Climate science plays an increasingly important role for European policy-makers and private sector companies. Basic research and development of effective strategies to mitigate climate change and deal with its impact on society are required, involving a wide range of experts from multiple disciplines. These expert need to access climate data, in particular data from model projections for the next decades and centuries, and to assess the suitability of that data for their purposes. Currently, even if large repositories of climate data are accessible, these repositories are poorly connected and described. The data is therefore difficult to understand, compare and exploit because there is no common information paradigm.The main objective of METAFOR is to define a Common Information Model (CIM) that describes in a standard way climate data and the models that produce the data. METAFOR will build on existing metadata (data describing data) currently used in existing data repositories and address issues like metadata fragmentation, gaps, or duplication. In close interaction with related initiatives at the international level, METAFOR will propose solutions to identify, access and use the climate data in these repositories. To support the adoption of the CIM, METAFOR will build CIM-based tools and services, allowing specific data and models to be found and compared between holdings at partner sites. METAFOR will therefore optimise the way climate data infrastructures are used to store knowledge, thereby adding value to primary research data for an increasingly wide range of stakeholders.METAFOR will take the first step in doing for climate data what search engines have done for the Internet: it will put users of climate data in touch with the information they need. Simply unlocking existing climate data repositories for new communities will provide new exciting opportunities for scientific research, policy making, and private sector competitiveness.