The present study explored how seventh graders develop their understanding of climate change issues. Particularly, I focused on identifying students' ways of reasoning in evaluating and generating arguments. I also investigated whether students reason differently about climate change issues depending on the relevance of the issues to their daily lives and whether male and female students employ different ways of reasoning. Scientists' debates on the impact of global warming on tornadoes and hurricanes were used as a context for the student tasks and data analysis. Students individually participated in two vignette-based think-aloud tasks in which I observed and interviewed them to elicit their beliefs, knowledge, and ways of reasoning. Through inductive content analysis and comparative analysis of the individual interviews, I identified six categories of students' ways of reasoning. It was common across the categories that students lacked scientific epistemological criteria for evaluating and generating arguments and their reasoning was often biased towards their prior beliefs and knowledge. Students' ways of reasoning in dealing with inconsistencies between their beliefs and knowledge and the scientists' arguments presented in the vignettes varied by category. In addition, I conducted statistical analyses and found that students' ways of reasoning did not significantly differ by the relevance of climate change issues or by gender. I discuss and propose explanations for the findings in comparison with the literature, and elaborate the implications for science and climate change education and future research. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]