Observing system needs for understanding carbon–climate feedbacks

Abstract Carbon–climate (CC) feedbacks — arising from response of land and ocean carbon sinks to elevated CO 2 and climate warming — are critical yet highly uncertain drivers of Earth’s climate trajectory. Processes such as permafrost thaw, tropical forest dieback, reduced ocean uptake, and intensifying climate extremes are already weakening natural carbon sinks, with potential to amplify warming and accelerate crossing of tipping points. Detecting and quantifying these dynamics requires sustained, high-resolution, spatially-comprehensive Earth Observations. Drawing on outcomes from a 2024 community workshop, we identify three core priorities for advancing CC feedback monitoring: (1) frequent, long-term measurements of carbon fluxes and stocks at sub-continental scales; (2) improved flux detectability using greenhouse gas partial columns; and (3) targeted monitoring of poorly-observed vulnerable regions, such as the tropics, high latitudes, and the Southern Ocean. We argue that a unified, multi-platform observing system, built on lower-cost, proven technologies and orbits and focused on high-risk observation gaps, would significantly reduce uncertainties in Earth System Models, provide early warnings of feedbacks and tipping points, inform climate mitigation strategies, and enhance transparency in carbon monitoring.