Carbon capture and storage (CCS) is a key climate mitigation strategy, but monitoring requirements vary across geological settings and operational contexts. This study conducts a comparative analysis of monitoring programs at two large‐scale CCS projects: offshore saline aquifer storage in Tomakomai, Japan, and onshore CO 2 ‐EOR in Jilin, China. Reservoir characteristics, monitoring systems, and injection outcomes were reviewed, followed by a systematic evaluation of how site‐specific and risk‐based assessments influenced monitoring design and performance. At Tomakomai, time‐lapse 3D seismic surveys and microseismic monitoring proved effective for tracking CO 2 plume migration in a large saline aquifer and for assessing potential links between injection and seismicity in an earthquake‐prone region. In contrast, Jilin employed primarily well‐based methods, including cross‐well seismic, gas tracer tests, and logging, to evaluate well integrity and CO 2 migration within a fractured reservoir. These distinct strategies reflect differences in geology, project scale, and regulatory requirements and illustrate trade‐offs between cost, sensitivity, and risk management priorities. Building on this comparison, a decision‐support matrix was developed to synthesize key parameters influencing monitoring design under diverse geological and operational conditions. The findings demonstrate that CCS monitoring cannot follow a one‐size‐fits‐all model and must instead be adapted to local risks and reservoir properties. This work provides practical insights for optimizing monitoring strategies in future CCS deployments, supporting both safe storage performance and stakeholder confidence.
Nguyen et al. (Thu,) studied this question.