Cover: Climate Change Dilemmas for UK Defence and Security

Climate Change Dilemmas for UK Defence and Security

Exploring implications, challenges, opportunities and threats through future scenarios

Published May 31, 2023

by Jacopo Bellasio, Lucia Retter, Nicolas Jouan, Kristin Thue, Maria Chiara Aquilino, Pauline Paillé

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Research Questions

  1. What defence and security dilemmas could the UK Government face due to climate change?
  2. How could climate change dilemmas evolve over time depending on average global temperature increases?
  3. How may climate change dilemmas influence great power competition, defence capabilities and decisions around science and technology (S&T) investments?
  4. What practical interventions could better prepare the UK for future climate change-induced defence and security dilemmas?

Climate change is set to fundamentally shape the future of humanity. It has been recognised as a threat multiplier and a driver of instability with the potential to alter geopolitics and state behaviours, as well as to aggravate political, socio-economic, and environmental tensions, and to foster violence and conflict. Climate change effects are expected to negatively affect the functioning of armed forces, putting significant strain on the resilience of infrastructure and capabilities, exacerbating operating environment conditions and hampering military capabilities' effectiveness.

In this context, the Global Strategic Partnership (GSP) led by RAND Europe conducted a study exploring the implications of climate-change-related developments on the UK Ministry of Defence (MOD)'s ability to deliver five priority outcomes:

  1. Strengthening the UK's national security by delivering threat-based defence decision-making.
  2. Protecting the UK and its Overseas Territories.
  3. Enhancing global security through persistent engagement and response to crises.
  4. Contributing to NATO's collective deterrence and defence.
  5. Modernising and integrating defence capabilities by taking a whole-force approach and increasing the use of technology and innovation.

To achieve the objective of this study, we developed narrative vignettes to facilitate discussion and analysis of climate change implications with stakeholders and experts in a participatory event.

Key Findings

Strengthen the UK's national security by delivering threat-based defence decision-making

  • Climate change effects are expected to contribute to establishing a volatile and uncertain geostrategic environment.
  • Changes to the threat landscape may arise due to adversaries' and competitors' climate adaptation and mitigation measures.
  • UK national security could be strengthened through well-implemented climate adaptation and mitigation measures.

Protect the UK and its overseas territories

  • Climate-change effects are expected to increase the frequency and scope of threats to the UK and its overseas territories.
  • Demand for HADR and MACA operations will likely grow, exerting a growing strain on defence.

Enhance global security through persistent crisis engagement and response

  • No single individual actor can face and address in isolation the multifarious challenges of climate change effects.
  • Climate change will amplify the need for global engagement and alliances.
  • The UK and others should make climate adaptation and mitigation challenges and requirements fair and balanced for low-and-middle-income countries.

Contribute to NATO's collective deterrence and defence

  • Climate-change challenges and threats will apply similarly to NATO Allies.
  • There is an opportunity for the UK MOD to act as thought leaders and champions within NATO on climate change.

Modernise and integrate defence capabilities by taking a whole-force approach and increasing technology and innovation use

  • Technology and innovation could be critical to meeting climate-change challenges.
  • Implementing an effective whole-force approach will be critical to addressing the growing demand for defence contributions and the concurrency of crises.
  • S&T and innovation may enable defence to harness climate adaptation and mitigation towards pursuing broader strategic objectives.


  • The MOD and Partners Across Government should run games and simulations of climate-change implications to identify responses to complex crises.
  • The UK Government should leverage its soft power to retain freedom of action when pre-empting or responding to climate crises.
  • The UK Government needs to build a robust narrative to gain public support for its approach to climate security risks.
  • The UK Government should continue its shift from 'emergency response' to 'resilience' for a more proactive climate adaptation.
  • Defence needs better market intelligence and foresight to harness S&T innovation and anticipate climate change impacts.
  • The MOD must establish realistic boundaries for military involvement in climate crises.

Research conducted by

This study was commissioned by the Climate-change and Sustainability (CC&S) Directorate within the UK Ministry of Defence (MOD), the Defence Science and Technology Laboratory (Dstl), the Secretary of State's Office for Net Assessment and Challenge (SONAC) and the Development, Concepts and Doctrine Centre (DCDC). The research was conducted by RAND Europe.

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