Issues to address before we can have an open climate modelling ecosystem

Earth system and climate models are complex assemblages of code which are an optimisation of what is known about the real world, and what we can afford to simulate of that knowledge. Modellers are generally experts in one part of the earth system, or in modelling itself, but very few are experts across the piste. As a consequence, developing and using models (and their output) requires expert teams which in most cases are the holders of the "institutional wisdom" about their model, what it does well,and what it doesn't. Many of us have an aspiration for an open modelling ecosystem, not only to provide transparency and provenance for results, but also to expedite the modelling itself. However an open modelling ecosystem will depend on opening access to code, to inputs, to outputs, and most of all, on opening the access to that institutional wisdom (in such a way that the holders of such wisdom are protected from providing undue support for third parties). Here we present some of the lessons learned from how the metafor and curator projects (continuing forward as the es-doc consortium) have attempted to encode such wisdom as documentation. We will concentrate on both technical and social issues that we have uncovered, including a discussion of the place of peer review and citation in this ecosystem. In particular, we will discuss the difference between the computational and scientific views of code, the importance of adequate descriptions of inputs (including the locations of the actual data), how we engage with information suppliers and consumers, and how we might use peer review to scientifically validate such information.