UNCERTAINTY, COMPLEXITY AND CONCEPTS OF GOOD SCIENCE IN CLIMATE-CHANGE MODELING - ARE GCMS THE BEST TOOLS

In this paper we explore the dominant position of a particular style o f scientific modelling in the provision of policy-relevant scientific knowledge on future climate change. We describe how the apical positio n of General Circulation Models (GCMs) appears to follow 'logically' b oth from conventional understandings of scientific representation and the use of knowledge, so acquired, in decision-making. We argue, howev er, that both of these particular understandings are contestable. In a ddition to questioning their current policy-usefulness, we draw upon e xisting analyses of GCMs which discuss model trade-offs, errors, and t he effects of parameterisations, to raise questions about the validity of the conception of complexity in conventional accounts. An alternat ive approach to modelling, incorporating concepts of uncertainty, is d iscussed, and an illustrative example given for the case of the global carbon cycle. In then addressing the question of how GCMs have come t o occupy their dominant position, we argue that the development of glo bal climate change science and global environmental 'management' frame works occurs concurrently and in a mutually supportive fashion, so uni ting GCMs and environmental policy developments in certain industriali sed nations and international organisations. The more basic questions about what kinds of commitments to theories of knowledge underpin diff erent models of 'complexity' as a normative principle of 'good science ' are concealed in this mutual reinforcement. Additionally, a rather t echnocratic policy orientation to climate change may be supported by s uch science, even though it involves political choices which deserve t o be more widely debated.