This chapter reframes climate change not as an external disturbance but as a constitutive force that both structures socio-ecological systems and propels their transformation. Observed warming is already about 1.1°C above 1850–1900 levels, and each of the last four decades has been successively warmer than any decade since 1850, confirming that climate change is now a defining structural feature of the Earth system. Using complexity theory and systems thinking, it explains how climate variability interacts with resource dynamics, settlement patterns, economic pressures, and governance to generate nonlinear feedbacks, cascading disruptions, and uneven vulnerabilities. The systems lens moves beyond linear cause-and-effect narratives by foregrounding thresholds, tipping points, and emergent behaviors through which incremental climatic shifts can trigger abrupt ecological and social reorganization. Integrating biophysical, political-economic, and cultural scales, the chapter develops a unified framework for tracing how climate shocks propagate across coupled human–natural systems, from local livelihoods to global stability. Methodologically, it demonstrates how system dynamics, agent-based modeling, and network approaches can reveal hidden interdependencies, map leverage points, and anticipate compound risks that conventional sector-by-sector assessments miss. The chapter closes by translating these insights into guidance for resilience and adaptation: building institutions that learn, remain flexible in the face of uncertainty, and align scientific forecasting with locally grounded knowledge and practice. By treating climate as both structure and process, the chapter advances a stronger explanatory basis for socio-ecological transformation. It offers practical pathways for governing climate risk in ways that are anticipatory, just, and sustainability-oriented.