The use of social robots has recently been investigated in various areas, including STEM (Science, Technology, Engineering, and Mathematics) education and artistic performances. To inform children of the seriousness of climate change and awareness that they can make change, we created the Robot Musical Theater performance. In this project, natural elements (wind, earth, fire, and water) were anthropomorphized and represented by humanoid robots (Pepper, Milo, and Nao). The robots were designed to motivate audience to participate in the action to prevent climate change. Because of COVID, only fourteen visitors as a single group were allowed to participate in real-time and posted to YouTube, where at the time of submission, 141 people have viewed the performance. The participants provided positive comments on the performance and showed their willingness to participate in the movement to prevent climate change, and expressed their further interest in STEM learning. This performance is expected to contribute to enhancing informal STEM and robotics learning, as well as advancing robotic arts.