This experiment aims to increase understanding of the conditions under which combining textual and visual information on CO, storage fosters comprehension of the technology. Specifically, it is investigated if and how precision in indicating the depth of CO2 injection in either text, visual, or combinations thereof influence estimates of CO2 injection depth and how this in turn influences perceived safety of and attitude towards CO2 injection. We used a 3x3 experimental design with two factors, resulting in 9 conditions: Textual description of depth of injection (absent, ambiguous, precise) X visualization of depth (absent, ambiguous, precise). three texts were developed explaining the background and process of CCS. They were similar in every respect except for the accuracy of indication of depth: Absent ("underground"); Ambiguous ("deep underground"); Precise ("1,000 meters or deeper underground"). Three visual conditions were developed displaying the depth of CO2 injection. They were similar in every respect except for the accuracy of indication of depth: Absent (no visual displayed); Ambiguous (visual not to scale, injection obviously too shallow); Precise (visual to scale). Respondents were a representative sample of the adult UK population (n = 429). Each of them received one of the nine conditions, followed by a short questionnaire. Results indicate that estimates of depth are generally most accurate in text-only conditions and least accurate in visual-only conditions. Interestingly, the condition in which people are given no information about depth at all scores in-between with a mean estimate of 869 meters. Regarding textual depictions of CO2 injection depth, results indicate that the more precise indication of depth in the text the better respondents' estimate of depth, but this effect is only found for respondents who enjoy reading text. Regarding visual depictions of CO, injection, results indicate that the presence of a visual worsens respondents' estimate of depth, and the more precise indication of depth in the visual the worse respondents' estimate of depth. No relation was found between respondents' depth estimate of CO2 injection and their attitude towards CCS and risk perceptions of CCS. However, a more positive attitude towards CCS was related to lower perceived risk. Explanations and implications for communication are discussed in the paper. (C) 2013 The Authors. Published by Elsevier Ltd. Open access under CC BY-NC-ND license.