Background Global climate change (GCC) has become one of the most debated socio-scientific issues after an increase in media attention. Recently, there have also been several studies describing students' and teachers' alternative conceptions about GCC. Therefore, designing learning environments at the college level that focus on accurate conceptions of GCC has become important in order for pre-service teachers to correct their alternative conceptions. There are, however, a limited number of studies that aim to both increase pre-service teachers' knowledge about these issues and explore their perceptions of teaching this subject.Purpose The purpose of this study was to investigate the effects of inquiry-based activities on pre-service teachers' knowledge about GCC and their perceptions of teaching this subject.Sample The participants were 102 pre-service middle school mathematics and science teachers who were enrolled in an environmental education course.Design and methods A one group pre-test-post-test design was employed to identify changes after pre-service teachers engaged in a learning unit on GCC. The inquiry-based GCC unit was implemented during the spring semester at a public university in northeastern Turkey. The unit was implemented over seven sessions. Data were collected through two questionnaires: the GCC content questionnaire' and the perceptions of teaching GCC questionnaire'. Each questionnaire was administered both before and after implementation of the unit. Content questionnaire responses were analyzed using a paired-samples t-test. Responses to the perceptions of teaching questionnaire were analyzed using inductive open coding.Results Results indicated that after the implementation the pre-service teachers significantly improved their understanding of GCC across all items in the content questionnaire, saw several benefits of and challenges about teaching GCC, and perceived themselves as better prepared to teach about GCC in their future classrooms.Conclusions Teacher education programs should integrate inquiry-based GCC instruction to increase pre-service teachers' knowledge as well as their preparedness to teach about this important planetary issue.