Climate change is one of the most pressing issues facing society today, yet many people seem to have significant misconceptions concerning whether it is happening, why it is happening, its consequences, and what can be done to address it. Large introductory courses present an opportunity to teach many students—some of whom will never go on to take another course related to climate, ecology, or the environment—about climate change. Here, we present the results of a study on Introductory Biology students at a large Midwestern university. We used quantitative approaches to ask what views students hold when they enter the course and how their views changed over the course of the semester. We found that student certainty about the science of climate change increased with instruction, even though students entered the course feeling that they could not easily change their views on climate change. Students became more worried about climate change during the course. At the end of the semester, more students correctly identified that climate change is already harming people, and more students reported feeling that climate change will harm them personally. However, qualitative analyses revealed important misconceptions and areas for improvement. Students rarely specify actors when discussing causes of climate change, and also describe impacts and solutions in impersonal ways. Finally, students develop some misconceptions during the course. Notably, they seem to conflate or confuse negative environmental issues that were covered in the course (e.g., climate change, plastic pollution, eutrophication). Together, our quantitative and qualitative analyses suggest that while introductory biology coursework has important benefits in improving student understanding of climate change, these gains are not always accompanied by an increased sense that these understandings can be meaningfully acted on, and students’ improved understandings are sometimes nested with subtle misunderstandings.