*Originally published in 2025 and preserved as part of our archive project.Get E-International Relations delivered directly to your inbox, free of charge. As you sign up, consider becoming a paid subscriber to support our work.

The climate crisis is not just an environmental challenge—it is a profound threat to global stability, touching every aspect of society, from livelihoods and health to governance and peace. As its impacts grow in frequency, intensity, and cost, the links between climate change and security are becoming increasingly clear. Extreme weather events, resource scarcity, and forced displacement are drivers of instability that ripple across borders, affecting human security, national resilience, and international relations. Germany has been at the forefront of efforts to broaden the understanding of security to include the risks posed by climate change. By framing climate impacts as a matter of human, national, and international security, Germany and other European countries aim to galvanize action at all levels (see Germany’s National Security Strategy 2023 and EU 2023). However, this approach has not been without controversy. Some emerging economies have expressed concerns about framing climate change as a security issue, warning of potential unintended consequences such as the marginalization of vulnerable groups or the securitization of climate governance.

This article starts by synthesizing findings from Germany’s National Interdisciplinary Climate Risk Assessment. It then explores critical debates surrounding the securitization of climate change, highlighting both the opportunities and risks of this framing. Finally, it looks toward the future, proposing how Germany and Brazil—two nations with distinct yet complementary roles in global climate policy—can work together to strengthen resilience, foster equitable development, and advance a global response to the intertwined crises of climate and security.

The Global Climate-Security Nexus

We are already living through the climate crisis, and it is set to worsen before it might get better–provided we prioritize ambitious climate policy measures. Global warming is accelerating: while temperatures rose at about 0.18°C per decade from 1970 to 2008, the current rate has increased to approximately 0.3°C per decade (Hausfather 2024). Hence, we find ourselves in uncharted territory. This has given rise to a policy nexus now often dubbed climate, peace and security (UN). Pacific Island countries have been among the most vocal on this issue. Their Boe Declaration on Regional Security unequivocally “reaffirm[s] that climate change remains the single greatest threat to the livelihoods, security and wellbeing of the peoples of the Pacific” (Pacific Island Forum Leaders 2018).  The African Union has similarly (and repeatedly) “acknowledged  inextricable link between climate change, peace and security in Africa” (AU 2016) and is in the process of finalizing a Common African Position on Climate, Peace and Security ahead of COP 30 (Amani Africa 2025). European countries have pushed this issue in the UN Security Council, where it has gained currency but not consensus, repeatedly becoming a key point of contention among its members (see here for a short history, see here for the key issues).

What security risks do Europeans, and Germany in particular, see emanating from the climate crisis? To explore this, the subsequent paragraphs will summarize Germany’s National Interdisciplinary Climate Risk Assessment, published earlier this year at the Munich Security Conference (Metis Institute et al. 2025). The assessment identifies three national security risks to Germany emanating from the climate crisis: firstly, direct climate impacts in Germany and the EU. Secondly, impacts elsewhere in the world that have direct implications for Germany and the EU. Thirdly indirect impacts that undermine the global system upon whose predictability and stability ultimately rely, as well as Germany’s prosperity and security.

Category 1: Direct Impacts: Germany and the EU Under Pressure. Germany is affected by an increasing amount of extreme weather events. They caused up to 145 billion euros of damage over the first two decades of this century, with some 1,400 deaths per year (Prognos et al. 2022). At the same time, Germany is also increasingly affected by droughts, which harm sectors like agriculture, (fluvial) transport, energy production (from cooling water shortages), and damage ecosystems. Moreover, heat is increasingly becoming a risk for health and productivity even in Germany while global warming drives the expansion of disease vectors such as mosquito and tick species.

Category 2: Global Impacts: Ripple Effects Beyond Borders. While Germany is undoubtedly affected by the climate crisis, the impacts are not as existential as in many other countries, where more severe physical effects and limited adaptive capacity create a vicious cycle of vulnerability and fragility.  Intensified competition over natural resources like water and arable land can drive migration and increase the risk of conflict, even if it does not lead to armed conflict directly. According to current mitigation pathways, modellers have calculated that, by the end of the century, between 22 and 39% of humanity will no longer live in a climate that sustains human life (Lenton 2023). The resulting strain on the governments and governance mechanisms should not be underestimated.

Category 3: Systemic Risks: Feedback Loops and Instability.Europe’s historical reliance on fossil fuels has funded autocratic regimes like Russia, undermining its own security—making the energy transition both a climate and strategic priority. However, decarbonization carries risks. It may destabilize fossil fuel-dependent states and spark new conflicts over critical minerals needed for green technologies, particularly in areas where these resources are mined (e.g., the eastern Democratic Republic of the Congo). Control over various stages of production offers significant........

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