Ensuring a comprehensive assessment of climate science is an important mandate of the Intergovernmental Panel on Climate Change (IPCC). However, there are accusations of bias towards certain disciplines and research fields based on limited empirical evidence. By analyzing the evidence base of IPCC reports, we show that integrated assessment modeling (IAM) research was influential in all six climate change mitigation assessments, particularly in the Summary for Policymakers (SPM). A small number of male IAM researchers from Western Europe and the USA dominated this contribution. This shows that there is an epistemic hierarchy in the IPCC, and that IAM research it at or near the top of it. Thus, global climate negotiations and science may have historically prioritized mitigation solutions dominant in IAM research, such as costs and targets, and missed solutions from other perspectives, such as from developing countries or non-male gender perspectives. However, we also show that the influence of IAM research has been shrinking, which suggests that the IPCC has already undertaken measures for leveling the playing field.
