This thesis explores the policy, institutional, and discursive conditions for green and atmospheric water governance in the Amazon region. Just as regions are connected through rivers over land, they are also dependent on each other through “flying rivers”: the atmospheric transport of moisture. Water continuously circulates through the hydrological cycle, partitioning into blue, green, and atmospheric forms. Rainfall infiltrates soils as green water or runs off as blue water, while soil moisture can either percolate to groundwater or return to the atmosphere through transpiration, forming atmospheric water. Terrestrial moisture recycling occurs when evapotranspiration from land surfaces generates precipitation locally or at distant sites. In South America, this process sustains regional rainfall regimes: the Amazon basin contributes between 25–35% of its own rainfall and up to 48–54% of rainfall in the wider region, specifically the La Plata Basin. The process of terrestrial moisture recycling is not isolated. Rather, human activities such as land use influence green and atmospheric water flows and subsequent precipitation patterns. This is problematic and creates new dilemmas, as countries and basins are interdependent on each other and might be impacted by land use decisions elsewhere, affecting water supply for agriculture, drinking water and more. Despite this, current water and environmental governance frameworks in South America, and globally, focus primarily on visible blue water—rivers, lakes, and aquifers—while neglecting green and atmospheric water. Although the academic literature on green and atmospheric water governance has grown, a critical gap remains regarding case-specific, interdisciplinary, and interpretive research into the policy, institutional, and discursive conditions necessary to guide implementation. Addressing this gap, this thesis applies a multi-method, iterative approach combining actor analysis, social network analysis, and framing analysis to examine four central research questions: (1) Which actors, stakeholders, and formal arrangements currently shape water and environmental governance in the Amazon and La Plata Basins? (2) What dilemmas are likely to emerge for green and atmospheric water governance across and between these basins? (3) How are actors connected to each other, and who are potential policy brokers for advancing governance? (4) How is green and atmospheric water framed within the current discursive landscape? Regionally, both basins’ member countries cooperate within intergovernmental basin organizations, respectively the Amazon Cooperation Treaty Organization (ACTO) and the Intergovernmental Coordinating Committee of the Countries of the Plata Basin (CIC). The ACTO and CIC can be considered key decision arenas, in which shared agreements and visions by the basin countries are made regarding transboundary water and environmental governance. However, it should be noted that the sovereignty of the countries remains central in these decision arenas, which is reflected in the differences of laws and regulations on the national level. Notably, no institutionally embedded mechanism for cooperation between the basins on (green and atmospheric) water governance was observed. The Rio Conventions and Sustainable Development Goals are significantly reflected in the basins’ projects related to water governance, primarily in terms of funding and organizational support. Over the years, both ACTO and CIC have formulated strategies for Integrated Water Resources Management (IWRM), which were facilitated through the Global Environment Facility (GEF) together with GEF implementing agencies. Overall, green and atmospheric water is primarily referred to in scientific terms, such as "soil moisture," "precipitation," and "evapotranspiration". This aligns with the general observation of the lack of politicization of green and atmospheric water in current water governance debate and is explained through path dependencies resulting from the hegemony of sustainable development discourses across water and environmental policy arenas. Beyond scientific frames, green and atmospheric are found to be framed in climatic, solutionist (technocratic), functional and metaphorical ways using a river as metaphor. Climatic frames are widespread and primarily refer to droughts and floods. The widespread problematization of droughts and floods creates discursive space for green and atmospheric water governance. A climatization of green and atmospheric water could be beneficial given the established recognition of climate change, institutionalized through UNFCCC, and the Paris Agreement. Moreover, an embeddedness within climate change policy would also allow additional funding mechanisms, for example through the GCF. Yet, there are also risks. Climate policy deliberations are volatile which could affect stability for green and atmospheric water governance and a (perceived) distance to climate change could lead to lower levers of public engagement. A solutionist frame refers to green and atmospheric water in technocratic ways as a means to solve local problems. Within this frame, atmospheric water is referred to as a local, "unconventional" water resource in times of water scarcity. Green water (soil moisture) is referred to in relation to land management techniques, primarily for agriculture. Whereas a solutionist framing allows for the relevance of green and atmospheric water to be highlighted, it risks reestablishing existing blue-water oriented discourses through addressing local blue water scarcity problems. A functional frame was often observed together with the metaphor of a “flying” river. Such a framing highlights the several uses of green and atmospheric water, for example, for rainfed agriculture. As such, the flying river metaphor shows potential to bridge across different policy arenas and discourses. Yet, upon using the metaphor, one should be considerate to not oversimplify the policy problem of green and atmospheric water governance. For green and atmospheric water governance to take shape in the Amazon and Plata basins, political readiness, policy entrepreneurship, and cross-sectoral coordination are needed. Global visibility can be enhanced by UN Water, while coalitions like “80x25” and the GCEW can act as policy entrepreneurs using the “flying rivers” metaphor. Regionally, ACTO and CIC should establish inter-program and interbasin commissions including multi-disciplinary experts, Indigenous and civil society actors, and industry, supported by shared monitoring systems. International funding, such as an extended GEF International Waters mandate, is essential to enable negotiations, policy-making, and effective implementation of transboundary green and atmospheric water governance. The study concludes with several policy implications. First, inter-basin mechanisms should be strengthened, embedding ACTO and CIC into decision-making while exploring inter-basin committees or broader hemispheric forums such as the OAS. Second, organizations like the Science Panel for the Amazon can serve as brokers between competing advocacy coalitions, provided their positioning within governance ecosystems is carefully considered. Third, communicative tools such as the “flying rivers” metaphor may help connect problem streams and broaden political readiness. Finally, deliberate efforts are needed to prevent discursive lock-in by fostering plurality and facilitating deliberative learning across scales and sectors. In this way, green and atmospheric water governance can move from being an underdeveloped policy arena toward becoming an integral part of water and environmental governance in South America and beyond. This research faces several methodological and analytical limitations. The exploratory and interpretive nature of the work means that the identification of actors, network relations, and discursive patterns inevitably involves an element of subjectivity. The actor analysis was static, even though actors and their resources evolve dynamically, and data limitations may have produced incomplete assumptions. The framing analysis, conducted through Atlas.ti, risked both missing relevant passages and including false positives, while focusing only on textual sources excluded visual framings and metaphors. Similarly, the social network analysis was limited to publicly available data, omitting informal and undocumented ties. All analyses provide only a static snapshot for 2020–2025, even though discursive and institutional practices evolve continuously. Language barriers, translation issues, and cultural differences may also have shaped findings, particularly when examining actors communicating in Spanish, Portuguese, or Indigenous languages. Future research should therefore address these limitations by incorporating longitudinal analyses of evolving actor roles and discursive framings, combining textual with visual and oral data. Greater attention should also be paid to informal coalitions and evolving cross-basin relations that may not appear in formal documentation. Beyond the Amazon and La Plata basins, comparative research in other ecological and political contexts could shed light on the transferability of green and atmospheric water governance concepts. Finally, further study is needed on how emerging storylines, such as those of the GCEW, are taken up or resisted by actors and basin stakeholders. Beyond these directions, a research agenda is suggested to guide further stages of the policy processes. This includes Comparative Cognitive Mapping approaches to understand causes of action and inaction based on actor’s system perspectives, alongside the creation of boundary objects to facilitate decision making under diverging interests and incomplete knowledge.