Defence & Security

The Critical Impacts of Climate Change on The Defence Sector

Published on
August 16, 2023

"Today, no nation can find lasting security without addressing the climate crisis. We face all kinds of threats in our line of work, but few of them truly deserve to be called existential. The climate crisis does, and climate change is making the world more unsafe, and we need to act."

– US Secretary of Defence Lloyd J. Austin III 

Climate change is one of the most pressing global challenges of our time, with far-reaching consequences that extend beyond environmental concerns. It directly affects economies, societies, and even national security, as noted in the comment above, delivered by the US Secretary of Defence in an address to the Leaders’ Summit on Climate in April 20211.

Defence and military infrastructure is not immune to the impacts of climate change either. As the world experiences rising temperatures, shifting weather patterns, and rising sea levels, the defence sector must adapt and implement strategies to ensure resilience and preparedness in the face of these environmental challenges.

If militaries fail to adapt effectively to climate change, several serious consequences could unfold, both in terms of operational capabilities and broader national and global security. These consequences are interrelated and can amplify each other, leading to increased instability and challenges for defence and security efforts.

Climate Change as a threat multiplier

“The character of warfare is changing fast; so is the climate. Both issues are changing the way our military fight, live and train in unfamiliar ways. Linking these issues together, they both demand that we adapt to the new circumstances that we face and take transformative action now. We need to change mindsets, and the way we operate in peace, in war and in persistent competition.”

Lt Gen. Richard Nugee - Climate Change and Sustainability Review Lead in Defence, 20212

Senior military and defence officials from many countries have recognized the significance of climate change as a factor that impacts military operations, readiness, and defence spending.  

The US department of defence (DoD) was the first body to officially refer to climate change as a threat multiplier in its 2010 Quadrennial Defence Review (QDR)3. The concept of climate change as a threat multiplier refers to its ability to exacerbate existing security challenges and potentially create new ones by intersecting with other global trends to increase the frequency and complexity of security challenges.

In 2014, the U.S. DoD released a roadmap for climate change adaptation4. This document outlined the ways in which climate change can act as a threat multiplier by interacting with other factors, such as political instability, resource scarcity, and extreme weather events. It emphasized the importance of adapting military infrastructure and operational planning to address the security risks posed by climate change.

In 2021, the UK MoD released its own Climate Change and Sustainability Strategic Approach2 which outlines the MoD's commitment to addressing climate change as a significant security challenge and lays out the key principles and actions that the MoD will undertake to enhance sustainability, resilience, and preparedness in the face of climate-related impacts.

Overall, the US characterization of climate change as a threat multiplier underscores the understanding that climate change is not just an environmental issue but also a critical factor that can amplify existing security challenges. This recognition has led to efforts to incorporate climate considerations into military planning, infrastructure adaptation, and disaster response to ensure that the military remains effective in a changing world.

The evolving role on military in disaster response

Climate change can significantly impact the way major militaries respond to environmental disasters in the future. As the frequency and intensity of climate-related disasters increase, armed forces around the world will face new challenges and must adapt their disaster response strategies and capabilities. This increased frequency can strain military resources and require more frequent and extensive disaster response operations, and the increased demand for disaster response can strain logistical resources such as personnel, equipment, and supplies.

Among some of the other challenges this will cause, climate-related disasters can result in complex humanitarian needs, including displaced populations, food and water shortages, and public health crises. Military response efforts may need to evolve to address these multifaceted challenges, potentially involving coordination with civilian agencies, NGOs, and international partners.

Also, climate change can expand the geographic scope of disaster response efforts. Regions that were historically less prone to certain types of disasters may experience them more often. This requires militaries to be prepared to respond to disasters in new areas and adapt to changing disaster patterns.

The vulnerability of military infrastructure

Climate change has already started to impact the military in various ways, and these effects are expected to become more pronounced in the future. Here are some specific examples of how climate change is affecting the military:

(1) Infrastructure Vulnerability

Military installations, especially those located near coastlines, are vulnerable to rising sea levels and increased frequency of severe storms. Naval bases, airfields and supply depots are at risk of flooding, erosion and storm damage, which can disrupt operations and require costly repairs. In 2018, Tyndall Air Force Base (AFB) in Florida experienced a direct hit from Hurricane Michael, causing $4 billion worth of damage5.

(2) Operational Challenges

Naval bases, airfields and supply depots near coastlines are at risk from rising sea levels, while other facilities are at risk from other changes in weather pattern and an increase in extreme weather events. These endanger the readiness and operational capabilities of armed forces. Changes in climate patterns can impact military operations, such as altering flight conditions, affecting navigation and influencing the effectiveness of certain weapons systems. These operational challenges require adjustments in tactics, techniques and procedures. In addition, Since the Gulf War, the United States has lost more F-22s to climate change than enemy combatants. While Tyndal AFB’s aircraft were not called to any operational missions during the extensive repairs required after Michael, the changing geopolitical landscape may soon levy heftier demands and leave little room for error when it comes to military readiness. 

(3) Training Disruptions

Extreme weather events, such as heatwaves, heavy rainfall and extreme cold, can disrupt training exercises. Intense heat can pose health risks to personnel, leading to the suspension of training activities. Adapting training programs to changing weather patterns becomes necessary.

(4) Resource Scarcity & Geopolitical Tensions

Climate change can exacerbate resource scarcity, leading to regional conflicts over water, food, and energy. This can increase the demand for military presence in certain regions and contribute to geopolitical tensions. In addition, climate change can disrupt the availability of essential resources, such as water and food, particularly in regions already facing resource challenges. This scarcity can intensify competition among nations for access to limited resources, potentially leading to conflicts over these critical commodities. Militaries may be required to protect resource supply routes, secure access to essential resources, or intervene in disputes arising from resource competition.

(5) Political Tensions

Climate change can amplify existing political tensions by exacerbating socioeconomic inequalities and creating conditions conducive to radicalization. These tensions may lead to increased security concerns and conflicts within and between nations. Militaries might be called upon to address these security threats, potentially diverting resources from other strategic priorities.

(6) Arctic Security

As the Arctic ice continues to melt due to climate change, new shipping routes become accessible. This has strategic implications, as countries compete for control over these routes and access to untapped resources. The melting Arctic ice also requires increased military presence for search and rescue operations and to maintain territorial claims.

(7) Health Impacts

The spread of vector-borne diseases, such as malaria and dengue fever, can be influenced by changing climate conditions. Deployed military personnel in affected regions may face increased health risks, leading to additional medical considerations and resource allocation.

(8) Migration & Instability

Climate change can contribute to population displacement and migration, especially in vulnerable regions. This migration can lead to regional instability and potentially result in conflicts that require military intervention or stabilization efforts.

To address these challenges, military organizations are implementing various strategies. The military's ability to adapt to and mitigate the impacts of climate change is essential not only for its operational effectiveness but also for global security and stability in the face of a changing climate.

Mitigation strategies to manage these impacts will be discussed in the author’s next article, ‘Climate Change and Defence: Strategies for Resilience and Preparedness’.


Written by
James Morris
James is a Manager of Climate Risk and Resilience in Accenture’s UKI Sustainability, supporting several organisations understanding the impacts of the climate crisis on their business. James has over 20-years of experience across a range of industries. He started his career with the UK government and development sector in Iraq and Afghanistan, before working in the mining industry in Sub-Saharan Africa.
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