Wargaming Climate Change: Reflections for the Strategic Defence Review

UK defence has recognised climate change as a dominant global trend and a risk multiplier. It has invested effort to understand how climate change may affect operations, and how it could exacerbate existing security risks to increase demands on the military. 

In 2023 the Integrated Review Refresh (IRR) stated that ‘systemic competition between states now represents the most immediate and substantial threat to UK interests’. It also acknowledged climate change as the ‘first thematic priority’.

Opportunities exist to further develop our understanding of the interaction between systemic competition and climate change. Allies, partners, competitors and adversaries are already experiencing the effects of climate change and are looking for support to respond to associated security risks such as drought, flooding and famine. Some are adapting to its effects, others are reacting. Climate change increases the ability of malign states and non-state actors to exploit instability for their own ends.

While it is impossible to predict the future, the Ministry of Defence (MoD) can utilise futures research methodologies to explore a range of possible scenarios. A common approach for engaging defence with new possible scenarios is wargaming.

The Wargame

Dstl was funded by the Secretary of State’s Office for Net Assessment and Challenge (SONAC), the Directorate for Climate Change and Environment (CCE) in the Ministry of Defence (MoD) to develop a wargame exploring environmental trends and global competition in the short-to-medium term (to 2045).

While there is no single definition of ‘wargaming’ as a practice, Defence Futures describe it as ‘a scenario-based warfare model in which the outcome and sequence of events affect, and are affected by, the decisions made by the players’, though it can also be used to explore wider scenarios which do not feature conflict. 

This game focused on a geographical region, and was played across 1.5 days. Players were assigned to teams representing global powers. Teams had a range of capabilities which they could use to execute actions during each year-long turn. Dstl adjudicators reviewed all actions and used this information to update the map and set the scene for the next turn. 

Reflections

Each country had a unique experience with regards to the risks, threats or requests encountered. Some developed a proactive approach to mitigating future risk, protecting their capacity to pursue long-term goals. Others found themselves overwhelmed and in a constant state of emergency triggered by successive or overlapping crises. Some found themselves struggling to maintain a long-term vision in the face of near-term requests for their support from the international community. The efficiency of actions taken was at times affected by wider factors including style of government, economic factors, and development needs.

The impacts of climate change on security are felt differently across the globe, but the solutions to mitigate these impacts will be multinational. Not all countries have the infrastructure or governance structures to manage their own risks, and others may seek to exploit these vulnerabilities. 

Responses to threats that are both immediate and enduring (such as energy, food or water insecurity) have the potential to support partners in crisis now, but also create more resilient conditions for the future.

A common thread throughout was the need to develop climate responses through cooperation, not conflict. Some opportunities will be captured by strengthening existing partnerships or finding opportunities for partners to come together to enable greater and quicker change. Some Global South relationships may require the UK to find new ways to consider the immediate needs of partners, offering greater agency in chosen solutions. The nature of relationships is crucial, as emerging powers are looking for reciprocal partners who will respond to the direct needs of their citizens, not foreign policy goals. 

The game reflected current expectations of geopolitical relationships, in that relationships with partners who overpromised and underdelivered suffered most, contributing to the increasingly volatile global geopolitical environment described in the IRR. The game developed insights into how allies might build successful engagement strategies with emerging middle powers. 

Some risks can become entangled (such as drought, food security and migration), requiring multinational responses to deliver effect at the required scale. The UK has a role to play in this landscape. Recent environmental disasters such as the wildfires in Greece demonstrate the need to prepare for multinational humanitarian responses. Different responses to disaster relief requests and implications for international relations played out in the game.

Climate-related requests for defence support could include disaster relief, humanitarian response, or capacity-building support. Focusing on the warfight and not planning for these requests would risk ceding influence to those willing step into the humanitarian vacuum, creating new security risks. The Strategic Defence Review (SDR) aims to strengthen security at home and abroad in response to growing and diversifying threats, including instability caused by climate change. This includes considering the UK’s international partnerships and alliances, and how these can be strengthened in the cause of collective security and deterrence.

The key finding is that the strategic effects of climate change will significantly alter our ability to achieve our key objectives.

Recommendations

The wargame resulted in the following recommendations. 

1. The MoD needs to ensure that defence and security policies and plans are informed by the potential effects of climate change, so that the decisions of today prepare the UK for the future operating environment.
2. The MoD needs to build upon existing activity to demonstrate the opportunity for the UK to maintain strategic advantage in a defence context – that is, the ability to fight and win. Developing existing strategies into policies and plans will help enable the shift from understanding to action. 
3. The MoD and cross-government departments should consider how to support stronger, integrated partnerships to build mutual understanding and resilience in response to climate-driven instability. 
4. The MoD needs to reconsider how to support and work with middle-ground powers in addressing climate impacts which may hinder their development. It is important that the UK regularly assesses its ability to provide stabilising effects.
5. Some countries expect changes in the UK’s approach for partnerships to feel mutually beneficial and therefore sustainable. 
6. The UK needs to consider how the results of climate change might shift the global balance of resources and populations, and how this affects all countries. This knowledge will enhance foresight, enabling improved monitoring of emerging security threats.

These recommendations support the academic evidence base describing the environmental and geopolitical effects of a changing climate, and will be fed into consultations for the SDR. They reinforce the findings of a series of essays funded by SONAC in 2023 to further explore the relationship between net zero and national security (circulated within the MoD). 

The Defence Review

The SDR Terms of Reference describe how the threats faced by the UK are growing and diversifying, identifying the instability caused by climate change as one of these threats. The SDR will determine the ‘roles, capabilities and reforms’ needed to respond to threats and opportunities. 

This wargame allowed the MoD to explore a range of climate-informed scenarios and potential responses to them in an international context. It highlighted a range of opportunities for international partnerships and alliances to be strengthened in pursuit of collective security or deterrence. It also allowed players to consider how whole-of-society changes such as the energy transition might affect defence decisions in areas like supply chain resilience. 

Work is ongoing to deliver a second wargame of the same scope in a different geography. This is supplemented by other projects on climate wargaming and exercising. These techniques help to enable cross-government coherence on climate security risks and explore multifaceted problems in a safe environment.

Building on this, wargaming with allies will help UK defence to develop interoperable responses to conflict or disaster. As climate change is a driver of instability, greater levels of international cooperation will be required to design and deliver the right responses. Through proactive, integrated responses to climate security risks, armed forces can build resilience and ensure interoperability with allies and partners.

A cross-Whitehall approach will also help the government to leverage the benefits of defence decisions, particularly where green technologies can help to secure national aims. This wargame has demonstrated that the UK has the chance to respond and ensure that it thinks strategically about its capability as a military force. 

The SDR team has the challenge of determining how such factors should inform the future shape of the UK armed forces, but also of ensuring that the capabilities procured are resilient to future operating environments and the threats contained within them. The results of its work on the nature of the climate threat and associated operational response will set the foundations for a resilient future for the UK’s fighting forces. 

The views expressed in this Commentary are the author’s, and do not represent those of RUSI, Dstl, CCE, SONAC or any other institution.

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