With the continued unfolding of major climatic shifts, questions continue to emerge about how to approach climate change in the science classroom, at least in the USA where it is often perceived as socio-politically controversial. Broadly, research in science education has shown that the learning process around climate change is highly complex and variable, and our understanding of it remains emergent. This study argues that when designing learning experiences for issues like climate change, we must consider students' prior knowledge of the social world. Using ideology as a theoretical lens, this study then examines discourse data of several classroom elicitation discussions in two sections of a 9th grade US classroom to clarify what intuitive understandings of the social world and assumptions students bring to their classroom learning about climate change. Moment-by-moment discourse analysis shows the emergence of assumptions of a sharply divided social world and the making material of an ideology that reflects these divisions. This study considers implications for such prior knowledge on scientific sensemaking and offers implications for science teaching and future research.