This brief describes the current critical situation of global warming and shows its solution by renewable energy use. The author has long studied the development of new materials with chemical functions and is renowned as the first advocate of power-to-gas. He established the technology to convert renewable energy to synthesized natural gas, methane by electrolytic hydrogen generation using surplus electricity from renewable energy, and subsequent methanation of carbon dioxide by reaction with hydrogen. In the first part of this brief, data on global warming and energy consumption are shown and analyzed from the author’s keen point of view. The second part introduces the author’s research results on key materials for global carbon dioxide recycling and constructed pilot plants based on them. Finally, an evidence-based solution to maintain sustainable development by using only renewable energy is described as a future prospect. This book is useful not only for researchersand students studying chemical engineering, materials, or energy, but also for general citizens who are interested in the global environment.