Climate change is an important theme in the investigation of human-environment interactions in geographic education. This study explored the nature of students' understanding of concepts and processes related to climate change. Through semi-structured interviews, data was collected from 27 Secondary 3 (Grade 9) students from Singapore. The data was subjected to thematic analysis using Chi and Roscoe's conceptual change framework. The results showed that the students' base knowledge of climate change is composed of incomplete and incorrect elements built within coherent and structurally sound mental models. Due to the consistency of the models in expanding the logic, albeit erroneous, of explaining the climate change conundrum, it is posited that students are unaware of mistakes inherent in their judgements. Transformation of these mental models through multiple and deliberate refutations should be foremost in a geography teacher's pedagogical approach.