Sub-national climate change risk assessment: A case analysis for Tibet and its prefecture-level cities

Avoiding climate change from exceeding its critical threshold is a serious challenge facing humanity at present and in the future. As the mode of global cooperative action is stranded, multi-center and multi-level efforts are needed to deal with global warming in the future. In order to provide information for the formulation of low-carbon development policies, it is essential to assess the maintain or cross of climate change threshold on different scales. In this study, the carbon footprint calculated based on the process coefficient approach is systematically integrated with the climate change indicator of the planetary boundaries framework improved with the goals of the Paris Agreement to identify the climate change risks of Tibet and its prefecture-level cities from 2000 to 2017. Moreover, the main driving factors behind carbon footprint were analyzed. The findings showed that: (1) Since 2000, Tibet's CO₂ emissions have demonstrated steady and rapid increase. The sector composition is dominated by cement production-related and transportation sector-related emissions. The type composition is dominated by diesel-related, process-related, and coal-related emissions. There are significant differences in CO₂ emissions among all prefecture-level cities, with Lhasa having the largest contribution. (2) Except for Lhasa and Shannan's CO₂ emissions that have crossed their critical threshold of climate change and are in an unsafe state, Tibet and other prefecture-level cities have not yet crossed their critical threshold. (3) Except for Ngari, per capita GDP, energy intensity, population size, and carbon intensity positively affect the increase of CO₂ emissions in Tibet and its prefecture-level cities. Our study helps actors at less aggregated scales to determine appropriate policy strengths based on globally agreed goals and ambitions in the process of responding to global warming in a bottom-up manner.