Communication of IPCC visuals: IPCC authors’ views and assessments of visual complexity

Scientific figures, i.e. visuals such as graphs and diagrams, are an important component of Intergovernmental Panel on Climate Change (IPCC) reports that support communication and policy-making. It is therefore imperative that figures are robust representations of the science and are accessible to target audiences. We interviewed IPCC authors (n = 18) to understand the development of figures in the IPCC Fifth Assessment Report (AR5) Working Group 1 (WG1) Summary for Policy-Makers (SPM). Authors expressed the view that the need to maintain scientific accuracy constrained making figures more accessible, with the consequence that figures retained complexity and often required specialists to explain the figures to others. Using sort tasks with IPCC authors and with a group of non-specialists (undergraduate students; n = 38), we found that IPCC authors generally had good awareness of which figures non-specialists perceived as being most difficult to understand. Further, by evaluating the visual complexity of the AR5 WG1 SPM figures using a computational measure, we found that greater visual complexity (i.e. high quantity of information, use of multiple colours and densely packed visual elements) is associated with greater perceived comprehension difficulty. Developing and integrating computational approaches to assess figures alongside user testing could help inform how to overcome visual complexity while maintaining scientific rigour and so enhance communication of IPCC figures and scientific visuals.