It is a truism, but unfortunately not true: policy-relevant climate information should be communicated such that non-scientists can understand. Through their assessment reports, the Intergovernmental Panel on Climate Change (IPCC) periodically assesses global climate research, and creates “Summaries for Policymakers” (SPM) which constitute a synopsis of the most policy-relevant findings. The SPMs' main principles include being “audience-appropriate” and “policy-relevant but not policy-prescriptive” (IPCC, 1998). To do justice to these principles, the communicated climate science must deliver an optimal basis for decision-making by non-scientists. However, SPMs are written in a highly scientific style. In a recent linguistic analysis, SPMs' readability proved to be extremely low, scoring even below scientific publications (Barkemeyer et al., 2015). There is, however, reason to believe that more effective climate communication is possible. Recent research has shown that despite a long-held skepticism (e.g., Sterman, 2008), accessible presentation formats can increase understanding of the dynamically complex determinants of climate change (Fischer et al., 2015). Importantly, the communication of highly scientific topics such as climate change or health is generally either intended to promote predefined behavior change in the recipient (e.g., anti- smoking-campaigns; messages that aim at the reduction of red meat consumption), or may induce premature closure around specific strategies by unintentionally shaping public discourse and opinion (Amelung and Funke, 2015). Because SPMs should not be policy-prescriptive, however, they should enable informed decision-making without promoting specific response strategies or unintentionally and prematurely narrowing down public debates. This article therefore is concerned with how to improve understanding—the accuracy of the recipient's reasoning—to allow for informed decision-making. A central aspect of improved communication is to reduce the amount of detail covered in the SPMs to a cognitively manageable degree, and to ensure that key information is conveyed. We selectively review cognitive process theories and findings derived from the area of health communication meant as starting points for empirical research toward more effective climate communication.