Humanity is facing major challenges as a result of global warming, where the digital carbon footprint constitutes a growing yet often invisible part of the overall environmental impact, particularly the impact from digital technologies. This thesis examines awareness of digital environmental impact among IT students (n=9) and whether a visual environmental and sustainability indicator on mobile devices can motivate users to adopt more resource-efficient behaviors. The selection of IT students is motivated by the fact that they are representative smartphone users who also have both the interest and future opportunities, as designers and developers, to contribute to sustainable design. The study adopts a qualitative methodological approach consisting of semi-structured interviews complemented by elements of a Future Workshop method, in which participants were asked to reflect upon and develop conceptual design proposals and solutions through both the fantasy and implementation phases. The collected data were processed using thematic analysis and interpreted through an overarching design approach within Sustainable Interaction Design (SID). The analysis was further deepened through a theoretical framework encompassing persuasive design, Socially Responsible Design (SRD), and theories of nudging, dark patterns and eco-feedback. The results indicate that even environmentally aware users are strongly influenced by persuasive design and that there may be reasons to continue exploring the concept of a sustainability indicator as an addition to mobile devices. Participants expressed a preference for a balance between visibility and user autonomy, where the indicator is visually discreet and provides real-time feedback that users can choose to activate or deactivate themselves. The findings emphasize the importance of constructive feedback and guidance rather than guilt-inducing approaches, as well as the potential of using gamification and subtle color changes as triggers to interrupt habitual mobile phone use. In conclusion, the study finds that interaction design can play a crucial role in making invisible environmental impacts visible and that IT students seek tools that support them in making sustainable choices without compromising their user experience.