Towards a new trait-based framework bringing together terrestrial and marine ecosystems in Earth system models.

The climate on Earth arises from multiple interactions between the different spheres, including the biosphere. Within the biosphere, the organisms composing the various types of ecosystem are characterized by a set of traits involved in biological processes that can influence the climate system. Identifying and integrating these traits into models such as earth system models (ESM) is thus crucial to predict the future of earth climate. While an important number of biological processes are similar, the amount and the type of traits considered to represent these processes can vary considerably among ecosystem types in current ESMs. Such inconsistencies could bias our perception of the global influence of biosphere on climate dynamics. Here we first list the biological traits that have been included in the terrestrial and oceanic modules of the CMIP5 Earth system models. By comparing the traits and associated processes, we reveal consistencies and inconsistencies in trait representation among both ecosystem types. Based on a critical evaluation we propose a new conceptual framework that allows to describe the climate relevant traits in a consistent way in terrestrial and oceanic modules of ESMs. This framework can also be used to identify new traits characterizing terrestrial and/or marine ecosystems, and to integrate them in ESMs.