Integrated Assessment Model — GCAM-China

The future energy activity projections in the Emissions Pathway Module of the CNCAP platform are generated by the integrated assessment model GCAM-China. Driven by exogenous assumptions on population and GDP, the model simulates energy transition pathways under a range of climate targets.

Since the 1960s, global environmental issues have attracted growing scholarly attention. The research community has come to recognize that addressing these challenges requires a multi-disciplinary, cross-sectoral, integrated, systematic, and dynamic mode of inquiry — a perspective that gave rise to the concept of "integrated assessment" (Nordhaus, 2008).

GCAM (Global Change Analysis Model) is a high-resolution global integrated assessment model that represents the behavior of — and the complex interactions among — five major systems: energy, water, agriculture and land use, ecosystems, and the climate system. Originally developed in 1982 (Edmonds and Reilly, 1983), GCAM has been developed and maintained by the Pacific Northwest National Laboratory (PNNL). It is now widely used for scenario design and policy assessment at both national and international scales (Fawcett et al., 2015; Calvin et al., 2017; Dong et al., 2018; Vittorio et al., 2018; Calvin et al., 2019; Wang et al., 2019), and is one of the standard tools employed by the IPCC in its assessments of climate impacts and adaptation (IPCC, 2007; IPCC, 2014).

The GCAM framework comprises three main components: the GCAM data system, the GCAM core model, and a suite of sub-models. The data system encompasses modules on energy, socio-economics, water resources, land use, emissions, and climate; it provides both historical and base-year calibration and the exogenous assumptions required to drive scenario-based future projections, and serves as the foundational input to the core model. The GCAM core model integrates five subsystems — macro-economy, energy, agriculture and land use, water resources, and geo-physics — and simulates the dynamic behavior of, and interactions between, human activity systems and the natural Earth system under alternative scenarios and policies, together with cost-optimizing economic decisions.

To study sub-national socio-economic and energy development pathways in China under climate change, PNNL further developed a regionally disaggregated Chinese version of the model, GCAM-China (Yu et al., 2019). In GCAM-China, China's provinces are represented as independent participants in a global carbon market, and energy supply and demand are simulated and projected at the provincial scale. This study adopts the GCAM-China model to project China's future energy transition and supply–demand dynamics at the provincial level under different climate-economic scenarios.