Annual Review of Environment and Resources - Volume 38, 2013

Tipping points—where a small perturbation triggers a large response—can occur in many complex environmental systems. They produce abrupt and sometimes irreversible change, are inherently difficult to predict, and thus pose considerable challenges to the occupants and managers of those systems. However, tipping points can also represent opportunities. Here, different mathematical types of tipping points and different environmental processes that can give rise to them are distinguished. Then, I chart the crucial role that tipping points played in creating the modern Earth system. Looking ahead, potential large-scale tipping points are briefly reviewed before highlighting systems that could harbor tipping points across mechanisms and scales. The prospects for anticipating tipping points, avoiding dangerous ones, and encouraging others are outlined. Finally, a series of virtuous tipping points are identified, which can help transform the relationships between human societies and the environmental systems we depend upon.

New scientific understanding could increase the cost-effectiveness of local and regional air quality management policies, enhance the acceptance of mitigation measures for long-lived greenhouse gas (GHG) emissions, and reveal win-win portfolios of controls for short-lived substances that yield immediate health and crop benefits while limiting temperature increase in the near term. However, although substantial efforts have been devoted to global analyses of the emissions of carbon dioxide (CO2) and other long-lived GHGs, air pollutant emissions have received only limited attention in the global context. Past and likely future trends in air pollutant emissions evolve rather differently from those of long-lived GHGs, so that superficial extrapolations of GHG trends would lead to misleading conclusions. In many world regions, the evolution of air pollutant emissions has effectively decoupled from economic growth. Since 1990, air pollutant emissions declined (sulfur dioxide, SO2), stabilized (nitrogen oxides, NOx), or increased slightly (black carbon, BC; organic carbon, OC; and ammonia, NH3). This review discusses to what extent structural changes, technological improvements, and dedicated environmental legislation have contributed to these changes. The scenarios of future emissions in the literature span a wide range, mainly owing to different assumptions about future environmental policies. Although the more recent scenarios agree on declining air pollutants up to 2030, avoiding potential rebounds of emissions after 2030 will require additional policy interventions.

Fire is an ancient influence on the Earth system, affecting biogeochemical cycles and ecosystems. Humans have had a profound influence on global fire activity through setting and controlling fires, modifying the flammability of landscapes, and, more recently, changing the climate through the combustion of fossil fuels. We review this web of complex direct and indirect effects of fire on Earth using the framework provided by the emerging discipline of pyrogeography that unites biological, atmospheric, and social perspectives on fire. We describe the transition from fire activity before humans evolved, through the hunter-gatherer and agricultural phases, to the current period in Earth history dominated by industrialization (Anthropocene). We illustrate how pyrogeography provides the necessary framework to understand fire in the Anthropocene, including the management of pyrogenic emissions, protection of human life, conservation of biodiversity, and provision of ecosystem services.

We present in two parts an assessment of global manufacturing. In the first part, we review economic development, pollution, and carbon emissions from a country perspective, tracking the rise of China and other developing countries. The results show not only a rise in the economic fortunes of the newly industrializing nations, but also a significant rise in global pollution, particularly air pollution and CO2 emissions largely from coal use, which alter and even reverse previous global trends. In the second part, we change perspective and quantitatively evaluate two important technical strategies to reduce pollution and carbon emissions: energy efficiency and materials recycling. We subdivide the manufacturing sector on the basis of the five major subsectors that dominate energy use and carbon emissions: (a) iron and steel, (b) cement, (c) plastics, (d) paper, and (e) aluminum. The analysis identifies technical constraints on these strategies, but by combined and aggressive action, industry should be able to balance increases in demand with these technical improvements. The result would be high but relatively flat energy use and carbon emissions. The review closes by demonstrating the consequences of extrapolating trends in production and carbon emissions and suggesting two options for further environmental improvements, materials efficiency, and demand reduction.

The application of life-cycle assessment (LCA) to electric power (EP) technologies is a vibrant research pursuit that is likely to continue as the world seeks ways to meet growing electricity demand with reduced environmental and human health impacts. Although LCA is an evolving methodology with a number of barriers and challenges to its effective use, LCA studies to date have improved our understanding of the life-cycle energy, greenhouse gas emissions, air pollutant emissions, and water-use implications of EP technologies. With continued progress, LCA offers promise for assessing and comparing EP technologies in an analytically thorough and environmentally holistic manner for more robust deployment decisions. This article summarizes (a) current challenges in applying LCA to EP technologies, (b) LCA results to date on various impacts of EP technologies, and (c) opportunities for improving LCAs of EP technologies.

Using the results of more than 20 different global models with a particular emphasis on two rapidly growing large countries (China and India), this paper discusses the cost estimation methods that are used in setting up information for organizing models and to illustrate their global applicability to China, Korea, Japan, India, Indonesia, Europe, Latin America, the Middle East, Africa, and the United States. Some clear points emerge from the intermodal comparison exercise. First, no single technology can play a leading role in global emission mitigation. Second, although participation of all the regions is important, regions where future demographic and economic growth is concentrated will share a large part of this burden. Third, different technologies are important for different regions for mitigating emissions in the most cost-effective way. Fourth, if stringent climate policy targets are to be met, then emission-reduction actions need to be undertaken as soon as possible.

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.

This review covers the current state of “smart” grid research and demonstration projects. At present, smart elements are making their way into traditional electricity grid systems at every level, from transmission down to distribution. The vast size of the power grid makes the extension of digitally enabled electric infrastructure a question of cost. Drivers for this development are the growing security requirements and sustainability of supply in the face of rising demand and aging infrastructure. Information technology (IT) is one of the key elements of smart grids because it enables cooperation of distributed energy resources, local control, and globalized energy markets. Smart grids are expected to make our power system more resilient, “green,” and efficient; a challenge that the automotive industry could only manage by introducing digital controls in engines. We now witness the same development in electric energy systems. This article provides an introduction to the topic, a snapshot of current activities, and a general outlook on what still is needed.

Water conservation is gaining ascendancy around the world as the most important strategy for water planning and management for the future decades. In the urban areas of the developed world, water conservation has to a certain extent achieved the objective of curbing consumption, especially in the more compact European cities. Urban water conservation depends on changing behaviors by water users, which may be influenced by personal factors (related to variables such as age, income, education, etc.) or may follow stimuli coming from the economic (i.e., pricing), technological, or public awareness spheres. The relative merit of each of these factors, as presented in this review, remains inconclusive, and conservation behaviors may vary in degree. However, conservation is also influenced by nonpurposeful factors, such as urban design, population, economic profile, and productive base. This article also discusses the governance context in which urban conservation practices take place. It is argued that conservation may influence governance (for instance, in the emergence of new, decentralized decision making networks) and also that governance, and especially the consolidation of certain nonpublic actors with specific agendas, may drive conservation practices.

Agricultural biotechnology and, specifically, the development of genetically modified (GM) crops have been controversial for several reasons, including concerns that the technology poses potential negative environmental or health effects, that the technology would lead to the (further) corporatization of agriculture, and that it is simply unethical to manipulate life in the laboratory. GM crops have been part of the agricultural landscape for more than 15 years and have now been adopted on more than 170 million hectares (ha) in both developed countries (48%) and developing countries (52%). On the basis of this substantial history and data spanning many years, the economic and environmental impacts of GM crops can now be summarized with some certainty, and the analysis indicates that, on balance, many benefits have accrued from the adoption of GM crops. There continue to be many ethical issues that are being debated, and many are being resolved through institutional interventions. The future of agricultural productivity would be better served if the genetic modification debate were less polarized and were focused on the potential for complementarity of GM technologies within a diversified farming system framework.

This article reviews the design approaches and technologies that have been used to reduce the energy requirements of new buildings by a factor of 2 to 4 compared to the energy use of otherwise comparable recent new buildings or that have been used to achieve comparable savings in retrofits of existing buildings. This is followed by a critical discussion of documented studies of the energy performance of new and retrofitted buildings from around the world, along with cost information where-ever available. The additional costs of meeting the Passive Standard for heating loads in new buildings, which represents a factor of 5 to 10 reduction of heating load compared to current standard practice, have ranged from 0% to 16% of the construction costs of reference buildings. High-performance commercial buildings, with overall energy intensities of 25–50% that of recent conventional buildings, have been built at less cost, or only at a few percent more cost, than conventional buildings.

Until recently, the main environmental concerns associated with information and communication technologies (ICTs) have been their use-phase electricity consumption and the chemicals associated with their manufacture, and the environmental effects of these technologies on other parts of the economy have largely been ignored. With the advent of mobile computing, communication, and sensing devices, these indirect effects have the potential to be much more important than the impacts from the use and manufacturing phases of this equipment. This article summarizes the trends that have propelled modern technological societies into the ultralow-power design space and explores the implications of these trends for the direct and indirect environmental impacts associated with these new technologies. It reviews the literature on environmental effects of information technology (also with an emphasis on low-power systems) and suggests areas for further research.

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.

This article reviews research on global environmental change and human security, providing retrospective and tentative prospective views of this field. It explains the roles that the concept of human security has played in research on environmental change, as well as the knowledge that it has contributed. It then discusses the Global Environmental Change and Human Security (GECHS) project as an example of how this research has encouraged a more politicized understanding of the problem of global environmental change, drawing attention to the roles of power, agency, and knowledge. Finally, the article considers new research frontiers that have emerged from this field, including research on social transformations as a means of promoting, sustaining, and enhancing human security in response to complex global environmental challenges. The potential contributions of human security approaches to the next generation of global change research are discussed.

Despite the rapid evolution and growing complexity in models of science-society interaction, the rate and breadth of use of scientific knowledge in environmental decision making, especially related to climate variability and change, remain below expectations. This suggests a persistent gap between production and use that, to date, efforts to rethink and restructure science production have not been able to surmount. We review different models of science-policy interfaces to understand how they have influenced the organization of knowledge production and application. We then explore how new approaches to the creation of knowledge have emerged, involving both growing integration across disciplines and greater interaction with users. Finally, we review climate information use in the United States and United Kingdom to explore how the structure of knowledge production and the characteristics of users and their decision environments expose the challenges of broadening usable climate science.

This review examines environmental market instruments—policies that pursue environmental or conservation goals by modifying conditions in existing markets or creating new ones, thereby providing flexibility and incentives for decentralized responses. We review these instruments' theoretical basis, historical development, major current enactments and proposals, and empirical studies of their effects. We consider experience with these instruments in the context of the increased demands that may be imposed on any policies by the pursuit of a large-scale transition to sustainability. Under these conditions, challenges likely to be particularly prominent for market instruments will include managing distributive effects when policies are enacted, effectively adapting policies under advancing knowledge, managing the tension between cost-reducing expansion of the scope of market instruments and the maintenance of environmental effectiveness, and designing systems to build complementarity between market incentives and related normative systems. Each of these implies priorities for research and policy experimentation.

This review analyzes the methods being used and developed in global environmental governance (GEG), an applied field that employs insights and tools from a variety of disciplines both to understand pressing environmental problems and to determine how to address them collectively. We find that methods are often underspecified in GEG research. We undertake a critical review of data collection and analysis in three categories: qualitative, quantitative, and modeling and scenario building. We include examples and references from recent studies to show when and how best to utilize these different methods to conduct problem-driven research. GEG problems are often characterized by institutional and issue complexity, linkages, and multiscalarity that pose challenges for many conventional methodological approaches. As a result, given the large methodological toolbox available to applied researchers, we recommend they adopt a reflective, pluralist, and often collaborative approach when choosing methods appropriate to these challenges.

Ecosystems provide many of the material building blocks for human well-being. Although quantification and appreciation of such contributions have rapidly grown, our dependence upon cultural connections to nature deserves more attention. We synthesize multidisciplinary peer-reviewed research on contributions of nature or ecosystems to human well-being mediated through nontangible connections (such as culture). We characterize these connections on the basis of the channels through which such connections arise (i.e., knowing, perceiving, interacting with, and living within) and the components of human well-being they affect (e.g., physical, mental and spiritual health, inspiration, identity). We found enormous variation in the methods used, quantity of research, and generalizability of the literature. The effects of nature on mental and physical health have been rigorously demonstrated, whereas other effects (e.g., on learning) are theorized but seldom demonstrated. The balance of evidence indicates conclusively that knowing and experiencing nature makes us generally happier, healthier people. More fully characterizing our intangible connections with nature will help shape decisions that benefit people and the ecosystems on which we depend.