In order to develop our society, human beings should consider the global environment where global cycles of materials are essentially important. Considering a global effect of an energy carrier such as hydrogen and hydrocarbons, the hydrogen cycle (water cycle) is compared with the carbon cycle in order to evaluate the effect of an energy carrier on natural cycles of materials. We introduced a new parameter named “Environmental impact factor”. The environmental impact factor was defined as a ratio of an annual quantity of materials produced by energy consumption of mankind to a natural movement on the earth. The environmental impact factor of water on the earth, 0.0001, is two orders of magnitude less than that of carbon, 0.036. This result means that the water cycle is superior to the carbon cycle considering the materials circulation for energy system of mankind on a global scale. In addition, we applied the environmental impact factor to cities and prefectures in Japan. For example, the environmental impact factor of water on the Tokyo metropolitan area, 0.12, is 5 orders of magnitude less than that of carbon, 35000. The environmental impact factor of water was always smaller than that of carbon in all cities and prefectures in Japan. This result indicates that hydrogen energy is friendly to the environment.