Abstract: In the context of carbon sequestration and emission reduction and the "Dual Carbon" goals, currently, the impact of climate change, characterized by the combined changes of elevated atmospheric carbon dioxide (CO2) concentration and warming, on the dynamic changes of soil organic carbon (SOC) has become a research hotspot. The interaction and coupling mechanism between climate change and SOC pools have always been a difficult issue in academic research. Most previous studies have examined the driving processes and mechanisms of climate change on SOC pool changes from the perspectives of plant growth, litter substrate quality, soil physicochemical properties, organic carbon physical/chemical components, and microbial community structure. Moreover, research on the impact of climate change on terrestrial ecosystem carbon processes is still based on a single factor of elevated CO2 concentration or warming. Based on the research progress at home and abroad, this review summarizes the effect and mechanism of elevated CO2 concentration and warming on soil organic carbon accumulation. We combine the coupling effects of soil organic carbon fractions, molecular composition, structural characteristic, differences in response between topsoil and subsoil, and organic carbon stability, so as to reveal the intrinsic mechanism of elevated CO2 concentration and warming on organic carbon accumulation and transformation. On this basis, future research should focus on (1) clarifying the coupling relationship between SOC end inputs, molecular composition, as well as structural characteristic, and (2) revealing the impact mechanism of long-term climate change on the stability and burial potential of SOC in multiple ecosystems. To clarify soil carbon source/sink functions, it is necessary to comprehensively and deeply understand the biogeochemical processes of SOC sources, transformation, burial, and decomposition in terrestrial ecosystems under climate change, aiming to provide scientific theoretical basis for soil carbon neutrality management decisions in the future.

Key words: climate change, soil organic carbon, molecular composition and structure, stability, subsoil, knowledge map of hot keywords