Nations rapidly industrialized after World War II, sharply increasing the extraction of resources from the natural world. Colonial empires broke up on land after the war, but they were re-created in the oceans. The United States, Japan, and the Soviet Union, as well as the British, Germans, and Spanish, industrialized their fisheries, replacing fleets of small-scale, independent artisanal fishermen with fewer but much larger government-subsidized ships. Nations like South Korea and China, as well as the Eastern Bloc countries of Poland and Bulgaria, also began fishing on an almost unimaginable scale. Countries raced to find new stocks of fish to exploit. As the Cold War deepened, nations sought to negotiate fishery agreements with Third World nations. The conflict over territorial claims led to the development of the Law of the Sea process, starting in 1958, and to the adoption of 200-mile exclusive economic zones (EEZ) in the 1970s.
Fishing expanded with the understanding that fish stocks were robust and could withstand high harvest rates. The adoption of maximum sustained yield (MSY) after 1954 as the goal of postwar fishery negotiations assumed that fish had surplus and that scientists could determine how many fish could safely be caught. As fish stocks faltered under the onslaught of industrial fisheries, scientists re-assessed their assumptions about how many fish could be caught, but MSY, although modified, continues to be at the heart of modern fisheries management.
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Environmental Science. Please check back later for the full article.
Integrated Pest Management (IPM) is an ecosystem management operational framework to make ecologically and economically sound environmental management decisions in ways that are selective for the pest encountered while minimizing effects not related to the problem at hand. The strength of IPM research and use is to constantly adapt methods and applications of the science behind adaptive decision making to ensure that the most modern and comprehensive problem-solving skills and techniques will be used to manage pest issues. Pests are ubiquitous in every human-managed ecosystem, most commonly encountered in production agriculture and forestry. Pests are also encountered by homeowners and in other environmental management regimes related to ecological restoration, just to name a few IPM use situations. IPM has been practiced by humans throughout the development of human agricultural practices, for major stable food and fiber crops since the advent of agriculture. However, the specific scientific discipline of truly integrating multiple management techniques, from pesticide application, to fertilizer regimes, to resistant plant variety selection, to ecological and cultural management, and finally to cost-benefit analyses to ensure the techniques used are comprehensive for the pest and the rest of the agricultural production system is a relatively new science, first rigorously tested and reviewed in the 1940s. The greatest strengths of the discipline are also its weakness; by being pest-taxon, crop specific, and flexible for a given environmental or management situation, there is a constant need for refinement of IPM decision making processes in very specific situations to be the most efficient and useful in a given pest situation. Given the number of sub-discipline inputs into the robust decision-making framework, many specialists need to be invested in the specific IPM program, or a highly trained and dedicated group must be accountable for wrangling diverse disciplines into a cohesive management regime. Finally, given the vast number of pests and pathogens that affect a production system, it is nearly impossible to have an IPM program for every crop, for every pest, in every system; yet this is what is called upon from the farmers or land managers in nearly every situation. Given the modern push to have answers ready at the push of a button, the discipline of IPM will continue to be refined to remain relevant and at the forefront of safe, efficient, environmentally accountable, and ultimately sustainable sciences in modern ever-changing agricultural production systems.
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.
Archis R. Ambulkar
Since the industrial revolution, societies across the globe have observed significant urbanization and population growth. Newer technologies, industries, and manufacturing plants have evolved over the period to develop sophisticated infrastructures and amenities for mankind. To achieve this, communities have utilized and exploited natural resources, resulting in sustained environmental degradation and pollution. Among various adverse ecological effects, nutrient contamination in water is posing serious problems for the water bodies worldwide.
Nitrogen and phosphorus are the basic constituents for the growth and reproduction of living organisms and occur naturally in the soil, air, and water. However, human activities are affecting their natural cycles and causing excessive dumping into the surface and groundwater systems. Higher concentrations of nitrogen and phosphorus-based nutrients in water resources lead to eutrophication, reduction in sunlight, lower dissolved oxygen levels, changing rates of plant growth, reproduction patterns, and overall deterioration of water quality. Economically, this pollution can impact the fishing industry, recreational businesses, property values, and tourism. Also, using nutrient-polluted lakes or rivers as potable water sources may result in excess nitrates in drinking water, production of disinfection by-products, and associated health effects.
Nutrients contamination in water commonly originates from point and non-point sources. Point sources are the specific discharge locations, like wastewater treatment plants (WWTP), industries, and municipal waste systems; whereas, non-point sources are discrete dischargers, like agricultural lands and storm water runoffs. Compared to non-point sources, point sources are easier to identify, regulate, and treat. WWTPs receive sewage from domestic, business, and industrial settings. With growing pollution concerns, nutrients removal and recovery at treatment plants is gaining significant attention. Newer chemical and biological nutrient removal processes are emerging to treat wastewater. Nitrogen removal mainly involves nitrification-denitrification processes; whereas, phosphorus removal includes biological uptake, chemical precipitation, or filtration. In regards to non-point sources, authorities are encouraging best management practices to control pollution loads to waterways.
Governments are opting for novel strategies like source nutrient reduction schemes, bioremediation processes, stringent effluent limits, and nutrient trading programs. Source nutrient reduction strategies such as discouraging or banning use of phosphorus-rich detergents and selective chemicals, industrial pretreatment programs, and stormwater management programs can be effective by reducing nutrient loads to WWTPs. Bioremediation techniques such as riparian areas, natural and constructed wetlands, and treatment ponds can capture nutrients from agricultural lands or sewage treatment plant effluents. Nutrient trading programs allow purchase/sale of equivalent environmental credits between point and non-point nutrient dischargers to manage overall nutrient discharges in watersheds at lower costs.
Nutrient pollution impacts are quite evident and documented in many parts of the world. Governments and environmental organizations are undertaking several waterways remediation projects to improve water quality and restore aquatic ecosystems. Shrinking freshwater reserves and rising water demands are compelling communities to make efficient use of the available water resources. With smarter choices and useful strategies, nutrient pollution in the water can be contained to a reasonable extent. As responsible members of the community, it is important for us to understand this key environmental issue as well as to learn the current and future needs to alleviate this problem.
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Environmental Science. Please check back later for the full article.
Pollution problems in aquatic sediments and on land can be quite varied—from the widespread contamination of a coastal bay receiving untreated urban or industrial discharge to the local leakage from underground petroleum tanks or pipelines. Such problems are related to the range of sediment and soil in which they occur. Sediments and soil particles can be carriers, receptors, and sources for contaminants. The effectiveness of these roles is largely related to their adsorptive capacity and is governed mainly by particle size, mineralogy, and organic matter as well as site-specific geochemical conditions. Sustainable use of land and marine areas requires a source-to-sink system perspective in order to prescribe remedial actions. Measures can focus on preventing release from the source, spreading along selective pathways, stabilization, and isolation to protect the receptor. Therefore, many traditional scientific goals, such as provenance (sediment source) identification, the interpretation of sediment transport modes and directions, and post-depositional (diagenetic) changes, are applicable and complementary tools to increase predictability between sampled sites.
The carrier function of aquatic sediments is emphasized when contaminates are transported to the site of accumulation. Ground pollution in terrestrial settings, on the other hand, is often due to more local sources. Nevertheless, retention and ecological exposure is dependent on the particle-solute interactions. The stratigraphic architecture of ground environments can also decisively influence the spread of contaminants, contrasting with the largely two-dimensional redistribution of eroded aquatic sediments. Diffuse pollution sources, including agriculture, urban, transportation, and industrial sources, contribute significantly to overall environmental stress. Quantitative modeling of contaminant fluxes is increasingly possible with database availability, but relative risk ranking is still a necessary simplification in many decision-support evaluations due to the complexity of sediment and ground environments.
Scott M. Moore
It has long been accepted that non-renewable natural resources like oil and gas are often the subject of conflict between both nation-states and social groups. But since the end of the Cold War, the idea that renewable resources like water and timber might also be a cause of conflict has steadily gained credence. This is particularly true in the case of water: in the early 1990s, a senior World Bank official famously predicted that “the wars of the next century will be fought over water,” while two years ago Indian strategist Brahma Chellaney made a splash in North America by claiming that water would be “Asia’s New Battleground.” But it has not quite turned out that way. The world has, so far, avoided inter-state conflict over water in the 21st century, but it has witnessed many localized conflicts, some involving considerable violence. As population growth, economic development, and climate change place growing strains on the world’s fresh water supplies, the relationship between resource scarcity, institutions, and conflict has become a topic of vocal debate among social and environmental scientists.
The idea that water scarcity leads to conflict is rooted in three common assertions. The first of these arguments is that, around the world, once-plentiful renewable resources like fresh water, timber, and even soils are under increasing pressure, and are therefore likely to stoke conflict among increasing numbers of people who seek to utilize dwindling supplies. A second, and often corollary, argument holds that water’s unique value to human life and well-being—namely that there are no substitutes for water, as there are for most other critical natural resources—makes it uniquely conductive to conflict. Finally, a third presumption behind the water wars hypothesis stems from the fact that many water bodies, and nearly all large river basins, are shared between multiple countries. When an upstream country can harm its downstream neighbor by diverting or controlling flows of water, the argument goes, conflict is likely to ensue.
But each of these assertions depends on making assumptions about how people react to water scarcity, the means they have at their disposal to adapt to it, and the circumstances under which they are apt to cooperate rather than to engage in conflict. Untangling these complex relationships promises a more refined understanding of whether and how water scarcity might lead to conflict in the 21st century—and how cooperation can be encouraged instead.
James B. London
Coastal zone management (CZM) has evolved since the enactment of the U.S. Coastal Zone Management Act of 1972, which was the first comprehensive program of its type. The newer iteration of Integrated Coastal Zone Management (ICZM), as applied to the European Union (2000, 2002), establishes priorities and a comprehensive strategy framework. While coastal management was established in large part to address issues of both development and resource protection in the coastal zone, conditions have changed. Accelerated rates of sea level rise (SLR) as well as continued rapid development along the coasts have increased vulnerability. The article examines changing conditions over time and the role of CZM and ICZM in addressing increased climate related vulnerabilities along the coast.
The article argues that effective adaptation strategies will require a sound information base and an institutional framework that appropriately addresses the risk of development in the coastal zone. The information base has improved through recent advances in technology and geospatial data quality. Critical for decision-makers will be sound information to identify vulnerabilities, formulate options, and assess the viability of a set of adaptation alternatives. The institutional framework must include the political will to act decisively and send the right signals to encourage responsible development patterns. At the same time, as communities are likely to bear higher costs for adaptation, it is important that they are given appropriate tools to effectively weigh alternatives, including the cost avoidance associated with corrective action. Adaptation strategies must be pro-active and anticipatory. Failure to act strategically will be fiscally irresponsible.