Climate change, as a multidimensional threat, has posed serious challenges to Iran's environmental security. This study, using a descriptive-analytical approach and a qualitative method based on document content analysis, examines the dimensions of the impact of climate change on water resources, food security, public health, and internal migration, and explains its security implications within the framework of the Copenhagen School's theory of securitization and the human security approach. The findings show that increasing temperatures, decreasing rainfall, and intensifying droughts have led to water crises, declining agricultural production, increased fine dust, and forced population migration, creating a chain of social, economic, and strategic threats that undermine the sustainability of national security. Existing laws, such as the Environmental Protection and Improvement Law and the Clean Air Law, although they have provided an initial framework, lack comprehensiveness and focus on climate adaptation, and have gaps in monitoring, budgeting, and integrated policymaking. The research is based on the hypothesis that climate change is a multidimensional strategic threat to Iran's environmental security and that the current legislative system is unable to respond effectively without structural reforms. Consequently, the Islamic Consultative Assembly can play a key role in securing this issue and enhancing national resilience by passing a comprehensive law on climate change adaptation, establishing a special commission, allocating targeted budgets, and requiring annual government reporting.