Security threats arising from the environment and climate change are not limited to asymmetric conflicts and non-state actors but are also increasingly influencing conventional military operations. Global warming, rising sea levels, and extreme weather events are forcing changes in defense strategies, impacting military infrastructure, operations, and personnel preparedness. Armed forces will need to adapt to new climatic conditions, facing challenges such as increased air turbulence or changes in maritime routes. Additionally, environmental changes are reshaping geopolitical geography, creating new opportunities and conflicts over control of natural resources, such as water and minerals essential for the energy transition. Coastal cities, vulnerable to natural disasters, pose a threat to internal security, as critical infrastructures can be damaged, as evidenced by events like Hurricane Katrina. Finally, climate change is becoming a central geopolitical factor, with potential rivalries among global powers to exploit transforming territories and resources, such as the Arctic. Managing these challenges will determine future security and stability, requiring international cooperation and investment in resilience.