GCAM-China-v8: An Integrated Global-to-Provincial Framework for Assessing China’s Energy and Emission Futures

Abstract. This paper describes Global Change Analysis Model-China version 8 (GCAM-China-v8), an open-source integrated assessment model that represents interactions among energy, economic, and water systems within a globally consistent framework, with explicit subnational representation for China. GCAM-China-v8 builds on the GCAM and represents the world as 31 geopolitical regions outside China, while disaggregating China into 31 province-level regions to capture regional heterogeneity. GCAM-China-v8 can be used to explore how changes in socioeconomic drivers, technological progress, and policy assumptions affect energy and water demand and production at the subnational level in China, while maintaining consistency with national and international boundary conditions. This paper documents the model structure and data inputs, with particular emphasis on the methodological updates introduced in GCAM-China-v8, including enhanced sectoral and temporal representations. To demonstrate the capabilities of the updated model, we apply GCAM-China-v8 to two illustrative scenarios with contrasting assumptions about future socioeconomic development and energy system transformation. This paper provides a transparent and extensible modeling framework for future research on China’s long-term energy and climate transitions. It also contributes to the broader Integrated Assessment Models (IAMs) community by advancing national-scale model development within an open and consistent framework.