Measuring the low-carbon energy transition in Chinese cities.

Cities' transition from fossil-based systems of energy production and consumption to renewable energy sources-the energy transition-is critical to mitigating climate change impact as cities' energy consumption and CO emissions account for two-thirds and over 70% of the world's total, respectively. Given cities' heterogeneity, they need specific low-carbon roadmaps instead of one-size-fits-all approaches. Here, we used an Energy Transition Index (ETI) to characterize the city-level energy transitions from energy system performance and transition readiness dimensions. The ETI scores for 282 cities in China revealed a significant heterogeneity across cities and over time, and the gap between the cities in the top and bottom quartiles was persistent. We estimated that China's energy and carbon intensity could decrease by 34% and 32%, respectively, and that carbon per capita could fall by 17% if each city modestly follows the sustainable development path forged by the best performing cities with similar economic structures.