This chapter reveals the overview of sustainability; the overview of environmental sustainability; environmental sustainability and climate change; environmental sustainability, water resources, and energy consumption; and the overview of sustainable tourism. Sustainability is the important issue that attempts to bridge social science with civic engineering and environmental science with the technology of the future. Environmental sustainability is important because it ensures people have water and resources, and adopting its practices protects the environment and human health. Sustainable tourism is a growing segment of the global tourism industry that makes the positive contributions to the environmental, socio-cultural, and economic well-being of destinations and local communities around the world. Sustainability, environmental sustainability, and sustainable tourism are rooted in three issues that are considerably linked to fossil fuel depletion, climate change due to carbon dioxide emissions, and the increasing costs of energy and water.