Schools need to prepare students to navigate complex and controversial dilemmas, and in turn to be able to make informed decisions. As part of an intervention study, we aimed to explore how a group of Norwegian 7th grade students worked with critical argumentation related to an authentic and local sustainability dilemma. A deductive, qualitative content analysis of students’ news articles and decision-making texts showed that the students based their justifications on emotions rather than knowledge and logic. Social justifications were mostly based on emotions, whilst economic and environmental perspectives were based more on rationality. Thus, we suggest that emotions should be an important element in the teaching of critical thinking, in addition to promoting the need for justifications based on logic and evidence. Based on our findings, we argue that authentic dilemmas are a suitable method for helping students identify different perspectives. Writing balanced news articles prior to composing decision-making texts with well-informed conclusions appears to be an effective approach to addressing complex value-laden questions.