Water is a crucial resource that can unite or divide nations, but throughout history, people have generally cooperated to solve water-related issues. However, as freshwater scarcity intensifies due to climate shifts and escalating human demands, it is critical to identify water-related conflicts and cooperation dynamics. For instance, changes in water patterns, including floods, droughts, and dam construction to manage varying precipitation, could lead to increased competition and conflict over water resources. Effective water management and collaboration could help resolve these issues and foster peaceful water governance. 

The main aim of this thesis is to examine the connections between how humans, the climate, and changes in water have affected cooperation and conflicts over water. This research involves investigating the interactions between changes in freshwater availability, water-related events such as conflicts and cooperation, and changes in human activities and climate. The focus is mainly on global and regional large-scale levels, and the work comprises four parts: (i) a scoping review of previous scientific literature to identify important conflict factors and research gaps; (ii) hydrological modeling to determine the direction and magnitude of hydroclimatic change relating to human activities; (iii) creation of an updated water-related conflict and cooperation database and analysis of current trends; and (iv) analyses of how socio-economic and climatic factors affect water events and cooperation mechanisms behind successful conflict mitigation.

The combined results from the four parts reveal that governance, policy, and climate change are important conflict factors worldwide. Agriculture emerges as particularly important in Africa and Asia, but there are regional variations in the importance of different conflict factors to these water conflicts. A significant research gap emerges for regions outside Africa and parts of Asia. This is problematic since influencing conflict factors appear to differ between regions. Scrutiny of the updated water event database showed that water events are increasing in frequency in most regions of the world but that cooperation is decreasing in parts of Africa, the Middle East, and South America. Changes in water events appear to be largely driven by climate change in Africa and by human activities in Asia. Changes in population density, urban-rural distribution, and precipitation have only small effects on conflict and cooperation outcomes, while economic factors such as gross domestic product (GDP) and export dependency have significant effects.

The thesis reveals the interplay between human activities, climate change, and water governance, shedding light on the global dynamics that shape water conflicts and cooperation. The results underscore the critical need for adaptive water management strategies informed by comprehensive, region-specific insights. Future studies should, therefore, seek to develop innovative governance frameworks, predictive models for conflict prevention, and resilient water-sharing agreements that can withstand the challenges posed by global environmental changes. Such work will require an integrated approach, combining socio-economic, hydrological, and climate perspectives, to foster sustainable water management and peacebuilding efforts in an era of increasing uncertainty.