Ecological problems coupled with climate change pose unprecedented challenges, requiring cooperation and adaptation to environmental issues. This is driving states into competition, as "Blue Gold" becomes a resource of extreme covetousness, not only between individuals, but also between states. The twenty-first century has seen the emergence of new types of conflict, known as "green conflicts", or horizontal and vertical conflicts of use, generated by the increasing scarcity of natural resources. Water is the most obvious example. To this end, cooperation between riparian states is essential to avoid water conflicts. This book shows that water is a real issue of cooperation, capable of promoting peace, socio-economic development for the well-being of riparian populations, sustainable management of ecosystems and species that depend on this resource, poverty reduction and the prevention of conflicts between riparian states. Nevertheless, if mismanaged or misused, water can become a catalyst for tensions.