CIAS – Community Integrated Assessment System CIAS

the Community Integrated Assessment System (CIAS), a new approach to integrated modelling for climate change policy. Previously existing integrated assessment can be categorised into cost-benefit models with detailed economics and relatively simple representations of climate and impacts, and biophysical impacts models that have more detailed information about physical climate changes and impacts. Policymakers are thus confronted with a series of outputs from several sets of different integrated models, each built at a single institution, each based upon a particular set of assumptions or scientific paradigms. The Community Integrated Assessment System (CIAS) was designed to overcome these drawbacks, for example providing robust estimates of avoided damages and mitigation costs through comparison of multiple climate policy scenarios compared to no-policy scenarios The advance that CIAS makes over existing integrated modelling approaches is that it is possible to estimate robustness through using different assemblages of component modules that represent similar processes (such as climate)in addition to the study of the robustness of the outputs to the values of uncertain parameters within the modules. CIAS allows users to compose many different individual integrated model combinations. This is particularly important when comparing the use of individual modules of different levels of complexity and detail or comparing the use of individual modules which may originate from different institutions having similar complexity but based on different modelling paradigms or value judgements originating from the different researchers who may be based at different institutions. Thus a broad range of perspectives is encompassed.