201-220 of 333 Results

Article

Industrial Policy as an Environmental Policy: Forest Preservation and the Industrialization of Manaus  

Alexandre A.F. Rivas and James R. Kahn

The world is experiencing a major dilemma between the need to reduce global warming and to promote economic development. Brazil has the largest tropical rainforest on the planet, which plays an important role in this scenario. In the heart of this forest there is a special economic zone (SEZ), the Manaus Free Trade Zone. Studies indicate that there is a positive relationship between this economic activity and the level of forest conservation in the state of Amazonas, where the Manaus Free Trade Zone is located. There is important literature on SEZs, examining their economic and environmental impact in general, and specifically examining the Manaus Free Trade Zone. There is also a proposal to turn this SEZ into a major Brazilian economic initiative to protect the Amazon rainforest.

Article

Infiltration of Water Into Soil  

John Nimmo and Rose Shillito

The infiltration of water into soil has profound importance as a central component of the hydrologic cycle and as the means of replenishing soil water that sustains terrestrial life. Systematic quantitative study of infiltration began in the 19th century and has continued through to the present as a central topic of soils, soil physics, and hydrology. Two forces drive infiltration: gravity, and capillarity, which results from the interaction of air-water surface tension with the solid components of soil. There are also two primary ways water moves into and within the soil. One is diffuse flow, through the pores between individual soil grains, moving from one to the next and so on. The other is preferential flow, through elongated channels such as those left by worms and roots. Diffuse flow is slow and continues as long as there is a net driving force. Preferential flow is fast and occurs only when water is supplied at high intensity, as during irrigation, major rainstorms, or floods. Both types are important in infiltration. Especially considering that preferential flow does not yet have a fully accepted theory, this means that infiltration entails multiple processes, some of them poorly understood. The soil at a given location has a limit to how much water it can absorb—the infiltration capacity. The interplay between the mode and rate of water supply, infiltration capacity, and characteristics of the soil and surrounding terrain determines infiltration into the soil. Much effort has gone into developing means of measuring and predicting both infiltration capacity and the actual infiltration rate. Various methods are available, and research is needed to improve their accuracy and ease of use.

Article

Input–Output Models Applied to Environmental Analysis  

Joaquim J.M. Guilhoto

Input–Output (I–O) models and analysis were originally conceived by the Nobel Prize winner Wassily Leontief in the 1930s as a tool that can be used by economists and economic policy makers to help in their decision process. The I–O models provide a “picture” of how the economy works, that is, what are the necessities to produce goods and services, how this production generates income, profits and taxes, and how this income is spent. In a simplified way the I–O models can be seen as the model implementation of the economy circular-flow diagrams usually shown in economics introductory courses. Associated with the theory behind I–O models and analysis, I–O tables contain the empirical information necessary to implement these models and theory. Taking, for example, the production of computer screens: • On the production side, the I–O models have information on: (a) how much is spent on the inputs, goods and services necessary to produce the screens; (b) whether these inputs have their origin in the domestic market or are imported; (c) how much was paid in tax to the government; (d) what was the total amount paid in wages and salaries; (e) what were the profits of the producing firms; (f) how many computer screens are sold on the domestic market or on the international market (exported); and (g) whether they are sold directly to the final consumer or are used as a production input, that is, incorporated into other goods, for example, a refrigerator with a computer screen; • On the demand side, the I–O models, taking into consideration the total income received by the different players in the economy, that is, households, firms, and government, have information on: (a) how the income of these players is spent on goods and services, and whether it is used for consumption or investment; (b) whether these goods and services were produced domestically or abroad (imported); and (c) how much consumer tax was paid. From the aforementioned structure of I–O models, and using economic mathematical models, it is possible to measure the direct and indirect inputs needed to produce goods and services in the economy, for example, to produce a car there is no need for agricultural goods as a direct input for production, but the fabric used in the car seats or on the car carpets could have come from cotton, which is an agricultural good, so, cotton is an indirect input used in car production. I–O models, by their capability to show a complete picture of the economic system, and tracing of the origin of direct and indirect inputs used in the production process, can be used in environmental studies by linking economic and environmental variables, on the production and consumption sides. From the production side it is possible to measure, by considering the direct and indirect inputs used, how many natural resources were used and how much pollution was generated in producing the goods and services. On the demand side it is possible to measure the environmental variables, natural resources, and pollution, embodied in the goods and services consumed in the economy. Expanding I–O models to a global scale, that is, using inter-country I–O models, it is possible to measure the environmental impacts, and contents, of the goods and services by country of origin of production and by countries of consumption.

Article

Institutional Fit in the Water Sector  

Cathy Rubiños and Maria Bernedo Del Carpio

Adequate water governance is necessary for the world’s sustainability. Because of its importance, a growing literature has studied ways to improve water governance, beginning in the early 2000s. Institutions, which refer to the set of shared rules, codes, and prescriptions that regulate human actions, are a particularly important element of sustainable water governance. Evidence shows that to design institutions that will generate sustainable economic, ecological, and cultural development, it is necessary to consider ecosystems and socioeconomic-cultural systems as social-ecological systems (SESs). In the past, practitioners and international agencies tried to find the government-led panaceas, but this search has been largely unsuccessful. Current views support efforts to move towards addressing complexity (e.g., Integrated Water Resources Management), and search for the fit between the institutional arrangements and SESs’ attributes. The literature on institutional fit in SESs encourages planners to design institutions by carefully considering the defining features of the problems they are meant to address and the SES context in which they are found. This literature has been developing since the 1990s and has identified different types of misfits. A comprehensive fitness typology that includes all the different types of fitness (ecological, social, SES, and intra-institutional fit) helps organize existing and future work on institutional fit and provides a checklist for governments to be used in the problem-solving process for increasing fitness. The water governance and institutional fitness literature provide examples of management practices and mechanisms for increasing institutional fit for each fitness type. Future research should focus on improving the methodologies to measure different types of fit and testing the effect of introducing fit on SES outcomes.

Article

Integrated Water Resource Management as an Organizing Concept  

Mohamed Ait-Kadi and Melvyn Kay

This is an immersive journey through different water management concepts. The conceptual attractiveness of concepts is not enough; they must be applicable in the real and fast-changing world. Thus, beyond the concepts, our long-standing challenge remains increasing water security. This is about stewardship of water resources for the greatest good of societies and the environment. It is a public responsibility requiring dynamic, adaptable, participatory, and balanced planning. It is all about coordination and sharing. Multi-sectoral approaches are needed to adequately address the threats and opportunities relating to water resources management in the context of climate change, rapid urbanization, and growing disparities. The processes involved are many and need consistency and long-term commitment to succeed. Climate change is closely related to the problems of water security, food security, energy security and environment sustainability. These interconnections are often ignored when policy-makers devise partial responses to individual problems. They call for broader public policy planning tools with the capacity to encourage legitimate public/collective clarification of the trade-offs and the assessment of the potential of multiple uses of water to facilitate development and growth. We need to avoid mental silos and to overcome the current piecemeal approach to solving the water problems. This requires a major shift in practice for organizations (governmental as well as donor organizations) accustomed to segregating water problems by subsectors. Our experience with integration tells us that (1) we need to invest in understanding the political economy of different sectors; (2) we need new institutional arrangements that function within increasing complexity, cutting across sectoral silos and sovereign boundaries; (3) top down approaches for resources management will not succeed without bottom-up efforts to help people improve their livelihoods and their capacity to adapt to increasing resource scarcity as well as to reduce unsustainable modes of production. Political will, as well as political skill, need visionary and strong leadership to bring opposing interests into balance to inform policy- making with scientific understanding, and to negotiate decisions that are socially accepted. Managing water effectively across a vast set of concerns requires equally vast coordination. Strong partnerships and knowledge creation and sharing are essential. Human civilization – we know- is a response to challenge. Certainly, water scarcity can be a source of conflict among competing users, particularly when combined with other factors of political or cultural tension. But it can also be an inducement to cooperation even in high tension areas. We believe that human civilization can find itself the resources to respond successfully to the many water challenges, and in the process make water a learning ground for building the expanded sense of community and sharing necessary to an increasingly interconnected world.

Article

Interface Urban Forest Management in an Urbanizing Landscape  

Maria A. Cunha-e-Sá and Sofia F. Franco

Although forests located near urban areas are a small fraction of the forest cover, a good understanding of the extent to which —wildland-urban interface (WUI) forest conversion affects local economies and environmental services can help policy-makers harmonize urban development and environmental preservation at this interface, with positive impact on the welfare of local communities. A growing part of the forest resource worldwide has come under urban influence, both directly (i.e., becoming incorporated into the interface or located at the interface with urban areas) and indirectly (as urban uses and values have come to dominate more remote forest areas). Yet forestry has been rather hesitant to recognize its urban mandate. Even if the decision to convert land at the WUI (agriculture, fruit, timber, or rural use) into an alternative use (residential and commercial development) is conditional on the relative magnitude and timing of the returns of alternative land uses, urban forestry is still firmly rooted in the same basic concepts of traditional forestry. This in turn neglects features characterizing this type of forestland, such as the urban influences from increasingly land-consumptive development patterns. Moreover, interface timber production-allocated land provides public goods that otherwise would be permanently lost if land were converted to an irreversible use. Any framework discussing WUI optimal rotation periods and conversion dates should then incorporate the urban dimension in the forester problem. It must reflect the factors that influence both urban and forestry uses and account for the fact that some types of land use conversion are irreversible. The goal is to present a framework that serves as a first step in explaining the trends in the use and management of private land for timber production in an urbanizing environment. Our framework integrates different land uses to understand two questions: given that most of the WUI land use change is irreversible and forestry at this interface differs from classic forestry, how does urban forestry build upon and benefit from traditional forestry concepts and approaches? In particular, what are the implications for the Faustmann harvesting strategy when conversion to an irreversible land use occurs at some point in the future? The article begins with a short background on the worldwide trend of forestland conversion at the WUI, focusing mostly on the case of developed countries. This provides a context for the theoretical framework used in the subsequent analysis of how urban factors affect regeneration and conversion dates. The article further reviews theoretical models of forest management practices that have considered either land sale following clear-cutting or a switch to a more profitable alternative land use without selling the land. A brief discussion on the studies with a generalization of the classic Faustmann formula for land expectation value is also included. For completeness, comparative statics results and a numerical illustration of the main findings from the private landowner framework are included.

Article

International Environmental Conventions on Biodiversity  

Matti Nummelin and Niko Urho

Conservation and sustainable use of biodiversity have been in the center of policy creation for half a century. The main international biodiversity conventions and processes include the Convention on Biological Diversity (CBD) and its protocols, the Convention on Trade in Endangered Species of Wild Fauna and Flora (CITES), the Convention on Wetlands of International Importance (Ramsar Convention), the World Heritage Convention (WHC), the Convention on Conservation of Migratory Species of Wild Animals (CMS), the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA), the International Plant Protection Convention (IPPC), the Commission on Genetic Resources for Food and Agriculture (CGRFA), and the International Convention on the Regulation of Whaling (ICRW). The governance of marine biodiversity in areas beyond national jurisdiction (BBNJ) is also discussed, as political focus has shifted to the protection of the oceans and is expected to culminate in the adoption of a new international convention under the United Nations Convention on Law of Seas (UNCLOS). Other conventions and processes with links to biodiversity include the United Nations Convention to Combat Desertification (UNCCD), the United Nations Framework Convention on Climate Change (UNFCCC), and the United Nations Forum on Forests (UNFF). Despite the multitude of instruments, governments are faced with the fact that biodiversity loss is spiraling and international targets are not being met. The Earth’s sixth mass extinction event has led to various initiatives to fortify the relevance of biodiversity in the UN system and beyond to accelerate action on the ground. In face of an ever more complex international policy landscape on biodiversity, country delegates are seeking to enhance efficiency and reduce fragmentation by enhancing synergies among multilateral environmental agreements and strengthening their science−policy interface. Furthermore, biodiversity has been reflected throughout the 2030 Agenda on Sustainable Development and is gradually gaining more ground in the human rights context. The Global Pact for the Environment, a new international initiative that is aiming to reinforce soft law commitments and increase coherence among environmental treaties, holds the potential to influence and strengthen the way biodiversity conventions function, but extensive discussions are still needed before concrete action is agreed upon.

Article

International Water Law and Its Developing Role in Conflict and Cooperation Over Transboundary Water Resources  

Susanne Schmeier

International water law plays a key role in guiding states’ behavior over water resources they share. Substantive and procedural principles provide an ex ante framework based on which states can interact in a manner that prevents or mitigates potential conflicts and fosters cooperation and its benefits while supporting the sustainable use and management of these transboundary resources. Through the international water law regime, cooperation has largely prevailed over conflict in the world’s transboundary basins. Nonetheless, international water law—and thus also its role in conflict prevention and cooperation promotion—faces various challenges as populations and economies grow, the climate changes, and states seem to increasingly value short-term unilateral considerations over long-term multilateralism gains. This will challenge key principles, such as the principle of equitable and reasonable utilization and the principle of no significant harm, and their implementation in different basins, possibly triggering new disagreements between riparian states. It will therefore be important for international water law to remain adaptive to change and ensure the long-term cooperative and sustainable governance of water resources shared between states.

Article

Lay Expertise, Botanical Science, and Botanic Gardens as “Contact Zones”  

Katja Neves

Botanic gardens came into existence in the late 1500s to document, study, and preserve plants originating from all over the world. The scientific field of botany was a direct outcome of these developments. From the 1600s onward, botanic gardens also paid key roles in acclimatizing plants across distinct ecosystems and respective climate zones. This often entailed the appropriation of Indigenous systems of plant expertise that were then used without recognition within the parameters of scientific botanical expertise. As such, botanic gardens operated as contact zones of unequal power dynamics between European and Indigenous knowledge systems. Botanic gardens were intimately embroiled with the global expansion of European colonialism and processes of empire building. They helped facilitate the establishment of cash-crop systems around the world, which effectively amounted to the extractive systems of plant wealth accumulation that characterize the modern European colonial enterprise. In the mid-20th century, botanic gardens began to take on leading roles in the conservation of plant biodiversity while also attending to issues of social equity and sustainable development. Relationships between lay expertise and scientific knowledge acquired renewed significance in this context, as did discussions of the knowledge politics that these interactions entailed. As a consequence of these transformations, former colonial exchanges within the botanical garden world between Indigenous knowledge practices and their appropriation by science came under scrutiny in the final decades of the 20th century. Efforts to decolonize botanic gardens and their knowledge practices emerged in the second decade of the 20th century.

Article

The Life Satisfaction Approach to Environmental Valuation  

Christopher Fleming and Christopher Ambrey

The method and practice of placing monetary values on environmental goods and services for which a conventional market price is otherwise unobservable is one of the most fertile areas of research in the field of natural resource and environmental economics. Initially motivated by the need to include environmental values in benefit–cost analysis, practitioners of nonmarket valuation have since found further motivation in national account augmentation and environmental damage litigation. Despite hundreds of applications and many decades of refinement, shortcomings in all of the techniques remain, and no single technique is considered superior to the others in all respects. Thus, techniques that expand the suite of options available to the non-market valuation practitioner have the potential to represent a genuine contribution to the field. One technique to recently emerge from the economics of happiness literature is the “experienced preference method” or “life satisfaction approach.” Simply, this approach entails the inclusion of non-market goods as explanatory variables within micro-econometric functions of life satisfaction along with income and other covariates. The estimated coefficient for the nonmarket good yields, first, a direct valuation in terms of life satisfaction and, second, when compared to the estimated coefficient for income, the implicit willingness to pay for the non-market good in monetary terms. The life satisfaction approach offers several advantages over more conventional non-market valuation techniques. For example, the approach does not ask individuals to directly value the non-market good in question, as is the case in contingent valuation. Nor does it ask individuals to make explicit trade-offs between market and non-market goods, as is the case in discrete choice modeling. The life satisfaction approach nonetheless has some potential limitations. Crucially, self-reported life satisfaction must be regarded as a good proxy for an individual’s utility. Furthermore, in order to yield reliable non-market valuation estimates, self-reported life satisfaction measures must: (1) contain information on respondents’ global evaluation of their life; (2) reflect not only stable inner states of respondents, but also current affects; (3) refer to respondents’ present life; and (4) be comparable across groups of individuals under different circumstances. Despite these conditions, there is growing evidence to support the suitability of individual’s responses to life satisfaction questions for non-market valuation. Applications of the life satisfaction approach to the valuation of environmental goods and services to date include the valuation of air quality, airport noise, green space, scenic amenity, floods, and drought.

Article

Machine Learning Tools for Water Resources Modeling and Management  

Giorgio Guariso and Matteo Sangiorgio

The pervasive diffusion of information and communication technologies that has characterized the end of the 20th and the beginning of the 21st centuries has profoundly impacted the way water management issues are studied. The possibility of collecting and storing large data sets has allowed the development of new classes of models that try to infer the relationships between the variables of interest directly from data rather than fit the classical physical and chemical laws to them. This approach, known as “data-driven,” belongs to the broader area of machine learning (ML) methods and can be applied to many water management problems. In hydrological modeling, ML tools can process diverse data sets, including satellite imagery, meteorological data, and historical records, to enhance predictions of streamflow, groundwater levels, and water availability and thus support water allocation, infrastructure planning, and operational decision-making. In water demand management, ML models can analyze historical water consumption patterns, weather data, and socioeconomic factors to predict future water demands. These models can support water utilities and policymakers in optimizing water allocation, planning infrastructure, and implementing effective conservation strategies. In reservoir management, advanced ML tools may be used to determine the operating rule of water structures by directly searching for the management policy or by mimicking a set of decisions with some desired properties. They may also be used to develop surrogate models that can be rapidly executed to determine the optimal course of action as a component of a decision-support system. ML methods have revolutionized water management studies by showing the power of data-driven insights. Thanks to their ability to make accurate forecasts, enhanced monitoring, and optimized resource allocation, adopting these tools is predicted to expand and consistently modify water management practices. Continued advancements in ML tools, data availability, and interdisciplinary collaborations will further propel the use of ML methods to address global water challenges and pave the way for a more resilient and sustainable water future.

Article

Macroeconomics and the Environment  

Partha Sen

Macroeconomics deals with economics at the aggregate level. This could be at a national level or that of the interaction between nations. Production of output necessarily involves pollution and degrading the environment. Therefore, environmental issues inevitably are a factor. Some problems that have been highlighted in the literature are surveyed here. It has been argued that a poor country deliberately lowers its environmental standards to steal jobs from other countries. What is the theoretical underpinning and the evidence for this assertion? The evidence is very weak in support of this. Moreover, in the fight against climate change, poorer countries claim exemption from tightening their emissions norms because of their poverty. Similarly, although equity demands this, it could pose serious challenges to fighting climate change—oil producers would pump oil faster if they foresaw it becoming useless. A piecemeal approach will not work. A more basic question is how to introduce natural resource use in national income accounts to give meaning to the notion of sustainability. National income accounts do not take into account non-market activities. Some progress has been made in the theory and empirical implementation of sustainability by including non-market activities. A lot of work has been done but a lot more still needs to be done in this area.

Article

Managed Aquifer Recharge as a Tool to Improve Water Security and Resilience  

Mary-Belle Cruz-Ayala and Sharon B. Megdal

Groundwater overdraft is an issue faced by urban and rural water users worldwide. With climate change making efforts to meet global water demands even more challenging, improving water security and resilience is of paramount importance. Managed aquifer recharge efforts are being deployed globally to further achieve water management goals, such as helping to reduce groundwater overdraft at a local level. Artificial recharge or managed aquifer recharge (MAR) is a concept that has been applied to describe diverse methods with the aim of both augmenting groundwater resources during times when water is available and recovering the water from the same aquifer in the future when it is needed. MAR projects are distributed in almost every continent. An extensive study published in 2018 identified that 15 countries and regions account for 76% of the installed MAR capacity (Australia, China, France, Finland, India, Israel, Italy, Jordan, Netherlands, Qatar, Southern Africa, Spain, United States, and United Kingdom). MAR is considered a viable tool to face the negative impacts of climate change and to increase public water supply at a local level. In arid and semiarid regions, MAR plays an important role because it allows the storage of large volumes of water without the risk of evaporation. MAR is used to provide water for agricultural activities in groundwater-dependent countries and regions. Increasingly, at least in India, many MAR projects are designed to protect domestic water supply. MAR is also used as a water source for maintaining environmental services, although this use is still incipient.

Article

Market Failures, the Environment, and Human Health  

Karyn Morrissey

Knowledge of the important role that the environment plays in determining human health predates the modern public health era. However, the tendency to see health, disease, and their determinants as attributes of individuals rather than characteristics of communities meant that the role of the environment in human health was seldom accorded sufficient importance during much of the 20th century. Instead, research began to focus on specific risk factors that correlated with diseases of greatest concern, i.e., the non-communicable diseases such as cardiovascular disease, asthma, and diabetes. Many of these risk factors (e.g., smoking, alcohol consumption, and diet) were aspects of individual lifestyle and behaviors, freely chosen by the individual. Within this individual-centric framework of human health, the standard economic model for human health became primarily the Grossman model of health and health care demand. In this model, an individual’s health stock may be increased by investing in health (by consuming health services, for example) or decreased by endogenous (age) or exogenous (smoking) individual factors. Within this model, individuals used their available resources, their budget, to purchase goods and services that either increased or decreased their health stock. Grossman’s model provides a consumption-based approach to human health, where individuals purchase goods and services required to improve their individual health in the marketplace. Grossman’s model of health assumes that the goods and services required to optimize good health can be purchased through market-based interactions and that these goods and services are optimally priced—that the value of the goods and services are reflected in their price. In reality, many types of goods and services that are good for human health are not available to purchase, or if they are available they are undervalued in the free market. Across the environmental and health literature, these goods and services are, today, broadly referred to as “ecosystem services for human health.” However, the quasi-public good nature of ecosystem services for human health means that the private market will generate a suboptimal environment for both individual and public health outcomes. In the face of continued austerity and scarce public resources, understanding the role of the environment in human health may help to alleviate future health care demand by decreasing (or increasing) environmental risk (or benefits) associated with health outcomes. However, to take advantage of the role that the environment plays in human health requires a fundamental reorientation of public health policy and spending to include environmental considerations.

Article

Material and Energy Flow Analysis  

Vincent Moreau and Guillaume Massard

The concept of metabolism takes root in biology and ecology as a systematic way to account for material flows in organisms and ecosystems. Early applications of the concept attempted to quantify the amount of water and food the human body processes to live and sustain itself. Similarly, ecologists have long studied the metabolism of critical substances and nutrients in ecological succession towards climax. With industrialization, the material and energy requirements of modern economic activities have grown exponentially, together with emissions to the air, water and soil. From an analogy with ecosystems, the concept of metabolism grew into an analytical methodology for economic systems. Research in the field of material flow analysis has developed approaches to modeling economic systems by assessing the stocks and flows of substances and materials for systems defined in space and time. Material flow analysis encompasses different methods: industrial and urban metabolism, input–output analysis, economy-wide material flow accounting, socioeconomic metabolism, and more recently material flow cost accounting. Each method has specific scales, reference substances such as metals, and indicators such as concentration. A material flow analysis study usually consists of a total of four consecutive steps: (a) system definition, (b) data acquisition, (c) calculation, and (d) interpretation. The law of conservation of mass underlies every application, which implies that all material flows, as well as stocks, must be accounted for. In the early 21st century, material depletion, accumulation, and recycling are well-established cases of material flow analysis. Diagnostics and forecasts, as well as historical or backcast analyses, are ideally performed in a material flow analysis, to identify shifts in material consumption for product life cycles or physical accounting and to evaluate the material and energy performance of specific systems. In practice, material flow analysis supports policy and decision making in urban planning, energy planning, economic and environmental performance, development of industrial symbiosis and eco industrial parks, closing material loops and circular economy, pollution remediation/control and material and energy supply security. Although material flow analysis assesses the amount and fate of materials and energy rather than their environmental or human health impacts, a tacit assumption states that reduced material throughputs limit such impacts.

Article

Measuring Soil Loss and Subsequent Nutrient and Organic Matter Loss on Farmland  

Vincenzo Bagarello and Vito Ferro

Field plots are often used to obtain experimental data (soil loss values corresponding to different climate, soil, topographic, crop, and management conditions) for predicting and evaluating soil erosion and sediment yield. Plots are used to study physical phenomena affecting soil detachment and transport, and their sizes are determined according to the experimental objectives and the type of data to be obtained. Studies on interrill erosion due to rainfall impact and overland flow need small plot width (2–3 m) and length (< 10 m), while studies on rill erosion require plot lengths greater than 6–13 m. Sites must be selected to represent the range of uniform slopes prevailing in the farming area under consideration. Plots equipped to study interrill and rill erosion, like those used for developing the Universal Soil Loss Equation (USLE), measure erosion from the top of a slope where runoff begins; they must be wide enough to minimize the edge or border effects and long enough to develop downslope rills. Experimental stations generally include bounded runoff plots of known rea, slope steepness, slope length, and soil type, from which both runoff and soil loss can be monitored. Once the boundaries defining the plot area are fixed, a collecting equipment must be used to catch the plot runoff. A conveyance system (H-flume or pipe) carries total runoff to a unit sampling the sediment and a storage system, such as a sequence of tanks, in which sediments are accumulated. Simple methods have been developed for estimating the mean sediment concentration of all runoff stored in a tank by using the vertical concentration profile measured on a side of the tank. When a large number of plots are equipped, the sampling of suspension and consequent oven-drying in the laboratory are highly time-consuming. For this purpose, a sampler that can extract a column of suspension, extending from the free surface to the bottom of the tank, can be used. For large plots, or where runoff volumes are high, a divisor that splits the flow into equal parts and passes one part in a storage tank as a sample can be used. Examples of these devices include the Geib multislot divisor and the Coshocton wheel. Specific equipment and procedures must be employed to detect the soil removed by rill and gully erosion. Because most of the soil organic matter is found close to the soil surface, erosion significantly decreases soil organic matter content. Several studies have demonstrated that the soil removed by erosion is 1.3–5 times richer in organic matter than the remaining soil. Soil organic matter facilitates the formation of soil aggregates, increases soil porosity, and improves soil structure, facilitating water infiltration. The removal of organic matter content can influence soil infiltration, soil structure, and soil erodibility.

Article

Mineral Dust Cycle  

Irina Sokolik

There is scientific consensus that human activities have been altering the atmospheric composition and are a key driver of global climate and environmental changes since pre-industrial times (IPCC, 2013). It is a pressing priority to understand the Earth system response to atmospheric aerosol input from diverse sources, which so far remain one of the largest uncertainties in climate studies (Boucher et al., 2014; Forster et al., 2007). As the second most abundant component (in terms of mass) of atmospheric aerosols, mineral dust exerts tremendous impacts on Earth’s climate and environment through various interaction and feedback processes. Dust can also have beneficial effects where it deposits: Central and South American rain forests get most of their mineral nutrients from the Sahara; iron-poor ocean regions get iron; and dust in Hawaii increases plantain growth. In northern China as well as the midwestern United States, ancient dust storm deposits known as loess are highly fertile soils, but they are also a significant source of contemporary dust storms when soil-securing vegetation is disturbed. Accurate assessments of dust emission are of great importance to improvements in quantifying the diverse dust impacts.

Article

Mining, Ecological Engineering, and Metals Extraction for the 21st Century  

Margarete Kalin, William N. Wheeler, Michael P. Sudbury, and Bryn Harris

The first treatise on mining and extractive metallurgy, published by Georgius Agricola in 1556, was also the first to highlight the destructive environmental side effects of mining and metals extraction, namely dead fish and poisoned water. These effects, unfortunately, are still with us. Since 1556, mining methods, knowledge of metal extraction, and chemical and microbial processes leading to the environmental deterioration have grown tremendously. Man’s insatiable appetite for metals and energy has resulted in mines vastly larger than those envisioned in 1556, compounding the deterioration. The annual amount of mined ore and waste rock is estimated to be 20 billion tons, covering 1,000 km2. The industry also annually consumes 80 km3 of freshwater, which becomes contaminated. Since metals are essential in modern society, cost-effective, sustainable remediation measures need to be developed. Engineered covers and dams enclose wastes and slow the weathering process, but, with time, become permeable. Neutralization of acid mine drainage produces metal-laden sludges that, in time, release the metals again. These measures are stopgaps at best, and are not sustainable. Focus should be on inhibiting or reducing the weathering rate, recycling, and curtailing water usage. The extraction of only the principal economic mineral or metal generally drives the economics, with scant attention being paid to other potential commodities contained in the deposit. Technology exists for recovering more valuable products and enhancing the project economics, resulting in a reduction of wastes and water consumption of up to 80% compared to “conventional processing.” Implementation of such improvements requires a drastic change, a paradigm shift, in the way that the industry approaches metals extraction. Combining new extraction approaches, more efficient water usage, and ecological engineering methods to deal with wastes will increase the sustainability of the industry and reduce the pressure on water and land resources. From an ecological perspective, waste rock and tailings need to be thought of as primitive ecosystems. These habitats are populated by heat-, acid- and saline-loving microbes (extremophiles). Ecological engineering utilizes geomicrobiological, physical, and chemical processes to change the mineral surface to encourage biofilm growth (the microbial growth form) within wastes by enhancing the growth of oxygen-consuming microbes. This reduces oxygen available for oxidation, leading to improved drainage quality. At the water–sediment interface, microbes assist in the neutralization of acid water (Acid Reduction Using Microbiology). To remove metals from the waste water column, indigenous biota are promoted (Biological Polishing) with inorganic particulate matter as flocculation agents. This ecological approach generates organic matter, which upon death settles with the adsorbed metals to the sediment. Once the metals reach the deeper, reducing zones of the sediments, microbial biomineralization processes convert the metals to relatively stable secondary minerals, forming biogenic ores for future generations. The mining industry has developed and thrived in an age when resources, space, and water appeared limitless. With the widely accepted rise of the Anthropocene global land and water shortages, the mining industry must become more sustainable. Not only is a paradigm shift in thinking needed, but also the will to implement such a shift is required for the future of the industry.

Article

The Mirage of Supply-Side Development: The Hydraulic Mission and the Politics of Agriculture and Water in the Nile Basin  

Harry Verhoeven

In an era of calamitous climate change, entrenched malnutrition, and the chronic exclusion of hundreds of millions of people from access to affordable energy, food, and water, evaluating the policy options of African states to address these challenges matters more than ever. In the Nile Basin especially, a region notorious for its poverty, violent instability and lack of industrialisation, states have invested their scarce resources and political capital in a “hydraulic mission” in the belief that they can engineer their way out of international marginalization. Incumbents have bet on large-scale hydro-infrastructure and capital-intensive agriculture to boost food production, strengthen energy security, and deal with water scarcity, despite the woeful track-record of such a supply-side approach to development. While ruling elites in the Nile Basin have portrayed the hydraulic mission as the natural way of developing the region’s resources—supposedly validated by the historical achievements of Pharaonic civilization and its mastery over its tough environment—this is a modern fiction, spun to justify politically expedient projects and the exclusion of broad layers of the population. In the last two hundred years, the hydraulic mission has made three major political contributions that underline its strategic usefulness to centralizing elites: it has enabled the building of modern states and a growing bureaucratic apparatus around a riverain political economy; it has generated new national narratives that have allowed unpopular regimes to rebrand themselves as protectors of the nation; and it has facilitated the forging of external alliances, linking the resources and elites of Egypt, Ethiopia, and Sudan to global markets and centers of influence. Mega-dams, huge canals and irrigation for export are fundamentally about power and the powerful—and the privileging of some interests and social formations over others. The one-sided focus on increasing supply—based on the false premise that this will allow ordinary people to access more food and water—transfers control over livelihoods from one (broad) group of people to (a much narrower) other one by legitimizing top-down interventionism and dislocation. What presents itself as a strategy of water resources and agricultural development is really about (re)constructing hierarchies between people. The mirage of supply-side development continues to seduce elites at the helm of the state because it keeps them in power and others out of it.

Article

Modeling the Impact of Environment on Infectious Diseases  

Giovanni Lo Iacono and Gordon L. Nichols

The introduction of pasteurization, antibiotics, and vaccinations, as well as improved sanitation, hygiene, and education, were critical in reducing the burden of infectious diseases and associated mortality during the 19th and 20th centuries and were driven by an improved understanding of disease transmission. This advance has led to longer average lifespans and the expectation that, at least in the developed world, infectious diseases were a problem of the past. Unfortunately this is not the case; infectious diseases still have a significant impact on morbidity and mortality worldwide. Moreover, the world is witnessing the emergence of new pathogens, the reemergence of old ones, and the spread of antibiotic resistance. Furthermore, effective control of infectious diseases is challenged by many factors, including natural disasters, extreme weather, poverty, international trade and travel, mass and seasonal migration, rural–urban encroachment, human demographics and behavior, deforestation and replacement with farming, and climate change. The importance of environmental factors as drivers of disease has been hypothesized since ancient times; and until the late 19th century, miasma theory (i.e., the belief that diseases were caused by evil exhalations from unhealthy environments originating from decaying organic matter) was a dominant scientific paradigm. This thinking changed with the microbiology era, when scientists correctly identified microscopic living organisms as the pathogenic agents and developed evidence for transmission routes. Still, many complex patterns of diseases cannot be explained by the microbiological argument alone, and it is becoming increasingly clear that an understanding of the ecology of the pathogen, host, and potential vectors is required. There is increasing evidence that the environment, including climate, can affect pathogen abundance, survival, and virulence, as well as host susceptibility to infection. Measuring and predicting the impact of the environment on infectious diseases, however, can be extremely challenging. Mathematical modeling is a powerful tool to elucidate the mechanisms linking environmental factors and infectious diseases, and to disentangle their individual effects. A common mathematical approach used in epidemiology consists in partitioning the population of interest into relevant epidemiological compartments, typically individuals unexposed to the disease (susceptible), infected individuals, and individuals who have cleared the infection and become immune (recovered). The typical task is to model the transitions from one compartment to another and to estimate how these populations change in time. There are different ways to incorporate the impact of the environment into this class of models. Two interesting examples are water-borne diseases and vector-borne diseases. For water-borne diseases, the environment can be represented by an additional compartment describing the dynamics of the pathogen population in the environment—for example, by modeling the concentration of bacteria in a water reservoir (with potential dependence on temperature, pH, etc.). For vector-borne diseases, the impact of the environment can be incorporated by using explicit relationships between temperature and key vector parameters (such as mortality, developmental rates, biting rate, as well as the time required for the development of the pathogen in the vector). Despite the tremendous advancements, understanding and mapping the impact of the environment on infectious diseases is still a work in progress. Some fundamental aspects, for instance, the impact of biodiversity on disease prevalence, are still a matter of (occasionally fierce) debate. There are other important challenges ahead for the research exploring the potential connections between infectious diseases and the environment. Examples of these challenges are studying the evolution of pathogens in response to climate and other environmental changes; disentangling multiple transmission pathways and the associated temporal lags; developing quantitative frameworks to study the potential effect on infectious diseases due to anthropogenic climate change; and investigating the effect of seasonality. Ultimately, there is an increasing need to develop models for a truly “One Health” approach, that is, an integrated, holistic approach to understand intersections between disease dynamics, environmental drivers, economic systems, and veterinary, ecological, and public health responses.