In 2022, the United States Geological Survey released a new diagram of the global hydrological cycle that, for the first time, included people and the social processes affecting freshwater. It was a significant step and also a long-anticipated change. Humans have appropriated more than their share of Earth’s freshwater for decades; thousands of mega-dams block rivers around the world, groundwater is pumped unsustainably in many places, and over half of the world’s lakes are in decline, largely owing to human impacts on local water systems and the planet’s climate (Postel et al. Reference Postel, Daily and Ehrlich1996; Yao et al. Reference Yao, Livneh and Rajagopalan2023). Even so, the update to the hydrological cycle arguably did not go far enough. This is because it is one thing to depict social processes that affect water and quite another to show the scale of anthropogenic impacts on the global water cycle (Abbott et al. Reference Abbott, Bishop and Zarnetske2019). Those impacts connect the planetary boundary for freshwater use to ethical concerns regarding how unequal distributions of water over time and space affect people, other species, and the processes that support life on Earth.

Like other planetary boundaries, calculations for freshwater change have undergone significant shifts since the framework was first proposed. In 2009, a boundary of 4,000 km³ worth of annual freshwater was estimated, with only 419 km³ having been used prior to the industrial era and a current estimate of 2,600 km³ (Rockström et al. Reference Rockström, Steffen and Noone2009). These planetary numbers don’t factor in regional disparities, such as arid versus humid regions or places where human demands for agriculture or industrial extraction already overburden freshwater systems that are the ‘bloodstream of the biosphere’ (Ripl Reference Ripl2003). Even so, the initial estimate for the freshwater boundary was criticized for focusing on what hydrologists call blue water, which is the visible water in lakes, rivers, and taps. This water represents only a fraction of the global water system, with invisible ‘green water’ circulating throughout the atmosphere, soils, and biota in ways also affected by anthropogenic impacts on the environment. Land-use and climate changes, for instance, both significantly impact green water, such when forests are converted to arable or urban land. Further, these changes affect the entire freshwater system in complex ways. Together, these concerns prompted a reassessment of the freshwater boundary to include both blue and green water (Gleeson et al. Reference Gleeson, Wang-Erlandsson and Zipper2020; Wang-Erlandsson et al. Reference Wang-Erlandsson, Tobian and Ent2022). In the 2023 update to the boundary for freshwater change, the assessments for both blue and green water showed significant departures from pre-industrial estimates, with both having been transgressed for some time. The boundary for blue water, on the new model, was passed in 1905 and that for green water in 1929 (Richardson et al. Reference Richardson, Steffen and Lucht2023). Although labelled as ‘preliminary’ findings, the direction of travel for the new boundary on freshwater change showed an increasing risk to a key variable that, in previous assessments, had been characterized as within a ‘safe space for humanity’.

Improved depictions of human impacts on global hydrology and redefining the boundary for freshwater change also raise ethical concerns the two chapters in this part examine. First, Nicole Wilson critically engages the freshwater boundary using the idea of a hydro-social cycle – an approach that does not begin by separating humans from nature, such as by making calculations of ‘natural’ or pre-industrial values from which the freshwater changes are calculated. Instead, hydro-social scholars emphasize how human-water systems are mutually co-constituted (Linton Reference Linton2010). For instance, although ecohydrologists like Carl Folke (Reference Folke2003) have long argued for a coevolutionary view of humans and water, hydro-social scholars prioritize social relations and situate science as one kind of social practice among others, such as those of Indigenous peoples. From this perspective, a ‘boundary’ to freshwater use also requires an ethic that respects the bounded, different ways of knowing and relating to the world. Second, Neelke Doorn considers how the planetary boundaries framework should impact philosophical thought. When it comes to freshwater, a significant ethical concern is how to understand risk, from floods and droughts to engineering decisions. But this is tricky ethical territory, she argues, because the freshwater boundary is global, yet risks are experienced locally. In this context, Doorn considers what science and ethics can offer to one another given the respective aims of each – how can the intrinsic issues of equity that don’t figure into the freshwater planetary boundary be addressed through a focus on justice, for instance? Doorn’s emphasis on disciplinary complementarity contrasts with Wilson’s disciplinary critique in ways that aren’t so much two poles of a wide spectrum as two respective attempts to get to grips with the plurality of approaches to science and ethics affecting freshwater change.

15.1 Introduction

The attention of philosophers to water is of recent date. While the flow of water as a metaphor for life goes back to the pre-Socratic philosophers (cf. the well-known quote panta rhei – everything flows, often attributed to Heraclitus), the importance of water for life – and with that its essential role for both humans and nature more generally – has received little attention in the normative philosophy literature before 2010. This is surprising as the different and often competing water uses, the exhaustion of the earth’s freshwater resources, and the effect of flood-prevention strategies on water availability and water quality pose questions that are deeply normative and by that in the heart of philosophical disciplines such as political philosophy, philosophy of risk, and ethics. Since 2010, maybe as a result of increasing attention to climate change, the topic of water is gradually receiving attention in the philosophical literature, focusing primarily on these normative questions and therefore often discussed under the label of water ethics (Doorn Reference Doorn2019; Meisch Reference Meisch, Springer and Grimm2018, Reference Meisch2019).

This chapter aims to explore how the planetary boundaries framework can be useful for thinking about water-related risks complementary to frameworks developed in the philosophical literature on water ethics and risk ethics. Hence, the aim is not to criticize or further refine the planetary boundaries but rather to see how the philosophy literature can benefit from the framework and vice versa. To do so, I highlight three points from the water ethics and risk ethics literature that are particularly relevant to our thinking about the water planetary boundary. The first concerns the division of labour between science and management, the second concerns the multitude of water-related risks and risk-risk trade-offs, and the third concerns the metric of intergenerational justice in water policy and engineering. By discussing these three points, I show how the planetary boundaries framework can play a role in water-related management and policy decisions. In the concluding Section 15.5, I reflect on the role of water ethics in these decisions.

15.2 The Reception of the Water Planetary Boundary in the Literature

The water planetary boundary is one of the nine boundaries that, taken together, propose quantitative limits for human perturbation of critical earth system processes (Rockström et al. Reference Rockström, Steffen and Noone2009). With the concept of planetary boundaries, Rockström and colleagues have developed a framework that can be used to demarcate a safe operating space for human activities. It is important to stress this goal: it is intended to develop the safe operating space itself, not the distribution within that space. The water boundary was originally labelled ‘freshwater use’, and in the early publications, it was formulated globally in terms of the maximum rate of consumptive use of blue water (Rockström et al. Reference Rockström, Steffen and Noone2009). In later publications, the boundary was further refined with a limit at the basin scale as well, formulated in terms of maximum monthly withdrawals as a percentage of mean monthly river flow (Steffen et al. Reference Steffen, Richardson and Rockström2015).

In recent years, the framework has received some criticism: some points of criticism are warranted and also accepted by the initiators of the framework, but some points of criticism also seem quite unfair. One rightful point, which could also be read as a modest revision or refinement of the water planetary boundary, is the metric of the boundary – and in a way also the label itself. As stated earlier, it was originally formulated in terms of blue water consumptive use, because Rockström et al. considered this a good proxy variable for the planetary limit, integrating the three largest anthropogenic manipulations of the water cycle: human impacts on precipitation patterns, modifications of soil moisture by land use and land cover, and water withdrawals from discharge for human use. In a later paper, it was suggested to move away from human water use as a metric and to conceptualize the water planetary boundary as ‘stores of the water cycle’ (Gleeson et al. Reference Gleeson, Wang-Erlandsson and Zipper2020). The reason for this move is that ‘the foundation of the planetary boundaries framework is the Earth System and, in the case of water, the Earth System functions of water’ (231). It makes indeed much more sense to express the boundaries in terms of geophysical variables directly related to this boundary (i.e., water stores) and not in terms of some indirect and aggregated variables like water use. In this later paper by Gleeson et al. (Reference Gleeson, Wang-Erlandsson and Zipper2020), which includes most of the original authors of the Rockström et al. (Reference Rockström, Steffen and Noone2009) paper, the authors carefully avoid the term ‘freshwater use boundary’ and replace it with ‘water boundary’. In this chapter, I will use this more recent label ‘water boundary’.

A different line of criticism comes from authors who attack the framework for not paying enough attention to contextual factors, including technological interventions and governance concepts (Bogardi et al. Reference Bogardi, Fekete and Vörösmarty2013), failing to consider questions of equity (cf. Steffen & Stafford Smith Reference Steffen and Stafford Smith2013), and insufficiently recognizing the impact of impaired water quality on the water system (One Earth 2020). With the changed focus from freshwater use to water stores, especially the reference to technological interventions does no longer seem apt. While these interventions may help us stay within the boundaries, they do in principle not affect the boundaries themselves.

Regarding equity, indeed, the planetary boundaries framework is not enough for resolving all issues. However, given the goal of the framework (‘to provide the safe operating space’), this incompleteness is not problematic per se and could even be considered a strength. The framework is not intended as an allocation framework but rather as a set of constraints – or at most as a partial allocation framework – spanning the space within which allocation can take place. As such, the model fits quite well in the traditional division of labour between science, on the one hand, and management or policy, on the other, as promoted in most of the risk literature. Of the points of criticism mentioned, the lack of attention to water quality issues seems the most serious one.

To gain more insight into how the planetary boundaries framework in general, and the water boundary in particular, can complement water ethics and risk ethics and vice versa, let us turn to some ethical perspectives on water-related risks.

15.3 Ethical Perspectives on Water-Related Risks

Until a decade ago, no subfield within applied philosophy explicitly dealt with water (Doorn Reference Doorn2013). Even though environmental ethics had developed into a solid field by that time (Jamieson Reference Jamieson2008), it was less concerned with the questions that are typical to water: the risks of water shortage, poor quality water, and inadequate flood protection, as well as questions of distributive justice related to these risks, and the importance of water for other sectors (Brennan & Lo Reference Brennan, Lo and Zalta2022). Around that time, the concept of water security emerged in the water literature as a lens through which to look at these questions (Lankford et al. Reference Lankford, Bakker, Zeitoun and Conway2013: ix; see also Cook & Bakker Reference Cook and Bakker2012; WaterAid 2012). Water security explicitly recognizes the interdependencies between different water-related risks and does not exclusively focus on either reducing water scarcity or water pollution, or on improving safety from flooding. This water security perspective allows us to move beyond water scarcity as an issue of competing water uses and allocation. It shows that it is also about decision-making, rights, distributive justice, and who has a say. Yet, this literature is still disconnected from the relevant philosophical literature.

In recent years, philosophical perspectives on water-related risks have been developed (cf. Doorn Reference Doorn2019; Meisch Reference Meisch, Springer and Grimm2018, Reference Meisch2019). In this section, I highlight three points that are particularly relevant to our thinking about the water planetary boundary. The first concerns the division of labour between science and management, the second concerns the multitude of water-related risks and risk–risk trade-offs, and the third concerns the metric of intergenerational justice in water policy and engineering.

15.4 Distribution and Allocation within the Boundaries

In The Division of Labour between Risk Analysis and Risk Management, we saw that the planetary boundaries framework fits in the traditional division of labour between risk analysis and risk management, or between science and policy in more general terms. The framework provides the safe operating space, but it does not provide guidance on how things should be allocated within those boundaries, and this is sometimes also mentioned as a weakness of the framework: given how small the remaining safe operation space is, does this planetary focus not come at the expense of vulnerable people currently alive (cf. Rammelt et al. Reference Rammelt, Gupta and Liverman2022)? Water ethics and political philosophy more generally can provide a valuable contribution here, conceptually as well as normatively. In political philosophy, a distinction is sometimes made between distribution and allocation (Rawls Reference Rawls1971), a quite technical, but yet relevant, distinction in the context of water. Distribution is concerned with the conception of society as a fair system of cooperation over time, and it is judged on whether it delivers the outcomes that people can expect based on being part of society. In that sense, the people have certain rightful claims. Allocation and relatedly allocative justice apply when a given collection of goods is to be divided among definite individuals who do not have a prior claim on the things to be divided because these things are not the product of their work nor do these individuals stand in any existing cooperative relations. Water ethics is particularly well-equipped to help our thinking about the appropriate rules for distribution and allocation. In the case of allocation, Rawls suggests allocation according to a utilitarian principle, but other allocation rules are also possible. However, in the context of water, more important than allocation is distribution. Water is essential for life, and when it comes to people’s basic needs, such as the water needed for drinking water and sanitation, we are dealing with questions of distributive justice. Here, many people defend a sufficientarian, prioritarian, or egalitarian distribution. Making it a matter of allocation seems at odds with basic human rights, such as the right to water or the right to sanitation. The same applies to the valuation of water other than in terms of direct use value, for example, the spiritual value of water. Water ethics is well-positioned to distinguish allocative questions from distributive ones and to develop corresponding conceptions of justice. This is typically something where water ethics can complement the planetary boundaries framework. In areas where basic needs are met and there is no competition for water, it is less controversial to look at the resources as an issue of allocation. As such, distributive justice in combination with the planetary boundaries framework together provides the space within which there is room for allocation.

15.5 Concluding Remarks

In this chapter, I briefly discussed three ways in which the planetary boundaries framework and the water boundary in particular can contribute to water ethics and risk ethics. I showed how the planetary boundaries framework provides a valuable contribution to ongoing discussions in the water ethics and risk ethics literature. Vice versa, water ethics and risk ethics can also contribute to the application of the planetary boundaries framework in practice.

Some points still need further development. The current framework focuses very much on freshwater, even though it has been renamed ‘water boundary’. So far, the relation with water safety, that is, safety from flooding, is not well-established and also water quality seems underdeveloped. For safety from flooding, a stronger link with the land system change planetary boundary could be established. The land system boundary currently focuses on cropland and forestry, but this boundary may require a more fine-grained operationalization to account for the impact of flood protection strategies on, for example, wetlands and brackish deltas.

Concerning water quality, the water boundary was originally expressed in terms of blue water use, that is, the use of groundwater and surface water for irrigation or processing (Falkenmark Reference Falkenmark2003). It did not account for the use of infiltrated rainwater (evaporation) for growing crops (green water), or for the effect of water pollution (grey water), which accounts for water use as a result of pollution (Chapagain et al. Reference Chapagain, Hoekstra, Savenije and Gautam2006). This was also recognized in the report written for the European Environment Agency (Häyhä et al. Reference Häyhä, Cornell, Hoff, Lucas and van Vuuren2018), which mentioned the need to account for green water use and its interactions with other boundaries, as well as water quality constraints (expressed as grey water). As explained in Section 15.2, in the most recent revision of the planetary boundaries framework, the research group no longer talks about the freshwater use boundary but about the water boundary instead, and by that, they have also included green water (Gleeson et al. Reference Gleeson, Wang-Erlandsson and Zipper2020). The reason for not including water quality is that water quality, like marine systems, is related to other planetary boundaries, such as ocean acidification, biogeochemical flows, climate change, and novel entities. Including it also in the water boundary would lead to duplication, according to Gleeson et al. (Reference Gleeson, Wang-Erlandsson and Zipper2020). Given that many interventions in the earth system involve several boundaries, water quality is not unique, and as long as boundaries are not assessed in isolation but comprehensibly, this choice by the authors seems justified.

To conclude, as explained in the introduction of Section 15.3, the framework is criticized as not being as objective as it claims to be and, indeed, the boundaries do not follow automatically from science. Yet, given the devastating environmental impact of many human activities, the earth – including its water stores – is probably better served by the precautionary approach promoted by the planetary boundaries framework than by the optimism about technological interventions described by Bogardi et al. (Reference Bogardi, Fekete and Vörösmarty2013). The planetary boundaries framework may exactly be the framework that allows us to distinguish naïve technofixes from sustainable solutions to leave a liveable planet for future generations.

16.1 Introduction

Water is essential to all life on earth. Water not only plays a fundamental role in maintaining the global biosphere, climate regulation, and carbon and nutrient cycling (Gleeson et al. Reference Gleeson, Wang‐Erlandsson and Porkka2020a) but also in supporting thriving human communities who maintain diverse and divergent relationships with, and understandings of, what water is (Wilson & Inkster Reference Wilson and Inkster2018; Yates et al. Reference Yates, Harris and Wilson2017). Changes in the water cycle observed globally are driven by a variety of sources of anthropogenic forcing including greenhouse gases, aerosol, and land use change while future water cycle changes will increasingly be dominated by anthropogenic climate change due to greenhouse gas emissions (Douville et al. Reference Douville, Raghavan and Renwick2021). These changes are considered to contribute to the ‘intensification’ of the global water cycle (Huntington et al. Reference Huntington, Weiskel, Wolock and McCabe2018). Such changes have the potential to disrupt processes and relationships across multiple scales – from the local to the global (Vörösmarty et al. Reference Vörösmarty, Pahl-Wostl, Bunn and Lawford2013). It is argued that in the newly entered era of the Anthropocene,Footnote ¹ the speed, scale, and magnitude of anthropogenic drivers of risk may trigger transitions that threaten the habitability of the Earth for human society (Barnosky et al. Reference Barnosky, Hadly and Bascompte2012; Gleeson et al. Reference Gleeson, Wang‐Erlandsson and Porkka2020a; Steffen et al. Reference Steffen, Rockström and Richardson2018).

The planetary boundaries (PB) framework proposes one approach to characterizing and managing the current anthropogenic pressures on the hydrologic system globally (Rockström et al. Reference Rockström, Steffen and Noone2009b). The PB for human freshwater use (water PB) relies on the global average of annual surface flows in rivers concerning environmental flow needs (Rockström et al. Reference Rockström, Steffen and Noone2009a; Steffen et al. Reference Steffen, Richardson and Rockström2015b). Proponents of the PB framework consider the water PB critical; however, this proposed boundary has been critiqued for oversimplifying in ways that fail to reflect the heterogeneity of water’s distribution (Gleeson et al. Reference Gleeson, Wang-Erlandsson and Zipper2020b), the complete range of human impacts on the global water cycle (Gleeson et al. Reference Gleeson, Wang-Erlandsson and Zipper2020b), and the complexities of developing global water governance to manage the water PB (Zipper et al. Reference Zipper, Jaramillo and Wang-Erlandsson2020). Recent works have sought to revise the water PB to transcend such critiques. For instance, Gleeson et al. (Reference Gleeson, Wang-Erlandsson and Zipper2020b) propose that a water PB would be more useful and scientifically sound if it were rearticulated to highlight the ways climate and ecosystems respond to alterations in water in all its forms ranging from atmospheric water, soil moisture, groundwater, and frozen water, as well as surface water. However, the complexity of human–water relationships and the relationship between socio-cultural, political, and hydrological dimensions across scales remain undertheorized.

While PBs are presented as ‘green limits’ – or in this case ‘blue limits’ – rooted in science, they are ultimately a normative concept rooted in particular understandings of human–environment relationships (Brown Reference Brown2017; Leach et al. Reference Leach, Raworth and Rockström2013). From the start, it has been made clear that PBs are not thresholds or tipping points (Rockström et al. Reference Rockström, Steffen and Noone2009a, Reference Rockström, Steffen and Noone2009b). Even where a threshold is likely to exist or is considered measurable (e.g., climate), boundaries are set in a precautionary manner at a ‘safe distance’ from thresholds to account for risk and uncertainty. In this way, PBs are intended to allow humans time to respond to ‘early warning signs that it might be approaching a threshold’ (Steffen et al. Reference Steffen, Richardson and Rockström2015b). Planetary boundaries therefore involve societal choice regarding how they are set and to what extent the precautionary principle is incorporated.

While the normative nature of PBs has been explicit from the start (Rockström et al. Reference Rockström, Steffen and Noone2009a, Reference Rockström, Steffen and Noone2009b), the politics of PBs including assumptions about global governance and privileging global over local concerns has resulted in considerable debate (Brown Reference Brown2017; Leach et al. Reference Leach, Raworth and Rockström2013). Melissa Leach et al. (Reference Leach, Raworth and Rockström2013) suggest that we need to identify a complementary social boundary to accompany each PB. In doing so they stress the contested and dynamic nature of ‘navigating alternative pathways’ in the space between social and planetary boundaries, where pathways are to varying extents ‘aligned with different cultures, visions, and values, and with different costs, risks, and distributions of power and benefits between social groups’ (Leach et al. Reference Leach, Raworth and Rockström2013: 86). The definition and choice between alternate pathways are, therefore, ‘deeply political’ and the process has significant potential to produce uneven and unjust outcomes across human communities. Unexamined assumptions about the nature of water and human relationships with it shape normative understandings of a ‘safe operating space for humanity’ and the necessary and possible pathways within it. Building on the PB framework and relevant critiques, Rockström et al. (Reference Rockström, Gupta and Qin2023) propose Earth System Boundaries for a number of domains including freshwater, developing a safe and just boundary that is more conservative than the biophysical water PB. Despite these advancements, many questions remain: How do PBs account for diversity and difference among and between human communities and their hydrosocial relationships? How might a water PB create or reinforce existing water inequities and injustices?

In this chapter, I begin with the normative assumption that the goal of responding to anthropogenic pressures is to advance more just and equitable water futures. I argue that a more nuanced picture of the socio-political dynamics involved in human–water relationships is needed to understand whether the water PB has the potential to advance water justice. Against this backdrop, I apply a hydrosocial approach to illuminate connections between the socio-cultural, political, and material dimensions of water in relation to the PB framework. Based on this analysis, I find that present framings of the water PB through Modern Water and Western techno-scientific understandings of water, privilege the hydrosocial relationships of some human communities over others in ways that can reinforce and even create new water inequities and injustices. More specifically, I engage with three interconnected dimensions of hydrosocial relations including (1) the heterogeneity of both water’s materiality and human relationships with it, (2) the inherently political nature of water, and (3) the production of water through particular relations and technologies. I conclude that the water PB is only useful to the extent that it can advance transformative change that addresses present inequities in hydrosocial relationships.

16.2 Hydrosocial Engagement with the Water Planetary Boundary

The rise of the Modern Water paradigm in the early twentieth century promoted the narrow understanding of water as a resource that can be controlled, managed, and exploited by humans (Linton Reference Linton2010). Modern Water is a normative concept that ignores the heterogeneous and, often unequal, nature of human–water relationships in favour of ‘bringing water’s social and evolutionary possibilities into the service of liberal forms of life’ (Schmidt Reference Schmidt2017: 7). Unexamined, these assumptions about water within the PB framework have the potential to influence any suggested actions or solutions that might be taken to address present challenges facing water systems globally.

The hydrosocial framework builds on the hydrologic cycle but moves beyond Modern Water through explicit attention to the social context and dynamics of water and resituates water as fundamentally political (Linton & Budds Reference Linton and Budds2014). In this way, a hydrosocial framework not only positions humans as endogenous to the hydrologic cycle but sees water as a socio-natural process where water and society co-constitute each other across spatial, geographic and temporal scales (Linton & Budds Reference Linton and Budds2014). The hydrosocial approach is a conceptual framework for engaging with the process of ‘making and remaking’ which offers insights into the production of water, the ways we come to know it and the power relationships that are embedded within processes of change (Linton & Budds Reference Linton and Budds2014).Footnote ² In applying this approach, I engage scholarship within the fields of political ecology (Budds & Sultana Reference Budds and Sultana2013; Harris Reference Harris, Harcourt and Nelson2015) and critical Indigenous studies (Curley Reference Curley2021; Whyte Reference Whyte, Adamson and Davis2017b) to carefully trace water ontologies, politics, and inequality, in the context of processes of capital accumulation and settler colonialism.

There are three key aspects of hydrosocial relationships that help us think about the water PB. First, water is heterogeneous in both its materiality and human relationships with it (Linton & Budds Reference Linton and Budds2014; Strang Reference Strang2004). As discussed, critiques of the water PB have highlighted the oversimplification of water’s materiality in the provisional water PB (Gleeson et al. Reference Gleeson, Wang‐Erlandsson and Porkka2020a, Reference Gleeson, Wang-Erlandsson and Zipper2020b). But the suggested revisions to the water PB stop short of acknowledging the hybrid nature of water or the ways that water’s diverse states, forms, and qualities make it act and give meaning in distinct ways (Linton & Budds Reference Linton and Budds2014). For example, relationships with surface water may differ from relationships with groundwater. Furthermore, different human communities may relate to the same forms of water in very different ways. Indeed, Indigenous peoples maintain diverse relationships with water, but these relationships often centre on understandings of water as a living entity that has agency or ‘spirit’ and carries deep spiritual and cultural meaning both generally and specific to particular bodies of water (Chiblow (Ogamauh annag qwe) Reference Chiblow (Ogamauh annag qwe)2019; Craft Reference Craft2018). These relationships with water are not projections of symbolic meaning onto water’s materiality but literal expressions of distinct worlds that flow from Indigenous onto-epistemologies (Todd Reference Todd2014; Watts Reference Watts2013). While scholars of the water PB refer to water using anthropomorphic metaphors such as the reference to freshwater as the ‘bloodstream of the biosphere’ (Gleeson et al. Reference Gleeson, Wang‐Erlandsson and Porkka2020a: 2), they stop short of acknowledging diverse water ontologies. Here, Modern Water’s assumption of water as a singular material substance or H₂O is also accompanied by the modernist assumption that social relations are contained within the same modernist ‘ontological matrix’ within which diverse populations construct symbolic meaning (Blaser Reference Blaser2009: 879), but multiple water ontologies in which distinct water worlds are at stake (Wilson & Inkster Reference Wilson and Inkster2018). The imposition of Modern water through the water PB framework is an example of onto-epistemological violence as it imposes boundaries around what is ‘real’. Anything outside that falls outside the boundaries of water as H₂O is ‘unreal’ (Hunt Reference Hunt2014).

Second, water is inherently political rather than merely a material substance that is the object of politics (Linton & Budds Reference Linton and Budds2014). In other words, water cycles through socio-political processes in ways that internalize and express water politics and conflict. Scholarship on the political ecology of water illustrates the fundamentally political nature of water by examining and articulating the ways that some human communities’ access and relationships with water are privileged over others (Boelens et al. Reference Boelens, Hoogesteger, Swyngedouw, Vos and Wester2016; Budds & Sultana Reference Budds and Sultana2013), including processes of capital accumulation (Ranganathan Reference Ranganathan2016) and settler colonialism (Daigle Reference Daigle2018; Leonard et al. Reference Leonard, David-Chavez and Smiles2023; Wilson et al. Reference Wilson, Montoya, Arseneault and Curley2021). This exclusion fails to acknowledge not only Indigenous rights and jurisdiction but also the epistemological and ontological politics of water or the conflicts that develop when different water worlds seek to maintain their own existence as they come into contact with each other (Wilson & Inkster Reference Wilson and Inkster2018; See also Blaser Reference Blaser2009).

The scalar politics of governing the water PB bring many dimensions of water justice into focus. Indeed, the PB framework has been critiqued for containing within it an implicit assumption of global governance (Brown Reference Brown2017; Leach et al. Reference Leach, Raworth and Rockström2013). Water scholars have also suggested that water governance at the global level is required to address anthropogenic impacts on water globally (Cooley et al. Reference Cooley, Ajami, Ha and Gleick2014; Gupta & Pahl-Wostl Reference Gupta and Pahl-Wostl2013). However, present water governance structures tend to occur at the local, national, or regional levels of the administrative scale (Dellapenna et al. Reference Dellapenna, Gupta, Li and Schmidt2013).Footnote ³ Following Gupta (Reference Gupta, Young, King and Schroeder2008), global problems need to be expressed in ways that attend to the expression of the issues at relevant levels of the administrative scale to help ‘ensure the legality, legitimacy, and effectiveness of institutional solutions’ (Gupta Reference Gupta, Young, King and Schroeder2008: 231). While water issues may be defined as a global problem, the problem takes varying forms at differing levels on administrative scales as it can be unpacked as a distinctive set of problems at each level. Zipper et al. (Reference Zipper, Jaramillo and Wang-Erlandsson2020) seek to reconcile the water PB with the complexities of existing governance structures through the idea of a locally ‘harmonized’ water boundary that would be ‘consistent with both global and local water sustainability goals and provide a framework for determining whether local water management is consistent with local socio-environmental processes and Earth System function’ (Zipper et al. Reference Zipper, Jaramillo and Wang-Erlandsson2020: 8–9). While this analysis is useful in its attempt to reconcile the global nature of the water PB with locally meaningful limits and thresholds, it fails to acknowledge the significant potential for the governance of the water PB to create and/or replicate existing political inequalities present in governance structures.

Third, water is produced or co-created by relations and technologies. Such considerations help us think about how water is produced through particular sets of relations and technologies. A hydrosocial framework moves beyond dualistic understandings of relationships between water and society as something that pre-exists to examine how water, society, and social power are co-constituted (Castree Reference Castree2005). For instance, Linton (Reference Linton2010) shows how drinking water technologies might privilege specific kinds of water relations. They discuss how a public drinking fountain might maintain water as a public good by providing free access, while a commercial bottled water vending machine makes water into a commodity. Each of these technologies produces different types of water and very different forms of access and citizenship.

The water PB develops out of new understandings of ‘global water’. Although water challenges have historically been understood and responded to locally, recent advancements in geophysical approaches (e.g., remote sensing, models, data integration systems) are rapidly changing our ability to recognize locally relevant patterns while at the same time producing a ‘unified view of the global hydrologic cycle’ (Vörösmarty et al. Reference Vörösmarty, Pahl-Wostl, Bunn and Lawford2013: 542). Remote sensing has played a transformative role in how we see the world. Along with other technologies, such as television and telephones, satellites have been called ‘world making’ devices as the ability to sense at a distance became central to ‘human’ faculties in the late twentieth century – rendering humans as ‘cyborg entities defined not by where they live but by the telematic flows they receive and emit’ (Tuathail Reference Tuathail1997: 44). Such advances are useful in considering the ways that global forces are driving local-scale water challenges and at the same time the ways that local stressors scale up to drive changes in water systems globally (Vörösmarty et al. Reference Vörösmarty, Pahl-Wostl, Bunn and Lawford2013). However, neither these technologies nor the forms of water they produce are politically neutral. In examining the political economy of remote sensing technologies including the use by a range of actors including governments, scientists, and commercial and non-governmental actors, Bennett et al. (Reference Bennett, Chen, Alvarez León and Gleason2022) argue that ‘[t]echnology’s reflection of societal and cultural biases demonstrates the need to provincialize remote sensing by examining how decisions made across the technical process, from satellite design to image analysis, and even commercialization, affect results’ (733). In other words, we must ask ourselves how the production of global water through these technologies creates different forms of access and citizenship. Whom does it privilege?

16.3 Towards Just Water Futures?

While the water PB may provide a metaphor for catalysing responses to anthropogenic impacts on water and other PBs, it is only useful if it results in more equitable and just water futures. In other words, as a ‘boundary object’ that facilitates communication across spheres while allowing different actors to maintain the diversity of their views (Morseletto et al. Reference Morseletto, Biermann and Pattberg2017), PBs are only useful as far as they advance transformative change – or a ‘fundamental’ change in natural or human systems (Walker et al. Reference Walker, Holling, Carpenter and Kinzig2004). Such shifts require consideration of the root causes of anthropogenic change, the factors that construct scarcity and vulnerability – exposing some human communities to greater impacts of change – and must ultimately reconfigure human–water systems towards more just and equitable futures (Shah et al. Reference Shah, Rodina and Burt2018). I, therefore, examine how the theory and practice of water justice can help evaluate the potential for the PB framework to advance more just water futures.

Water justice is a relational and contextual concept that acknowledges the material, economic, cultural, and political dimensions of water while taking seriously the political contestation, negotiation, and struggle related to the inequitable distribution of water access (Sultana Reference Sultana2018; Zwarteveen & Boelens Reference Zwarteveen and Boelens2014). Water justice helps us think through the critiques of the water PB identified by a hydrosocial perspective. First, in helping us reconsider how water is known a hydrosocial critique of the water PB identifies the need for onto-epistemological justice or the idea that we must take seriously the heterogeneity of water and the existence of multiple water worlds including ways of being, knowing, and relating with water that fall outside of the assumptions of Modern water (Wilson & Inkster Reference Wilson and Inkster2018). For instance, planetary-scale understandings of water are co-produced by Western scientific relations and technologies (e.g., remote sensing). Thus, we must ask ourselves how the water PB might marginalize Indigenous onto-epistemologies rooted in understandings of water as a living entity with which people have reciprocal responsibilities (Chiblow (Ogamauh annag qwe) Reference Chiblow (Ogamauh annag qwe)2019; Yazzie & Baldy 2017). Diverse ways of knowing and being are needed to imagine more just water futures that might not be conceived of in assessments that rely on Western scientific knowledge alone (Wilson et al. Reference Wilson, Shah and Montoya2024).

Second, a hydrosocial critique asks us to consider the implications of the water PB for the distribution of waters benefits and harms also known as ‘distributive justice’ (Fraser Reference Fraser2000; Schlosberg Reference Schlosberg2004). According to a ‘trivalent’ understanding of environmental justice, distributive justice is closely connected to procedural (who is involved or has influence?) and recognitional justice (who or what is valued or respected?) (Fraser Reference Fraser2000; Schlosberg Reference Schlosberg2004). Gupta et al. (Reference Gupta, Liverman and Bai2021) also propose three additional domains of justice relevant to the PB framework that includes responsibilities between humans and the more than human world (interspecies justice), between the generations (intergenerational justice) and between diverse segments within present human populations (intragenerational) (see also Gupta et al. Reference Gupta, Liverman and Prodani2023).

While questions of water justice have been accounted for to a greater extent (Rockström et al. Reference Rockström, Gupta and Qin2023), there are many potential water justice questions that should be asked. For instance, the potential of the water PB to advance just water futures is contingent on addressing the politics of scale or rescaling to the global in exacerbating or creating new water injustices. Rescaling water governance to the global level is highly political and requires consideration of whose interests would be privileged through such a hydro-scalar shift (Cohen Reference Cohen, Termeer, Padt, Polman and Opdam2014; Harris & Alatout Reference Harris and Alatout2010).

Third, water justice must consider how unjust histories shape the potential for harm in the present context. Shue (Reference Shue and Shue2014) notes that these ‘compound injustices’ occur ‘when an initial injustice paves the way for a second’ (4). In other words, any action taken as the result of the mobilization of the water PB framework must be considered in light of existing water injustices and the potential for that action to produce more or less just water futures for marginalized groups including consideration for intersecting identities along the lines of gender, race and ethnicity, class, Indigeneity, and more (Harris et al. Reference Harris, McKenzie, Rodina, Shah, Wilson, Holifield, Chakraborty and Walger2017) or the systemic inequalities created through capitalism, colonialism, and white supremacy. Failing to address systemic inequalities created through capitalism, (settler-)colonialism, and other forms of inequality will mean that any governance system intended to address anthropogenic impacts on the water system has the potential to reproduce these inequalities. For instance, through colonial histories, Indigenous peoples have been excluded from existing colonial water governance frameworks at all administrative levels from the local to global (Wilson Reference Wilson2020).

Assessments of the water potential for the PB to advance just water futures must also advance climate justice, given that future water cycle changes will increasingly be dominated by anthropogenic climate change (Douville et al. Reference Douville, Raghavan and Renwick2021). Climate justice is a growing body of theory and civic action that pays close attention to how different populations have contributed to varying extents to the root causes of climate change and how climate impacts people differently and disproportionately (Sultana Reference Sultana2022). Furthermore, while the water PB seems to naturalize anthropogenic contributions to greenhouse gas emissions, we must look beyond this to examine the root causes of climate change. Potawatomi scholar Kyle Whyte (Reference Whyte2017a) reminds us that colonialism and capitalism are inextricably tied together and have laid the groundwork for the carbon-intensive economics which is driving climate change. Assessments of water justice and the water PB must also consider climate justice given that (a) there is a positive feedback loop between water injustice and climate vulnerability and (b) any solution to climate change will have implications for water justice (Mills-Novoa et al. Reference Mills-Novoa, Boelens, Hoogesteger and Letcher2022).

Where present framings of the water PB lean heavily toward the creation of new water global governance frameworks, we can learn from present injustices in climate governance. Recent research has shown that the inclusion of Indigenous peoples and their knowledge systems in global climate governance without acknowledging their self-determination and governance systems is likely to replicate existing colonial injustices (Cifuentes Reference Cifuentes2021; Reed et al. Reference Reed, Brunet and McGregor2022). Given the ways that global climate governance has been ineffective at mitigating climate change while also exacerbating existing inequalities, what faith should we have in the potential for a new global water governance framework for the water PB to advance water or climate justice?

16.4 Conclusion

The PB framework proposes one approach to characterizing and managing the current anthropogenic pressures on the hydrologic system globally (Rockström et al. Reference Rockström, Steffen and Noone2009b). The understanding of the water PB has evolved to acknowledge issues of equity and responsibility in responding to present water challenges (Steffen et al. Reference Steffen, Richardson and Rockström2015b; Zipper et al. Reference Zipper, Jaramillo and Wang-Erlandsson2020). However, following Katrina Brown (Reference Brown2017: 121), I argue present examinations of the politics and implications of the water PB still fail to address ‘the core issues of the social processes driving change, the socially differentiated nature of that change, its impacts, and agency and policy to act in response’. I illustrated some of the limitations of the water PB by examining how present framings rely on Modern Water and Western techno-scientific understandings of water in ways that privilege the hydrosocial relationships of some human communities over others in ways that can reinforce and even create new water inequities and injustices. More specifically, I have applied a hydrosocial framework to reveal a more nuanced understanding of the socio-political dynamics in human–water relationships including water’s materiality as well as its histories, epistemologies, ontologies and scalar politics, and corresponding governance frameworks. Drawing on these hydrosocial critiques, I showed what is at stake for the water PB framework to advance just water futures and highlighted areas where further consideration of the multiple dimensions of justice is needed.