Evaluating national and subnational CO2 mitigation goals in China's thirteenth five-year plan from satellite observations

Good-quality emission data are essential to validate national climate commitments and implement domestic policies. However, conventional bottom-up data collection is costly and subject to potential manipulation by stakeholders when data pass through their hands, which could pose challenges on the efficiency and effectiveness of compliance monitoring especially in developing countries. Satellite observations, specifically OCO-2 XCO2 measurements, are utilized in this study to develop a relatively independent and timely dataset for screening the attainment statuses of national and subnational CO2 mitigation goals in China's 13th Five-Year Plan (FYP, 2016-2020). We establish CO2 emission estimation models at both pixel and provincial levels. As interpolated with the pixel-level model, CO2 emissions of prefecture-level municipalities indicate that approximately three fifth of them had accomplished their individualized FYP mitigation goals by 2019, while our provincial-level estimation suggests that three quarters of provinces had attained theirs. More resources for compliance monitoring could thus be directed to other presumably-unattaining local governments. National aggregate absolute emissions showed 8.0-18.3% reduction in 2019 across three provincial models from the 2015 level, while national CO2 intensity dropped by 28.8-36.8% to imply attaining the 18% reduction goals.