The Transition Autonomization Threshold (TAT): A Foundational Framework for Studying Self-Sustaining Decarbonization Transitions

Why do some decarbonization transitions sustain and accelerate their own transformation, while others remain structurally dependent on continuous external policy support? This foundational research paper introduces the Transition Autonomization Threshold (TAT) framework to address this critical gap in sustainability transitions literature. Moving beyond traditional, output-oriented metrics (e.g., carbon abatement velocity), the TAT framework investigates how socio-technical systems progressively cultivate internal economic, institutional, cognitive, relational, and social capacities. When these capacities become sufficiently aligned, the system undergoes a qualitative shift—crossing a critical threshold from an exogenous-driven phase to a self-reinforcing, endogenous-driven regime. To operationalize this hypothesis, this paper introduces the Transition Autonomization Index (TAI). Utilizing a non-compensatory geometric mean aggregation, the TAI mathematically ensures that severe structural bottlenecks in one dimension cannot be masked by isolated strengths in another. The framework builds a rigorous, falsifiable scientific research program by presenting explicit testable predictions, Popperian conditions of falsification, and exploratory qualitative applications across five global pathways (Denmark, Germany, China, United States, and India). The TAT framework provides an actionable macro-economic diagnostic matrix designed for the post-2024 landscape of climate policy volatility and regulatory fatigue.