPPR Commission on National Security in the Twenty-first Century, ‘Shared Responsibilities: A National Security Strategy for the UK’ (London: IPPR, 2009), p. 11

[4] Reuters, ‘John Reid on Climate Change and Global Security’, 5 December 2009.                

[5] Ministry of Defence, ‘Climate Change Strategy’, 2009.

[6] Cabinet Office, ‘The National Security Strategy of the United Kingdom: Security in an Interdependent World’, 2008; Cabinet Office, ‘The National Security Strategy of the United Kingdom Update 2009: Security for the Next Generation’, 2009.

[7] Nick Mabey, ‘Security and Threat Misperceptions’, in Paul Cornish, Britain and Security (London: Smith Institute, 2007), p. 40.

[8] Based on research carried out by the Defence Scientific Advisory Council, DEFRA and UKCIP.

[9] Nicholas Stern, ‘The Stern Review’, 2006.

[10] IPPR, op. cit., p. 65.

[11] Defence Scientific Advisory Council, ‘Defence in a Changing Climate’, 2007, p. 2.

[12] Defence Concepts and Doctrine Centre, ‘DCDC Global Strategic Trends Programme: 2007-2036’, Third Edition, 2007, p. 10.    

[13] Cabinet Office, ‘National Security Strategy Update’, op. cit., p. 54.  

[14] DEFRA, ‘UK climate change sustainable development indicator: 2006 greenhouse gas emissions, final figures’, 31 January 2008.

[15] DCDC, op. cit., p. 11.

Duncan Depledge

Associate Fellow

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