Climate change and sustainability challenges are intricate and multifaceted, requiring an approach considering the entire complex interconnected system of resources. To untie some of this complexity, Integrated Assessment Models (IAMs) have been developed to provide a comprehensive and multidisciplinary framework for analyzing and solving problems in energy security, environmental degradation, economic growth, and social equality. In an educational setting, IAMs can be helpful tools because they help students build the critical thinking and systems-level perspective they will need to tackle sustainability issues and make well-informed decisions in the future. However, their complexity and abstraction mean that IAMs can be challenging to learn in one semester. This paper uses a toy model of the complex but powerful MESSAGEix IAM as a novel and practical pedagogical approach. Our analysis investigates how students approach complex problems and the methods to help them learn and understand complex concepts. In our evaluation, we consider the difficulties associated with imparting knowledge of complex IAMs to a wide range of learners. Finally, we discuss ways teachers might help students develop a systems perspective and an appreciation for the interconnectedness of multiple social and environmental aspects through tools such as grading rubrics strategically designed to measure students' critical thinking skills. Because of the interdisciplinary nature of IAMs, students could pursue areas of study that particularly interested them, whether in the geographical, temporal, or sectoral aspects.