The Sustainability Paradox of Ecological Restoration: Gains and Reversal Risks Across China's Forestry Megaprojects

ABSTRACT In the context of global efforts to combat land degradation, the long‐term sustainability of large‐scale ecological restoration projects is a critical determinant of their success. As the world's largest land restoration initiative, China's major forestry projects offer a unique, continental‐scale natural experiment to assess their effectiveness. Leveraging the Google Earth Engine platform, this study employs a validated Remote Sensing Ecological Index (RSEI) framework to assess the spatiotemporal dynamics of ecological quality, long‐term sustainability, and key drivers across six major forestry project areas from 2000 to 2022. The results reveal significant spatial heterogeneity in restoration outcomes: while regions like the Middle Yellow River successfully reversed severe land degradation, the ecological quality in the Upper‐Middle Yangtze River area exhibited a declining trend, demonstrating that restoration success is highly contingent on regional context. However, a significant knowledge gap remains: existing evaluations often rely on short‐term monitoring or static “snapshot” assessments, which fail to capture the non‐linear dynamic characteristics and long‐term stability of ecosystem evolution, thereby overlooking potential future reversal risks. Crucially, the Hurst exponent analysis reveals a sustainability paradox: historical greening trends do not guarantee future stability. Despite significant past gains, regions like the Liaohe River and Huaihe‐Taihu basins face exceptionally high risks of future degradation (reversal risks reaching 41.56% and 68.78%, respectively), posing a severe challenge to the long‐term efficacy of these interventions. The study finds that while large‐scale restoration projects are effective in addressing historical degradation under low socioeconomic pressure, their capacity to sustain ecosystem integrity is limited in areas with high‐intensity human activity. This underscores the necessity of integrated policies that couple ecological engineering with sustainable land‐use planning to secure long‐term returns on global investments in land restoration.