Persuasive Pathways: The Practice of Integrated Assessment Modelling in Climate Politics

As the planet becomes an ever more hostile place, the need for radical societal transformation intensifies. In response, countries globally have set ambitious climate targets. Both scientifically and politically, these goals strongly rely on specific type of computer model: Integrated Assessment Models (IAMs). IAMs are global models that represent the complex interactions between human activities and changes in the climate system. By simulating multiple mitigation scenarios, they provide insights into the trade-offs between mitigation options and the long-term effects. But they are less well-suited to imagine radically different societies and take social justice into account. While IAMs over time attained clearly defined and prominent role in the science-policy interface, their role in the societal debate is far less self-evident. This thesis explores this tension by investigating the role of IAMs in climate policy (Part I) and exploring alternative future roles of IAMs in policy and society (Part II). Part I finds that from the 1970s onwards, IAMs became increasingly prominent in the science-policy interface. The analytical qualities of IAMs and the advances in data availability or computer technology were important. But their prominence also strongly relied on modellers’ capacity to anticipate and respond to policy-makers demands. This ‘political calibration’ is an important mechanism through which modellers maintain policy-relevant. But it also renders some potentially harmful and just futures more persuasive than others, which in turn become influential drivers of climate policy. The rapid normalisation of carbon dioxide removal is a case in point. This is problematic because of the growing plurality of actors in climate politics and the increasing attention for climate justice. Part II therefore explores how this possibility space can be opened up through three transdisciplinary experiments involving artists and citizens. By bringing modellers into conversation with fiction writers, it finds that climate fiction is a particularly fruitful practice to seek interactions, given that both practices engage in world-building but rely on different mechanisms to build plausibility. An artist residency further demonstrated how artists can challenge and transform existing ways of working through an artistic intervention. However, engaging with artists does not guarantee more radical imagination. This potential is hampered by viewing artists merely as science communicators. Artists are also restricted by the genres and norms of their own artistic practice. Another way to open-up the possibility space is through citizen engagement. This thesis explores how expertise is mobilized in emerging citizen engagement practices on the national level, where modelling continues to play an influential role. Again, it finds that citizen engagement does not guarantee an opening-up of possible futures; experts can strongly influence the outcomes of citizen engagement practices. It depends on the particular way in which expertise in such practices is mobilised. This thesis concludes with a reflection on the future of IAMs in climate politics from a climate justice perspective. It argues that IAMs should not be viewed as ‘tools’ to explore futures, but as practices that bring futures into being. The answer therefore lies not therefore lies not in improving the models, but in reconfiguration of modelling in climate politics. While this is no easy task, this thesis demonstrates that the prominence of IAMs is not set in stone and alternative configurations are already in the making.