Annual Review of Environment and Resources - Volume 40, 2015

Patterns of abundance, biomass, and species richness are reviewed for deep-sea ecosystems. Long-term monitoring studies have indicated that deep-sea ecosystems are sensitive to climatic variability through its influence on the quantity and quality of surface primary production. The potential impacts of climate change, through its effects on primary production and through changes in the temperature, pH, and oxygenation of the deep ocean are explored. It is concluded that deep-sea ecosystems are likely to be highly sensitive to changes in food supply and the physical environment driven by global climate change. As a result, ecosystem services will be negatively impacted with likely positive feedbacks to atmospheric CO2 levels. It is a matter of urgency that baselines are established for diversity, abundance, and biomass of deep-sea ecosystems, particularly for the pelagic realm and that a mechanistic understanding is developed of how food supply and physical parameters affect community structure and function.

Rewilding is being promoted as an ambitious alternative to current approaches to nature conservation. Interest is growing in popular and scientific literatures, and rewilding is the subject of significant comment and debate, outstripping scientific research and conservation practice. Projects and research are found the world over, with concentrations in Europe, North America, and on tropical islands. A common aim is to maintain, or increase, biodiversity, while reducing the impact of present and past human interventions through the restoration of species and ecological processes. The term rewilding has been applied to diverse concepts and practices. We review the historical emergence of the term and its various overlapping meanings, aims, and approaches, and illustrate this through a description of four flagship rewilding case studies. The science of rewilding has centered on three different historical baselines: the Pleistocene, the Holocene, and novel contemporary ecosystems. The choice of baseline has differing implications for conservation in a variety of contexts. Rewilding projects involve a range of practical components—such as passive management, reintroduction, and taxon substitution—some of which have attracted criticism. They also raise a series of political, social, and ethical concerns where they conflict with more established forms of environmental management. In conclusion, we summarize the different goals, approaches, tools, and contexts that account for the variations in rewilding and identify priorities for future research and practice.

Soils represent a significant reservoir of biological diversity that underpins a broad range of key processes and moderate ecosystem service provision. Our understanding of the role that soil organisms play in ecosystems is still developing, but the increased investigation into biodiversity-ecosystem functioning relationships in soils over the past couple of decades has provided insights that have greatly enhanced our ability to sustainably manage soil biodiversity. In this review, we synthesize emerging knowledge of soil biodiversity as a natural resource that supports the functioning of terrestrial ecosystems and their delivery of ecosystem services. We explore how environmental changes alter soil biodiversity and how this in turn can affect ecosystem processes as well as resistance and resilience to environmental changes. We then discuss ways to include soil biodiversity in management strategies for sustainable production and biodiversity conservation. We conclude by highlighting key research challenges to further improve our knowledge of soil biodiversity and its management.

The Anthropocene is characterized by a widespread biodiversity crisis that is rivaling prehistoric mass extinctions. Amphibians are the most threatened class of vertebrates. In addition to traditional threats such as land-use conversion and pollution, climate change and introduced diseases are expected to further reduce amphibian biodiversity. The fungal disease chytridiomycosis has caused the rapid extirpation of tens to possibly hundreds of amphibian species. Recent advances have revealed a deep evolutionary history and considerable variation in the virulence of strains of the fungal pathogen, patterns that need to be reconciled with the rapid spread of disease and demise of host populations. A conservation priority is surveillance of a newly discovered species of chytrid fungus that is killing European salamanders. The accelerated discovery of new amphibian species challenges existing conservation resources, but it is an opportunity to fill geographical gaps and to enhance programs aimed at preserving amphibian biodiversity.

Approximately 40% of the global population relies on traditional bioenergy, accounting for 9% of global energy use and 55% of global wood harvest. However, knowledge about the environmental impacts of traditional bioenergy is fragmented. This review addresses several persistent questions and summarizes recent research on land cover change (LCC) and pollution emissions resulting from traditional bioenergy use. We also review recent studies analyzing transitions from traditional bioenergy to cleaner stoves and fuels.

Between 27 and 34% of the wood fuel harvest in 2009 was unsustainable, with large geographical variations. Almost 300 million rural people live in wood fuel “hotspots,” concentrated in South Asia and East Africa, creating risks of wood-fuel-driven degradation. Different fuels and stoves show variation in climate-forcing emissions. Many, but not all, nontraditional stoves result in lower emissions than traditional models. Traditional bioenergy makes substantial contributions to anthropogenic black carbon (BC) emissions (18–30%) and small contributions to total anthropogenic climate impacts (2–8%). Transitions from traditional fuels and devices have proven difficult. Stacking, i.e., the use of multiple devices and fuels to satisfy household energy needs, is common, showing the need to shift stove interventions from the common approach that promotes one fuel and one device to integrated approaches that incorporate deep understanding of local needs and practices, and multiple fuels and devices, while monitoring residual use of traditional technologies.

We outline the frameworks that shape and hold apart waste debates in and about the Global North and Global South and that hinder analysis of flows between them. Typically, waste is addressed as municipal waste, resulting in a focus on domestic consumption and urban governance and an emphasis on cities and the national scale. The prevailing ways of addressing the increasingly global flows of wastes between the North and South are those of global environmental justice and are underpinned by the geographical imagination encoded in the Basel Convention. New research on the trades in used goods and recycling in lower income countries challenges these accounts. It shows that arguments about dumping on the South need revision. Wastes are secondary resources for lower income countries, harvesting them is a significant economic activity, and consequent resource recovery is a key part of the global economy. Four areas for future research are identified: (a) changing patterns of global harvesting, (b) attempts to rescale resource recovery and the challenges faced, (c) the geopolitics of resource recovery, and (d) changes in resource recovery in lower income countries.

The livestock and environment nexus has been the subject of considerable research in the past decade. With a more prosperous and urbanized population projected to grow significantly in the coming decades comes a gargantuan appetite for livestock products. There is growing concern about how to accommodate this increase in demand with a low environmental footprint and without eroding the economic, social, and cultural benefits that livestock provide. Most of the effort has focused on sustainably intensifying livestock systems. Two things have characterized the research on livestock and the environment in the past decade: the development of increasingly disaggregated and sophisticated methods for assessing different types of environmental impacts (climate, water, nutrient cycles, biodiversity, land degradation, deforestation, etc.) and a focus on examining the technical potential of many options for reducing the environmental footprint of livestock systems. However, the economic or sociocultural feasibility of these options is seldom considered. Now is the time to move this agenda from knowledge to action, toward realizable goals. This will require a better understanding of incentives and constraints for farmers to adopt new practices and the design of novel policies to support transformative changes in the livestock sector. It will also require novel forms of engagement, interaction, and consensus building among stakeholders with enormously diverse objectives. Additionally, we have come to realize that managing the demand trajectories of livestock products must be part of the solution space, and this is an increasingly important research area for simultaneously achieving positive health and environmental outcomes.

Well into the 21st century, safe and affordable drinking water remains an unmet human need. At least 1.8 billion people are potentially exposed to microbial contamination, and close to 140 million people are potentially exposed to unsafe levels of arsenic. Many new technologies, water quality assessments, health impact assessments, cost studies, and user preference studies have emerged in the past 20 years to further the laudable goal of safe drinking water for all. This article reviews (a) the current literature on safe water approaches with respect to their effectiveness in improving water quality and protectiveness in improving human health, (b) new work on the uptake and use of safe water systems among low-income consumers, (c) new research on the cash and labor costs of safe water systems, and (d) research on user preferences and valuations for safe water. Our main recommendation is that safe water from “source to sip” should be seen as a system; this entire system, rather than a discrete intervention, should be the object of analysis for technical, economic, and health assessments.

Consumption, although often considered an individual choice, is deeply ingrained in behaviors, cultures, and institutions, and is driven and supported by corporate and government practices. Consumption is also at the heart of many of our most critical ecological, health, and social problems. What is referred to broadly as sustainable consumption has primarily focused on making consumption more efficient and gradually decoupling it from energy and resource use. We argue for the need to focus sustainable consumption initiatives on the key impact areas of consumption—transport, housing, energy use, and food—and at deeper levels of system change. To meet the scale of the sustainability challenges we face, interventions and policies must move from relative decoupling via technological improvements, to strategies to change the behavior of individual consumers, to broader initiatives to change systems of production and consumption. We seek to connect these emerging literatures on behavior change, structural interventions, and sustainability transitions to arrive at integrated frameworks for learning, iteration, and scaling of sustainability innovations. We sketch the outlines of research and practice that offer potentials for system changes for truly sustainable consumption.

Access to electricity changes lives but only when people can afford electricity-powered services to meet their basic needs, and this is more than just two light bulbs and a fan. Decentralized renewable energy (RE) minigrids, particularly solar photovoltaic (PV) minigrids, can cost-effectively electrify a large share of currently unelectrified rural populations. But the cost of using appliances with this electricity is still much higher than what the poor can afford without deep subsidies. This affordability gap stunts the sustainability and growth of RE minigrids. Significant improvements in the economics of supplying electricity with minigrids, combined with higher-efficiency appliances, are needed to reduce the effective cost of using electricity in decentralized RE minigrids. These would bridge the affordability gap and improve business opportunities and value to users, investors, and service providers and thus create market-driven expansion to overcome the acute lack of funding that they currently face. Technology breakthroughs that can help in this respect include (a) significantly cheaper solar PV components to reduce up-front costs of solar PV minigrids; (b) significantly more affordable and energy-efficient appliances; (c) better-performing bulk storage at a significantly lower cost; (d) affordable and easy-to-use grid management solutions, and (e) a utility in a box for a simpler, cheaper, and faster way to set up minigrids.

Urban heat island (UHI) manifests as the temperature rise in built-up urban areas relative to the surrounding rural countryside, largely because of the relatively greater proportion of incident solar energy that is absorbed and stored by man-made materials. The direct impact of UHI can be significant on both daytime and night-time temperatures, and the indirect impacts include increased air conditioning loads, deteriorated air and water quality, reduced pavement lifetimes, and exacerbated heat waves. Modifying the thermal properties and emissivity of roofs and paved surfaces and increasing the vegetated area within the city are potential mitigation strategies. A quantitative comparison of their efficacies and costs suggests that so-called cool roofs are likely the most cost-effective UHI mitigation strategy. However, additional research is needed on how to modify surface emissivities and dynamically control surface and material properties, as well as on the health and socioeconomic impacts of UHI.

The European Union (EU) is influential in environmental politics and policy-making across its 28 member states, around its periphery, and globally. Building on a diverse analytical and empirical literature, this article's seven sections each highlights important research findings and outcomes from more than four decades of EU environmental governance. These include (a) a substantial transfer of legal authority from member states to the supranational level; (b) a growing involvement of EU bodies, advocacy groups, and civil society in regional goal-setting and decision-making; (c) the development of elaborate governance systems and mechanisms for making, implementing, and enforcing policy; (d) EU exercise of considerable influence over countries seeking membership before and after joining the Union; (e) increased EU participation and influence in international fora; (f) a mixed record of uneven implementation and varied environmental outcomes in Europe and across the world; and (g) continuing challenges in nascent attempts to engender greater resource efficiency and sustainability in Europe and beyond. All of these findings and outcomes suggest numerous areas and directions for additional research.

Environmental movements are networks of informal interactions that may include individuals, groups, and organizations engaged in collective action motivated by shared identity or concern about environmental issues. This article reviews literature on environmental movements (including antinuclear energy movements) according to four main aspects: the social bases and values underlying the movements' mobilization, the resources supporting their mobilization, the political opportunities channeling their mobilization, and the cultural framing processes through which environmental issues are defined as social and political problems to be addressed through mobilization. In addition, we consider the historical antecedents and roots of environmental movements. Finally, we discuss the interplay between the local and the global levels and the movements' impacts, a long neglected issue in the social movement literature. Our review highlights three main features of environmental movements: they are heterogeneous; they have profoundly transformed themselves; and they have generally become more institutionalized.

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.

International policies for mitigation of climate change provide a global public good and thus suffer from “free riding,” i.e., inaction of governments. In 25 years of negotiations under the UN Framework Convention on Climate Change (UNFCCC), the regime has changed its character from a top-down approach based on mandatory emissions commitments to a bottom-up system of voluntary government pledges. At the same time, various initiatives by governments at all levels and private companies have been established, but most are limited to emissions reporting and exchange of knowledge on mitigation technologies. None of the alternatives has shown a higher mitigation effectiveness than the Kyoto Protocol. Generally, the transition toward a bottom-up regime risks a reduction of transparency and increases in the transaction costs of mitigation. Although it could give rise to a club of countries engaging in strong mitigation that could expand over time, it is unlikely to be ambitious enough to achieve the target of limiting warming to 2°C. On the one hand, carbon prices will be applied in a larger number of jurisdictions, and mitigation technologies diffuse around the world. On the other hand, carbon price levels will remain relatively low, and their mitigation benefits will be more than outweighed by the growth of infrastructure and consumption. Thus, a temperature increase of at least 3°C by 2100 becomes more and more likely.

To satisfy a growing population, much of Earth's surface has been designed to suit humanity's needs. Although these ecosystem designs have improved human welfare, they have also produced significant negative environmental impacts, which applied ecology as a field has attempted to address and solve. Many of the failures in applied ecology to achieve this goal of reducing negative environmental impacts are design failures, not failures in the science. Here, we review (a) how humans have designed much of Earth's surface, (b) the history of design ideas in ecology and the philosophical and practical critiques of these ideas, (c) design as a conceptual process, (d) how changing approaches and goals in subfields of applied ecology reflect changes and failures in design, and (e) why it is important not only for ecologists to encourage design fields to incorporate ecology into their practice but also for design to be more thoroughly incorporated into ours.

Inclusive wealth is a measure designed to address whether society is on a sustainable development trajectory. Inclusive wealth is defined as the aggregate value of all capital assets. Increases in inclusive wealth indicate an improved productive base capable of supporting a higher standard of living in the future. To be truly inclusive, measures of inclusive wealth must include the value of all forms of capital that contribute to human well-being: human capital, manufactured capital, natural capital, and social capital. Sustainability concerns have increased attention on the ways of measuring the value of natural capital. We review various attempts to measure natural capital and to incorporate these into inclusive wealth including estimates using national wealth accounts and integrated ecological and economic models used to estimate ecosystem services. Empirically measuring the value of various types of capital in terms of a common metric is hugely challenging, and no current attempt to date can be said to be fully inclusive. Despite the empirical challenges, inclusive wealth provides a clear, coherent, and systematic framework for addressing sustainable development. Combining measures of semi-inclusive wealth that capture forms of capital that can be relatively easily measured in monetary terms with a set of biophysical metrics capturing important aspects of natural capital that are difficult to measure in monetary terms may provide a good set of signals of whether society is proceeding along a sustainable development trajectory.

We review the challenges and future perspectives of regional climate model (RCM), or dynamical downscaling, activities. Among the main technical issues in need of better understanding are those of selection and sensitivity to the model domain and resolution, techniques for providing lateral boundary conditions, and RCM internal variability. The added value (AV) obtained with the use of RCMs remains a central issue, which needs more rigorous and comprehensive analysis strategies. Within the context of regional climate projections, large ensembles of simulations are needed to better understand the models and characterize uncertainties. This has provided an impetus for the development of the Coordinated Regional Downscaling Experiment (CORDEX), the first international program offering a common protocol for downscaling experiments, and we discuss how CORDEX can address the key scientific challenges in downscaling research. Among the main future developments in RCM research, we highlight the development of coupled regional Earth system models and the transition to very high-resolution, cloud-resolving models.