This module examines the physical processes, dynamics and wider significance of extreme environments, focusing on glacial and arid regions and their sensitivity to climatic and environmental change. Students explore how ice sheets, mountain glaciers, deserts and drylands operate within the Earth System and assess the local to global impacts of their rapid transformation including implications for water and food security, and hazards arising from each environment. Through research-led lectures, case studies and scenario-based activities, students analyse the interactions between environmental change, hazards, livelihoods and policy. The module is assessed via two essays, informed both by lectures and “war game” sessions that will apply scientific concepts to physically plausible but hypothetical scenarios. The module develops an integrated understanding of how scientific evidence can inform decision-making in regions undergoing rapid change, preparing students to evaluate the future trajectories and challenges of governing Earth’s most dynamic and vulnerable environments.