Science has played a critical role in defining the international policy response to climate change. This application of science to address a policy issue characterised by risk and uncertainty is replicated across various domains. Social science research has to-date focused on the international arena. The ratification of the Paris Agreement in 2016 altered the policy focus on climate change from globally to nationally determined responses. In this context, there is a need to consider whether the science that informed international policy is also the science at the national level that informs mitigation policy? If not, what does the science look like in different states and how does that science differ from the global science? Such inquiry builds off literature demonstrating that science is co-produced or socially constructed, rather than objective facts as commonly viewed. From this perspective, where the political/social context shifts with the move from global to national level, the science that is produced is affected. I study this issue by focusing on how the science is understood (independent of the content). To do this I present a conceptual framework developed for this research based around three possible characteristics of how science is understood - status, mode of determination, and function. This framework is applied to study the cases of India, the United Kingdom, and the United States, as well as the Intergovernmental Panel on Climate Change (IPCC). The analysis of the national cases focuses on the engagement with the science of the IPCC in legislative committees and processes. The analysis of the IPCC focuses on institutional procedures and formal messages communicated. Based on the analysis I describe in detail the distinct understanding of the science of climate change in each case. The variation I identify across cases is important from academic and practice perspectives because, if the science in states is different to the science of the IPCC, then the way we understand the process by which states develop climate change mitigation policy needs to reflect this fact.
