ALBERT

Description: ▪ Abstract  With continued human pressure on marine fisheries and ocean resources, aquaculture has become one of the most promising avenues for increasing marine fish production in the future. This review presents recent trends and future prospects for the aquaculture industry, with particular attention paid to ocean farming and carnivorous finfish species. The benefits of farming carnivorous fish have been challenged; extensive research on salmon has shown that farming such fish can have negative ecological, social, and health impacts on areas and parties vastly separated in space. Similar research is only beginning for the new carnivorous species farmed or ranched in marine environments, such as cod, halibut, and bluefin tuna. These fish have large market potential and are likely to play a defining role in the future direction of the aquaculture industry. We review the available literature on aquaculture development of carnivorous finfish species and assess its potential to relieve human pressure on marine fisheries, many of which have experienced sharp declines.

Description: Almost 20 years ago, the first CO2 capture and storage (CCS) project began injecting CO2 into a deep geological formation in an offshore aquifer. Relevant science has advanced in areas such as chemical engineering, geophysics, and social psychology. Governments have generously funded demonstrations. As a result, a handful of industrial-scale CCS projects are currently injecting about 15 megatons of CO2 underground annually that contribute to climate change mitigation. However, CCS is struggling to gain a foothold in the set of options for dealing with climate change. This review explores why and discusses critical conditions for CCS to emerge as a viable mitigation option. Explanations for this struggle include the absence of government action on climate change, economic crisis–induced low carbon prices, public skepticism, increasing costs, and advances in other options including renewables and shale gas. Climate change action is identified as a critical condition for progress in CCS, in addition to community support, safe storage, robust policy support, and favorable CCS market conditions.

Description: ▪ Abstract  This review critically surveys an extensive literature on mining, development, and environment. It identifies a significant broadening over time in the scope of the environment question as it relates to mining, from concerns about landscape aesthetics and pollution to ecosystem health, sustainable development, and indigenous rights. A typology compares and contrasts four distinctive approaches to this question: (a) technology and management-centered accounts, defining the issue in terms of environmental performance; (b) public policy studies on the design of effective institutions for capturing benefits and allocating costs of resource development; (c) structural political economy, highlighting themes of external control, resource rights, and environmental justice; and (d) cultural studies, which illustrate how mining exemplifies many of society's anxieties about the social and environmental effects of industrialization and globalization. Each approach is examined in detail.

Description: The Central African forests, the planet's second largest rainforest block, are key to global environmental health. They influence climate change through their crucial role in carbon sinking and storage, affect weather patterns across Africa, and safeguard unique species and biodiverse communities. Their fate is important to everyone, not just today's inhabitants. The forests cover seven countries, and the differing socioeconomic histories and trajectories of these nations determine divergent fates for people, trees, and wildlife across the region. We review current knowledge of how the Central African forests have been shaped by climate and human activity within the region and assess how they may evolve under future climate change, population growth, and the Anthropocene race for wealth and energy. We highlight three different environmental trajectories for the countries of the region, identify key current regional issues that have an international dimension, and highlight five new points of future concern.

Description: ▪ Abstract  Feedback between plants and the soil is frequently invoked on the basis of evidence of mutual effects. Feedback can operate through pathways involving soil physical properties, chemical and biogeochemical properties and processes, and biological properties, including the community composition of the microbiota and soil fauna. For each pathway, we review the mechanistic basis and assess the evidence that feedback occurs. We suggest that several properties of feedback systems (for example, their complexity, specificity, and strength relative to other ecological factors, as well as the temporal and spatial scales over which they operate) be considered. We find that the evidence of feedback is strongest for plants growing in extreme environments and for plant-mutualist or plant-enemy interactions. We conclude with recommendations for a more critical appraisal of feedback and for new directions of research. Let us not make arbitrary conjectures about the greatest matters. Heraclitus ( 1 )

Description: ▪ Abstract  Sustainable development has broad appeal and little specificity, but some combination of development and environment as well as equity is found in many attempts to describe it. However, proponents of sustainable development differ in their emphases on what is to be sustained, what is to be developed, how to link environment and development, and for how long a time. Despite the persistent definitional ambiguities associated with sustainable development, much work (over 500 efforts) has been devoted to developing quantitative indicators of sustainable development. The emphasis on sustainability indicators has multiple motivations that include decision making and management, advocacy, participation and consensus building, and research and analysis. We select a dozen prominent examples and use this review to highlight their similarities and differences in definition of sustainable development, motivation, process, and technical methods. We conclude that there are no indicator sets that are universally accepted, backed by compelling theory, rigorous data collection and analysis, and influential in policy. This is due to the ambiguity of sustainable development, the plurality of purpose in characterizing and measuring sustainable development, and the confusion of terminology, data, and methods of measurement. A major step in reducing such confusion would be the acceptance of distinctions in terminology, data, and methods. Toward this end, we propose an analytical framework that clearly distinguishes among goals, indicators, targets, trends, driving forces, and policy responses. We also highlight the need for continued research on scale, aggregation, critical limits, and thresholds.

Description: ▪ Abstract  In this review, we highlight new insights into the conceptualization of the vulnerability of social-environmental systems and identify critical points of convergence of what otherwise might be characterized as disparate fields of research. We argue that a diversity of approaches to studying vulnerability is necessary in order to address the full complexity of the concept and that the approaches are in large part complementary. An emerging consensus on the issues of critical importance to vulnerability reduction—including concerns of equity and social justice—and growing synergy among conceptual frameworks promise even greater relevancy and utility for decision makers in the near future. We synthesize the current literature with an outline of core assessment components and key questions to guide the trajectory of future research.

Description: Vegetation modifies land-surface properties, mediating the exchange of energy, moisture, trace gases, and aerosols between the land and the atmosphere. These exchanges influence the atmosphere on local, regional, and global scales. Through altering surface properties, vegetation change can impact on weather and climate. We review current understanding of the processes through which tropical land-cover change (LCC) affects rainfall. Tropical deforestation leads to reduced evapotranspiration, increasing surface temperatures by 1–3 K and causing boundary layer circulations, which in turn increase rainfall over some regions and reduce it elsewhere. On larger scales, deforestation leads to reductions in moisture recycling, reducing regional rainfall by up to 40%. Impacts of future tropical LCC on rainfall are uncertain but could be of similar magnitude to those caused by climate change. Climate and sustainable development policies need to account for the impacts of tropical LCC on local and regional rainfall.

Description: The ecosystem services (ES) framework was developed to articulate and measure the benefits humans receive from ecosystems. Cultural ecosystem services (CES), usually defined as the intangible and nonmaterial benefits ecosystems provide, have been relatively neglected by researchers and policy-makers compared to provisioning, supporting, and regulating services. Although valuing CES poses several conceptual and methodological difficulties, it is of huge interest and importance because of the linkages between cultural values, valuation methods, and the individual and collective decision-making that influence ecosystems and human wellbeing. This review is not a how-to guide, but rather examines key conceptual issues and maps critical areas of debate. There is a range of potential approaches to assessing CES; however, choices regarding valuation methods and their role in decision-making are shaped by cultural and political dynamics. CES are at a crossroads. They can potentially act as a fruitful conceptual container for a broad range of interdisciplinary research into human-environment relations and transform how decisions regarding the environment are made, but they can also be used to legitimize and entrench modes of decision-making that marginalize and undermine the very values they are intended to protect.

Description: Phosphorus security is emerging as one of the twenty-first century's greatest global sustainability challenges. Phosphorus has no substitute in food production, and the use of phosphate fertilizers in the past 50 years has boosted crop yields and helped feed billions of people. However, these advantages have come at a serious cost. Mobilizing phosphate rock into the environment at rates vastly faster than the natural cycle has not only polluted many of the world's freshwater bodies and oceans, but has also created a human dependence on a single nonrenewable resource. The 2008 phosphate price spike attracted unprecedented attention to this global situation. This review provides an updated and integrated synthesis of the biophysical, social, geopolitical, and institutional challenges and opportunities for food security. Remaining phosphorus resources are becoming increasingly scarce, expensive, and inequitably distributed. All farmers require fertilizers, yet a sixth of the world's farmers and their families are too poor to access fertilizer markets. Inefficient use of this fossil resource from mine to field to fork calls for substantial reduction in demand through efficiency and recycling. Phosphorus governance at global, regional, and local scales is required to stimulate and support context-specific sustainable strategies to ensure all the world's farmers have sufficient access to phosphorus to feed the world and ensure ecosystem integrity and farmer livelihoods.

Description: ▪ Abstract  Since the 1970s, supply augmentation strategies to meet water needs have waned, and governments have increasingly focused on demand management measures, including voluntary water transfers. Water demands have also changed as expanding urban growth, changes in agriculture, and increasing concern for the environment compete for water. Water rights regimes based on queuing principles lead to an inefficient allocation of water resources and may also result in other inefficiencies, such as overuse of land and inadequate adoption of capital-intensive conservation technologies. Water trading based on transferable water rights has been advanced as a solution to these problems. Trading helps equalize the marginal prices faced by various water users, thereby providing information about the value of water in alternative uses and creating compatible incentives. Putting water markets into practice introduces real-world complications of transaction costs and third-party externalities. We present these complications along with some major criticisms of water markets, and actual cases of water trading are discussed. We conclude with avenues of potential future research.

Description: Land-management options for greenhouse gas removal (GGR) include afforestation or reforestation (AR), wetland restoration, soil carbon sequestration (SCS), biochar, terrestrial enhanced weathering (TEW), and bioenergy with carbon capture and storage (BECCS). We assess the opportunities and risks associated with these options through the lens of their potential impacts on ecosystem services (Nature's Contributions to People; NCPs) and the United Nations Sustainable Development Goals (SDGs). We find that all land-based GGR options contribute positively to at least some NCPs and SDGs. Wetland restoration and SCS almost exclusively deliver positive impacts. A few GGR options, such as afforestation, BECCS, and biochar potentially impact negatively some NCPs and SDGs, particularly when implemented at scale, largely through competition for land. For those that present risks or are least understood, more research is required, and demonstration projects need to proceed with caution. For options that present low risks and provide cobenefits, implementation can proceed more rapidly following no-regrets principles.

Description: Inspired by the success of evidence-based medicine, environmental scholars and practitioners have grown enthusiastic about applying a similar evidence-based approach to solve some of the world's most pressing environmental problems. An important component of the evidence-based movement is the empirical evaluation of program and policy impacts. Impact evaluations draw heavily from recent advances in the empirical study of causal relationships—the effect of one thing on another. This review highlights the key components of these advances and characterizes the way in which they contribute to better evaluations of the environmental and social impacts of environmental programs. The review emphasizes that a solid understanding of these advances is required before environmental scholars and practitioners can begin to collect the relevant data, analyze them within credible research designs, and generate reliable evidence about the effectiveness of the myriad proposed solutions to the world's environmental and social problems.

Description: Realizing a low-carbon energy future requires pervasive changes in consumer behavior. Here, we examine the role of social influence in transitioning toward new low-carbon products and practices. We review and critique five research perspectives of how social interactions affect the spread of new behaviors through social networks: diffusion of functional information across social groups; conformity to others' behaviors; dissemination by organized, resourceful social groups motivated to promote societal goods; translation of consumers' perceptions between social groups; and reflexivity of individuals' continual search for self-development and expression through lifestyle practices, including their social context and consumption. Each perspective observes different social processes and holds different implications for policies and strategies to achieve low-carbon energy transitions. No single perspective seems adequate to characterize social influence. We conclude with a set of priorities to develop an integrative framework to guide strategy and policy.

Description: Sanitation research focuses primarily on containing human waste and preventing disease; thus, it has traditionally been dominated by the fields of environmental engineering and public health. Over the past 20 years, however, the field has grown broader in scope and deeper in complexity, spanning diverse disciplinary perspectives. In this article, we review the current literature in the range of disciplines engaged with sanitation research in low- and middle-income countries (LMICs). We find that perspectives on what sanitation is, and what sanitation policy should prioritize, vary widely. We show how these diverse perspectives augment the conventional sanitation service chain, a framework describing the flow of waste from capture to disposal. We review how these perspectives can inform progress toward equitable sanitation for all [i.e., Sustainable Development Goal (SDG) 6]. Our key message is that both material and nonmaterial flows—and both technological and social functions—make up a sanitation “system.” The components of the sanitation service chain are embedded within the flows of finance, decision making, and labor that make material flows of waste possible. The functions of capture, storage, transport, treatment, reuse, and disposal are interlinked with those of ensuring equity and affordability. We find that a multilayered understanding of sanitation, with contributions from multiple disciplines, is necessary to facilitate inclusive and robust research toward the goal of sanitation for all.

Description: Australia is a mineral-rich country with low and variable rainfall and, hence, biological productivity, as well as a predominately coastal population. Since European settlement in 1788, a range of landscape impacts, species introductions, and freshwater conflicts have led to serious environmental issues. Contemporary drivers of environmental change include population growth and associated development; water use for food production; resource extraction by the fishery, forestry, mining, and oil and gas industries; and climate change. A range of international agreements have influenced domestic environmental policy, culminating in Australia's foremost piece of environmental legislation, the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. Despite sound legislative instruments and policy intentions, a range of contemporary environmental issues associated with coal seam gas extraction, freshwater allocation, fisheries, and climate change illustrate that shortcomings in resolving environmental issues and obstacles remain with regard to improving the status of the environment. Given the increasing pressures on the environment, greater oversight and efficient enforcement are needed, particularly given population projections and plans for economic development.

Description: Achieving a truly sustainable energy transition requires progress across multiple dimensions beyond climate change mitigation goals. This article reviews and synthesizes results from disparate strands of literature on the coeffects of mitigation to inform climate policy choices at different governance levels. The literature documents many potential cobenefits of mitigation for nonclimate objectives, such as human health and energy security, but little is known about their overall welfare implications. Integrated model studies highlight that climate policies as part of well-designed policy packages reduce the overall cost of achieving multiple sustainability objectives. The incommensurability and uncertainties around the quantification of coeffects become, however, increasingly pervasive the more the perspective shifts from sectoral and local to economy wide and global, the more objectives are analyzed, and the more the results are expressed in economic rather than nonmonetary terms. Different strings of evidence highlight the role and importance of energy demand reductions for realizing synergies across multiple sustainability objectives.

Description: Sustainability and gender have been prominent on the development agenda since the 1980s, but there has been little systematic study of the links between the two. This review draws on ecofeminist theory, feminist political ecology, intrahousehold literature, and natural resource management case studies and reviews to examine how gender shapes the motives, means, and opportunities for men and women to contribute to sustainability. Particular attention is given to evidence on closeness to nature, focus on conservation, rights to resources, opportunities to exploit resources, and constraints to adoption of sustainable practices. Despite early claims that women are naturally more conserving of resources, the empirical literature, in particular, gives a more mixed and nuanced picture. Conservation is influenced not only by gender but also by a host of tangible and intangible factors, including local ecology, context, and culture, that affect incentives and the ability to adopt sustainable extraction and provision practices.

Description: ▪ Abstract  No other industry in the United States uses more materials by weight than the construction industry. Because of its economic strength and societal importance, it is also a significant polluter and a target of growing stakeholder scrutiny. This review offers an extended, supply chain inclusive framework for the study of the construction industry that serves all the life-cycle stages of society's infrastructure systems, and it summarizes selected literature on the life-cycle environmental assessment of construction materials, designs, and processes. On the basis of identified knowledge gaps, a research agenda is discussed for lesser-studied questions in order to first understand and then eventually reduce the environmental impacts of construction materials, processes, and activities.

Description: Environmental cost-benefit analysis, or CBA, refers to the economic appraisal of policies and projects that have the deliberate aim of improving the provision of environmental services or actions that might affect (sometimes adversely) the environment as an indirect consequence. Vital advances have arisen in response to the challenges that environmental problems and environmental policy pose for CBA. In this article, we review a number of these developments. Perhaps most notably this includes continuing progress in techniques to value environmental changes. Growing experience of these methods has resulted in, on the one hand, ever greater sophistication in application and, on the other hand, scrutiny regarding their validity and reliability. Distributional concerns have led to a renewal of interest in how appraisals might throw light on questions about equity as well as efficiency, and there have been substantial new insights for discounting costs and benefits in the far-off future. Uncertainty about what is lost when environmental assets are degraded or depleted has resulted in a number of distinct proposals although precaution is the watchword in each. Just as importantly, there is a need to understand when CBA is used in practice and why environmental decisions are often made in a manner apparently inconsistent with cost-benefit thinking.

Description: ▪ Abstract  This review surveys five major efforts to identify and declare values essential to global sustainability; describes empirical trends (as measured by multinational and global-scale surveys) in values, attitudes, and behaviors related to human and economic development, the environment, and driving forces (population, affluence, technology, and entitlements); and describes empirical trends in attitudes toward contextual values that condition sustainable development (e.g., freedom and democracy, capitalism, globalization, and equality). Finally, the review identifies important barriers between attitudes and behavior; draws several conclusions regarding the value, attitudinal, and behavioral changes needed to achieve global sustainability; and suggests future research directions.

Description: ▪ Abstract  One of the most important aspects of the rise of post-1945 global capitalism has been the call for transnational corporations to conform to basic human rights principles. This chapter reviews the efforts within the oil industry (with a particular focus on their operations in the less-developed countries) to develop corporate social responsibility and the related development of voluntary, legal, and statutory programs by governments, nongovernmental organizations (NGOs), civic groups, and multilateral agencies to ensure that the oil industry is compliant with important human, social, political, and environmental rights. In reviewing these developments, I outline the current political economy of the oil industry, new bodies of research on the relations between oil, violence, and human rights violations, which include case studies of the human rights records of transnational and joint-venture oil operations.

Description: The electric power sector around the world is undergoing long-term technical, economic, and market transformations. Part of these transformations is the challenge of integrating high shares of renewable energy, particularly variable wind and solar. The concept of flexibility of a power system is key in terms of balancing these variable sources while keeping the lights on. On the supply side, flexibility arises from innovations in flexible coal and gas power plants, energy storage, and renewables. On the demand side, many distributed resources—generation, flexible demand, storage, and electric vehicles—can also contribute, and likewise transmission and distribution networks, grid operations, and market designs. Experience with measures and innovations for grid integration in all these categories is given, from several jurisdictions like Germany, Denmark, and California, where renewables already provide 20–40% shares of electricity and plans to reach 50% exist. Questions point to areas of technology, economics, planning, operations, business, and policy that need further understanding and learning from experience.

Description: Biodiversity conservation interventions often aim to benefit both nature and people; however, the social impacts of these interventions remain poorly understood. We reviewed recent literature on the social impacts of four marine conservation interventions to understand the synergies, tradeoffs, and equity (STE) of these impacts, focusing on the direction, magnitude, and distribution of impacts across domains of human wellbeing and across spatial, temporal, and social scales. STE literature has increased dramatically since 2000, particularly for marine protected areas (MPAs), but remains limited. Few studies use rigorous counterfactual study designs, and significant research gaps remain regarding specific wellbeing domains (culture, education), social groups (gender, age, ethnic groups), and impacts over time. Practitioners and researchers should recognize the role of shifting property rights, power asymmetries, individual capabilities, and resource dependency in shaping STE in conservation outcomes, and utilize multi-consequential frameworks to support the wellbeing of vulnerable and marginalized groups.

Description: This article examines renewable energy (RE) technologies in a multiple-objective framework of sustainable development. We begin by locating RE in a portfolio of options available for climate change mitigation. Observing current trends in technologies, deployment levels, and costs, we discuss the future deployment levels envisioned in mitigation scenarios. We focus on biomass, given its importance in climate mitigation scenarios and because of the ongoing debates about its role in sustainability objectives. We also examine trends and successes in RE support policies. We conclude by linking the multiple objectives of sustainability to multiple policy instruments, emphasizing the need to closely consider the interaction between different policy instruments incentivizing sustainable development.

Description: ▪ Abstract  The effect of anthropogenic emissions from activities, such as fossil-fuel, biomass, and biofuel burning; transportation; and land-clearing; have a profound impact on the climate system. The impact of these activities is manifested in observed changes in temperature, precipitation, sea-level rise, melting of glaciers, air quality, health, and agriculture yields, to name a few. The obvious question to ask is the role that these different processes play in affecting climate and what action could one impose to curtail or constrain adverse human impacts on climate. Greenhouse gases have long been studied, as they play a major role in changing climate. But over the past 10–20 years, aerosols have emerged as the other big contenders in climate change studies. This review focuses on the current understanding of the effects of aerosols on climate, with an emphasis on the thermodynamical and indirect aerosol effects. We also examine available measurements that could be used to decipher the aerosol influence on climate, with an outlook on how the uncertainties in aerosol effects may impact future climate predictions and policy changes.

Description: Transportation systems contribute significantly to air pollution and ∼15% globally and ∼25% in the United States to emissions climate-changing gases. In the United States, the Corporate Average Fuel Economy (CAFE) standards for motor vehicles were significantly raised in 2012 for the first time in almost three decades. The standards now call for an average across manufacturers of 54.5 miles per gallon (mpg) for new passenger cars by 2025, or 163 grams per mile (g/mi) of greenhouse gas (GHG) emissions, and of 47 mpg (196 g/mi) by 2021. The light truck standards, which include minivans and sport utility vehicles, call for fuel economy levels of 31 mpg (287 g/mi) in 2021 and of 40 mpg (222 g/mi) in 2025. Given approximately equal expected splits between car and light truck sales, these estimates imply combined car and light truck fleet averages of ∼40 to 41 mpg (217 to 222 g/mi) in 2021 and 50 mpg (178 g/mi) in 2025. However, because automakers have strategies to reduce GHGs in parallel with fuel economy, the actual in-use fuel economy of the fleet is expected to be somewhat lower. In this review, several automobile technology advances are described and assessed for providing relatively cost-effective solutions to meet CAFE standards for fuel economy and GHG reductions through 2025. The key points this review makes are that (a) loopholes in the current regulations will allow automakers to meet CAFE program goals with relatively minor incremental improvements to current technologies through 2025 and that (b) going beyond the current program, past 2025 to higher fuel economy levels and lower GHG emissions approaching 100 g/mi, is likely to involve heavier use of newer technologies especially including drivetrain electrification.

Description: Water security is a major challenge for science and society. We review the rapidly growing literature on water security from the perspective of risk science and management. Competing definitions and indicators of water security reflect unsettled conceptual and methodological issues. However, risk concepts have become prevalent in defining water security; measuring it quantitatively; tracking indicators of hazards, exposure, and vulnerability; and informing management options to reduce water-related risks. We examine water security indicators and indices to identify thresholds for water-related risks across multiple dimensions of water security and examine how these vary across different scales and socioeconomic contexts. Water security indicators reveal a disparity in hazards and vulnerability across geographic and political-economic conditions. Recognition of water security as a major societal challenge has been closely followed by a strong commitment to academic, government, development, and policy responses. Pathways to water security capture the sequence of investments in institutions and infrastructure to reduce water-related risks and manage trade-offs. Two well-studied water management case studies illustrate the pathways to water security and the need for more systematic comparative assessment.

Description: We review the literature that investigates the relationship between foreign direct investment (FDI) and the environment. After reviewing the theoretical literature, we discuss two broad strands of research. First, the impact of environmental regulations on the choice of plant location and second, the impact of FDI on the emissions of various pollutants and the related question of whether we can observe environmental spillovers from foreign to domestic firms. Finally, we review the more recent literature on environmental outsourcing as an alternative to FDI and conclude with suggestions for future research.

Description: The extent to which natural capital can be substituted with manufactured or human capital in production is a key determinant of the possibility of long-run sustainable economic development. We review empirical literature pertaining to the degree of substitutability between natural capital and other forms of capital. We find that most available substitutability estimates do not stand up to careful scrutiny. Moreover, accurate substitutability estimates are even more difficult to produce for unpriced or mispriced resources. Finally, we provide evidence from industrial energy use, and agricultural land use, that suggests substitutability of natural capital with other forms of capital may be low to moderate.

Description: We compile global data to examine the current status, trends, threats, and opportunities in the world's wild-capture fisheries. We find that global fisheries have largely diverged—well-managed, often industrial fisheries tend to be in reasonably good health, while coastal fisheries, often from low-governance regions, tend to be in poor health. Good governance seems to play a central role, and we summarize key findings from the literature on how effective fishery management can simultaneously increase food security, livelihoods, and conservation outcomes. Other solutions, such as marine protected areas and big data, can be useful but will not, by themselves, solve the main fishery challenges. We conclude by examining notorious threats, such as climate change and lack of governance on the high seas, and find that these can be largely neutralized with good fishery management, suggesting that overall, the future of wild fisheries can be bright with effective fishery management interventions.

Description: Water managers and planners are slowly beginning to change their perspective and perceptions about how best to meet human needs for water; they are shifting from a focus on building supply infrastructure to improving their understanding of how water is used and how those uses can best be met. This review discusses definitions of water use, explores the history of water use around the world and in characteristic regions, identifies problems with collecting and analyzing water data, and addresses the question of improving water-use efficiency and productivity in different regions and economic sectors. There is growing interest on the part of water managers around the world to implement these approaches to lessen pressures on increasingly scarce water resources, reduce the adverse ecological effects of human withdrawals of water, and improve long-term sustainable water use.

Description: ▪ Abstract  Although human-induced changes to the global environment and natural biotic resources, collectively labeled “global change” and the “biodiversity crisis,” have accelerated with industrialization over the past 300 years, such changes have a much longer history. Particularly since the rise of agriculturally based societies and associated population expansion during the early Holocene, humans have had cumulative and often irreversible impacts on natural landscapes and biotic resources worldwide. Archaeologists, often working closely with natural scientists in interdisciplinary projects, have accumulated a large body of empirical evidence documenting such changes as deforestation, spread of savannahs, increased rates of erosion, permanent rearrangements of landscapes for agriculture, resource depression and depletion (and in many cases, extinction) in prehistory. In some areas and time periods, environmental change led to long-term negative consequences for regional human populations, whereas in other cases, changes favored intensification of production and increased population sizes. Drawing upon case studies from North America, Mesoamerica, the Mediterranean, Near East, India, Australia, and the Pacific Islands, the diversity of types of prehistoric human-induced environmental change is assessed, along with the kinds of empirical evidence that support these interpretations. These findings have important implications both for the understanding of long-term human socioeconomic and political changes and for ecologists who need to assess current environmental dynamics in the context of longer-term environmental history.

Description: ▪ Abstract  This review examines experience with private-sector participation (PSP) in the water supply and sanitation (W&S) sector. Common ideological, theoretical, and practical justifications for and objections to PSP in water and sanitation are presented. Review of empirical evidence suggests that where gains in efficiency, investment, and environmental stewardship have been realized through privatization, they have often been achieved through unpopular yet predictable strategies such as retrenchment and tariff increases. Challenges persist regarding ensuring access to and affordability of services for low-income households during privatization, and evidence suggests that PSP will not benefit the majority of the 1.2 billion people who lack access to improved water supply and live in the world's poorest countries. The challenging features of W&S economics, along with mounting public opposition to privatization and globalization in the sector, will likely reduce PSP in the sector over the short term, particularly where the private sector is expected to assume commercial risk as well as responsibility for capital investment in municipal W&S networks.

Description: Most modeling studies on terrestrial feedbacks to warming over the twenty-first century imply that the net feedbacks are negative—that changes in ecosystems, on the whole, resist warming, largely through ecosystem carbon storage. Although it is clear that potentially important mechanisms can lead to carbon storage, a number of less well-understood mechanisms, several of which are rarely or incompletely modeled, tend to diminish the negative feedbacks or lead to positive feedbacks. At high latitudes, negative feedbacks from forest expansion are likely to be largely or completely compensated by positive feedbacks from decreased albedo, increased carbon emissions from thawed permafrost, and increased wildfire. At low latitudes, negative feedbacks to warming will be decreased or eliminated, largely through direct human impacts. With modest warming, net feedbacks of terrestrial ecosystems to warming are likely to be negative in the tropics and positive at high latitudes. Larger amounts of warming will generally push the feedbacks toward the positive.

Description: Differentiating the impacts of climate change between 1.5°C and 2°C requires a regional and sector-specific perspective. Whereas for some regions and sectors the difference in climate variables might be indistinguishable from natural variability, other areas especially in the tropics and subtropics will experience significant shifts. In addition to region-specific changes in climatic conditions, vulnerability and exposure also differ substantially across the world. Even small differences in climate hazards can translate into sizeable impact differences for particularly vulnerable regions or sectors. Here, we review scientific evidence of regional differences in climate hazards at 1.5°C and 2°C and provide an assessment of selected hotspots of climate change, including small islands as well as rural, urban, and coastal areas in sub-Saharan Africa and South Asia, that are particularly affected by the additional 0.5°C global mean temperature increase. We interlink these with a review of the vulnerability and exposure literature related to these hotspots to provide an integrated perspective on the differences in climate impacts between 1.5°C and 2°C.

Description: I review the shocking current status of terrestrial mammals and then describe an approach to solving it, embracing a continuum of spatial and intellectual scales, from groundedness to geopolitics. Starting with an illustrative arena, the interface between agriculture and wildlife, I then outline the litany of threats to mammals and some successful approaches to their conservation, and document some broad-scale patterns regarding ecosystems, the mammalian communities within, and some implications for conservation. Observing that the battle for mammalian conservation is being badly lost, I dedicate the third part of this article to a combination of top-down and bottom-up, interdisciplinary studies, aspiring to a holistic approach that sets conservation in the wider sphere of the human enterprise and that I term transdisciplinary conservation.

Description: This review focuses on transnational governance in the minerals and mining sector. Although several initiatives have emerged to address specific governance challenges in this sector, knowledge of these efforts is piecemeal and little is known about patterns in transnational governance development across this issue area. We address these gaps by reviewing the extant research literature and analyzing empirical examples of transnational minerals and mining governance, using the gold sector as an illustrative case. We identify the social, humanitarian, security, and environmental problems manifest along the mineral lifecycle and consider the extent to which existing transnational governance initiatives address these issues. We call for future scholarship that addresses the diversity of transnational governance practices in the minerals and mining sector and explains emergent patterns in the particular forms of governance that dominate this issue area, as well the types of problems that have (and have not) received attention.

Description: Digitalization has opened up a wealth of new goods and services with strong consumer appeal alongside potential emission-reduction benefits. Examples range from shared, on-demand electric mobility and peer-to-peer trading of electricity, food, and cars to grid-responsive smart appliances and heating systems. In this review, we identify an illustrative sample of 33 digital consumer innovations that challenge emission-intensive mainstream consumption practices in mobility, food, homes, and energy domains. Across these domains, digital innovations offer consumers a range of potentially appealing attributes from control, choice, and convenience to independence, interconnectedness, and integration with systems. We then compile quantitative estimates of change in activity, energy, or emissions as a result of consumers adopting digital innovations. This novel synthesis of the evidence base shows clear but variable potential emission-reduction benefits of digital consumer innovations. However, a small number of studies show emission increases from specific innovations as a result of induced demand or substitution effects that need careful management by public policy. We also consider how concurrent adoption of digital consumer innovations across mobility, food, homes, and energy domains can cause broader disruptive impacts on regulatory frameworks, norms, and infrastructures. We conclude by arguing for the importance of public policy in steering the digitalization of consumer goods and services toward low-carbon outcomes.

Description: Despite hazard mitigation efforts and scientific and technological advances, extreme weather events continue to cause substantial losses. The impacts of extreme weather result from complex interactions among physical and human systems across spatial and temporal scales. This article synthesizes current interdisciplinary knowledge about extreme weather, including temperature extremes (heat and cold waves), precipitation extremes (including floods and droughts), and storms and severe weather (including tropical cyclones). We discuss hydrometeorological aspects of extreme weather; projections of changes in extremes with anthropogenic climate change; and how social vulnerability, coping, and adaptation shape the societal impacts of extreme weather. We find four critical gaps where work is needed to improve outcomes of extreme weather: (a) reducing vulnerability; (b) enhancing adaptive capacity, including decision-making flexibility; (c) improving the usability of scientific information in decision making, and (d) understanding and addressing local causes of harm through participatory, community-based efforts formulated within the larger policy context.

Description: This review critically assesses a large and growing literature on multiactor environmental governance. The first section provides an historical and conceptual background to the observed increase in such arrangements. The second section describes the diversity of governance arrangements and the related actor constellations to address environmental issues, and the third section offers some explanations for the origins, form, and effectiveness of multiactor governance arrangements. The conclusion reflects on some of the key challenges in advancing and deepening research in this area and suggests some fruitful avenues for future work.

Description: Understanding the cultural dimensions of climate change requires understanding its religious aspects. Insofar as climate change is entangled with humans, it is also entangled with all the ways in which religion attends human ways of being. Scholarship on the connections between religion and climate change includes social science research into how religious identity figures in attitudes toward climate change, confessional and constructive engagements of religious thought with climate change from various communities and traditions, historical and anthropological analyses of how climate affects religion and religion interprets climate, and theories by which climate change may itself be interpreted as a religious event. Responses to climate change by indigenous peoples challenge the categories of religion and of climate change in ways that illuminate reflexive stresses between the two cultural concepts.

Description: This chapter reviews recent literature assessing the impacts of regulatory policies on the environmental performance of manufacturing firms. After showing substantial industry and national variation in resource consumption and pollution impacts, the review examines the role environmental policy instruments play in changing industry's burdens on the environment. Policies clearly shape industrial impacts, although the effect seems to be diminishing. Moving to uncouple economic and environmental performance, the review examines how regulations affect competitiveness, innovation, and capital flight. Similarly, corporate environmental voluntarism promises—and sometimes delivers—improved environmental performance; however, meaningful indicators are still few and far between. The article concludes with a call for research that further explains why some sectors perform better than others, and what lessons policy makers can draw upon, especially to move firms toward the best performance that is technologically possible and environmentally sustainable.

Description: Despite their heterogeneity, small island developing states (SIDS) are recognized as being particularly at risk to climate change, and, as they share numerous common traits, the United Nations recognizes them as a special group. SIDS have been quite vocal in calling attention to the challenges they face from climate change and advocating for greater international ambition to limit global warming. Here, we unpack factors that are helpful in understanding the relationship between climate change and SIDS through a review of studies that span disciplines and methodologies. We assess patterns of hazards, exposure, and vulnerability; impacts and risks; awareness and knowledge; adaptation planning and implementation; mitigation; loss and damage; and climate justice to provide an overarching review of literature on climate change and SIDS.

Description: Corruption significantly affects the large majority of countries, and it has negative social and economic impacts. Its impacts on environmental and resource management (ERM) sectors are less well understood. We review corruption in the extractive industries, irrigation, agriculture, forestry, fisheries, and conservation activities with a focus on the management of protected areas and the wildlife trade. There is significant evidence that corruption in ERM sectors is systemic. Corruption in these sectors has significant negative environmental and economic impacts, which can be expected to result in negative social impacts. Many of the anti-corruption policies proposed for the ERM sectors draw on the principal-agent theory. The political science literature on corruption found that theory to have limited application when corruption is systemic and the principal is corrupt. The analysis of corruption and anti-corruption in countries with systemic corruption should draw to a greater extent on collective action theory to identify more effective policies. We highlight some anti-corruption policies relevant to ERM sectors.

Description: To appreciate the beauty or the fragility of our environment and our cultural responses to it, we need to understand how artists have portrayed the environment in the past and how they are continuing to portray it in the present. Environmental art is presented in this paper as a new genre to describe works of art that are not only directly representational of the environment (e.g., Constable's Cloud Series or Monet's London Series) but also works of art that are clearly nonrepresentational and performative, such as Long's A Line Made by Walking or Turrell's Skyspaces. The need for an overarching new genre to describe nonrepresentational performative environmental art is more obvious because there has been a host of labels given to this type of art since the late 1960s, such as land art, earthworks, site-specific art, destination art, ecological art, eco-art, and environmental sculpture. The review is also concerned with the potential of environmental art for communicating climate change.

Description: Biological diversity of agriculture consists of several analytic levels and spatial management scales that are subject to complex interactions with global change. The complexity of interactions is related to the bidirectional impacts and influences of global land use and climate change in combination with social-environmental shifts (globalization of agricultural development; market integration; technological change; and regulation through global treaties, policies, and institutions). This article develops a conceptual framework of the complexity of interactions using four thematic nodes—biological diversity in agriculture; global change; management and scale; and social-environmental adaptation, vulnerability, and resilience. It argues for the increased relevance of this framework. Linking expanded scientific research and policy to this group of conceptual nodes yields insight into the impacts of global change on biological diversity in agriculture and into the design of conservation strategies, monitoring approaches, and sustainability policies. Future policy must anticipate interactions of biological diversity, agroecosystem complexity, and global change stemming from the acceleration and integration of region-scale land-use intensification and disintensification.

Description: Through integrative assessment, experts evaluate the state of knowledge on complex problems relevant to societies. In this review, we take stock of recent advances and challenges, rooting our analysis in climate change assessment. In particular, we consider four priorities in assessment: (a) integrating diverse evidence including quantitative and qualitative results and understanding, (b) applying rigorous expert judgment to evidence and its uncertainties, (c) exploring widely ranging futures and their connections to ongoing choices and actions, and (d) incorporating interactions among experts and decision makers in assessment processes. Across these assessment priorities, we survey past experiences, current practices, and possibilities for future experimentation, innovation, and learning. In our current era of climate and broader global change, integrative assessment can bolster decisions about contested and uncertain futures. We consider both opportunities and pitfalls in synthesizing and encompassing evidence and perspectives. Our aim is to advance transparent assessment for a sustainable future.

Description: In recent years, analytical tools and approaches to model the costs and benefits of energy storage have proliferated in parallel with the rapid growth in the energy storage market. Some analytical tools focus on the technologies themselves, with methods for projecting future energy storage technology costs and different cost metrics used to compare storage system designs. Other tools focus on the integration of storage into larger energy systems, including how to economically operate energy storage, estimate the air pollution and greenhouse gas emissions effects of storage, or understand how policy and market rules influence storage deployment and operation. Given the confluence of evolving technologies, policies, and systems, we highlight some key challenges for future energy storage models, including the use of imperfect information to make dispatch decisions for energy-limited storage technologies and estimating how different market structures will impact the deployment of additional energy storage.

Description: Communities of soil microorganisms (soil microbiomes) play a major role in biogeochemical cycles and support of plant growth. Here we focus primarily on the roles that the soil microbiome plays in cycling soil organic carbon and the impact of climate change on the soil carbon cycle. We first discuss current challenges in understanding the roles carried out by highly diverse and heterogeneous soil microbiomes and review existing knowledge gaps in understanding how climate change will impact soil carbon cycling by the soil microbiome. Because soil microbiome stability is a key metric to understand as the climate changes, we discuss different aspects of stability, including resistance, resilience, and functional redundancy.We then review recent research pertaining to the impact of major climate perturbations on the soil microbiome and the functions that they carry out. Finally, we review new experimental methodologies and modeling approaches under development that should facilitate our understanding of the complex nature of the soil microbiome to better predict its future responses to climate change.

Description: The demand for electricity—closely linked to human, social, and economic development—is expected to rise significantly in the coming decades, especially in developing countries. Coal power currently is, and is expected to remain, an important part of the global electric power mix with much of the future growth again in developing countries. At the same time, coal-based power generation results in multiple, significant externalities with human health and potential climate change impacts being particularly important. This has spurred much effort over the decades to better determine the range and value of the impacts. Although uncertainties still remain in many aspects, it has become quite clear that the existing health and potential climate impacts from coal-power use are considerable. More stringent regulations are already being enforced and planned in developed countries, and developing countries are beginning to follow suit. Improved coal-based power generation technologies (deployed often as a result of regulations) can play an important role in mitigating these impacts, but their further development and deployment is complicated by a number of interrelated factors: the urgency of the climate imperative, the lack of coherent policies, the scale and complexity of the transition to cleaner-coal power, and the level of technological effort being devoted to (or available for) such a transition. Looking ahead, even as the wait for more stringent climate policies continues, there is a need to catalyze the innovation cycle through research and development (R&D) efforts while facilitating uptake and appropriate international cooperation to ensure rapid technology adoption across the globe.

Description: The total world catch from marine and freshwater wild stocks has peaked and may be slightly declining. There appear to be few significant resources to be developed, and the majority of the world's fish stocks are intensively exploited. Many marine ecosystems have been profoundly changed by fishing and other human activities. Although most of the world's major fisheries continue to produce substantial sustainable yield, a number have been severely overfished, and many more stocks appear to be heading toward depletion. The world's fisheries continue to be heavily subsidized, which encourages overfishing and provides society with a small fraction of the potential economic benefits. In most of the world's fisheries there is a “race for fish” in which boats compete to catch the fish before a quota is achieved or the fish are caught by someone else. The race for fish leads to economic inefficiency, poor quality product, and pressure to extract every fish for short-term gain. A number of countries have instituted alternative management practices that eliminate the race for fish and encourage economic efficiency, use lower exploitation rates that deliberately do not attempt to maximize biological yield, and encourage reduced fishing costs and increased value of products. In fisheries where this transition has taken place, we see the potential for future sustainability, but in those fisheries where the race for fish continues, we anticipate further declines in abundance, further loss of jobs and fishing communities, and potential structural change to marine ecosystems.

Description: ▪ Abstract  Variability of the atmospheric and oceanic circulations in the earth system gives rise to an array of naturally occurring dynamical modes. Instead of being spatially independent or spatially uniform, climate variability in different parts of the globe is orchestrated by one or a combination of several climate modes, and global changes take place with a distinctive spatial pattern resembling that of the modes-related climate anomalies. Climate impact on the dynamics of terrestrial and marine biosphere also demonstrates clear signals for the mode effects. In this review, we view modes as an important attribute of climate variability, changes, and impact and emphasize the emerging concept that future climate changes may be manifest as changes in the leading modes of the climate system. The focus of this review is on three of the leading modes: the North Atlantic Oscillation, the El Niño-Southern Oscillation, and the Pacific Decadal Oscillation.

Description: This review explores what past environmental change in Africa—and African people's response to it—can teach us about how to cope with life in the Anthropocene. Organized around four drivers of change—climate; agriculture and pastoralism; megafauna; and imperialism, colonialism, and capitalism (ICC)—our review zooms in on key regions and debates, including desertification; rangeland degradation; megafauna loss; and land grabbing. Multiscale climate change is a recurring theme in the continent's history, interacting with increasingly intense human activities from several million years onward, leading to oscillating, contingent environmental changes and societally adaptive responses. With high levels of poverty, fast population growth, and potentially dramatic impacts expected from future climate change, Africa is emblematic of the kinds of social and ecological precariousness many fear will characterize the future globally. African people's innovation and adaptation to contingency may place them among the avant-garde with respect to thinking about Anthropocene conditions, strategies, and possibilities.

Description: The Anthropocene, the concept that the Earth has moved into a novel geological epoch characterized by human domination of the planetary system, is an increasingly prevalent framework for debate both in academia and as a wider cultural and policy zeitgeist. This article reviews the proliferation of literature surrounding this concept. It explores the origins and history of the concept, as well as the arguments surrounding its geological formalization and starting date ranging from the Pleistocene to the twentieth century. It examines perspectives and critiques of the concept from the Earth system sciences, ecological and geological sciences, and social sciences and humanities, exploring its role as a cultural zeitgeist and ideological provocation. I conclude by offering a personal perspective on the concept of the Anthropocene and its utility.

Description: This article describes the field of the detection and attribution of climate change and highlights recent progress, major issues, and future directions. The attribution of global temperature variations over the past century to a combination of anthropogenic and natural influences is now well established, with the anthropogenic factors dominating. Other aspects of the climate system, including regional quantities, are increasingly being found to also show a detectable signal of human influence. Of particular interest, though, is the attribution of changes in nonmeteorological quantities, such as hydrological and ecological measures, and of changes in the risk of extreme weather events to anthropogenic emissions. Methods are being developed for tackling these two problems but are still in the early stages. As the field gradually includes a service focus, the biggest challenges will become the integration of various approaches into an overall framework and the communication of the capabilities and limitations of that framework to the outside community.

Description: The Intergovernmental Panel on Climate Change (IPCC) conducts policy-relevant but not policy-prescriptive assessments of climate science. In this review, we engage with some of the key design features, achievements, and challenges that situate and characterize the IPCC as an intergovernmental organization that is tasked with producing global environmental assessments (GEAs). These include the process of working through consensus to assess and summarize climate science and the need to include knowledge from as many of the 195 IPCC nation-states as possible, despite the structural inequalities between developed and developing countries. To highlight salient features that are unique to the IPCC but that offer lessons for other organizations that conduct GEAs, we include case studies on the politics of climate denialism, the use of geoengineering in mitigation scenarios, and the links between adaptive capacity, adaptation, and global development. We conclude with a discussion of institutional reflexivity. We consider how the IPCC can model an ethical and participatory response to climate change by critically examining, and being transparent about, the relation between science and politics.

Description: Human habitations require energy and water, which are increasingly interdependent. Energy systems have changed from using water for mechanical energy to building dams to provide irrigation water for agriculture and hydroelectricity. Large volumes of water are required to cool thermal electricity-generating stations—whether coal, natural gas, nuclear, or solar powered. Changes in cooling technology are reducing water withdrawals while increasing water consumption. Water produced from fossil fuel production represents environmental challenges and supply opportunities. Some renewable energy sources, such as wind turbines and photovoltaics, have far lower water requirements. Increasing development of biofuels creates a direct connection between water and energy systems. Energy, mostly for pumps, is necessary for supplying potable water and treating wastewater. Pumping from deeper underground as well as removing more contaminants (e.g., medicines, agricultural chemicals) and salt requires more energy. Water and wastewater treatment can dominate electricity demand in municipalities. Water reuse requires energy for treatment and pumping. Life cycle assessments and integrated resource planning strive to account for the total impacts.

Description: Current material supply-demand imbalances are driven by situational rather than physical scarcities, resulting in a growing interest among government, civil society, and industry groups to consider not only the availability of mineral resources, but also the sustainability implications of their production. This, in turn, places increasing pressure on mining companies to broaden their concerns when planning new mining projects, covering its “social license to operate” by incorporating strategies for limiting negative socioenvironmental impacts alongside calculations of the project's economic viability as well as balancing a large number of potential stakeholders. Accordingly, understanding also the sociopolitical context of mineral development is crucial for the creation of sustainable practices within the mining industry. By applying a sustainable development framework, this article outlines the complex web of challenges associated with sustainable mineral extraction, ranging from technological and economic development to political and institutional concerns on how to govern and manage scarce resources in a globalized world.

Description: Corporate environmentalism (CE) pertains to firm-level efforts to reduce pollution and resource use along with protecting natural habitats. Importantly, firms pledge to undertake these actions beyond the requirements of the law. Although historically CE efforts focused on resource conservation, their contemporary focus is on pollution reduction to reduce direct harm to humans and their communities and on the protection of environmental sinks. We review two broad categories of CE: direct CE and indirect CE. Direct CE, whether undertaken unilaterally or collectively, pertains to firms themselves adopting policies that reduce the environmental impact of their activities, or disclosing information about their environmental performance. Indirect CE refers to policies of actors (such as financial institutions) that encourage firms seeking their resources (through loans, venture capital, etc.) to commit to environmental stewardship policies. Three key lessons emerge. First, firm-level characteristics, particularly size and economic performance, encourage CE. Second, although pressure from external stakeholders, especially environmental nongovernmental organizations (NGOs), has played an important role in discouraging policies that harm the environment, its effect on encouraging proenvironmental activities remains unclear. Third, the literature is ripe with serious methodological issues. The endogeneity between firms’ economic and environmental record and their CE efforts poses difficulty in drawing causal inferences.

Description: ▪ Abstract  The term industrial ecology was conceived to suggest that industrial activity can be thought of and approached in much the same way as a biological ecosystem and that in its ideal form it would strive toward integration of activities and cyclization of resources, as do natural ecosystems. Beyond this attractive but fuzzy notion, little has been done to explore the usefulness of the analogy. This paper examines the structural framework of biological ecology and the tools used for its study, and it demonstrates that many aspects of biological organisms and ecosystems (for example, food webs, engineering activities, community development) do have parallels in industrial organisms and ecosystems. Some of the tools of biological ecology appear to be applicable to industrial ecology, and vice versa. In a world in which no biological ecosystem is free of human influence and no industrial ecosystem is free of biological influence, it is appropriate to abandon the artificial division between the two frameworks and develop a new synthesis—Earth system ecology—as the logical construct for all of Earth's ecosystems.

Description: ▪ Abstract  This paper reviews the available data and models on energy and material flows through the world's 25 largest cities. Throughput is categorized as stored, transformed, or passive for the major flow modes. The aggregate, fuel, food, water, and air cycles are all examined. Emphasis is placed on atmospheric pathways because the data are abundant. Relevant models of urban energy and material flows, demography, and atmospheric chemistry are discussed. Earth system–level loops from cities to neighboring ecosystems are identified. Megacities are somewhat independent of their immediate environment for food, fuel, and aggregate inputs, but all are constrained by their regional environment for supplying water and absorbing wastes. We elaborate on analogies with biological metabolism and ecosystem succession as useful conceptual frameworks for addressing urban ecological problems. We conclude that whereas data are numerous for some individual cities, cross-cutting compilations are lacking in biogeochemical analysis and modeling. Synthesis of the existing information will be a crucial first step. Cross-cutting field research and integrated, multidisciplinary simulations will be necessary.

Description: ▪ Abstract  Geoengineering is the intentional large-scale manipulation of the environment, particularly manipulation that is intended to reduce undesired anthropogenic climate change. The post-war rise of climate and weather modification and the history of U.S. assessments of the CO2-climate problem is reviewed. Proposals to engineer the climate are shown to be an integral element of this history. Climate engineering is reviewed with an emphasis on recent developments, including low-mass space-based scattering systems for altering the planetary albedo, simulation of the climate's response to albedo modification, and new findings on iron fertilization in oceanic ecosystems. There is a continuum of human responses to the climate problem that vary in resemblance to hard geoengineering schemes such as space-based mirrors. The distinction between geoengineering and mitigation is therefore fuzzy. A definition is advanced that clarifies the distinction between geoengineering and industrial carbon management. Assessment of geoengineering is reviewed under various framings including economics, risk, politics, and environmental ethics. Finally, arguments are presented for the importance of explicit debate about the implications of countervailing measures such as geoengineering.

Description: ▪ Abstract  Water vapor is the dominant greenhouse gas, the most important gaseous source of infrared opacity in the atmosphere. As the concentrations of other greenhouse gases, particularly carbon dioxide, increase because of human activity, it is centrally important to predict how the water vapor distribution will be affected. To the extent that water vapor concentrations increase in a warmer world, the climatic effects of the other greenhouse gases will be amplified. Models of the Earth's climate indicate that this is an important positive feedback that increases the sensitivity of surface temperatures to carbon dioxide by nearly a factor of two when considered in isolation from other feedbacks, and possibly by as much as a factor of three or more when interactions with other feedbacks are considered. Critics of this consensus have attempted to provide reasons why modeling results are overestimating the strength of this feedback. Our uncertainty concerning climate sensitivity is disturbing. The range most often quoted for the equilibrium global mean surface temperature response to a doubling of CO2 concentrations in the atmosphere is 1.5°C to 4.5°C. If the Earth lies near the upper bound of this sensitivity range, climate changes in the twenty-first century will be profound. The range in sensitivity is primarily due to differing assumptions about how the Earth's cloud distribution is maintained; all the models on which these estimates are based possess strong water vapor feedback. If this feedback is, in fact, substantially weaker than predicted in current models, sensitivities in the upper half of this range would be much less likely, a conclusion that would clearly have important policy implications. In this review, we describe the background behind the prevailing view on water vapor feedback and some of the arguments raised by its critics, and attempt to explain why these arguments have not modified the consensus within the climate research community.

Description: ▪ Abstract  Renewable energy is shifting from the fringe to the mainstream of sustainable development. Past donor efforts achieved modest results but often were not sustained or replicated, which leads now to greater market orientation. Markets for rural household lighting with solar home systems, biogas, and small hydro power have expanded through rural entrepreneurship, government programs, and donor assistance, serving millions of households. Applications in agriculture, small industry, and social services are emerging. Public programs resulted in 220 million improved biomass cook stoves. Three percent of power generation capacity is largely small hydro and biomass power, with rapid growth of wind power. Experience suggests the need for technical know-how transfer, new replicable business models, credit for rural households and entrepreneurs, regulatory frameworks and financing for private power developers, market facilitation organizations, donor assistance aimed at expanding sustainable markets, smarter subsidies, and greater attention to social benefits and income generation.

Description: ▪ Abstract  Carbon dioxide is a radiatively active gas whose atmospheric concentration increase is likely to affect Earth's climate. CO2 is added to the atmosphere by biomass burning and the combustion of fossil fuels. Some added CO2 remains in the atmosphere. However, substantial amounts are taken up by the oceans and land biosphere, attenuating the atmospheric increase. Atmospheric O2 measurements provide one constraint for partitioning uptake rates between the ocean and the land biosphere. Here we review studies of atmospheric O2 concentration variations and discuss their implications for CO2 uptake by the ocean and the land biosphere. We compare estimates of anthropogenic carbon fluxes from O2 studies with estimates from other approaches and examine the contribution of natural ocean carbon fluxes to atmospheric O2 variations.

Description: Due to the health consequences of lead exposure, as well as to the introduction of catalytic converters, many countries have reduced or eliminated use of lead additives in motor gasolines. But in many other countries, leaded gasoline remains the norm. In these countries there is often confusion about the health significance of gasoline lead, the ability of cars to use unleaded gasoline, and the costs of unleaded gasoline. This chapter shows that leaded gasoline is a major source of human lead exposure. All cars, with or without catalytic converters, and with or without hardened exhaust valve seats, can use unleaded gasoline exclusively. Unleaded gasoline typically costs on the order of $0.01 more per liter than leaded gasoline to produce. Recent concerns about benzene exposure from unleaded gasoline have been addressed through choice of gasoline formulation and other measures.

Description: The public trust doctrine (PTD) is a legal concept with ancient roots, and it is increasingly being examined as a framework for modern conservation. At its core, the PTD is based on the idea that certain natural resources cannot be fairly or effectively managed by private owners. Rather, these resources should be held in trust by government, which must manage their consumptive use and protection on behalf of present and future citizens. Although historically the PTD applied to a limited set of natural resources such as shellfish beds and submerged lands, courts and legal scholars have expanded the definition of trust resources to include wildlife, oceans, and ecosystem services generally. The wide range of interpretations of the PTD is seen as both a weakness (because it leads to uncertainty in property ownership) and a strength (because it can adapt to accommodate emerging science about what it takes to protect ecosystems).

Description: India is a significant player in climate policy and politics. It has been vocal in international climate negotiations, but its role in these negotiations has changed over time. In an interactive relationship between domestic policy and international positions, India has increasingly become a testing ground for policies that internalize climate considerations into development. This article critically reviews the arc of climate policy and politics in India over time. It begins by examining changes in knowledge and ideas around climate change in India, particularly in the areas of ethics, climate impacts, India's energy transition, linkages with sustainability, and sequestration. The next section examines changes in politics, policy, and governance at both international and national scales. The article argues that shifts in ideas and knowledge of impacts, costs, and benefits of climate action and shifts in the global context are reflected and refracted through discourses in India's domestic and international policies.

Description: Codes of environmental management practice emerged as a tool of environmental policy in the late 1980s. Industry and other groups have developed codes for two purposes: to change the environmental behavior of participating firms and to increase public confidence in industry's commitment to environmental protection. This review examines five codes of environmental management practice: Responsible Care, the International Chamber of Commerce's Business Charter for Sustainable Development, ISO 14000, the CERES Principles, and The Natural Step. The first three codes have been drafted and promoted primarily by industry; the others have been developed by non-industry groups. These codes have spurred participating firms to introduce new practices, including the institution of environmental management systems, public environmental reporting, and community advisory panels. The extent to which codes are introducing a process of cultural change is considered in terms of four dimensions: new consciousness, norms, organization, and tools.

Description: ▪ Abstract  Ethanol made from lignocellulosic biomass sources, such as agricultural and forestry residues and herbaceous and woody crops, provides unique environmental, economic, and strategic benefits. Through sustained research funding, primarily by the U.S. Department of Energy, the estimated cost of biomass ethanol production has dropped from ∼$4.63/gallon in 1980 to ∼$1.22/gallon today, and it is now potentially competitive for blending with gasoline. Advances in pretreatment by acid-catalyzed hemicellulose hydrolysis and enzymes for cellulose breakdown coupled with recent development of genetically engineered bacteria that ferment all five sugars in biomass to ethanol at high yields have been the key to reducing costs. However, through continued advances in accessing the cellulose and hemicellulose fractions, the cost of biomass ethanol can be reduced to the point at which it is competitive as a pure fuel without subsidies. A major challenge to realizing the great benefits of biomass ethanol remains to substantially reduce the risk of commercializing first-of-a-kind technology, and greater emphasis on developing a fundamental understanding of the technology for biomass conversion to ethanol would reduce application costs and accelerate commercialization. Teaming of experts to cooperatively research key processing steps would be a particularly powerful and effective approach to meeting these needs.

Description: ▪ Abstract  Six methods for attributing ambient pollutants to emission sources are reviewed: emissions analysis, trend analysis, tracer studies, trajectory analysis, receptor modeling, and dispersion modeling. The ranges of applicability, types of information provided, limitations, performance capabilities, and areas of active research of the different methods are compared. For primary, nonreactive pollutants whose effects of concern occur on a global scale, an accounting of emissions rates by source type and location largely characterizes source contributions. For other pollutants or smaller spatial scales, accurate estimates of emissions are needed for identifying the emissions reduction potentials of possible control measures and as inputs to dispersion models. Emission levels are frequently known with factor-of-two accuracy or worse, and improved estimates are needed for dispersion modeling. The analysis of regional or urban-scale trends in emissions and ambient pollutant concentrations can provide qualitative information on source contributions, but quantitative results are limited by the confounding influence of variations in meteorology and uncertainties in the areas over which emissions affect concentrations. Tracer studies are useful for quantifying dispersion characteristics of plumes, qualitatively characterizing transport directions, and providing empirical data for evaluating trajectory and dispersion models. Data are usually temporally limited to a short study period, typically do not provide information on vertical pollutant distributions, and are most applicable to the transport of primary, nonreactive pollutants. Trajectory analyses are routinely used to estimate atmospheric transport directions. Trajectory errors of about 20% of travel distance are considered typical of the better models and data sets. Receptor models use measurements of ambient pollutant concentrations to quantify the contributions of different source types to primary particulate matter or volatile organic compounds, or to characterize source-region contributions to a single pollutant. Accuracy rates of ∼30% are often achieved when quantifying the contributions from different types of emission sources. Dispersion models are well-suited for estimating quantitative source-receptor relationships, as the effects of individual emission sources or source regions can be studied. Lagrangian and Gaussian dispersion models are computationally efficient and can simulate the transport of nonreactive primary or linear secondary species. Eulerian models are computationally intensive but lend themselves to the simulation of nonlinear chemistry. Careful evaluation of modeling accuracy is needed for a model application to fulfill its potential for source attribution. Accuracy can be evaluated through a combination of performance evaluation, sensitivity analysis, diagnostic evaluation, and corroborating analyses.

Description: ▪ Abstract  Industrial symbiosis, as part of the emerging field of industrial ecology, demands resolute attention to the flow of materials and energy through local and regional economies. Industrial symbiosis engages traditionally separate industries in a collective approach to competitive advantage involving physical exchange of materials, energy, water, and/or by-products. The keys to industrial symbiosis are collaboration and the synergistic possibilities offered by geographic proximity. This paper reviews the small industrial symbiosis literature and some antecedents, as well as early efforts to develop eco-industrial parks as concrete realizations of the industrial symbiosis concept. Review of the projects is organized around a taxonomy of five different material exchange types. Input-output matching, stakeholder processes, and materials budgeting appear to be useful tools in advancing eco-industrial park development. Evolutionary approaches to industrial symbosis are found to be important in creating the level of cooperation needed for multi-party exchanges.

Description: ▪ Abstract  An ultimate limit on the extent that biomass fuels can be used to displace fossil transportation fuels, and their associated emissions of CO2, will be the land area available to produce the fuels and the efficiencies by which solar radiation can be converted to useable fuels. Currently, the Brazil cane-ethanol system captures 33% of the primary energy content in harvested cane in the form of ethanol. The US corn-ethanol system captures 54% of the primary energy of harvested corn kernels in the form of ethanol. If ethanol is used to substitute for gasoline, avoided fossil fuel CO2 emissions would equal those of the substituted amount minus fossil emissions incurred in producing the cane- or corn-ethanol. In this case, avoided emissions are estimated to be 29% of harvested cane and 14% of harvested corn primary energy. Unless these efficiencies are substantially improved, the displacement of CO2 emissions from transportation fuels in the United States is unlikely to reach 10% using domestic biofuels. Candidate technologies for improving these efficiencies include fermentation of cellulosic biomass and conversion of biomass into electricity, hydrogen, or alcohols for use in electric drive-train vehicles.

Description: ▪ Abstract  The field of restoration ecology represents an emerging synthesis of ecological theory and concern about human impact on the natural world. Restoration ecology can be viewed as the study of how to repair anthropogenic damage to the integrity of ecological systems. However, attempts to repair ecological damage should not diminish protection of existing healthy ecosystems. Restoration ecology allows for the testing of ecological theories; however, restoration ecology is not limited to, nor is it a subdiscipline of, the field of ecology. Restoration ecology requires approaches that integrate ecology and environmental sciences, economics, sociology, and politics. This review illustrates these points by providing a conceptual map of the origin, present practices, and future directions of the field.

Description: Weighing functions are extremely useful tools for evaluating the relative effects of gases affecting global atmospheric ozone and climate. In particular. the concepts of Ozone Depletion Potentials (OOPs) and Global Warming Potentials (GWPs) are extensively used in policy consideration and scientific studies of the ozone and climate issues. OOPs provide a relative measure of the expected cumulative impact on stratospheric ozone from trace gas emissions, and are being used to examine the relative effects on ozone from CFCs, halons and other halocarbons currently being used and to evaluate the potential effects of possible replacement compounds. GWPs provide a means for comparing the relative effects on climate expected from various greenhouse gases. This chapter examines these weighing functions and other indices being used in evaluating concerns about global ozone and climate, discusses the science underlying these indices, and presents the current state-of-the-art for numerical indices and their uncertainties.

Description: ▪ Abstract  During the period 1995–1999, the President's Committee of Advisors on Science and Technology (PCAST) produced three major energy studies, at President Clinton's request. The panels that conducted these studies were broadly constituted from the academic, industrial, and NGO (nongovernmental organization) sectors, and their recommendations were unanimous. These efforts (a) helped lay the foundation for several major energy initiatives of the second Clinton term, including the Climate Change Technology Initiative, the Nuclear Energy Research Initiative, and the International Clean Energy Initiative; (b) helped launch energy R&D activities on methane hydrates and geological sequestration of carbon dioxide; and (c) strengthened related activities, such as the Partnership for a New Generation of Vehicles, the Partnership for Advancing Technologies in Housing, the fossil power Vision-21 Program, and the National Bioenergy Initiative. Federal budgets for research, development, demonstration, and deployment of advanced energy technologies have increased substantially over the past four years, but they still fall short of PCAST's recommendations; and a number of the PCAST recommendations on matters other than budget have yet to be fully implemented. The PCAST energy studies demonstrate the possibility of forging consensus around key energy issues and provide a foundation on which, it is hoped, the continuing pursuit of a coherent national policy on energy innovation will be able to build.

Description: ▪ Abstract  This paper reviews the empirical evidence for the following five hypotheses from the economic growth-liberalization-pollution debate: (a) economic growth will lead to a worsening pollution problem; (b) tighter environmental regulation will reduce economic growth; (c) trade liberalization will exacerbate environmental degradation, especially in developing countries with weak environmental protection; (d) tighter environmental protection in the developed countries will lead to a loss of competitiveness compared with that of countries with lower standards, especially in polluting industries; and (e) tighter environmental protection in the developed countries will lead to relocation of investment to developing countries with lax regulation, especially in polluting industries (the pollution haven hypothesis). Overall, the evidence for these hypotheses is found to be ambiguous and weak. It is further suggested that the growth-liberalization-environment empirical literature has neglected three important elements: (a) environmental innovation, (b) the international diffusion of environmental technologies, and (c) the economic benefits of a cleaner environment. Future research should integrate these elements into the debate. Analyses of endogenous environmental innovation in response to environmental policy, the tradable nature of environmental technologies, the role of trade and foreign direct investment as channels of environmental-technology transfer to developing countries, the effects of local environmental policies in encouraging the adoption of such technologies in developing countries, and the economic benefits of a cleaner environment would contribute to the development of sound, well-coordinated economic and environmental policies.

Description: [Figure: see text] ▪ Abstract  An analysis of the forces that have shaped energy and energy-related environmental policies is presented through the eyes of an active participant in their evolution over the past 53 years. The problem of self-interest in taking energy and environmental policy positions is addressed candidly. The “energy crisis” is cited as an example. Its credibility depended on excessive demand projections, coupled with erroneous assessments of US and global hydrocarbon resources and of prospects for making these resources economically recoverable through technology advances. Many energy crisis proponents benefited from the misguided government response and from the large investments in uneconomic synthetic fuel technologies. Today, proponents of catastrophic anthropogenic climate change, again claiming scientific consensus, threaten to create even greater energy market distortions at large social and economic costs. The author traces his conversion to energy contrarian to the general failure of consensus and to his own misjudgments in these critical policy areas.

Description: ▪ Abstract  Growing urban transport congestion is a major cause of environmental problems, as well as delays. One may argue that this is a classic problem of externalities and can be readily corrected by means of the price mechanism. However, although interest is increasing in pricing as an element in any solution, the answer is not so easy. Despite the falling cost of microelectronics, urban road pricing remains complex, expensive to administer, and politically controversial. Nevertheless, modeling exercises and limited practical experience suggest that most, if not all, of these problems can now be overcome and that road pricing may now be successfully implemented. But the continued opposition to road pricing makes consideration of the alternatives necessary. Indeed, both for political and economic reasons, road pricing appears much more likely to be successfully implemented as part of a package of measures than in isolation.

Description: [Figure: see text] ▪ Abstract  FAUST: Ich fühl's, vergebens hab' ich alle Schätze Des Menschengeists auf mich herbeigerafft, Und wenn ich mich am Ende niedersetze, Quilt innerlich doch keine neue Kraft; Ich bin nicht um ein Haar breit höher, Bin dem Unendlichen nicht näher. Goethe's Faust, Part I, lines 1810–15. 1 A dedication to research in the physical sciences together with the circumstances of World War II, led me into theoretical and observational studies of the global physical climate. For all practical purposes, I was on my own when working in Cambridge and London, England, and I went whereever my interests led me. I organized three atmospheric observatories (two in England). I have also worked at many astronomical observatories. As time progressed, I became increasingly involved in studies of atmospheric radiation as a controlling factor for the Earth's climate. I am often taken to be a specialist in atmospheric radiation, but I have never regarded it as more than an important element in climate studies. But radiative transfer and global questions did not become important for climate science until later, and in the 1950s and 1960s I found myself drawn to studies of planetary atmospheres as an arena in which my skills were of central importance. Mars and Venus were the focus of my work for many years, and I was partly responsible for launching the Pioneer Venus mission, which placed probes into the Venus atmosphere in 1978. Much later, the experience I gained in space instrumentation and in the structure of atmospheres led me back to climate science, where I started. Then my interest was in observing the climate and testing the credibility of climate predictions. I still maintain some activity in this field. Outside these research activities, I created a Center for Earth and Planetary Physics at Harvard University to take over the activities of the Blue Hill Observatory, when that Observatory ceased to be a viable facility. The purpose of the Center was to teach earth science in the context of the discipline of physical science. The Center had some notable achievements but eventually had to give way to requirements for environmental sciences in the University, a change that I regret. During my active life in the United States, I invested a great deal of effort in support of the work of the National Research Council (NRC), including many years spent on report review. I am increasingly troubled by the postmodern view of science that appears to dominate these activities. But that may be no more than a biased rosy view of the past with its exciting early experiences and hopes.