As Our Common Future insisted in 1987, “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Since the Industrial Revolution, human development has accelerated so much that its sustainability has come into question. Here I would like to present my proposal for what we should do to make our civilization sustainable. There are three major problems, namely the restriction of population growth, the maintenance and restoration of vegetation, and the utilization of renewable energy.