Armed forces across Europe are increasingly including climate matters in their agendas since their priorities are based on their readiness, operations, and strategy to ensure their nation’s security. Climate change poses both direct and indirect risks for European military forces, including increased migration, growing instability in critical regions, possibility for alarming transformations in sensitive geopolitical areas such as the Arctic, and natural disasters on the continent. European militaries need to consider options for further cooperation considering such challenges. Most threats presented by climate change are not confined to national borders, which provides a unique opportunity for advancing the current collaborative defence and security structures. This illustrates the necessity for armed forces to integrate climate change into their conceptualisation of contemporary European defence strategies. This study reflects on the impact of climate change on European armed forces. It seeks to detect how climate change influences existing defence patterns, and how the challenges posed by climate change can become milestones for further European interoperability.