The extent to which GMES information products are sufficiently well accepted in potential user communities remains limited. This quote from the Aeronautics and Space Work Programme 2002-2006 is part of the call that was addressed by GNU. The statement is still true today, that is, the potential of GMES as an innovative and standardised monitoring system is not yet fully realised. Thus, there is a need to investigate and document the backgrounds of this situation and to suggest improvements.

GNU defragments the environmental GMES user communities. Currently, user federations of GMES projects are isolated from each other due to the topical approaches (land, atmosphere, marine, geology, sea-ice, etc.). GNU now provides the opportunity to address the cross-cutting issues.

GNU enables independent and unfiltered user statements. Thus far, user federations exist only within the frame of projects led by service providers. These user groups have no or little access to project resources which impedes their active participation. Moreover, current GMES project structures do not always provide an adequate frame for users to articulate their views.

GNU links data-related and human aspects of the socio-technological system GMES. Users' appraisals of GMES data products are collated and differentiated. The backgrounds of these documented user statements are elucidated, considering that some are very detailed, others rather unspecified, and some were influenced or interpreted by the respective service providers. An analysis of user-provider relations on the project level enables articulating recommendations to foster an effective communication. Currently, most of the observed problems within GMES projects relate to communication issues rather than to technology development.

GNU provides a mouthpiece for the needs of GMES users of the subsidiary, that is national and regional, levels. Several European level users already have established effective communication channels to articulate their needs within GMES. However, the specific needs of the subsidiary level users are not within the scope of the GMES Core Services. Therefore, the downstream sector, and, specifically its interface with the core sector, must be well defined to achieve maximum benefits for subsidiary level users.

GNU outlines major prerequisites for users to easily access GMES data. Data portals play an essential role in GMES because they not only give users access to data they are looking for, but also provide an overview to users which services and products GMES offers to them. GNU will contribute to this essential topic in that current GMES and related data portals are evaluated and criteria for the design of user-friendly data portals are worked out.