In response to diverse socioenvironmental challenges, urban water utilities in the United States are transitioning to more sustainable management practices that are often designed to reduce total water consumption. Although these practices can effectively maximize the use of limited water supplies, they may simultaneously exacerbate socioeconomic disparities if their implications for equity are not fully considered. This research examines the potential tradeoffs between effectiveness and equity in urban water transitions by analyzing Miami-Dade County's high-efficiency toilet (HET) voluntary rebate program (VRP) as an example of a sustainable water management practice. Using data on HET-VRP participation, water consumption and billing, and socioeconomic indicators, we analyze the relationship between HET-VRP uptake and benefit distribution among residents. Through parametric and spatial statistical analyses, we find that areas with higher income and education levels have both higher water consumption and more HET-VRP participation, indicating potential program effectiveness. However, lower participation in vulnerable communities raises equity concerns, underscoring the need for targeted outreach and policies that consider distributional impacts. These findings suggest that urban water systems should better incorporate equity considerations in the planning and implementation of water conservation policies intended to promote sustainable water management.

A well-functioning society requires well-functioning institutions that ensure prosperity, fair distribution of wealth, social participation, security, and informative media. Such institutions are built on a foundation of trust. However, while trust is essential for economic success and good governance, interconnected mechanisms inherent in weakly governed market economies tend to undermine the very trust on which such success depends. These mechanisms include the intrinsic tendency for inequality to grow, media to boost perceived unfairness, and self-interest to gain rewards at the expense of others. These mechanisms, if left unchecked, allow wealth concentration to result in state capture where institutions facilitate further wealth concentration instead of the promoting the common good. As a result, people may become alienated and untrusting of fellow citizens and of institutions. Several democracies now experience such dynamics, the United States being a prime example. We discuss ways in which well-functioning democracies can design institutions to help avoid this social trap, and the much harder challenge of escaping the trap once in it. Successful cases such as the ability of Scandinavian democracies to maintain high-trust, and the US progressive era in the early 20th century provide instructive examples.

The idea of planetary boundaries sets limits for a safe operating space for humanity and offers a guide for tackling global sustainability challenges. But staying within these limits requires understanding how globally interconnected social, environmental, and technological systems behave when decisions are made with incomplete information. Here, we draw on the notions of observability and controllability from modern control theory, an engineering approach to steering complex systems, to show how decision-makers can act in real time without perfect models or full knowledge. Our analysis illustrates a natural mapping of design parameters onto real-world policy decisions and highlights how to manage the interplay between past, real-time, and projected information to improve the controllability, and thus the sustainability, of social-ecological-technical systems.

Designing urban water systems to respond to the accelerating and unpredictable changes of the Anthropocene will require changes not only to built infrastructure and operating rules, but also to the governance arrangements responsible for investing in them. Yet, inclusion of this political-economic feedback in dynamic models of infrastructure systems and socio-hydrology has lagged behind operational feedback concerns. We address this gap through a dynamical systems application of the Coupled Infrastructure Systems (CIS) Framework, which provides the conceptual building blocks for analyzing social-ecological systems through various classes of infrastructure and the flows of material and information among them. In the model, political-economic feedback involves three decisions-infrastructure investment, rate-setting, and short-term demand curtailment-and each decision is constrained by institutional friction, the aggregation of decision and transaction costs associated with taking action. We apply the model to three cities in the Phoenix Metropolitan Area to compare how institutional friction interacts with a city's water resource portfolio and financial position to determine its sensitivity, or the degree to which its performance (e.g., providing sufficient supply to meet demand) changes given reductions in Colorado River water availability. We find that the slowing effect of institutional friction on investment and rate-setting decisions can increase the sensitivity of a city's supply, but it can also promote objectives that compete with over-response (e.g., rate burden). The effect is dependent on the initial operating capacity of the CIS and flexibility within the institutions, highlighting the need to consider political-economic and operational feedback together when evaluating infrastructure systems. Urban water systems must grapple with accelerating social and environmental change that requires them to not only consider future infrastructure needs, but also, the configuration of decisions responsible for infrastructure investment. Unfortunately, inclusion of political-economic feedback has lagged behind operational feedback in models that examine water systems response to changing environments. We present a modeling approach to trace the flow of water, information, and investment in a general urban water system that must make three annual decisions: infrastructure investment, rate-setting, and short-term demand curtailment. Each decision is influenced by costs to taking action and the flexibility involved in setting action magnitudes. We apply the model to three cities in the Phoenix Metropolitan Area to compare how these institutional constraints interact with existing infrastructure and finances to affect their sensitivity, or the degree to which their performance (e.g., providing sufficient supply to meet demand) changes given reductions in Colorado River water. We find that when institutional barriers to action increase, cities are more sensitive to supply shocks, but such barriers can benefit other objectives like rate burden. The effect is dependent on the presence of redundant supplies, demand growth, and decision-making flexibility, highlighting the need to consider both political-economic and operational concerns when evaluating water systems. Having sufficient supply redundancy can outweigh the negative effect of slow institutions on a city's ability to address supply shocks The supplies of cities with institutions that require more stress to act are more sensitive to shocks, but their rates are less sensitive Adding flexibility to institutions can ease the burden of large investments on ratepayers and improve the reliability of slow institutions

Much of the discourse around climate change and the situation of diverse human societies and cultures in the Anthropocene focuses on responding to scientific understanding of the dynamics of the biosphere by adjusting existing institutional and organizational structures. Our emerging scientific understanding of human behaviour and the mechanisms that enable groups to achieve large-scale coordination and cooperation suggests that incrementally adjusting existing institutions and organizations will not be sufficient to confront current global-scale challenges. Specifically, the transaction costs of operating institutions to induce selfish rational actors to consider social welfare in their decision-making are too high. Rather, we highlight the importance of networks of shared stories that become real—imagined orders—that create context, meaning and shared purpose for framing decisions and guiding action. We explore imagined orders that have contributed to bringing global societies to where they are and propose elements of a science-informed imagined order essential to enabling societies to flourish in the Anthropocene biosphere. This article is part of the theme issue ‘Bringing nature into decision-making’.

Farmer-Managed Irrigation Systems (FMIS) have successfully governed the use of water resources for irrigation for many decades in Nepal. However, in the ensuing years, Nepal’s agriculture sector has been subjected to multiple stressors. These stressors have impacted society as a whole and irrigated agriculture as well. This study examines the major changes in irrigation institutions, the factors driving observed institutional changes, and the aspects of rules, norms, and organizational procedures through which changes have been institutionalized. Nine FMIS included in the Nepal Irrigation Institutions and Systems (NIIS) database were selected from Lamjung, Kaski, Chitwan, and Nawalpur districts. Institutional information on the selected systems was collected using the same set of questionnaires that were used to create the NIIS database. These data were supplemented with information on drivers of the institutional change from interviews as well as literature review. Institutional change was evaluated in relation to change in seven types of working rules. The most substantive changes were observed in payoff and information rules followed by position, choice, boundary, and scope rules. Changes to payoff rules included fines for breaking rules, the basis of labor mobilization, sanctioning by appropriators or monitors, and the form of compensation paid to monitors. Similarly, status and deployment of monitors were major changes in position rules, and changes to information rules included those regarding keeping records of resources condition, maintenance work, and cultivated land. Changes in these rules appear to be associated with increased dependence on remittances and non-farm income. The continued value of the resource itself, however, is evident in the limited changes associated with boundary rules, where in a context of climatic trends and uncertainty, water access for subsistence rice production continues to be a valued asset.

AbstractFew disagree that we should pass on the Earth in good shape to future generations, and many scientists want their work to contribute to that goal. Recent work has shown that hopelessness stands in the way of people taking an active attitude. At the same time, it is becoming clear what can be done about that: providing compelling visions of attractive futures and highlighting feasible pathways. Currently, science and the humanities are not well designed for this task. Practices that stand in the way of a more holistic change‐making approach include proposal‐based funding, paralyzing rigor requirements, and a focus on explanation rather than action. Removing those barriers may require culture shifts, a notoriously difficult and slow kind of change. Meanwhile, realistic inspiring future scenarios can be developed by bringing diverse thinkers together in environments where time, space, and immediate outcomes are not pressing.

Equity is core to sustainability, but current interventions to enhance sustainability often fall short in adequately addressing this linkage. Models are important tools for informing action, and their development and use present opportunities to center equity in process and outcomes. This Perspective highlights progress in integrating equity into systems modeling in sustainability science, as well as key challenges, tensions, and future directions. We present a conceptual framework for equity in systems modeling, focused on its distributional, procedural, and recognitional dimensions. We discuss examples of how modelers engage with these different dimensions throughout the modeling process and from across a range of modeling approaches and topics, including water resources, energy systems, air quality, and conservation. Synthesizing across these examples, we identify significant advances in enhancing procedural and recognitional equity by reframing models as tools to explore pluralism in worldviews and knowledge systems; enabling models to better represent distributional inequity through new computational techniques and data sources; investigating the dynamics that can drive inequities by linking different modeling approaches; and developing more nuanced metrics for assessing equity outcomes. We also identify important future directions, such as an increased focus on using models to identify pathways to transform underlying conditions that lead to inequities and move toward desired futures. By looking at examples across the diverse fields within sustainability science, we argue that there are valuable opportunities for mutual learning on how to use models more effectively as tools to support sustainable and equitable futures.

Abstract The notion of a safe operating space for humanity has recently emerged as a conceptual guide for global-scale sustainability policy challenges. While the Planetary Boundaries Framework defines this space and has spurred empirical work to determine where the Earth system is relative to its boundaries, even less is known regarding the capacity of globally interconnected societies to navigate towards or remain within a safe operating space when constrained by imperfect information. This study leverages notions of observability and controllability from modern control systems theory to explore the link between information and the capacity to navigate Earth system dynamics in three interrelated sustainability problems. The analysis highlights the critical dependence of the notion of a safe operating space on information and decision processes and the subtle interplay between how past, real-time, and projected information on a particular observation is weighted and the controllability of a system.

Urban drinking water systems in the US face diverse challenges and stressors, threatening their ability to reliably provide safe, affordable drinking water. To effectively address these challenges, utilities must understand the complex relationships among the community, biophysical, infrastructural, and institutional attributes of their system and how they impact overall system performance. In this study, we conduct a comparative case study analysis of 16 large-scale US urban drinking water systems to identify underlying conditions associated with the provision of both affordable and high-quality drinking water. Using qualitative comparative analysis and nonnegative matrix factorization to analyze clusters of conditions related to diverse system attributes, we find that community attributes, including moderate population growth and low poverty, play a significant role in shaping affordability and quality (AQ) outcomes. Moreover, there is an association between biophysical challenges and the development of robust institutional and infrastructural attributes. Cities confronted by marked biophysical challenges seem to be at the forefront in fostering adaptive institutional frameworks and proactive infrastructural measures. Concurrently, our study reveals that a water utility's commitment to conservation measures also impacts its performance in provision of affordable and high quality water. The study improves our understanding of the relationships between various attributes affecting the provision of affordable and high-quality urban drinking water. This can aid utilities in identifying pathways to ensure adequate service under increasing stress.

Transformational change is possible, but design and implementation must seek to avoid lock-in.

Combating environmental degradation requires global cooperation. We here argue that institutional designs for such efforts need to account for human behavior. The voyage of the Titanic serves as an analogous case to learn from, and we use behavioral insights to identify critical aspects of human behavior that serve as barriers or opportunities for addressing the challenges we face. We identify a set of public goods that may help us mitigate identified negative aspects of human behavior, while leveraging the positive aspects: standards and best practices, mechanisms for large-scale coordination, and curation of information to raise awareness and promote action. We use existing international organizations, providing at least one of these capacities, as cases to learn from before applying our insights to existing institutional solutions for global environmental protection. We identify institutional design features that, if adapted to better account for human behavior, could lead to more effective institutional solutions.

Over the last 12,000 y, human populations have expanded and transformed critical earth systems. Yet, a key unresolved question in the environmental and social sciences remains: Why did human populations grow and, sometimes, decline in the first place? Our research builds on 20 y of archaeological research studying the deep time dynamics of human populations to propose an explanation for the long-term growth and stability of human populations. Innovations in the productive capacity of populations fuels exponential-like growth over thousands of years; however, innovations saturate over time and, often, may leave populations vulnerable to large recessions in their well-being and population density. Empirically, we find a trade-off between changes in land use that increase the production and consumption of carbohydrates, driving repeated waves of population growth over thousands of years, and the susceptibility of populations to large recessions due to a lag in the impact of humans on resources. These results shed light on the long-term drivers of human population growth and decline.

This study explores social-psychological barriers that may affect resilience in the context of sustainability. These barriers can be understood as unobserved processes that reduce the capacity of a social-ecological system to recover after a perturbation or transformation. Analyzing social-psychological processes enables us to distinguish passive and active processes, at the individual and collective levels. Our work suggests that interacting social and psychological processes should be considered as dynamically evolving determinants of resilience, especially when perturbations can change the psychology of individuals, and thus the underlying dynamics of social-ecological systems. Hence, considering social-psychological barriers and the conditions under which they emerge may provide decision makers with useful insights for coping with ineluctable uncertainties that reduce systems’ transformative capacity and thus their general resilience.

Urban water management is increasingly challenged by the need to balance cost-effectiveness with equity considerations. This study presents a multi-objective approach to water conservation within the Las Vegas valley water district, analyzing a comprehensive dataset of water consumption and socioeconomic indicators across all single-family residences. We assess policy scenarios under two primary objectives: maximizing water savings to enhance economic efficiency and improving water affordability to promote equity. Our analysis reveals that while strategies focused on water savings reduce water use more efficiently, they tend to favor higher-income, predominantly white neighborhoods whereas prioritizing water affordability shifts resources towards lower-income, communities of color. The analysis of intermediate policy scenarios reveals the trade-offs and potential synergies between water savings and affordability. Our findings suggest that local water sustainability can be achieved by allocating resources to both high-demand and socioeconomically disadvantaged households. Highlighting the importance of integrating equity considerations into water management policies, this study provides insights for policymakers in crafting more inclusive and sustainable urban water management practices.

Despite years of debate, the factors that control the long-term carrying capacity of human populations are not well understood. In this paper, we assess the effect of changes in resource extraction and climate-driven changes in ecosystem productivity on the carrying capacity of hunter-gatherer populations in a terrestrial and coastal ecosystem. To make this assessment, we build time-series estimates of changes in resource extraction using stable isotopes and ecosystem productivity using paleoclimate models and geomorphic records of flood events. These estimates of resource extraction and ecosystem productivity allow us to assess a complex model of population expansion that proposes linked changes between population density, resource extraction, and intensification. We find that changes in resource extraction had a larger effect on carrying capacity in both the terrestrial and coastal ecosystems than climate drivers of ecosystem productivity. Our results are consistent with the idea that both Malthusian limits on resources and Boserupian pressures to reorganize economic systems operate in hunter-gatherer populations over the long term. Our data and analysis contribute to evaluating complex models of population growth and subsistence change across archaeological cases.

We propose a model that may explain long-term population growth and decline events among human populations: The intensification of production generates a tradeoff between the adaptive capacity of individuals to generate a surplus of energy to maximize their fitness in the short-run and the long-term capacity of a population as a whole to experience a smooth transition into a demographic equilibrium. The model reconciles the conflicting insights of dynamic systems models of human population change, and we conduct a preliminary test of this model's implications in Central Texas by developing time-series that estimate changes in human population density, modeled ecosystem productivity, human diet, and labor over the last 12,500 years. Our analysis indicates that Texas hunter-gatherers experienced three long-term population growth overshoots and recessions into quasi equilibria. Evidence indicates that each of these overshoots and recessions associate with changes in diet and labor devoted to processing high density, lower quality resources to unlock calories and nutrients. Over the long-term, population recessions may be necessary for populations to experiment with social and physical infrastructure changes that raise the carrying capacity of their environment.

Sustainable management of social-ecological systems requires an understanding of how anthropogenic climate -and land use change may disrupt interactions between human societies and the ecosystem processes they depend on. In this study, we expand an existing stylized social-ecological system model by explicitly considering how urbanizing societies may become less dependent on local ecosystem functioning. This expansion is motivated by a previously developed conceptual framework suggesting that societies may reside in either a green loop and be strongly dependent on local ecosystem processes, or in a red loop where this dependency is weaker due to im-ports of natural resources from elsewhere. Analyzing the feasibility and stability of local social-ecological system states over a wide range of environmental and socio-economic conditions, we observed dynamics consistent with the notion of green loop-dominated and red loop-dominated societies comprising alternate stable social -ecological states. Based on systems' inherent dependencies on local ecosystem processes, responses to environ-mental change could comprise either transitions between green loop-and red loop-dominated states, or collapse of either of these states. Our quantitative model provides an internally consistent mapping of green loop-and red loop-dominated states, as well as transitions between or collapses of these states, along a gradient of environ-mental conditions.