Curricula worldwide aim to prepare students for the society they will engage with in the future. The climate crisis and the ecological challenges facing the global community necessitate addressing these issues within the school context. Given the interdisciplinary nature of these crises, topics are often complex and do not neatly align with specific subjects. Consequently, teachers and schools need to teach across subjects to address these complex sustainability challenges. This study contributes to the existing body of knowledge on teachers' approaches to sustainability education, particularly when teaching across various subjects. We place special emphasis on curriculum units designed by teachers, aiming to understand how teachers combine subject-specific and interdisciplinary teaching and learning, and how their curriculum units encompass a holistic approach to sustainability issues, in light of the Anthropocene. We analysed 20 curriculum units designed and implemented by teachers from lower secondary schools in Norway, guided by environmental, social and economic dimensions of sustainability, in addition to a framework that facilitates pedagogical approaches to education for sustainable development. This framework highlights interdisciplinary and subject-specific aspects of teaching and learning complex sustainability issues, including time, space and emotional aspects. Findings suggest that the teachers designed and implemented interdisciplinary curriculum units integrating all three dimensions of sustainability. Several teachers reported that they facilitated for students' emotional engagement with sustainability issues, however, affective aspects received least attention. A key implication from this study is that involving teacher-teams in curriculum design might enable them to implement interdisciplinary and holistic approaches to sustainable development, rather than adhering to pre-designed programs.