A large online survey of Colorado public school science teachers (n = 628) on the topic of climate change instruction was conducted in 2007. A majority of Earth science teachers were found to include climate and climate change in their courses. However, the majority of teachers of other science subjects only informally discuss climate change, if at all. Teachers are motivated to include this topic in the curriculum when they perceive it is represented in their standards and when they receive direct encouragement from members of their school and wider communities. At the time of this study, only a small minority of teachers had experienced pressure to avoid teaching climate change. Certain misconceptions about climate change are widespread among teachers, as is the belief that "both sides" of the public controversy over human causes of climate change should be presented to students. The patterns of instruction, knowledge gaps, and a lack of learning experiences for teachers documented here suggest that all science teachers would benefit from professional development focused on climate science, best practices in climate instruction, and climate communication.