A.2.1. World Scale
The initial map of world prospectivity was elaborated in 2005 by IPCC  and proposed the following ranking of sedimentary basins:
- Highly Prospective
This map (Figure 53) represents a qualitative assessment of the likelihood that suitable storage exits in a given area based on available information. The quality of information differs from one region to another. As mentioned in the IPCC report , this map is subject to changes over time when new information and new studies are performed on regional basis. It is noteworthy to mention that several regional assessment studies were performed or are ongoing around the world. Here below are some of the main studies used:
- NETL North America Atlas 
- Europe GeoCapacity 
- PNNL Studies on 
- CARBMAP in [39,40]
- Saneri South African Atlas 
- IEA study on 
- CST Atlas on 
The map presented in Figure 6 summarizes the availability of the information about the assessment of CO2 geological storage potential in regions addressed in this study.
To compensate the lack of publicly available information on areas like Russia, North Africa or Middle East, the geological map of the world  was used.
The map presented in Figure 51 extrapolated from the data available allows identifying seven geological domains of importance as a first step identification of CO2 geological storage potential:
- Sedimentary basins
- Continental margins
- Extrusive volcanic rocks
- Endogenous rocks
- Oceanic crust
- Seamount, oceanic plateau, anomalous oceanic crust
We used these lithological properties to refine existing IPCC map (Figure 53) and to distinguish the sedimentary basins from other geological domains.
After separating non sedimentary areas from sedimentary basins, the next step was to define an appropriate ranking.
Such a ranking should serve to identify storage gaps for CCS industrial deployment by 2020 and beyond. After analysis of the various rankings in the published geological storage assessment studies, a common scale was defined for a world consistent analysis: a four level scale and a special category for basaltic rocks have been used.
The final ranking is, for sedimentary basins and continental margins:
- Highly Suitable
And for extrusive volcanic rocks (basalts)
The deep offshore, water depth of more than 1500m, was considered as ”Unsuitable” area due to cost reasons.