| CO2 sequestered or stored |
Stock changes can be monitored over time. |
Injected carbon can be measured. |
Injected carbon can be measured. |
| Ownership |
Stocks will have a discrete location and can be associated with an identifiable owner. |
Stocks will be mobile and may reside in international waters. |
Stocks may reside in reservoirs that cross national or property boundaries and differ from surface boundaries. |
| Management decisions |
Storage will be subject to continuing decisions about land- use priorities. |
Once injected there are no further human decisions about maintenance once injection has taken place. |
Once injection has taken place, human decisions about continued storage involve minimal maintenance, unless storage interferes with resource recovery. |
| Monitoring |
Changes in stocks can be monitored. |
Changes in stocks will be modelled. |
Release of CO2 can be detected by physical monitoring. |
| Expected retention time |
Decades, depending on management decisions. |
Centuries, depending on depth and location of injection. |
Essentially permanent, barring physical disruption of the reservoir. |
| Physical leakage |
Losses might occur due to disturbance, climate change, or land-use decisions. |
Losses will assuredly occur as an eventual consequence of marine circulation and equili- bration with the atmosphere. |
Losses are unlikely except in the case of disruption of the reservoir or the existence of initially undetected leakage pathways. |
| Liability |
A discrete land-owner can be identified with the stock of sequestered carbon. |
Multiple parties may contribute to the same stock of stored CO2 and the CO2 may reside in international waters. |
Multiple parties may contribute to the same stock of stored CO2 that may lie under multiple countries. |
