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We demonstrate how programmable shape evolution and deformation can be induced in plant-based natural materials through standard digital printing technologies. With nonallergenic pollen paper as the substrate material, we show how specific geometrical features and architectures can be custom designed through digital printing of patterns to modulate hygrophobicity, geometry, and complex shapes. These autonomously hygromorphing configurations can be "frozen" by postprocessing coatings to meet the needs of a wide spectrum of uses and applications. Through computational simulations involving the finite element method and accompanying experiments, we develop quantitative insights and a general framework for creating complex shapes in eco-friendly natural materials with potential sustainable applications for scalable manufacturing. [ABSTRACT FROM AUTHOR]

The need for faster and deeper transitions toward more sustainable development pathways is now widely recognized. How to meet that need has been at the center of a growing body of academic research and real-world policy implementation. This paper presents our perspective on some of the most powerful insights that have emerged from this ongoing work. In particular, we highlight insights on how sustainability transitions can be usefully conceptualized, how they come about and evolve, and how they can be shaped and guided through deliberate policy interventions. Throughout the paper, we also highlight some of the many how questions that remain unresolved and on which progress would be especially helpful for the pursuit of sustainable development. Our approach to these "how" questions on sustainability transitions draws on two strands of solution-driven research and policy advice: one emerging from studies of how human societies interact with nature and the other emerging from studies of how those societies interact with their technologies. Consumption-production systems have been a focus of extensive work in both strands. To help build bridges between them, we recently brought together a cross-section of relevant scholars for a PNAS Special Feature on "Sustainability transitions in consumption-production systems." Their contributions are summarized in a companion paper we have written to introduce the Special Feature [F. W. Geels, F. Kern, W. C. Clark, Proc. Natl. Acad. Sci. U.S.A. (2023)]. We draw on that work in the Perspective we present here as well as our reading of the relevant literatures. [ABSTRACT FROM AUTHOR]

Growth models with resources and environmental externalities typically assume that planet Earth is a closed economy. However, private firms like Blue Origin and SpaceX have reduced the cost of rocket launches by a factor of 20 over the last decade. What if these costs continue to decline, making mining from asteroids or the moon feasible? What would be the implications for economic growth and the environment? This paper provides stylized facts about cost trends, geology, and the environmental impact of mining on Earth and potentially in Space. We extend a neoclassical growth model to investigate the transition from mining on Earth to Space. We find that such a transition could potentially allow for continued growth of metal use, while limiting environmental and social costs on Earth. Acknowledging the high uncertainty around the topic, our paper provides a starting point for research on how Space mining could contribute to sustainable growth on Earth. [ABSTRACT FROM AUTHOR]

Implementing electromobility is a central component in the de-carbonization of personal mobility. In recent years, the absolute number of electric vehicles (EVs) and their market share has increased sharply in many countries. This paper focuses on Norway, a pioneer market for EVs that other countries can learn from. The analysis highlights how a combination of local and national policies over a 30-y period, which targeted both industry development and vehicle demand, were important drivers of this development. It also highlights the importance of advocacy groups and strong networks in promoting EVs, as well as changes in user preferences. The paper demonstrates how the EV diffusion has been driven by alignments of multiple processes across different levels, involving interactions between multiple actors and social groups with different interests and views about desirable futures as described by the multi-level perspective (MLP). Building on the MLP, the study of EV diffusion in Norway illustrates how niches are often sustained through demonstrations, experimentation, strategic alliances, and actors securing favorable political and economic conditions. Further, it shows how local or national niches may depend on international regime actors, such as the car manufacturing industry and policies developed abroad. The paper also explores how the introduction of EVs has opened for wider effects, including innovation within production-consumption systems beyond mobility. Based on this analysis, we argue for a nuanced perspective on the relationship between incremental, regime-internal innovation, and wider transformative changes, where the merits of societal learning and experience with battery electricity for transportation are highlighted. [ABSTRACT FROM AUTHOR]

A widespread sense of the unsustainability of the food system has taken hold in recent years, leading to calls for fundamental change. The role of animal agriculture is central to many of these debates, leading to interest in the possibility of a "protein transition," whereby the production and consumption of animal-derived foods is replaced with plant-based substitutes or "alternative proteins." Despite the potential sustainability implications of this transition, the developmental trajectories and transformative potential of the associated technologies remain underexplored. This article sheds light on these dynamics by addressing two questions: 1) how have alternative protein innovations developed over the past three decades, and 2) what explains their more recent acceleration? To answer these questions, the article makes an empirical analysis of four alternative protein innovations, and the partial destabilization of the animal agriculture system between 1990 and 2021, guided by the multi-level perspective. The analysis highlights an intensification in corporate engagement with alternative protein development and diffusion. This intensification is judged to be consistent with the beginnings of a wider corporate reorientation, occurring alongside a rise in pressures on the animal agriculture system, notably an increasing scientific consensus and societal awareness of the links between climate change and meat-intensive diets. The paper demonstrates how differences in technological maturity across the niche innovations have resulted in potentially transformative pressures, which are consistent with an emerging sustainability transition, manifesting differently in terms of the extent of diffusion of the alternative protein niches. [ABSTRACT FROM AUTHOR]

The role of exogenous shocks in influencing transition processes is of significant interest to a wide variety of research in sustainability science (SS). Such events disturb and interrupt path-dependent processes in sociotechnical systems. Sometimes this can lead to radical departures from existing trajectories, while at other times existing systems can be more resilient, adapting, or reconfiguring in response to a shock. In this paper, we explore the role that exogenous shocks can have on institutional change. The sustainability transition literature, as shaped by the multilevel perspective, has usually focused on shocks as windows of opportunity (WoO) where alternatives can break through due to strategic action. We offer the perspective of imprinting, which places primary attention on shocks leading to immediate and irreversible institutional change with long-term consequences. The usefulness of this concept is explored by examining the impact of two major shocks to the energy system: World War II and the 1973 oil crisis. It is concluded that the imprinting concept enables analysis that is attentive to how the underlying institutions of a system can be rapidly and deeply altered by the dynamics of exogenous shocks. It is argued that imprinting is an important complementary concept, next to windows of opportunity, for sustainability science research aiming to understand the period of turbulence we are living through. [ABSTRACT FROM AUTHOR]

Urbanization can challenge sustainable development if it produces unequal outcomes. Infrastructure is an important urbanization dimension, providing services to support diverse urban activities. However, it can lock in unequal outcomes due to its durable nature. This paper studies inequalities in infrastructure distributions to derive insights into the structure and characteristics of unequal outcomes associated with urbanization. We analyzed infrastructure inequalities in two emerging economies in the Global South: India and South Africa. We developed and applied an inequality measure to understand the structure of inequality in infrastructure provisioning (based on census data) and infrastructure availability (based on satellite nighttime lights [NTLs] data). Consistent with differences in economic inequality, results show greater inequalities in South Africa than in India and greater urban inequalities than rural inequalities. Nevertheless, inequalities in urban infrastructure provisioning and infrastructure availability increase from finer to coarser spatial scales. NTL-based inequality measurements additionally show that inequalities are more concentrated at coarse spatial scales in India than in South Africa. Finally, results show that urban inequalities in infrastructure provisioning covary with urbanization levels conceptualized as a multidimensional phenomenon, including demographic, economic, and infrastructural dimensions. Similarly, inequalities in urban infrastructure availability increase monotonically with infrastructure development levels and urban population size. Together, these findings underscore infrastructure inequalities as a feature of urbanization and suggest that understanding urban inequalities requires applying an inequality lens to urbanization. [ABSTRACT FROM AUTHOR]

Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, general, empirical support. These facts help to explain the challenges of achieving sustainability in land use and thus also point toward solutions. The 10 facts are as follows: 1) Meanings and values of land are socially constructed and contested; 2) land systems exhibit complex behaviors with abrupt, hard-to-predict changes; 3) irreversible changes and path dependence are common features of land systems; 4) some land uses have a small footprint but very large impacts; 5) drivers and impacts of land-use change are globally interconnected and spill over to distant locations; 6) humanity lives on a used planet where all land provides benefits to societies; 7) land-use change usually entails trade-offs between different benefits--"win-wins" are thus rare; 8) land tenure and land-use claims are often unclear, overlapping, and contested; 9) the benefits and burdens from land are unequally distributed; and 10) land users have multiple, sometimes conflicting, ideas of what social and environmental justice entails. The facts have implications for governance, but do not provide fixed answers. Instead they constitute a set of core principles which can guide scientists, policy makers, and practitioners toward meeting sustainability challenges in land use. [ABSTRACT FROM AUTHOR]

This paper introduces a special feature on biodiversity conservation and poverty traps. We define and explain the core concepts and then identify four distinct classes of mechanisms that define important interlinkages between biodiversity and poverty. The multiplicity of candidate mechanisms underscores a major challenge in designing policy appropriate across settings. This framework is then used to introduce the ensuing set of papers, which empirically explore these various mechanisms linking poverty traps and biodiversity conservation. [ABSTRACT FROM AUTHOR]

The author discusses the publication of several papers about sustainability science. He mentions that sustainability science is distributed widely and includes many authors beyond the normal focus in centers of traditional science as the U.S., Western Europe and Japan. He states that sustainability science, as contemplated in the classification of the journals where papers are published, is also multidisciplinary which spans the social, technological and natural sciences.

Succinic acid (SA), a dicarboxylic acid of industrial importance, can be efficiently produced by metabolically engineered Mannheimia succiniciproducens. Although the importance of magnesium (Mg2+) ion on SA production has been evident from our previous studies, the role of Mg2+ ion remains largely unexplored. In this study, we investigated the impact of Mg2+ ion on SA production and developed a hyper-SA producing strain of M. succiniciproducens by reconstructing the Mg2+ ion transport system. To achieve this, optimal alkaline neutralizer comprising Mg2+ ion was developed and the physiological effect of Mg2+ ion was analyzed. Subsequently, the Mg2+ ion transport system was reconstructed by introducing an efficient Mg2+ ion transporter from Salmonella enterica. A high-inoculum fed-batch fermentation of the final engineered strain produced 152.23 ± 0.99 g/L of SA, with a maximum productivity of 39.64 ± 0.69 g/L/h. These findings highlight the importance of Mg2+ ions and transportation system optimization in succinic acid production by M. succiniciproducens. [ABSTRACT FROM AUTHOR]

Clean production of hydrogen peroxide (H2O2) with water, oxygen, and renewable energy is considered an important green synthesis route, offering a valuable substitute for the traditional anthraquinone method. Currently, renewable energy-driven production of H2O2 mostly relies on soluble additives, such as electrolytes and sacrificial agents, inevitably compromising the purity and sustainability of H2O2. Herein, we develop a solution plasma catalysis technique that eliminates the need for soluble additives, enabling eco-friendly production of concentrated H2O2 directly from water and O2. Screening over 40 catalysts demonstrates the superior catalytic performance of carbon nitride interacting with discharge plasma in water. High-throughput density functional theory calculations for 68 models, along with machine learning using 29 descriptors, identify cyano carbon nitride (CCN) as the most efficient catalyst. Solution plasma catalysis with the CCN achieves concentrated H2O2 of 20 mmol L-1, two orders of magnitude higher than photocatalysis by the same catalyst. Plasma diagnostics, isotope labeling, and COMSOL simulations collectively validate that the interplay of solution plasma and the CCN accounts for the significantly increased production of singlet oxygen and H2O2 thereafter. Our findings offer an efficient and sustainable pathway for H2O2 production, promising wide-ranging applications across the chemical industry, public health, and environmental remediation. [ABSTRACT FROM AUTHOR]

Climate change is an existential threat to the environmental and socioeconomic sustainability of the coastal zone and impacts will be complex and widespread. Evidence from California and across the United States shows that climate change is impacting coastal communities and challenging managers with a plethora of stressors already present. Widespread action could be taken that would sustain California's coastal ecosystems and communities. In this perspective, we highlight the main threat to coastal sustainability: the compound effects of episodic events amplified with ongoing climate change, which will present unprecedented challenges to the state. We present two key challenges for California's sustainability in the coastal zone: 1) accelerating sea-level rise combined with storm impacts, and 2) continued warming of the oceans and marine heatwaves. Cascading effects from these types of compounding events will occur within the context of an already stressed system that has experienced extensive alterations due to intensive development, resource extraction and harvesting, spatial containment, and other human use pressures. There are critical components that could be used to address these immediate concerns, including comanagement strategies that include diverse groups and organizations, strategic planning integrated across large areas, rapid implementation of solutions, and a cohesive and policy relevant research agenda for the California coast. Much of this has been started in the state, but the scale could be increased, and timelines accelerated. The ideas and information presented here are intended to help expand discussions to sharpen the focus on how to encourage sustainability of California's iconic coastal region. [ABSTRACT FROM AUTHOR]

Indigenous communities in the North American Arctic are characterized by mixed economies that feature hunting, fishing, gathering, and trapping activities--and associated sharing practices--alongside the formal wage economy. The region is also undergoing rapid social, economic, and climate changes, including, in Canada, carbon taxation, which is impacting the cost of fuel used in local food harvesting. Because of the importance of local foods to nutrition, health, and well-being in Arctic Indigenous communities, there is an urgent need to better understand the sensitivity of Arctic food systems to social, economic, and climate changes and to develop plans for mitigating potential adverse effects. Here, we develop a Bayesian model to calculate the substitution value and carbon emissions of market replacements for local food harvests in the Inuvialuit Settlement Region, Canada. Our estimates suggest that under plausible scenarios, replacing locally harvested foods with imported market substitutes would cost over 3.1 million Canadian dollars per year and emit over 1,000 tons of CO2-equivalent emissions per year, regardless of the shipping scenario. In contrast, we estimate that gasoline inputs to harvesting cost approximately $295,000 and result in 315 to 497 tons of emissions. These results indicate that climate change policies that fail to account for local food production may undermine emissions targets and adversely impact food security and health in Arctic Indigenous communities, who already experience a high cost of living and high rates of food insecurity. [ABSTRACT FROM AUTHOR]

California agriculture will undergo significant transformations over the next few decades in response to climate extremes, environmental regulation and policy encouraging environmental justice, and economic pressures that have long driven agricultural changes. With several local climates suited to a variety of crops, periodically abundant nearby precipitation, and public investments that facilitated abundant low-priced irrigation water, California hosts one of the most diverse and productive agroecosystems in the world. California farms supply nearly half of the high-nutrient fruit, tree nut, and vegetable production in the United States. Climate change impacts on productivity and profitability of California agriculture are increasing and forebode problems for standard agricultural practices, especially water use norms. We highlight many challenges California agriculture confronts under climate change through the direct and indirect impacts on the biophysical conditions and ecosystem services that drive adaptations in farm practices and water accessibility and availability. In the face of clear conflicts among competing interests, we consider ongoing and potential sustainable and equitable solutions, with particular attention to how technology and policy can facilitate progress. [ABSTRACT FROM AUTHOR]

Nature is home to a variety of microorganisms that create materials under environmentally friendly conditions. While this offers an attractive approach for sustainable manufacturing, the production of materials by native microorganisms is usually slow and synthetic biology tools to engineer faster microorganisms are only available when prior knowledge of genotype-phenotype links is available. Here, we utilize a high-throughput directed evolution platform to enhance the fitness of whole microorganisms under selection pressure and identify genetic pathways to enhance the material production capabilities of native species. Using Komagataeibacter sucrofermentans as a model cellulose-producing microorganism, we show that our droplet-based microfluidic platform enables the directed evolution of these bacteria toward a small number of cellulose overproducers from an initial pool of 40,000 random mutants. Sequencing of the evolved strains reveals an unexpected link between the cellulose-forming ability of the bacteria and a gene encoding a protease complex responsible for protein turnover in the cell. The ability to enhance the fitness of microorganisms toward a specific phenotype and to unravel genotype-phenotype links makes this high-throughput directed evolution platform a promising tool for the development of new strains for the sustainable manufacturing of materials. [ABSTRACT FROM AUTHOR]

Hydropower has been the leading source of renewable energy across theworld, accounting for up to 71% of this supply as of 2016. This capacity was built up in North America and Europe between 1920 and 1970 when thousands of dams were built. Big dams stopped being built in developed nations, because the best sites for dams were already developed and environmental and social concerns made the costs unacceptable. Nowadays, more dams are being removed in North America and Europe than are being built. The hydropower industry moved to building dams in the developing world and since the 1970s, began to build even larger hydropower dams along the Mekong River Basin, the Amazon River Basin, and the Congo River Basin. The same problems are being repeated: disrupting river ecology, deforestation, losing aquatic and terrestrial biodiversity, releasing substantial greenhouse gases, displacing thousands of people, and altering people's livelihoods plus affecting the food systems, water quality, and agriculture near them. This paper studies the proliferation of large dams in developing countries and the importance of incorporating climate change into considerations of whether to build a dam along with some of the governance and compensation challenges. We also examine the overestimation of benefits and underestimation of costs along with changes that are needed to address the legitimate social and environmental concerns of people living in areas where dams are planned. Finally, we propose innovative solutions that can move hydropower toward sustainable practices together with solar, wind, and other renewable sources. [ABSTRACT FROM AUTHOR]

Fundamental transitions in natural resources technologies, institutions, and management approaches are often difficult to see in advance, or even in the midst, of actual changes. Such a transformation now appears to be underway for freshwater resources, driven by increasingly severe water-related crises around the world. These include mismatches between supply and demand; the continued failure to meet basic human needs for water and sanitation; expanding ecological degradation due to extraction of water from natural systems and human-caused climate changes; the development of new technologies for using, treating, monitoring, and reporting on water use; new conceptual work; and growing attention given to water issues by the public and scientific communities. Similar transitions, with additional implications for water, also appear to be underway in the energy and climate fields. For such transitions to be successful, it is important to understand what drives deep changes in the perceptions, management, and use of natural resources; the factors that encourage or discourage changes; and whether strategies can be developed to improve and accelerate those changes that lead to social, economic, and environmental sustainability goals. This paper addresses the concept of resource or environmental transitions in the context of freshwater; reviews theories, data, and frameworks for identifying and analyzing transitions; offers some examples; and identifies key policies to help manage effective and successful transitions. [ABSTRACT FROM AUTHOR]

This paper evaluates current stakeholder involvement (SI) practices in science through a web-based survey among scholars and researchers engaged in sustainability or transition research. It substantiates previous conceptual work with evidence from practice by building on four ideal types of SI in science. The results give an interesting overview of the varied landscape of SI in sustainability science, ranging from the kinds of topics scientists work on with stakeholders, over scientific trade-offs that arise in the field, to improvements scientists wish for. Furthermore, the authors describe a discrepancy between scientists' ideals and practiceswhenworking with stakeholders. On the conceptual level, the data reflect that the democratic type of SI is the predominant one concerning questions on the understanding of science, the main goal, the stage of involvement in the research process, and the science-policy interface. The fact that respondents expressed agreement to several types shows they are guided by multiple and partly conflicting ideals when working with stakeholders. We thus conclude that more conceptual exchange between practitioners, as well as more qualitative research on the concepts behind practices, is needed to better understand the stakeholder-scientist nexus. [ABSTRACT FROM AUTHOR]

The Amazon River Basin's extraordinary social-ecological system is sustained by various water phases, fluxes, and stores that are interconnected across the tropical Andes mountains, Amazon lowlands, and Atlantic Ocean. This "Andes-Amazon-Atlantic" (AAA) pathway is a complex hydroclimatic system linked by the regional water cycle through atmospheric circulation and continental hydrology. Here, we aim to articulate the AAA hydroclimate pathway as a foundational system for research, management, conservation, and governance of aquatic systems of the Amazon Basin. We identify and describe the AAA pathway as an interdependent, multidirectional, and multiscale hydroclimate system. We then present an assessment of recent (1981 to 2020) changes in the AAA pathway, primarily reflecting an acceleration in the rates of hydrologic fluxes (i.e., water cycle intensification). We discuss how the changing AAA pathway orchestrates and impacts social-ecological systems. We conclude with four recommendations for the sustainability of the AAA pathway in ongoing research, management, conservation, and governance. [ABSTRACT FROM AUTHOR]

Transforming smallholder farms is critical to global food security and environmental sustainability. The science and technology backyard (STB) platform has proved to be a viable approach in China. However, STB has traditionally focused on empowering smallholder farmers by transferring knowledge, and wide-scale adoption of more sustainable practices and technologies remains a challenge. Here, we report on a long-term project focused on technology scale-up for smallholder farmers by expanding and upgrading the original STB platform (STB 2.0). We created a formalized and standardized process by which to engage and collaborate with farmers, including integrating their feedback via equal dialogues in the process of designing and promoting technologies. Based on 288 site-year of field trials in three regions in the North China Plain over 5 y, we find that technologies cocreated through this process were more easily accepted by farmers and increased their crop yields and nitrogen factor productivity by 7.2% and 28.1% in wheat production and by 11.4% and 27.0% in maize production, respectively. In promoting these technologies more broadly, we created a "one-stop" multistakeholder program involving local government agencies, enterprises, universities, and farmers. The program was shown to be much more effective than the traditional extension methods applied at the STB, yielding substantial environmental and economic benefits. Our study contributes an important case study for technology scale-up for smallholder agriculture. The STB 2.0 platform being explored emphasizes equal dialogue with farmers, multistakeholder collaboration, and long-term investment. These lessons may provide value for the global smallholder research and practitioners. [ABSTRACT FROM AUTHOR]

Policy action for sustainability transformation faces inherent and ever-present sources of conflict, pushback, and resistance (i.e., discord). However, conceptual frameworks and policy prescriptions for sustainability transformations often reflect an undue image of accord. This involves simplified assumptions about consensus, steering, friction, discreteness, and additiveness of policy action, conferring an unrealistic view of the potential to deliberately realize transformation. Instead, negotiating discord through continuously finding partial political settlements among divided actors needs to become a key focus of policy action for sustainability transformations. Doing so can help to navigate deeply political settings through imperfect but workable steps that loosen deadlock, generate momentum for further policy action, and avoid complete derailment of transformation agendas when discord arises. [ABSTRACT FROM AUTHOR]

Organic carbon availability in soil is crucial for shaping microbial communities, yet, uncertainties persist concerning microbial adaptations to carbon levels and the ensuing ecological and evolutionary consequences. We investigated organic carbon metabolism, antibiotic resistance, and virus-host interactions in soils subjected to 40 y of chemical and organic fertilization that led to contrasting carbon availability: carbon-poor and carbon-rich soils, respectively. Carbon-poor soils drove the enrichment of putative genes involved in organic matter decomposition and exhibited specialization in utilizing complex organic compounds, reflecting scramble competition. This specialization confers a competitive advantage of microbial communities in carbon-poor soils but reduces their buffering capacity in terms of organic carbon metabolisms, making them more vulnerable to environmental fluctuations. Additionally, in carbon-poor soils, viral auxiliary metabolic genes linked to organic carbon metabolism increased host competitiveness and environmental adaptability through a strategy akin to "piggyback the winner." Furthermore, putative antibiotic resistance genes, particularly in low-abundance drug categories, were enriched in carbon-poor soils as an evolutionary consequence of chemical warfare (i.e., interference competition). This raises concerns about the potential dissemination of antibiotic resistance from conventional agriculture that relies on chemical-only fertilization. Consequently, carbon starvation resulting from long-term chemical-only fertilization increases microbial adaptations to competition, underscoring the importance of implementing sustainable agricultural practices to mitigate the emergence and spread of antimicrobial resistance and to increase soil carbon storage. [ABSTRACT FROM AUTHOR]

The interplay of human actions and natural processes over varied spatial and temporal scales can result in abrupt transitions between contrasting land surface states. Understanding these transitions is a key goal of sustainability science because they can represent abrupt losses of natural capital. This paper recognizes flickering between alternate land surface states in advance of threshold change and critical slowing down in advance of both threshold changes and noncritical transformation. The early warning signals we observe are rises in autocorrelation, variance, and skewness within millimeterresolution thickness measurements of tephra layers deposited in A.D. 2010 and A.D. 2011. These signals reflect changing patterns of surface vegetation, which are known to provide early warning signals of critical transformations. They were observed toward migrating soil erosion fronts, cryoturbation limits, and expanding deflation zones, thus providing potential early warning signals of land surface change. The record of the spatial patterning of vegetation contained in contemporary tephra layers shows how proximity to land surface change could be assessed in the widespread regions affected by shallow layers of volcanic fallout (those that can be subsumed within the existing vegetation cover). This insight shows how we could use tephra layers in the stratigraphie record to identify "near misses," close encounters with thresholds that did not lead to tipping points, and thus provide additional tools for archaeology, sustainability science, and contemporary land management. [ABSTRACT FROM AUTHOR]

Humans challenge the phenotypic, genetic, and cultural makeup of species by affecting the fitness landscapes on which they evolve. Recent studies show that cities might play a major role in contemporary evolution by accelerating phenotypic changes in wildlife, including animals, plants, fungi, and other organisms. Many studies of ecoevolutionary change have focused on anthropogenic drivers, but none of these studies has specifically examined the role that urbanization plays in ecoevolution or explicitly examined its mechanisms. This paper presents evidence on the mechanisms linking urban development patterns to rapid evolutionary changes for species that play important functional roles in communities and ecosystems. Through a metaanalysis of experimental and observational studies reporting more than 1,600 phenotypic changes in species across multiple regions, we ask whether we can discriminate an urban signature of phenotypic change beyond the established natural baselines and other anthropogenic signals. We then assess the relative impact of five types of urban disturbances including habitat modifications, biotic interactions, habitat heterogeneity, novel disturbances, and social interactions. Our study shows a clear urban signal; rates of phenotypic change are greater in urbanizing systems compared with natural and nonurban anthropogenic systems. By explicitly linking urban development to traits that affect ecosystem function, we can map potential ecoevolutionary implications of emerging patterns of urban agglomerations and uncover insights for maintaining key ecosystem functions upon which the sustainability of human well-being depends. [ABSTRACT FROM AUTHOR]

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 FROM AUTHOR]

Climate change might catalyze and exacerbate the trend of outmigration from low-lying atoll islands. There is speculation that migration away from atolls may not stop until such islands are abandoned. Yet migration creates both opportunities and risks for the sustainability of atoll communities. There is a trade-off between reduced demographic pressure on increasingly fragile atoll island environments and the financial and human resources necessary to adapt to climate change that can result from migration. Here we propose and analyze belonging as the centripetal force that makes migration a process that enhances the sustainability of atoll populations. We examine the relationship between migration, belonging, and the sustainability of populations on atoll islands based on data collected in three atoll islands in the Pacific: the island state of Niue; Namdrik Atoll in the Republic of the Marshall Islands; and Budibudi atoll (Laughlan Islands) in Papua New Guinea. In each case, belonging binds the people who live in and migrate from these places into a collective commitment to their continuity, yet it does so to different degrees according to the economic opportunities available to migrants and the infrastructure that enables extended communities to remain connected. [ABSTRACT FROM AUTHOR]

Sustainability and migration are typically treated as discrete policy spheres in international, national, and local fora, separated in governance structures and institutions. This results in policy incoherence that hinders just transitions toward more sustainable societies cognizant of mobile realities. This explorative effort identifies the (dis)connections between policy domains using data collected on how the sustainability-migration nexus is governed in four countries with a special emphasis on urban areas: Belgium, the Netherlands, Sweden, and the United States. Results of 73 interviews show that migration and sustainability actors find it challenging to see how they could be working together and that migrants are rarely conceived of as sustainability actors and/or targeted populations of sustainability policy. Despite the cross-sectoral nature of sustainability, it appears that migration and sustainability are sequestered into silos that hinder collaborative actions. Lamenting the existence of silos is not enough to encourage new lines of thinking or practice in how sustainability is governed; therefore, we examine the evidence to ascertain current barriers blocking synergetic governance and the opportunities for change perceived by respondents via three critical elements of transformations toward sustainability: structural, systemic, and enabling conditions. We argue that for sustainability transitions to happen, a wider set of societal actors needs to be included from policy intention to action, but that this transformation may require more than policy integration via horizontal coordination. It demands reflexivity and pluralistic pathways that close vertical gaps between national and municipal levels and diminish structural inequalities as they intersect with migration type and status. [ABSTRACT FROM AUTHOR]

Industrial ecology has revolutionized our understanding of material stocks and flows in our economy and society. For this important discipline to have even deeper impact, we must understand the inherent nature of these materials in terms of human health and the environment. This paper focuses on methods to design synthetic chemicals to reduce their intrinsic ability to cause adverse consequence to the biosphere. Advances in the fields of computational chemistry and molecular toxicology in recent decades allow the development of predictive models that inform the design of molecules with reduced potential to be toxic to humans or the environment. The approach presented herein builds on the important work in quantitative structure-activity relationships by linking toxicological and chemical mechanistic insights to the identification of critical physical-chemical properties needed to be modified. This in silico approach yields design guidelines using boundary values for physiochemical properties. Acute aquatic toxicity serves as a model endpoint in this study. Defining value ranges for properties related to bioavailability and reactivity eliminates 99% of the chemicals in the highest concern for acute aquatic toxicity category. This approach and its future implementations are expected to yield very powerful tools for life cycle assessment practitioners and molecular designers that allow rapid assessment of multiple environmental and human health endpoints and inform modifications to minimize hazard. [ABSTRACT FROM AUTHOR]

Electricity system decarbonization is key for environmental sustainability. From a consumption-production perspective, much attention has been paid to changes in how electricity is generated and used, but electricity systems also rely on a grid infrastructure that connects and integrates production and consumption, and which will also need to transform. At the same time, new technologies in the electricity system, including the grid, offer the potential for more socially sustainable ways of producing and consuming energy. However, in practice, change has been slow, uneven, and often dysfunctional. A socio-technical transitions approach offers insights into why this is so, seeing electricity system change not simply in technical and economic terms, but also as the outcomes of interactions between technology and social and political processes. The approach draws attention to the particular challenges of achieving rapid transitions in complex critical infrastructures like electricity with strong institutional logics of security. This article applies this approach to the case of Great Britain, where despite strong commitments to sustainability in the form of high-level climate policy, the electricity grid has often been a constraint on the pace of change. The nature of the British transition is explained partly by weak links between these high-level goals on the one hand and the detailed rules and practices in the electricity system on the other. It is also explained by patterns of ownership and grid regulation in the British case that protect incumbents and make it difficult for new actors to develop the system in more socially sustainable directions. [ABSTRACT FROM AUTHOR]

While the negative environmental, social and health impacts of the current food system have been acknowledged and evidenced for several decades, the recent and current transformations in food systems at diverse scales are not yet addressing the many inter-related stakes at play. Due to the much wider set of interactions in this consumptionproduction system, new conceptual tools are required for understanding and assessing sustainability transitions and what prevents them. The article will draw on the cases of France and the UK to examine these countries' national food systems' historical trajectories and suggest a periodization of these in order to reveal common characteristics and differences. This will show that despite common major trends and common transition or inertia mechanisms, pathways differ, especially from the 1990s, due to different configurations of power relationships between the state, economic actors and civil society in a context of an increasing competition between sustainability narratives that leads to an increasing fragmentation in food systems. It will lead us to join the recent progress in the sustainability transitions' community towards a shift in the analysis from a focus on niches' trajectories and effects to a deeper focus on power configurations and competing narratives, as well as to suggest a larger inclusion of socioecological and spatial dimensions. [ABSTRACT FROM AUTHOR]

The need for rapid and ambitious conservation and restoration is widely acknowledged, yet concern exists that the widespread reallocation of land to nature would disproportionately affect the world’s poor. Conservation and restoration may limit nutrition and livelihood options and thus negatively affect social development objectives. Although much research looks into global-scale scenarios and planning of conservation and restoration, spatial evaluations of these trade-offs in terms of equity remain limited. We fill this gap by identifying areas where conservation or restoration under different future scenarios and prioritization maps expand nature into landscapes that likely support land-dependent communities in their local food security. By contrasting the expansion of nature into areas supporting land-dependent communities vs. places where the food system is supported by regional to global markets, we highlight the need for disaggregated indicators that reflect the diversity of human land-use needs in order to identify more equitable pathways. Conservation prioritizations were found to result in more equitable land-use outcomes than the land-use outcomes of widely used socioeconomic scenarios. Accounting for differentiated social impacts in model-based conservation and restoration planning and global scale scenario assessment can help achieve a more inclusive transition to sustainability as well as reduce barriers to meaningful change. [ABSTRACT FROM AUTHOR]

Scientists seek to understand the causal processes that generate sustainability problems and determine effective solutions. Yet, causal inquiry in nature–society systems is hampered by conceptual and methodological challenges that arise from nature–society interdependencies and the complex dynamics they create. Here, we demonstrate how sustainability scientists can address these challenges and make more robust causal claims through better integration between empirical analyses and process- or agent-based modeling. To illustrate how these different epistemological traditions can be integrated, we present four studies of air pollution regulation, natural resource management, and the spread of COVID-19. The studies show how integration can improve empirical estimates of causal effects, inform future research designs and data collection, enhance understanding of the complex dynamics that underlie observed temporal patterns, and elucidate causal mechanisms and the contexts in which they operate. These advances in causal understanding can help sustainability scientists develop better theories of phenomena where social and ecological processes are dynamically intertwined and prior causal knowledge and data are limited. The improved causal understanding also enhances governance by helping scientists and practitioners choose among potential interventions, decide when and how the timing of an intervention matters, and anticipate unexpected outcomes. Methodological integration, however, requires skills and efforts of all involved to learn how members of the respective other tradition think and analyze nature–society systems. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction is a challenging process that requires achieving high ammonia yield rate and reasonable faradaic efficiency. To address this issue, this study developed a catalyst by in situ anchoring interfacial intergrown ultrafine MoO2 nanograins on N-doped carbon fibers. By optimizing the thermal treatment conditions, an abundant number of grain boundaries were generated between MoO2 nanograins, which led to an increased fraction of oxygen vacancies. This, in turn, improved the transfer of electrons, resulting in the creation of highly active reactive sites and efficient nitrogen trapping. The resulting optimal catalyst, MoO2/C700, outperformed commercial MoO2 and state-of-the-art N2 reduction catalysts, with NH3 yield and Faradic efficiency of 173.7 µg h-1 mg-1 cat and 27.6%, respectively, under - 0.7 V vs. RHE in 1 M KOH electrolyte. In situ X-ray photoelectron spectroscopy characterization and density functional theory calculation validated the electronic structure effect and advantage of N2 adsorption over oxygen vacancy, revealing the dominant interplay of N2 and oxygen vacancy and generating electronic transfer between nitrogen and Mo(IV). The study also unveiled the origin of improved activity by correlating with the interfacial effect, demonstrating the big potential for practical N2 reduction applications as the obtained optimal catalyst exhibited appreciable catalytic stability during 60 h of continuous electrolysis. This work demonstrates the feasibility of enhancing electrocatalytic nitrogen reduction by engineering grain boundaries to promote oxygen vacancies, offering a promising avenue for efficient and sustainable ammonia production. [ABSTRACT FROM AUTHOR]

Linking knowledge to action requires understanding how decision-makers conceptualize sustainability. This paper empirically analyzes farmer "mental models" of sustainability from three winegrape-growing regions of California where local extension programs have focused on sustainable agriculture. The mental models are represented as networks where sustainability concepts are nodes, and links are established when a farmer mentions two concepts in their stated definition of sustainability. The results suggest that winegrape grower mental models of sustainability are hierarchically structured, relatively similar across regions, and strongly linked to participation in extension programs and adoption of sustainable farm practices. We discuss the implications of our findings for the debate over the meaning of sustainability, and the role of local extension programs in managing knowledge systems. [ABSTRACT FROM AUTHOR]

Despite broad interest in using payment for ecosystem services to promote changes in the use of natural capital, there are few expost assessments of impacts of payment for ecosystem services programs on ecosystem service provision, program cost, and changes in livelihoods resulting from program participation. In this paper, we evaluate the Paddy Land-to-Dry Land (PLDL) program in Beijing, China, and associated changes in service providers' livelihood activities. The PLDL is a land use conversion program that aims to protect water quality and quantity for the only surface water reservoir that serves Beijing, China's capital city with nearly 20 million residents. Our analysis integrates hydrologic data with household survey data and shows that the PLDL generates benefits of improved water quantity and quality that exceed the costs of reduced agricultural output. The PLDL has an overall benefit-cost ratio of 1.5, and both downstream beneficiaries and upstream providers gain from the program. Household data show that changes in livelihood activities may offset some of the desired effects of the program through increased expenditures on agricultural fertilizers. Overall, however, reductions in fertilizer leaching from land use change dominate so that the program still has a positive net impact on water quality. This program is a successful example of water users paying upstream landholders to improve water quantity and quality through land use change. Program evaluation also highlights the importance of considering behavioral changes by program participants. [ABSTRACT FROM AUTHOR]

This paper introduces urban land teleconnections as a conceptual framework that explicitly links land changes to underlying urbanization dynamics. We illustrate how three key themes that are currently addressed separately in the urban sustainability and land change literatures can lead to incorrect conclusions and misleading results when they are not examined jointly: the traditional system of land classification that is based on discrete categories and reinforces the false idea of a rural-urban dichotomy; the spatial quantification of land change that is based on place-based relationships, ignoring the connections between distant places, especially between urban functions and rural land uses; and the implicit assumptions about path dependency and sequential land changes that underlie current conceptualizations of land transitions. We then examine several environmental "grand challenges" and discuss how urban land teleconnections could help research communities frame scientific inquiries. Finally, we point to existing analytical approaches that can be used to advance development and application of the concept. [ABSTRACT FROM AUTHOR]

Morocco's argan oil is now the most expensive edible oil in the world. High-value argan markets have sparked a bonanza of argan activity. Nongovernmental organizations, international and domestic development agencies, and argan oil cooperatives aggressively promote the win-win aim of simultaneously benefiting local people and the health of the argan forest. This paper tests some of these win-win claims. Analysis of a panel of detailed household data suggests that the boom has enabled some rural households to increase consumption, increase their goat herds (which bodes poorly for the argan forest), and send their girls to secondary school. The boom has predictably made households vigilant guardians of fruit on the tree, but it has not incited investments in longer term tree and forest health. We evaluate landscape-level impacts of these changes using commune-level data on educational enrollment and normalized difference vegetation index data over the period from 1981 to 2009. The results of the mesoanalysis of enrollment are consistent with the microanalysis: the argan boom seems to have improved educational outcomes, especially for girls. Our normalized difference vegetation index analysis, however, suggests that booming argan prices have not improved the forest and may have even induced degradation. We conclude by exploring the dynamic interactions between argan markets, local institutions, rural household welfare, and forest conservation and sustainability. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) are a promising area in environmental catalysis. We report on a bimetallic Co–Mo SAC that shows excellent performance in activating peroxymonosulfate (PMS) for sustainable degradation of organic pollutants with high ionization potential (IP > 8.5 eV). Density Functional Theory (DFT) calculations and experimental tests demonstrate that the Mo sites in Mo–Co SACs play a critical role in conducting electrons from organic pollutants to Co sites, leading to a 19.4-fold increase in the degradation rate of phenol compared to the CoCl2–PMS group. The bimetallic SACs exhibit excellent catalytic performance even under extreme conditions and show long-term activation in 10-d experiments, efficiently degrading 600 mg/L of phenol. Moreover, the catalyst has negligible toxicity toward MDA-MB-231, Hela, and MCF-7 cells, making it an environmentally friendly option for sustainable water treatment. Our findings have important implications for the design of efficient SACs for environmental remediation and other applications in biology and medicine. [ABSTRACT FROM AUTHOR]

The environmental fragility of cities under advanced urbanization has motivated extensive efforts to promote the sustainability of urban ecosystems and physical infrastructures. Less attention has been devoted to neighborhood inequalities and fissures in the civic infrastructure that potentially challenge social sustainability and the capacity of cities to collectively address environmental challenges. This article draws on a program of research in three American cities—Boston, Chicago, and Los Angeles—to develop hypotheses and methodological strategies for assessing how the multidimensional and multilevel inequalities that characterize contemporary cities bear on sustainability. In addition to standard concerns with relative inequality in income, the article reviews evidence on compounded deprivation, racial cleavages, civic engagement, institutional cynicism, and segregated patterns of urban mobility and organizational ties that differentially connect neighborhood resources. Harnessing “ecometric” measurement tools and emerging sources of urban data with a theoretically guided framework on neighborhood inequality can enhance the pursuit of sustainable cities, both in the United States and globally. [ABSTRACT FROM AUTHOR]

The electrochemical conversion of waste nitrate (NO3-) to valuable ammonia (NH3) is an economical and environmentally friendly technology for sustainable NH3 production. It is beneficial for environmental nitrogen pollution management and is also an appealing alternative to the current Haber--Bosch process for NH3 production. However, owing to the competing hydrogen evolution reaction, it is necessary to design highly efficient and stable electrocatalysts with high selectivity. Herein, we report a rational design of Fe nanoparticles wrapped in N-doped carbon (Fe@N10-C) as a high NH3 selective and efficient electrocatalyst using a metal--organic framework precursor. We constructed a catalyst with new active sites by doping with nitrogen, which activated neighboring carbon atoms and enhanced metal-to-carbon electron transfer, resulting in high catalytic activity. These doped N sites play a key role in the NO3- electroreduction. As a result, the Fe@N10-C nanoparticles with optimal doping of N demonstrated remarkable performance, with a record-high NO3- removal capacity of 125.8 ± 0.5 mg N gcat-1 h-1 and nearly 100 % (99.7 ± 0.1%) selectivity. The catalyst also delivers an impressive NH3 production rate of 2647.7 µg h-1 cm-2 and high faradaic efficiency of 91.8 ± 0.1%. This work provides a new route for N-doped carbon--iron catalysis application and paves the way for addressing energy and environmental issues. [ABSTRACT FROM AUTHOR]

The world’s oceans are currently facing major stressors in the form of overexploitation and anthropogenic climate change. The Baltic Sea was home to the first “industrial” fishery ∼800 y ago targeting the Baltic herring, a species that is still economically and culturally important today. Yet, the early origins of marine industries and the long-term ecological consequences of historical and contemporary fisheries remain debated. Here, we study long-term population dynamics of Baltic herring to evaluate the past impacts of humans on the marine environment. We combine modern whole-genome data with ancient DNA (aDNA) to identify the earliest-known long-distance herring trade in the region, illustrating that extensive fish trade began during the Viking Age. We further resolve population structure within the Baltic and observe demographic independence for four local herring stocks over at least 200 generations. It has been suggested that overfishing at Øresund in the 16th century resulted in a demographic shift from autumn-spawning to spring-spawning herring dominance in the Baltic. We show that while the Øresund fishery had a negative impact on the western Baltic herring stock, the demographic shift to spring-spawning dominance did not occur until the 20th century. Instead, demographic reconstructions reveal population trajectories consistent with expected impacts of environmental change and historical reports on shifting fishing targets over time. This study illustrates the joint impact of climate change and human exploitation on marine species as well as the role historical ecology can play in conservation and management policies. [ABSTRACT FROM AUTHOR]

Seawater electrolysis is an intriguing technology for sustainable hydrogen production that will not exacerbate the global shortage of freshwater or increase carbon emissions. However, due to the undesirable anodic chlorine evolution reaction and the strong corrosiveness of seawater, this technology is significantly hindered by a lack of robust oxygen evolution reaction (OER) electrocatalysts that exhibit high activity, high selectivity, and good stability. Here, we demonstrate a homogeneous multimetallic catalyst consisting of Ni and Fe coincorporated into CuCo layered double hydroxide (denoted as NiFe-CuCo LDH) that serves as an active and durable OER electrode for high-performance seawater electrolysis. With abundant exposed multimetal sites and well-defined micronanostructures, the NiFe-CuCo LDH catalyst requires overpotentials of only 259, 278, and 283 mV to yield current densities of 100, 300, and 500 mA cm−2, respectively, in 6 M KOH seawater electrolyte. Moreover, it exhibits very high OER selectivity (Faradaic efficiency of 97.4% for O2 at 500 mA cm−2) and superior durability during operation, working stably under a large current density of 500 mA cm−2 for up to 500 h in 6 M KOH seawater electrolyte. This multimetallic electrocatalyst is one of the best performing ones among all reported transition-metal-based OER electrocatalysts in alkaline seawater electrolyte, which boosts the development of seawater electrolysis technology. [ABSTRACT FROM AUTHOR]

Diet shifts and food waste reduction have the potential to reduce the land and biodiversity footprint of the food system. In this study, we estimated the amount of land used to produce food consumed in the United States and the number of species threatened with extinction as a result of that land use. We predicted potential changes to the biodiversity threat under scenarios of food waste reduction and shifts to recommended healthy and sustainable diets. Domestically produced beef and dairy, which require vast land areas, and imported fruit, which has an intense impact on biodiversity per unit land, have especially high biodiversity footprints. Adopting the Planetary Health diet or the US Department of Agriculture (USDA)-recommended vegetarian diet nationwide would reduce the biodiversity footprint of food consumption. However, increases in the consumption of foods grown in global biodiversity hotspots both inside and outside the United States, especially fruits and vegetables, would partially offset the reduction. In contrast, the USDA-recommended US-style and Mediterranean-style diets would increase the biodiversity threat due to increased consumption of dairy and farmed fish. Simply halving food waste would benefit global biodiversity more than half as much as all Americans simultaneously shifting to a sustainable diet. Combining food waste reduction with the adoption of a sustainable diet could reduce the biodiversity footprint of US food consumption by roughly half. Species facing extinction because of unsustainable food consumption practices could be rescued by reducing agriculture's footprint; diet shifts and food waste reduction can help us get there. [ABSTRACT FROM AUTHOR]

Paleoclimatic evidence indicating a series of droughts in the Yucatan Peninsula during the Terminal Classic period suggests that climate change may have contributed to the disruption or collapse of Classic Maya polities. Although climate change cannot fully account for the multifaceted, political turmoil of the period, it is clear that droughts of strong magnitude could have limited food availability, potentially causing famine, migration, and societal decline. Maize was undoubtedly an important staple food of the ancient Maya, but a complete analysis of other food resources that would have been available during drought remains unresolved. Here, we assess drought resistance of all 497 indigenous food plant species documented in ethnographic, ethnobotanical, and botanical studies as having been used by the lowland Maya and classify the availability of these plant species and their edible components under various drought scenarios. Our analysis indicates availability of 83% of food plant species in short-term drought, but this percentage drops to 22% of food plant species available in moderate drought up to 1 y. During extreme drought, lasting several years, our analysis indicates availability of 11% of food plant species. Our results demonstrate a greater diversity of food sources beyond maize that would have been available to the Maya during climate disruption of the Terminal Classic period than has been previously acknowledged. While drought would have necessitated shifts in dietary patterns, the range of physiological drought responses for the available food plants would have allowed a continuing food supply under all but the most dire conditions. [ABSTRACT FROM AUTHOR]

Intensive systems with two or three rice (Oryza sativa L.) crops per year account for about 50% of the harvested area for irrigated rice in Asia. Any reduction in productivity or sustainability of these systems has serious implications for global food security. Rice yield trends in the world’s longest-running long-term continuous cropping experiment (LTCCE) were evaluated to investigate consequences of intensive cropping and to draw lessons for sustaining production in Asia. Annual production was sustained at a steady level over the 50-y period in the LTCCE through continuous adjustment of management practices and regular cultivar replacement. Within each of the three annual cropping seasons (dry, early wet, and late wet), yield decline was observed during the first phase, from 1968 to 1990. Agronomic improvements in 1991 to 1995 helped to reverse this yield decline, but yield increases did not continue thereafter from 1996 to 2017. Regular genetic and agronomic improvements were sufficient to maintain yields at steady levels in dry and early wet seasons despite a reduction in the yield potential due to changing climate. Yield declines resumed in the late wet season. Slower growth in genetic gain after the first 20 y was associated with slower breeding cycle advancement as indicated by pedigree depth. Our findings demonstrate that through adjustment of management practices and regular cultivar replacement, it is possible to sustain a high level of annual production in irrigated systems under a changing climate. However, the system was unable to achieve further increases in yield required to keep pace with the growing global rice demand. [ABSTRACT FROM AUTHOR]