The Carbon Visuals Exit document explains how images can be used to make carbon dioxide 'real' (physical) and not just a number. The images provide a physical sense of scale and allow people without strong numeracy to engage in quantitative arguments.
You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.- A set of US reference images – methodology (PDF)(6 pp, 441 K)