Few things have a greater impact on our lives than water. Water is a paradox: it is a seemingly abundant and renewable resource, while only a tiny amount of it is accessible and drinkable. Moreover, global water resources are unevenly distributed and many of them have been contaminated. Millions of people struggle with water scarcity, in many cases leading to water-related international conflict. Water is an international public good and is associated with common pool resources (CPR) and collective action problems whose solution calls for international cooperation and action. Well-developed ancient civilizations have disappeared because of human environmental degradation, bad resource management and related socio-political problems...