Assessing China's Scope 2 CO2 emissions and mitigation pace from space

China is committed to CO2 emissions peaking by 2030 and carbon neutrality by 2060. This study aims to explore a method to measure its progressing pace largely independently for providing feedback. With OCO-2 carbon satellite and NPP-VIIRS night-time light data, we develop and apply a satellite-based approach to estimate provincial Scope 2 CO2 emissions, which refers to those emissions stemming from electricity trade, from 2015 to 2020. Our results can reflect the spatial disparity of electricity trade and energy structure across China. Furthermore, a Carbon Mitigation Index (CMI) is defined, through combining information from carbon and night-time light satellites, to measure China's national and provincial CO2 mitigation pace toward carbon neutrality, which indicates the composite progress of various key drivers, including energy transition, electrification, net electricity import, socio-economic development, and energy efficiency. Because the CMI requires only satellite data but not bottom-up statistics in its application, it offers an opportunity for external assessment from space.