UCLA

Abstract Managing carbon stocks in the land, ocean, and atmosphere under changing climate requires a globally‐integrated view of carbon cycle processes at local and regional scales. The growing Earth Observation (EO) record is the backbone of this multi‐scale system, providing local information with discrete coverage from surface measurements and regional information at global scale from satellites. Carbon flux information, anchored by inverse estimates from spaceborne Greenhouse Gas (GHG) concentrations, provides an important top‐down view of carbon emissions and sinks, but currently lacks global continuity at assessment and management scales (<100 km). Partial‐column data can help separate signals in the boundary layer from the overlying atmosphere, providing an opportunity to enhance surface sensitivity and bring flux resolution down from that of column‐integrated data (100–500 km). Based on a workshop held in September 2024, the carbon cycle community envisions a carbon observation system leveraging GHG partial columns in the lower and upper troposphere to weave together information across scales from surface and satellite EO data, and integration of top‐down/bottom‐up analyses to link process understanding to global assessment. Plain Language Summary The iconic CO 2 data set initiated by C.D. Keeling at Mauna Loa, Hawaii has been instrumental in our understanding of the global carbon cycle and underpins policy efforts aimed to mitigate carbon emissions and climate change impacts. As our knowledge of the carbon cycle grows, it becomes increasingly critical to acquire information at finer spatial scales to better understand the complexity of carbon movement across the ocean and land. At the same time, policies that seek to mitigate carbon emissions benefit from observations to guide actions at city‐to‐national scales. The scientific community has developed a suite of carbon observations spanning multiple scales, demanding traceability, integration, and global context. Satellite measurements can fill this role but rely on further efforts to link with natural and anthropogenic processes. In this position paper, carbon cycle scientists call for an integrated carbon observing system leveraging near‐surface partial‐column Greenhouse Gas data—capturing the atmosphere closest to forests, cities, and oceans—to better resolve finer spatial scales (<100 km) where key carbon cycle processes and management decisions occur. This system should be anchored by ground observations that are not dependent on any single nation‐state to provide internationally recognized carbon emissions products for policy and planning. Key Points Managing carbon stocks under climate forcing requires a global view of local and regional scale processes Near surface partial column Greenhouse Gas data can improve the ability to resolve carbon fluxes at assessment and management scales (<100 km) A carbon observation system providing actionable information should integrate partial columns with sustained Earth observations and models