What does climate change have to do with defence and military operations?
What does climate change have to do with defence and military operations? Building a framework of symmetric regulation for green security
Rossana Gemeli Roncato Carloto
Abstract: Climate change has transformed the foundations of global defence and security, acting as a “threat multiplier” that heightens instability and accelerates environmental degradation. This article suggests the adoption of the concept of symmetric regulation — a framework that integrates sustainability into operational readiness as a strategic pillar for peace, resilience, and environmental responsibility. By examining NATO, the European Union, and national strategies from the United Kingdom, Italy, Norway, Brazil, Canada, and the United States, the paper argues that Green Defence represents not only an ecological necessity but also a geopolitical imperative for the twenty-first century.
Climate Change as a Security Challenge
According to NASA (2024), global surface temperatures have risen by about 1.2°C since the late 19th century, while sea levels have increased by over 20 cm, now rising 3.4 mm per year. The Arctic loses 13 % of its ice each decade, and extreme heat, droughts, and floods intensify worldwide, affecting food security and displacing millions. Nearly 1.8 billion people face severe water scarcity. As noted by the Global Peace Index (2025) and SIPRI (2022), climate change acts as a “risk multiplier,” eroding stability and merging environmental, humanitarian, and defence agendas into a shared challenge for global security.
2. Institutional Adaptation in Europe: NATO and the EU
Both NATO and the European Union have formally acknowledged climate change as a defining security threat. The EU Joint Communication on the Climate and Security Nexus (2023) identifies environmental degradation as a growing risk to peace, noting that twelve of the twenty countries most vulnerable to climate change were already affected by conflict.
NATO’s Climate Change and Security Action Plan (2021) and its 2023 report The Impact of Climate Change on Security and Defence emphasise that floods, storms, and rising sea levels threaten bases, ports, and supply chains. The creation of the Climate Change and Security Centre of Excellence in Montréal institutionalises research, innovation, and operational adaptation.
This convergence between NATO and the EU illustrates a shared strategic logic: integrating environmental sustainability into defence planning and capability development through coordinated, multilateral action.
3. European Pathways to Green Defence
Across Europe, governments are embedding environmental responsibility into defence strategy.
The United Kingdom has declared climate change and biodiversity loss its top security priorities. Through the Climate Change and Sustainability Strategic Approach (2021) and Defence Adaptation and Resilience Strategy (2024), the Ministry of Defence is building a “climate-prepared Defence.” Measures include reducing emissions, climate-proofing bases, adopting sustainable aviation fuels, and preserving biodiversity. According to the Climate Change and Sustainability Strategic Approach (UK Ministry of Defence, 2021), climate change threatens peace as environmental emergencies exacerbate poverty, deepen gender inequality, and generate instability. Its cascading effects include competition over scarce resources, mass migration, health crises, state-to-state rivalry, civil unrest, opportunities for non-state actors, governance breakdown, economic disruption, and energy geopolitics — manifested through famine, droughts, wildfires, sea-level rise, flooding, and heatwaves.
Other European countries are also integrating climate adaptation into defence planning. Italy’s defence and foreign policy are increasingly framed within a broader climate diplomacy agenda.
Italy is aligning defence policy with environmental sustainability. The Strategic Concept of the Chief of Defence (Ministero della Difesa, 2022) and the Strategic Energy Plan of Defence (SED) define sustainability and energy efficiency as pillars of national security (Camera dei Deputati, La transizione ecologica della Difesa, 2022). The Ministry of Foreign Affairs (Diplomazia Climatica e Ambientale, 2024) integrates climate diplomacy and defence within the EU’s path toward carbon neutrality by 2050. Initiatives such as Caserme Verdi, Basi Blu, and Aeroporti Azzurri promote renewable energy and circular practices, consolidating a model of Green Defence and symmetric regulation that unites sustainability and operational readiness.
In parallel, Norway provides a Nordic perspective connecting climate adaptation, indigenous rights, and defence resilience. Its Defence Sector Climate and Environmental Strategy 2023–2030 sets clear targets: a 55% emission reduction by 2030 and up to 95% by 2050. It defines five priorities — cutting energy use, minimising environmental impacts, protecting biodiversity, fostering a circular economy, and adapting operations to a changing climate.
Complementing this, Norway’s Second Adaptation Communication (2024) details severe impacts: a 1.2°C temperature increase since 1900, 18% higher annual precipitation, and coastal sea-level rise of 3 mm per year. These shifts affect infrastructure, agriculture, and Sami communities. The strategy integrates scientific knowledge, gender, and indigenous perspectives, monitored through four-year national assessments.
Together, these initiatives reveal a continental shift from reactive environmental management to proactive Green Defence — where ecological stewardship and military capability evolve as mutually reinforcing dimensions of collective security.
4. Beyond Europe: Global Approaches
Outside Europe, the principles of Green Defence are gaining ground.
The United States has recognised the implications of climate change for military operations since the early 1990s. The pioneering report Global Climate Change: Implications for the United States Navy (U.S. Naval War College, 1990) already warned that sea-level rise and the thermal heating of the oceans and atmosphere would affect naval readiness and global stability. Over the following decades, numerous defence documents — issued between 2003 and 2022 — continued to address climate-related risks and adaptation measures. In 2023, this trajectory culminated in three major strategic publications: the DoD Operational Energy Strategy (2023), the DoD Plan to Reduce Greenhouse Gas Emissions (2023), and the U.S. Department of the Air Force Climate Campaign Plan (2023). Together, these institutionalise climate resilience and decarbonisation within U.S. defence governance, marking a decisive step toward integrating environmental responsibility into national security.
Similarly, the Government of Canada, through its Defence Climate and Sustainability Strategy 2023–2027 (DCSS), links national security to green innovation, cooperation with Indigenous peoples, and climate adaptation. The country also plays a leading role in NATO’s Climate Change and Security Centre of Excellence in Montréal.
In South America, Brazil’s Livro Verde de Defesa & Meio Ambiente (2017) pioneered a national vision of Defesa com Sustentabilidade, promoting renewable energy, eco-efficient logistics, and biodiversity protection within the Armed Forces.
From Washington to Brasília, defence institutions increasingly view climate action as strategic foresight. The global turn toward Green Defence shows that sustainability is now a force multiplier for peace and stability. By embracing symmetric regulation, nations recognise that defending the Earth ultimately means defending ourselves.
5. Conclusion: Building Symmetric Regulation
It is now a broad consensus that climate change and security are deeply interconnected. Rising sea levels, mass migration, resource scarcity, and extreme weather intensify instability, particularly in post-conflict contexts where reconstruction and peace maintenance become fragile. As highlighted by the United Kingdom’s Climate Change and Sustainability Strategic Approach (2021), environmental crises exacerbate poverty, inequality, and governance breakdown — creating fertile ground for unrest and state fragility.
In this context, climate change operates as a threat multiplier, amplifying pre-existing vulnerabilities and challenging military operations through disrupted supply chains, degraded infrastructure, and humanitarian emergencies. Nations and alliances are thus reconfiguring their defence doctrines under the logic of Green Defence, integrating environmental stewardship into readiness, logistics, and strategic planning.
Symmetric regulation provides a framework for this transformation, where sustainability and security advance together. Far from being a limitation, sustainability becomes a strategic multiplier — strengthening resilience, reducing vulnerability, and aligning the ethics of peace with the practice of defence. Safeguarding the planet has become inseparable from safeguarding peace — and from redefining what it means to defend humanity in the Anthropocene.
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About the Author
Rossana Gemeli Roncato Carloto: Brazilian-Italian interdisciplinary researcher with a Master’s in Law (UFMS, 2024) focused on Human Rights, and postgraduate training in international relations, international and constitutional law, conflict resolution and negotiation, history of war, digital and public law. Her research covers the right to peace, IHL, international and environmental law, digitalized warfare, and defense. She works in Portuguese, Italian, English, Spanish, German, and French.
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