Agricultural soils are among the largest terrestrial carbon reservoirs and play a critical role in mitigating climate change through carbon sequestration. However, their capacity to store carbon is increasingly threatened by the combined pressures of groundwater depletion and climate variability. Groundwater is essential for sustaining crop yields, soil organic matter inputs, and microbial processes, all of which underpin soil carbon storage. Yet, declining aquifers reduce irrigation security, disrupt nutrient cycling, and heighten vulnerability to climatic stressors. Simultaneously, climate variability—manifested through irregular precipitation, temperature extremes, droughts, and floods—alters soil moisture regimes, accelerates decomposition, and undermines carbon stabilization. Importantly, the interaction between these two drivers produces nonlinear effects: groundwater depletion amplifies the impacts of climate-induced drought, while climate variability increases irrigation demand, accelerating aquifer decline. This review synthesizes current evidence on the interactive effects of groundwater depletion and climate variability on agricultural carbon sequestration. We evaluate mechanisms, case studies, and model-based findings, highlighting how coupled water–carbon dynamics shape the resilience of agroecosystems. Finally, we discuss management strategies such as sustainable groundwater use, climate-smart agriculture, and integrated policy approaches that can safeguard both carbon storage and food security. Understanding these interdependencies is crucial for designing future agricultural systems that remain productive while contributing meaningfully to climate change mitigation.
