A new study published in Nature has recalibrated expectations for global carbon storage, setting a “prudent” capacity limit of 1,460 gigatons of CO2.
Unlike earlier, higher technical estimates, this cap integrates engineering, safety, and governance constraints, positioning geologic storage as a scarce and strategic resource.
The study warns that subsurface reservoirs used for carbon capture and storage (CCS) and carbon dioxide removal (CDR) are not limitless. Instead, they represent a finite resource that will require careful allocation between industrial abatement and removals, with significant implications for energy, industry, and climate strategies worldwide.
A Scarce Resource with Industrial-Scale Demands
While the raw global inventory suggests about 11,800 GtCO2 of theoretical storage, the prudent cap reduces usable capacity to just 12% of that figure.
Even so, reaching net-zero will demand injections of nearly 8.7 GtCO2 annually at peak, on par with the scale of today’s global oil industry in terms of infrastructure and logistics. That means pipelines, wells, compressors, ports, and monitoring systems must all expand dramatically to handle the projected flows.
Geographically, capacity is unevenly distributed. Large sedimentary basins in the US, Russia, China, Brazil, and Australia retain significant storage potential, while countries such as India, Norway, Canada, and parts of the EU face sharper constraints once safety and geological filters are applied.
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Dr Robert Sansom, a member of the IET’s Sustainability and Net Zero Policy Centre, echoed studies findings, adding: “[Carbon capture and storage (CCS)] is a powerful tool in the fight against climate change, but it’s not a bottomless solution. We must treat it as a strategic and finite resource.”
This imbalance is likely to reshape CO2 transport routes, encouraging cross-border pipelines and shipping corridors to injection hubs.
The study also highlights the importance of robust legal and liability frameworks, particularly for offshore storage where jurisdictional boundaries and long-term monitoring obligations complicate financing.
Ultimately, the findings signal a need for a clear hierarchy of use. Power generation, cement, and other “hard-to-abate” sectors may take priority due to the concentration and reliability of their emissions streams, while large-scale CDR deployment could be limited by storage scarcity.
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Experts question findings
However, the study also provoked criticism. Prof Stuart Haszeldine, Professor of Carbon Capture and Storage at the University of Edinburgh, said: “This article takes a high-level view to challenge selected assumptions of risks in storage performance.”
“With a conclusion that commercial capacity reserves may be just 10% of current resource estimates. However evaluations from high-level can lack resolution of important details at ground-truth.”
Jack Andreasen Cavanaugh of the Center on Global Energy Policy also shared his criticisms of some of the findings, including that “the study only looks a sedimentary basins (saline aquifers and depleted oil and gas reservoirs), and we have gigatons of storage potential in mineral storage (basalts, peridotites) as well as coal seams.”
The Global CCS Institute issued a response to the study, which expresses the organization’s agreement with some of the key conclusions. However, it raises concerns about the study’s methodology and its “restrictive assumptions about risk and technical parameters of CCS projects.”
“The Institute would generally agree that the research correctly frames geological storage as a finite intergenerational resource requiring strategic management. This supports prioritising CCS for essential applications – industrial point sources that cannot be electrified and durable carbon removal technologies. The critical question is not whether adequate storage capacity exists, but rather the speed at which it can be utilised at scale,” the response says.
