personal benefit or align with the agreed-upon rules or norms that promote collective benefits.Likewise, they may jointly contribute to the infrastructure maintenance so the system generates Chapter 1 2 more water for everyone, or freeride on efforts by others. The harvesting and investment decisions are complex and depend on the agents' attributes (inequality, preferences, and experiences), and are shaped by the institutions in place. In some cases, water is managed by local communities following informal institutions such as social norms that prescribe who can take how much water and when. Those social norms are usually enforced through interpersonal communication by means of peer sanctions or reputational concerns. In other cases, water is managed through formal institutions, where written rules are enforced by the local government or a farmer organization.Obviously, the interactions between the subsystems of water, users, and institutions are complex and may produce emergent outcome that may in turn feedback other parts of the system (Ostrom 2009; Muneepeerakul and Anderies 2020). The resilience of this system and its sustainability depends largely on the self-organizing capacity of the social system for collective action such as cooperation (Schill et al. 2019;Anderies et al. 2004; Perez et al. 2016;Lansing et al. 2017). Ostrom ( 2009) has identified a set of key variables that may interact with the self-organizing capacity of the system, among which are system productivity (e.g. resource scarcity) and social norms and social capital. This thesis investigates the role of resource scarcity, either exogenously caused by climate change or endogenously, caused by resource users to maintain the water infrastructure (a public good), and its coupling with some key contextual variables through the lens of institutions (Anderies et al. 2004). The key question in this thesis is what kind of institutional configurations facilitate cooperation and can thus accommodate the changes in the face of increasing scarcity due to climate change. To answer the question, I will discuss briefly first the theme, rationale and contribution of each or a combination of chapter(s) and then the methodological approach.Informal institutions such as social norms play an important role in water governance, especially under climate change (Pahl-Wostl 2009; Herrfahrdt-Pähle and Pahl-Wostl 2012). A social norm is a common behavioral pattern that is socially approved, collectively understood and maintained through social interactions within a group (Nyborg et al. 2016). In small communities that self-govern common pool resources, social norms can play important roles to facilitate cooperation (Ostrom 2000). With appropriate conditions, social norms can even address global problems (Nyborg et al. 2016). A social norm, however, is not always obeyed , especially when following it does not yield better personal outcomes. An enforcement Agrawal, Arun. 2008. "The Role of Local Institutions in Adaptation to Climate Change."