Three-Dimensional analysis of carbon source events in the Yellow River Basin: Lifecycles, Triggers, and linkages to long-term trend mutations

Understanding the dynamics of terrestrial carbon cycling is imperative for mitigating climate change. However, conventional analyses of Net Ecosystem Productivity (NEP) often treat extreme events as mere fluctuations, obscuring the mechanistic linkage between short-term disturbances and long-term ecosystem stability. To address this gap, we developed a novel analytical framework integrating three-dimensional event identification, long-term trend mutation detection, and machine learning-based attribution to analyze NEP in the Yellow River Basin (YRB) from 1982 to 2022. We found that: (1) The YRB’s overall greening trend conceals a complex reality of widespread structural changes, with “accelerated growth” patterns coexisting alongside alarming “increase-to-decrease” reversals, revealing significant underlying risks. (2) Our three-dimensional analysis, validated with independent data, identified 58 extreme carbon source events and established them as the direct trigger for the most frequent long-term trend mutations. (3) Water availability is the absolute dominant factor, and its quantified critical threshold (e.g., < 189 mm annual precipitation) provide a unified mechanistic framework that explains the basin’s spatial vulnerabilities, trend reversals, and extreme events. By pioneering an event-based, three-dimensional perspective, our study offers a new paradigm for assessing ecosystem resilience. The established linkages among short-term events, long-term mutations, and their hydro-climatic thresholds provide critical insights for developing proactive ecological risk management strategies.