An investigation of middle school students' alternative conceptions of global warming

Because global warming presents a serious potential threat to our biosphere, it is receiving considerable attention by scientists, policy makers, and educators. This article presents alternative conceptions about global warming held by a sample of 24 grade 6 to 8 students. Students completed interviews on global warming approximately two weeks after instruction from a Science-Technology-Society (STS) global warming unit. The majority of students introduced 'ozone layer' or 'ultraviolet radiation' in response to the question, 'When you think about global warming, what comes to mind?' Approximately one-half of the students held the alternative conceptions that ozone layer depletion is a major cause of global warming and that carbon dioxide destroys the ozone layer. These and other alternative conceptions evidenced by the students suggest that global warming instruction should help students clarify that ozone layer depletion and global warming are different environmental problems and that the ozone 'hole' does nor enhance the greenhouse effect.