Navigating Ambition and Equity: Systemic Codependency in China's Carbon Neutrality Pathways

Translating global climate targets into national decarbonization roadmaps is profoundly uncertain. To navigate this uncertainty for China, we employ a national-scale energy system model developed in the MESSAGEix framework─calibrated to China's energy balances─that uniquely combines provincial-level resolution for key sectors with a high-granularity representation of intra-annual (48 time slices) power system dynamics. Across three temperature targets (1.5, 1.6, 2.0 °C) and six allocation principles, our analysis reveals that wind and solar consistently emerge as "no-regret" pillars, CCS is essential for heavy-industry abatement, and hydrogen's sourcing shifts with budget stringency. A critical systemic codependency exists across scenarios with stringent emissions constraints: the power sector must transform into a net carbon sink to enable the decarbonization of heavy industry, creating stark path dependencies across technology choices. The 1.6 °C pathway under the Grandfathering principle presents a pragmatic alignment with China's 2060 neutrality pledge and offers a detailed blueprint for this transition. Our provincial-level analysis distinguishes high-stakes decisions from robust "no-regret" investments, offering a framework to guide China's journey to carbon neutrality.