Deliverable D3: Global climatic features over the next million years and recommendation for specific situations to be considered. Work Package 2, Simulation of the future evolution of the biosphere system using the hierarchical strategy. Modelling Sequential Biosphere Systems under Climate Change for Radioactive Waste Disposal (BIOCLIM)

The BIOCLIM project aims at assessing the possible long-term impacts of climate change on the safety of waste repositories in deep formations using climate simulations of the long-term climate in various European areas. One of the objectives of the project is to develop two strategies for representing sequential climatic changes to the geosphere-biosphere system for different sites over Europe, addressing the time scale of one million years. The results of this work will be interpreted in terms of global or regional changes of climate and of vegetation. The first strategy (hierarchical strategy) will use the full hierarchy of existing climate models (a climate model is a numerical simplified representation of the climate system behaviour and evolution). Simple models (LLN 2-D NH and threshold models; see the description here after) will simulate the overall long-term evolution of the global climate. Their results will then be used as inputs to more complex models (LMD climate models possibly coupled with vegetation models, either SECHIBA or ORCHIDE) and finally climate and vegetation cover will be determined for specific sites at specific times. A second strategy (integrated strategy) will consist in building an integrated climate model, which represents most of the physical mechanisms for studying long-term climatic variations. The results will then be interpreted on a regional scale. This deliverable is the first step of the hierarchical strategy. The purpose of this deliverable is to identify and justify some specific climatic situations amongst different long-term simulations that are of interest for assessing the safety of radioactive waste repository sites and that will be further studied with GCMs (General Circulation Model).