  The voluntary carbon market is an important building block in the fight
against climate change. However, it is not trivial for consumers to verify
whether carbon offset projects deliver what they promise. While technical
solutions for measuring their impact are emerging, there is a lack of
understanding of how to translate this data into interface designs that mediate
the establishment of trust. With interaction between users and offset projects
mainly happening online, it is critical to meet this design challenge. To this
end, we designed and evaluated interfaces with varying trust cues for carbon
offset projects in a randomized online experiment (n=244). Our results show
that content design, particularly financial and forest-related quantitative
data presented at the right detail level, increases the perceived
trustworthiness, while images have no significant effect. We contribute the
first specific guidance for interface designers for carbon offsets and discuss
implications for interaction design.
