1-20 of 45 Results  for:

  • Environmental Economics x
Clear all

Article

Along with ceramics production, sedentism, and herding, agriculture is a major component of the Neolithic as it is defined in Europe. Therefore, the agricultural system of the first Neolithic societies and the dispersal of exogenous cultivated plants to Europe are the subject of many scientific studies. To work on these issues, archaeobotanists rely on residual plant remains—crop seeds, weeds, and wild plants—from archaeological structures like detritic pits, and, less often, storage contexts. To date, no plant with an economic value has been identified as domesticated in Western Europe except possibly opium poppy. The earliest seeds identified at archaeological sites dated to about 5500–5200 bc in the Mediterranean and Temperate Europe. The cultivated plants identified were cereals (wheat and barley), oleaginous plant (flax), and pulses (peas, lentils, and chickpeas). This crop package originated in the Fertile Crescent, where it was clearly established around 7500 bc (final Pre-Pottery Neolithic B), after a long, polycentric domestication process. From the middle of the 7th millennium bc, via the Balkan Peninsula, the pioneer Neolithic populations, with their specific economies, rapidly dispersed from east to west, following two main pathways. One was the maritime route over the northwestern basin of the Mediterranean (6200–5300 bc), and the other was the terrestrial and fluvial route in central and northwestern continental Europe (5500–4900 bc). On their trajectory, the agropastoral societies adapted the Neolithic founder crops from the Middle East to new environmental conditions encountered in Western Europe. The Neolithic pioneers settled in an area that had experienced a long tradition of hunting and gathering. The Neolithization of Europe followed a colonization model. The Mesolithic groups, although exploiting plant resources such as hazelnut more or less intensively, did not significantly change the landscape. The impact of their settlements and their activities are hardly noticeable through palynology, for example. The control of the mode of reproduction of plants has certainly increased the prevalence of Homo sapiens, involving, among others, a demographic increase and the ability to settle down in areas that were not well adapted to year-round occupation up to that point. The characterization of past agricultural systems, such as crop plants, technical processes, and the impact of anthropogenic activities on the landscape, is essential for understanding the interrelation of human societies and the plant environment. This interrelation has undoubtedly changed deeply with the Neolithic Revolution.

Article

Worldwide, governments subsidize agriculture at the rate of approximately 1 billion dollars per day. This figure rises to about twice that when export and biofuels production subsidies and state financing for dams and river basin engineering are included. These policies guide land use in numerous ways, including growers’ choices of crop and buyers’ demand for commodities. The three types of state subsidies that shape land use and the environment are land settlement programs, price and income supports, and energy and emissions initiatives. Together these subsidies have created perennial surpluses in global stores of cereal grains, cotton, and dairy, with production increases outstripping population growth. Subsidies to land settlement, to crop prices, and to processing and refining of cereals and fiber, therefore, can be shown to have independent and largely deleterious effect on soil fertility, fresh water supplies, biodiversity, and atmospheric carbon.

Article

Kevin J. Boyle and Christopher F. Parmeter

Benefit transfer is the projection of benefits from one place and time to another time at the same place or to a new place. Thus, benefit transfer includes the adaptation of an original study to a new policy application at the same location or the adaptation to a different location. The appeal of a benefit transfer is that it can be cost effective, both monetarily and in time. Using previous studies, analysts can select existing results to construct a transferred value for the desired amenity influenced by the policy change. Benefit transfer practices are not unique to valuing ecosystem service and are generally applicable to a variety of changes in ecosystem services. An ideal benefit transfer will scale value estimates to both the ecosystem services and the preferences of those who hold values. The article outlines the steps in a benefit transfer, types of transfers, accuracy of transferred values, and challenges when conducting ecosystem transfers and ends with recommendations for the implementation of benefit transfers to support decision-making.

Article

A number of challenges are faced by practitioners seeking to elicit values associated with water in a world of global change. These values are needed to assist in decision-making around the use of water as a country’s key asset. Five different pathways show the complexity of the relationship between global change and environmental valuation of water: a climate change pathway, ecosystem infrastructure pathway, population/demographics pathway, income pathway, and technological change/innovation pathway. The challenges are most acute for water when it is related to ecosystem services since values need to be elicited through the use of non-market survey-based valuation techniques. In addition, environmental valuation will be important to inform the determination of water quality standards associated with different uses of water (drinking, recreation, etc.) and the allocation of resources to provide these different services. Several case studies illustrate issues and solutions. The article concludes with an appreciation of future challenges and opportunities.

Article

Johanna Brühl, Leonard le Roux, Martine Visser, and Gunnar Köhlin

The water crisis that gripped Cape Town over the 2016–2018 period gained global attention. For a brief period of time in early 2018, it looked as if the legislative capital of South Africa would become the first major city in the world to run out of water. The case of Cape Town has broad implications for how we think about water management in a rapidly urbanizing world. Cities in the global South, especially, where often under-capacitated urban utilities need to cope with rapid demographic changes, climate change, and numerous competing demands on their tight budgets, can learn from Cape Town’s experience. The case of Cape Town draws attention to the types of decisions policymakers and water utilities face in times of crisis. It illustrates how these decisions, while being unavoidable in the short term, are often sub-optimal in the long run. The Cape Town drought highlights the importance of infrastructure diversification, better groundwater management, and communication and information transparency to build trust with the public. It also shows what governance and institutional changes need to be made to ensure long-term water security and efficient water management. The implementation of all of these policies needs to address the increased variability of water supplies due to increasingly erratic rainfall and rapidly growing urban populations in many countries. This necessitates a long-term planning horizon.

Article

The domestication of livestock animals has long been recognized as one of the most important and influential events in human prehistory and has been the subject of scholarly inquiry for centuries. Modern understandings of this important transition place it within the context of the origins of food production in the so-called Neolithic Revolution, where it is particularly well documented in southwest Asia. Here, a combination of archaeofaunal, isotopic, and DNA evidence suggests that sheep, goat, cattle, and pigs were first domesticated over a period of several millennia within sedentary communities practicing intensive cultivation beginning at the Pleistocene–Holocene transition. Resulting from more than a century of data collection, our understanding of the chronological and geographic features of the transition from hunting to herding indicate that the 9th millennium bce and the region of the northern Levant played crucial roles in livestock domestication. However, many questions remain concerning the nature of the earliest predomestic animal management strategies, the role of multiple regional traditions of animal management in the emergence of livestock, and the motivations behind the slow spread of integrated livestock husbandry systems, including all four domestic livestock species that become widespread throughout southwest Asia only at the end of the Neolithic period.

Article

Deforestation causes up to 10% of global anthropogenic carbon emissions. Reducing emissions from deforestation and degradation and enhancing forest carbon stocks can contribute to controlling greenhouse gas (GHG) emissions and limit global warming and climate change. However, global warming cannot be limited without decreasing the use of fossil fuel or emission-intensive energy sources. The forestry sector could contribute 7%–25% of global emissions reduction by 2020. Apart from emissions reduction and sink (mitigation), forests also provide cobenefits such as ecosystem services (providing food, timber, and medicinal herbs); biodiversity conservation; poverty reduction; and water quality, soil protection, and climate regulation. In 2005, the UNFCCC introduced a cost-effective mitigation strategy to reduce emissions from deforestation (RED) in developing countries. The UN’s initiative to reduce emissions from deforestation and forest degradation (REDD+) aims to transform forest management in developing countries, where the majority of tropical forests are located, using finances from developed countries. REDD+ seeks to reward actors for maintaining or restoring forests, acting as an economic instrument by putting a monetary value on every tonne of CO2 that is prevented from entering the atmosphere. Implementation of REDD+ requires economic and policy instruments that can help to control GHG emissions by enhancing carbon sinks, reducing deforestation and forest degradation, and managing sustainable forests. Payment for environmental services offers opportunities for either cofinancing or economic valuation in regard to REDD+ implementation. The challenge is to identify the most appropriate and cost-effective instrument. REDD+ fulfills the current needs for economic instruments and incentives that can be implemented with existing land use and forestry policies to control global GHG emissions. However, REDD+ requires forest governance, law enforcement, clarification of land and resource rights, and forest monitoring to work in the long term. REDD+ payments can be made for results-based actions, and the UNFCCC has identified potential ways to pay for them, but challenges remain, such as clarifying financing or funding sources, distribution of funding and sharing of benefits or incentives, carbon rights, and so on. Different aspects pf the implementation, effectiveness, and scale of REDD+ and their interactions with economic, social, and environmental benefits are important for successful REDD+ implementation.

Article

There are continuing developments in the analysis of hunger and famines, and the results of theoretical and empirical studies of hunger and food insecurity highlight cases where hunger intensifies sufficiently to be identified as famine. The varying ability of those affected to cope with the shocks and stresses imposed on them are central to the development of food insecurity and the emergence of famine conditions and to explaining the complex interrelationships between agriculture, famine, and economics. There are a number of approaches to understanding how famines develop. The Malthusian approach, which sees population growth as the primary source of hunger and famine, can be contrasted with the free market or Smithian approach, which regards freely operating markets as an essential prerequisite for ensuring that famine can be overcome. A major debate has centered on whether famines primarily emerge from a decline in the availability of food or are a result of failure by households to access sufficient food for consumption, seeking to distinguish between famine as a problem related to food production and availability and famine as a problem of declining income and food consumption among certain groups in the population. These declines arise from the interaction between food markets, labor markets and markets for livestock and other productive farm resources when poor people try to cope with reduced food consumption. Further revisions to famine analysis were introduced from the mid-1990s by authors who interpreted the emergence of famines not as a failure in markets and the economic system, but more as a failure in political accountability and humanitarian response. These approaches have the common characteristic that they seek to narrow the focus of investigation to one or a few key characteristics. Yet most of those involved in famine analysis or famine relief would stress the multi-faceted and broad-based nature of the perceived causes of famine and the mechanisms through which they emerge. In contrast to these approaches, the famine systems approach takes a broader view, exploring insights from systems theory to understand how famines develop and especially how this development might be halted, reversed, or prevented. Economists have contributed to and informed different perspectives on famine analysis while acknowledging key contributions from moral philosophy as well as from biological and physical sciences and from political and social sciences. Malthus, Smith, and John Stuart Mill contributed substantially to early thinking on famine causation and appropriate famine interventions. Increased emphasis on famine prevention and a focus on food production and productivity led to the unarguable success of the Green Revolution. An important shift in thinking in the 1980s was motivated by Amartya Sen’s work on food entitlements and on markets for food and agricultural resources. On the other hand, the famine systems approach considers famine as a process governed by complex relationships and seeks to integrate contributions from economists and other scientists while promoting a systems approach to famine analysis.

Article

Jinbo Song, Lulu Jin, Chen Qian, and Yan Sun

With the upgrading of living standards and rapid urbanization around the globe, waste treatment has become a ubiquitous environmental issue. Increased waste generation and narrowed prospects for landfill and composting have brought strong growth prospects for the waste-to-energy (WtE) industry. WtE is considered an effective method for waste treatment because it can significantly reduce the land use and environmental pollutants caused by other methods and can generate energy by means of electricity or heat from the treatment of waste. However, there have been supportive and opposing opinions about WtE from the economic, environmental, and social perspectives. Whether WtE plants are the best option depends not only on associated investment and operating costs but also on the environmental and social costs (termed as external cost) as compared to other waste treatment options. Economic costs are generally estimated by market price of materials, labor, and equipment. Social costs normally refer to health effects, transportation congestion, and environmental impacts, including the emission of gas and leachate. Qualitative and quantitative methods are proposed to assist in decision making on waste disposal alternatives. The qualitative method relies on the expert experience to rank waste treatment options, such as analytic hierarchy process and multicriteria decision model, while the quantitative method, such as life cycle assessment and social cost-benefit analysis, calculates the economic cost and monetizes the abstract external cost in the light of the historical data. The two methods offer different advantages and disadvantages, and thus cater to different conditions. In developed countries, along with the rapid development of WtE and the increase in available cost data, the estimation of the economic, environmental, and social costs is achievable, which promotes the popularization of quantitative method. In China and other developing countries, quantitative analysis is limited to the estimation of economic cost and the qualitative method is still dominated in the evaluation of environmental and social impacts due to the lack of cost data.

Article

Mark Eiswerth, Chad Lawley, and Michael H. Taylor

Introductions of non-native invasive species can harm ecosystems, heighten the risk of native species extinctions and population reductions, and lead to substantial economic damages on a worldwide scale. Increasingly, economists have made contributions that help other researchers, policymakers, and society better understand the economic implications of invasive species as well as the most economically efficient approaches for managing them. The complexity of invasive species management problems has pushed economists to ask novel economic questions and to develop new analytical approaches in order to address specific policy questions. There are three areas, in particular, where the economic analysis of invasive species management has led to significant innovations. First, there are substantial challenges to quantifying economic damages from invasive species for application in benefit−cost analysis. The challenges relate to defining the counterfactual state of an invaded ecosystem with and without management/policy and to the fact that, in a given ecosystem, estimates of economic damages are available for only a subset of the species and for only a subset of damages for any one species. Recent economic research has proposed innovative approaches to systematically dealing with these two issues in the context of invasive species that have implications for applied benefit−cost analysis more broadly. Second, unique among natural resource management problems, invasive species have the feature that their current and future extents are directly tied to a country’s participation in international trade. This feature has led to innovative research into the design of efficient measures to prevent or delay invasive species introductions along national borders, and into the trade-offs between these measures and the use of border controls as protectionist tools. The issues of optimal inspection policy and the use of nontariff barriers as a form of covert protectionism both have implications beyond invasive species management. Third, researchers have developed bioeconomic models that integrate economic and biological factors in order to analyze strategies to more cost-effectively reduce the damages caused by invasive species. These modeling efforts have dealt with issues related to temporal and spatial dynamics of the biological invasions, imperfect information regarding the extent of the invasion and the effectiveness of management, linkages between management applied at different stages of an invasion, and complications arising from ecosystems’ crossing over ecological thresholds due to invasions. In the face of increasingly rapid ecosystem change due to global climate change, increases in extreme weather, urban encroachment into wild lands, and other factors, many of these features of invasive species management problems are likely to become features of ecosystem management more broadly in the near future if they are not so already.

Article

Dominic Moran and Jorie Knook

Climate change is already having a significant impact on agriculture through greater weather variability and the increasing frequency of extreme events. International policy is rightly focused on adapting and transforming agricultural and food production systems to reduce vulnerability. But agriculture also has a role in terms of climate change mitigation. The agricultural sector accounts for approximately a third of global anthropogenic greenhouse gas emissions, including related emissions from land-use change and deforestation. Farmers and land managers have a significant role to play because emissions reduction measures can be taken to increase soil carbon sequestration, manage fertilizer application, and improve ruminant nutrition and waste. There is also potential to improve overall productivity in some systems, thereby reducing emissions per unit of product. The global significance of such actions should not be underestimated. Existing research shows that some of these measures are low cost relative to the costs of reducing emissions in other sectors such as energy or heavy industry. Some measures are apparently cost-negative or win–win, in that they have the potential to reduce emissions and save production costs. However, the mitigation potential is also hindered by the biophysical complexity of agricultural systems and institutional and behavioral barriers limiting the adoption of these measures in developed and developing countries. This includes formal agreement on how agricultural mitigation should be treated in national obligations, commitments or targets, and the nature of policy incentives that can be deployed in different farming systems and along food chains beyond the farm gate. These challenges also overlap growing concern about global food security, which highlights additional stressors, including demographic change, natural resource scarcity, and economic convergence in consumption preferences, particularly for livestock products. The focus on reducing emissions through modified food consumption and reduced waste is a recent agenda that is proving more controversial than dealing with emissions related to production.

Article

Maria L. Loureiro and Maria Alló

Vessel oil spills are very serious natural hazards that have affected coasts worldwide for many decades. Although oil spills from tankers are highly publicized, very little is known about the role played by the incentives and regulatory instruments in place to prevent them. In order to shed some light on these issues, data were collected worldwide on large oil spills from multiple databases, starting in the 1970s, and merged with other socioeconomic records. A crucial concern is that that large oil spills have been undercompensated over time with respect to the damages caused. A meta-analysis was estimated in order to assess relevant factors affecting the damage claimed in oil spills and the compensations received by the affected parties. Meta-regression results show that the legislation applied (strict unlimited liability versus limited liability) played a crucial role in both the amount claimed and the final compensation received. Also, time-trend variables are shown as determining factors for both the damages and claims that are finally paid. To correct the large gap between damage claimed and compensation scenarios, it is recommended to strengthen compensation funds, while carrying out more comprehensive assessment studies which apply valuation methods comparable with those proposed by green capital initiatives for marine ecosystem services, and which could be used successfully during the litigation process.

Article

Reforestation is the natural or intentional restocking of existing forests and woodlands that have been harvested or depleted, and afforestation is the establishing of a forest in an area where there were no trees. For economic and practical purposes, reforestation and afforestation have similar goals and processes and thus can be treated as identical activities. Although reforestation and afforestation have a long history, large-scale reforestation and afforestation activities started with industrialization, which caused scarcity in timber and forest-based ecosystem services. In a unified economic model of reforestation and afforestation, factors influencing investments in reforestation and in afforestation on private and public lands include timber prices, unit reforestation cost, interest rate, the responsiveness of tree growth to silviculture, and the value of nontimber benefits, such as ecosystem services. Market and public policies may facilitate, enhance, or hinder reforestation and afforestation activities, and nontimber benefits are an increasingly important motive for reforestation and, especially, afforestation efforts around the world.

Article

Water scarcity has long been recognized as a key issue challenging China’s water security and sustainable development. Economically, China’s water scarcity can be characterized by the uneven distribution of limited water resources across space and time in hydrological cycles that are inconsistent with the rising demand for a sufficient, stable water supply from rapid socioeconomic development coupled with a big, growing population. The limited water availability or scarcity has led to trade-offs in water use and management across sectors and space, while negatively affecting economic growth and the environment. Meanwhile, inefficiency and unsustainability prevail in China’s water use, attributable to government failure to account for the socioeconomic nature of water and its scarcity beyond hydrology. China’s water supply comes mainly from surface water and groundwater. The nontraditional sources, wastewater reclamation and reuse in particular, have been increasingly contributing to water supply but are less explored. Modern advancement in solar and nuclear power development may help improve the potential and competitiveness of seawater desalination as an alternative water source. Nonetheless, technological measures to augment water supply can only play a limited role in addressing water scarcity, highlighting the necessity and importance of nontechnological measures and “soft” approaches for managing water. Water conservation, including improving water use efficiency, particularly in the agriculture sector, represents a reasonable strategy that has much potential but requires careful policy design. China’s water management has started to pay greater attention to market-based approaches, such as tradable water rights and water pricing, accompanied by management reforms. In the past, these approaches have largely been treated as command-and-control tools for regulation rather than as economic instruments following economic design principles. While progress has been made in promoting the market-based approaches, the institutional aspect needs to be further improved to create supporting and enabling conditions. For water markets, developing regulations and institutions, combined with clearly defining water use rights, is needed to facilitate market trading of water rights. For water pricing, appropriate design based on the full cost of water supply needs to be strengthened, and policy implementation must be enforced. An integrated approach is particularly relevant and greatly needed for China’s water management. This approach emphasizes integration and holistic consideration of water in relation to other resource management, development opportunities, and other policies across scales and sectors to achieve synergy, cost-effectiveness, multiple benefits, and eventually economic efficiency. Integrated water management has been increasingly applied, as exemplified by a national policy initiative to promote urban water resilience and sustainability. While economics can play a critical role in helping evaluate and compare alternative measures or design scenarios and in identifying multiple benefits, there is a need for economic or social cost–benefit analysis of China’s water policy or management that incorporates nonmarket costs and benefits.

Article

Watersheds are physical regions from which all arriving water flows to a single exit point. The shared hydrology means that other biophysical systems are linked, typically with upper-gradient regions influencing lower-gradient ones. This situation frames the challenge of managing economic and other uses of watersheds both in terms of individual activities and their influence on other connected processes and activities. Economics provides concepts and methods that help managers with decision making in the complex physical, biological, and institutional environment of a watershed. Among the important concepts and methods that help characterize watershed processes are externalities, impacts of economic activity that fall upon individuals not party to the activity, and third parties, individuals impacted without consent. Public goods and common pool resources describe categories of things or processes that by their nature are not amenable to regular market transactions. Their regulation requires special consideration and alternative approaches to markets. Benefit-cost analysis and valuation are related methods that provide a means to compare alternative uses of the same system. Each is based on the normative argument that the best use provides the greatest net benefits to society. And intergenerational equity is a value orientation that argues for preservation of watershed processes for the benefit of future generations. The need for effective watershed management methods pushed 20th-century economists to adapt their discipline to the complexity of watersheds, from which emerged subdisciplines of natural resource economics, environmental economics, and ecological economics. The field is still evolving with a growing interest in data gathering through land-based low-cost data collection systems and remote sensing, and in emerging data analysis techniques to improve management decisions.

Article

Marisol Rivera-Planter, Carlos Muñoz-Piña, and Mariza Montes de Oca

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. While most attention on the use of economic instruments for environmental protection has centered on their applications in industrialized countries, middle-income countries have made important inroads as well. Among them, Mexico stands out for its application to the agenda of a wide array of green and brown issues. Starting in 2001, with the introduction of fees to access natural protected areas, followed in 2003, with the establishment of the Payment for Ecosystems Services program for forests, and then in 2014, the introduction of the environmental tax on pesticides, the use of complementary price signals through the fiscal system has sought to influence, in a decentralized manner, the decisions of both consumers and resource owners towards protecting key elements of Mexico’s natural capital. As the central promise from economic instruments is to reduce compliance costs of reaching a certain goal by providing flexibility on how to meet individual obligations, the use of market-based mechanisms in regulations has also been explored with some success in Mexico. Partial incorporation of such a mechanism was applied to the design of its national Federal Fuel Efficiency standards for automobiles, by redefining compliance as meeting a corporate average standard starting from 2006 onwards. More recently, full use of market mechanisms was introduced, in 2016, into the strategy to reach Mexico’s Clean Energy requirement goals. The demonstration by utilities of compliance with the milestone of the national 2024 goal of 35% share of clean energy in power generation can be done either by holding or purchasing Clean Energy Certificates in their secondary market. This allows utilities to separate the decision to purchase energy at the lowest cost, and to meet environmental requirements, also at their lowest cost. Both tax and market mechanisms are converging with Mexico’s Climate Change policy. The Fiscal Reform of 2014 introduced Mexico’s first explicit carbon tax in the form of an excise tax applied to fossil fuels, just as its G20 commitments to phase-out negative carbon pricing (i.e., fossil fuel subsidies) were being fulfilled. With price signals pushing towards more energy efficiency and a lower carbon footprint for the economy, Mexico is on the right track for carbon pricing and is showing leadership at a global scale. It will be interesting to observe how this will mix with a proposed cap-and-trade carbon mechanism, obviously touted as a complementary instrument. The establishment of such a mechanism to meet the emission reduction goals of Mexico’s Climate Change legislation and international commitments is the subject of intense debate and analysis. It represents an interesting decision point for a middle-income country such as Mexico, where all costs are local in nature, the emissions per capita are at the world’s average, and indirect benefits of the energy transition are only partial. In the political economy debate, the linkage to international markets, such as California and Quebec, is not only an option but a central motivation to launch the market, as gains from trade are the driving force.

Article

Geologists’ reframing of the global changes arising from human impacts can be used to consider how the insights from environmental economics inform policy under this new perspective. They ask a rhetorical question. How would a future generation looking back at the records in the sediments and ice cores from today’s activities judge mankind’s impact? They conclude that the globe has entered a new epoch, the Anthropocene. Now mankind is the driving force altering the Earth’s natural systems. This conclusion, linking a physical record to a temporal one, represents an assessment of the extent of current human impact on global systems in a way that provides a warning that all policy design and evaluation must acknowledge that the impacts of human activity are taking place on a planetary scale. As a result, it is argued that national and international environmental policies need to be reconsidered. Environmental economics considers the interaction between people and natural systems. So it comes squarely into conflict with conventional practices in both economics and ecology. Each discipline marginalizes the role of the other in the outcomes it describes. Market and natural systems are not separate. This conclusion is important to the evaluation of how (a) economic analysis avoided recognition of natural systems, (b) the separation of these systems affects past assessments of natural resource adequacy, and (c) policy needs to be redesigned in ways that help direct technological innovation that is responsive to the importance of nonmarket environmental services to the global economy and to sustaining the Earth’s living systems.

Article

Ruda Zhang, Patrick Wingo, Rodrigo Duran, Kelly Rose, Jennifer Bauer, and Roger Ghanem

Economic assessment in environmental science means measuring and evaluating environmental impacts, adaptation, and vulnerability. Integrated assessment modeling (IAM) is a unifying framework of environmental economics, which attempts to combine key elements of physical, ecological, and socioeconomic systems. The first part of this article reviews the literature on the IAM framework: its components, relations between the components, and examples. For such models to inform environmental decision-making, they must quantify the uncertainties associated with their estimates. Uncertainty characterization in integrated assessment varies by component models: uncertainties associated with mechanistic physical models are often assessed with an ensemble of simulations or Monte Carlo sampling, while uncertainties associated with impact models are evaluated by conjecture or econometric analysis. The second part of this article reviews the literature on uncertainty in integrated assessment, by type and by component. Probabilistic learning on manifolds (PLoM) is a machine learning technique that constructs a joint probability model of all relevant variables, which may be concentrated on a low-dimensional geometric structure. Compared to traditional density estimation methods, PLoM is more efficient especially when the data are generated by a few latent variables. With the manifold-constrained joint probability model learned by PLoM from a small, initial sample, manifold sampling creates new samples for evaluating converged statistics, which helps answer policy-making questions from prediction, to response, and prevention. As a concrete example, this article reviews IAMs of offshore oil spills—which integrate environmental models, transport models, spill scenarios, and exposure metrics—and demonstrates the use of manifold sampling in assessing the risk of drilling in the Gulf of Mexico.

Article

The environmental Kuznets curve (EKC) is a hypothesized relationship between environmental degradation and GDP per capita. In the early stages of economic growth, pollution emissions and other human impacts on the environment increase, but beyond some level of GDP per capita (which varies for different indicators), the trend reverses, so that at high income levels, economic growth leads to environmental improvement. This implies that environmental impacts or emissions per capita are an inverted U-shaped function of GDP per capita. The EKC has been the dominant approach among economists to modeling ambient pollution concentrations and aggregate emissions since Grossman and Krueger introduced it in 1991 and is even found in introductory economics textbooks. Despite this, the EKC was criticized almost from the start on statistical and policy grounds, and debate continues. While concentrations and also emissions of some local pollutants, such as sulfur dioxide, have clearly declined in developed countries in recent decades, evidence for other pollutants, such as carbon dioxide, is much weaker. Initially, many understood the EKC to imply that environmental problems might be due to a lack of sufficient economic development, rather than the reverse, as was conventionally thought. This alarmed others because a simplistic policy prescription based on this idea, while perhaps addressing some issues like deforestation or local air pollution, could exacerbate environmental problems like climate change. Additionally, many of the econometric studies that supported the EKC were found to be statistically fragile. Some more recent research integrates the EKC with alternative approaches and finds that the relation between environmental impacts and development is subtler than the simple picture painted by the EKC. This research shows that usually, growth in the scale of the economy increases environmental impacts, all else held constant. However, the impact of growth might decline as countries get richer, and richer countries are likely to make more rapid progress in reducing environmental impacts. Finally, there is often convergence among countries, so that countries that have relatively high levels of impacts reduce them more quickly or increase them more slowly, all else held constant.

Article

Haitao Yin, Xuemei Zhang, and Feng Wang

China’s environmental challenges are unprecedented in terms of their size and severity. The country’s constantly evolving regulatory systems are a blend of lessons learned from Western market- and information-based regulations, China’s own unique political and administrative context as an authoritarian country, the complex relationship between its central and local governments, and the balance between the needs for environmental protection and economic growth. A close look at China’s environmental regulatory system may offer useful insights to those working toward a more sustainable future. In the 21st century, the environmental regulatory system in China is entering a new era. Over the last three decades, efforts have focused on developing regulatory standards for air, water, and solid waste, among many other pollutants. This regulatory system primarily follows a command-and-control approach and is often criticized for its failure to curb China’s increasingly severe environmental degradation. In the future, the Chinese government may pursue two routes. The first is to increase the use of market mechanisms and information tools to enable and incentivize more stakeholders, such as consumers, nongovernmental organizations, and communities, to engage in the development and enforcement of environmental regulations, for instance, through cap-and-trade systems, information-disclosure programs, and environmental insurance. However, existing evidence shows that the usefulness of these new instruments is limited. Another route is to develop new mechanisms to strengthen the enforcement of traditional command-and-control regulations. Examples include making environmental performance a key performance indicator (KPI) in the performance appraisals of government officials or leveraging the power of financial sectors. These approaches are a footnote to the new argument in favor of environmental authoritarianism, which suggests that authoritarian regimes, setting authoritarian rules, may be more capable of handling complex environmental pressures. More studies need to be conducted on the effectiveness of these new approaches and the mechanisms by which they may achieve success.