Status and Trend Analysis of Atmospheric Methane Satellite Measurement for Carbon Neutrality and Carbon Peaking in China

Methane (CH₄) is an important greenhouse gas, and its radiative forcing is second only to that of carbon dioxide (CO₂). Reducing CH₄ emissions is necessary to control global warming and achieve carbon neutrality. To achieve carbon neutrality by 2060, quickly locating emission sources and accurately estimating the distribution of global and regional CH₄ sources and sinks are of great practical importance for formulating, implementing, and evaluating mitigation measures. In addition, combining long-term CH₄ observation data and climate system models to explore the changing trend in atmospheric CH₄ concentration is a premise for predicting and actively responding to climate change. The 49th session of the Intergovernmental Panel on Climate Change (IPCC 49) proposed a “top-down” approach to calculating fluxes to verify emission inventories. This method is mainly based on atmospheric measurements, indicating the importance of obtaining high-precision, global-scale CH₄ observation data with high spatial and temporal resolution. To achieve carbon neutrality, we start with several key scientific issues that must be solved in atmospheric CH₄ research to analyze the requirements of CH₄ satellite measurement. In this paper, we also summarize the status and development trend of CH₄ satellite measurement and briefly introduce the implementation of China’s next-generation carbon satellite. Space-based CH₄ measurement relies on high-precision retrieval algorithms to provide reliable data products for monitoring and further applications. On the basis of the status of the CH₄ satellite remote sensing retrieval algorithm and the application of corresponding data products in emission monitoring and flux estimation, we further discuss the necessity of improving calculation efficiency and accuracy for the remote sensing retrieval algorithm and flux inversion algorithm. As for monitoring and controlling the anthropogenic emission process, developing a rapid identification algorithm for methane plumes and an emission evaluation method should also be considered. Finally, this paper summarizes the detection, data acquisition, and application of satellite-based CH₄ measurements and indicates the scientific application potential of CH₄ satellite observations for carbon neutrality goals.