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Soil erosion by water is a natural process that cannot be avoided. Soil erosion depends on many factors, and a distinction should be made between humanly unchangeable (e.g., rainfall) and modifiable (e.g., length of the field) soil erosion factors. Soil erosion has both on-site and off-site effects. Soil conservation tries to combine modifiable factors so as to maintain erosion in an area of interest to an acceptable level. Strategies to control soil erosion have to be adapted to the desired land use. Knowledge of soil loss tolerance, T, i.e., the maximum admissible erosion from a given field, allows technicians or farmers to establish whether soil conservation practices need to be applied to a certain area or not. Accurate evaluation of the tolerable soil erosion level for an area of interest is crucial for choosing effective practices to mitigate this phenomenon. Excessively stringent standards for T would imply over expenditure of natural, financial, and labor resources. Excessively high T values may lead to excessive soil erosion and hence decline of soil fertility and productivity and to soil degradation. In this last case, less money is probably spent for soil conservation, but ineffectively. Basic principles to control erosion for different land uses include maintaining vegetative and ground cover, incorporating biomass into the soil, minimizing soil disturbance, increasing infiltration, and avoiding long field lengths. Preference is generally given to agronomic measures as compared with mechanical measures since the former ones reduce raindrop impact, increase infiltration, and reduce runoff volumes and water velocities. Agronomic measures for soil erosion control include choice of crops and crop rotation, applied tillage practices, and use of fertilizers and amendments. Mechanical measures include contour, ridging, and terracing. These measures cannot prevent detachment of soil particles, but they counter sediment transport downhill and can be unavoidable in certain circumstances, at least to supplement agronomic measures. Simple methods can be applied to approximately predict the effect of a given soil conservation measure on soil loss for an area of interest. In particular, the simplest way to quantitatively predict mitigation of soil erosion due to a particular conservation method makes use of the Universal Soil Loss Equation (USLE). Despite its empirical nature, this model still appears to represent the best compromise between reliability of the predictions and simplicity in terms of input data, which are generally very difficult to obtain for other soil erosion prediction models. Soil erosion must be controlled soon after burning.
The emergence of environment as a security imperative is something that could have been avoided. Early indications showed that if governments did not pay attention to critical environmental issues, these would move up the security agenda. As far back as the Club of Rome 1972 report, Limits to Growth, variables highlighted for policy makers included world population, industrialization, pollution, food production, and resource depletion, all of which impact how we live on this planet.
The term environmental security didn’t come into general use until the 2000s. It had its first substantive framing in 1977, with the Lester Brown Worldwatch Paper 14, “Redefining Security.” Brown argued that the traditional view of national security was based on the “assumption that the principal threat to security comes from other nations.” He went on to argue that future security “may now arise less from the relationship of nation to nation and more from the relationship between man to nature.”
Of the major documents to come out of the Earth Summit in 1992, the Rio Declaration on Environment and Development is probably the first time governments have tried to frame environmental security. Principle 2 says: “States have, in accordance with the Charter of the United Nations and the principles of international law, the sovereign right to exploit their own resources pursuant to their own environmental and developmental policies, and the responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of national.”
In 1994, the UN Development Program defined Human Security into distinct categories, including:
• Economic security (assured and adequate basic incomes).
• Food security (physical and affordable access to food).
• Health security.
• Environmental security (access to safe water, clean air and non-degraded land).
By the time of the World Summit on Sustainable Development, in 2002, water had begun to be identified as a security issue, first at the Rio+5 conference, and as a food security issue at the 1996 FAO Summit. In 2003, UN Secretary General Kofi Annan set up a High-Level Panel on “Threats, Challenges, and Change,” to help the UN prevent and remove threats to peace. It started to lay down new concepts on collective security, identifying six clusters for member states to consider. These included economic and social threats, such as poverty, infectious disease, and environmental degradation.
By 2007, health was being recognized as a part of the environmental security discourse, with World Health Day celebrating “International Health Security (IHS).” In particular, it looked at emerging diseases, economic stability, international crises, humanitarian emergencies, and chemical, radioactive, and biological terror threats. Environmental and climate changes have a growing impact on health. The 2007 Fourth Assessment Report (AR4) of the UN Intergovernmental Panel on Climate Change (IPCC) identified climate security as a key challenge for the 21st century. This was followed up in 2009 by the UCL-Lancet Commission on Managing the Health Effects of Climate Change—linking health and climate change.
In the run-up to Rio+20 and the launch of the Sustainable Development Goals, the issue of the climate-food-water-energy nexus, or rather, inter-linkages, between these issues was highlighted. The dialogue on environmental security has moved from a fringe discussion to being central to our political discourse—this is because of the lack of implementation of previous international agreements.
Jean Louis Weber
Environmental accounting is an attempt to broaden the scope of the accounting frameworks used to assess economic performance, to take stock of elements that are not recorded in public or private accounting books. These gaps occur because the various costs of using nature are not captured, being considered, in many cases, as externalities that can be forwarded to others or postponed. Positive externalities—the natural resource—are depleted with no recording in National Accounts (while companies do record them as depreciation elements). Depletion of renewable resource results in degradation of the environment, which adds to negative externalities resulting from pollution and fragmentation of cyclic and living systems. Degradation, or its financial counterpart in depreciation, is not recorded at all. Therefore, the indicators of production, income, consumption, saving, investment, and debts on which many economic decisions are taken are flawed, or at least incomplete and sometimes misleading, when immediate benefits are in fact losses in the long run, when we consume the reproductive functions of our capital. Although national accounting has been an important driving force in change, environmental accounting encompasses all accounting frameworks including national accounts, financial accounting standards, and accounts established to assess the costs and benefits of plans and projects.
There are several approaches to economic environmental accounting at the national level. Of these approaches, one purpose is the calculation of genuine economic welfare by taking into account losses from environmental damage caused by economic activity and gains from unrecorded services provided by Nature. Here, particular attention is given to the calculation of a “Green GDP” or “Adjusted National Income” and/or “Genuine Savings” as well as natural assets value and depletion. A different view considers the damages caused to renewable natural capital and the resulting maintenance and restoration costs. Besides approaches based on benefits and costs, more descriptive accounts in physical units are produced with the purpose of assessing resource use efficiency. With regard to natural assets, the focus can be on assets directly used by the economy, or more broadly, on ecosystem capacity to deliver services, ecosystem resilience, and its possible degradation. These different approaches are not necessarily contradictory, although controversies can be noted in the literature.
The discussion focuses on issues such as the legitimacy of combining values obtained with shadow prices (needed to value the elements that are not priced by the market) with the transaction values recorded in the national accounts, the relative importance of accounts in monetary vs. physical units, and ultimately, the goals for environmental accounting. These goals include assessing the sustainability of the economy in terms of conservation (or increase) of the net income flow and total economic wealth (the weak sustainability paradigm), in relation to the sustainability of the ecosystem, which supports livelihoods and well-being in the broader sense (strong sustainability).
In 2012, the UN Statistical Commission adopted an international statistical standard called, the “System of Environmental-Economic Accounting Central Framework” (SEEA CF). The SEEA CF covers only items for which enough experience exists to be proposed for implementation by national statistical offices. A second volume on SEEA-Experimental Ecosystem Accounting (SEEA-EEA) was added in 2013 to supplement the SEEA CF with a research agenda and the development of tests. Experiments of the SEEA-EEA are developing at the initiative of the World Bank (WAVES), UN Environment Programme (VANTAGE, ProEcoServ), or the UN Convention on Biological Diversity (CBD) (SEEA-Ecosystem Natural Capital Accounts-Quick Start Package [ENCA-QSP]).
Beside the SEEA and in relation to it, other environmental accounting frameworks have been developed for specific purposes, including material flow accounting (MFA), which is now a regular framework at the Organisation for Economic Co-operation and Development (OECD) to report on the Green Growth strategy, the Intergovernmental Panel on Climate Change (IPCC) guidelines for the UN Framework Convention on Climate Change (UNFCCC), reporting greenhouse gas emissions and carbon sequestration. Can be considered as well the Ecological Footprint accounts, which aim at raising awareness that our resource use is above what the planet can deliver, or the Millennium Ecosystem Assessment of 2005, which presents tables and an overall assessment in an accounting style. Environmental accounting is also a subject of interest for business, both as a way to assess impacts—costs and benefits of projects—and to define new accounting standards to assess their long term performance and risks.
Leonor Rodriguez Sinobas
Center-pivot irrigation systems started in the United States in the mid-20th century as an irrigation method which surpassed the traditional surface irrigation methods. At that time, they had the potential to bring about higher irrigation efficiencies with less water consumption although their requirements in energy were higher too. Among their benefits, it is highlighted the feasibility to control water management as well as the application of agro-chemicals dissolved in the irrigation water and thus, center-pivot irrigation systems have spread worldwide. Nevertheless, since the last decade of the 20th century, they are facing actual concerns regarding ecosystem sustainability and water and energy efficiencies. Likewise, the 21st century has brought about the cutting edge issue “precision irrigation” which has made feasible the application of water, fertilizers, and chemicals as the plant demands taking into account variables such as: sprinkler´s pressure, terrain topography, soil variability, and climatic conditions. Likewise, it could be adopted to deal with the current key issues regarding the sustainability and efficiency of the center-pivot irrigation to maintain the agro-ecosystems but still, other issues such as the organic matter incorporation are far to be understood and they will need further studies.
Global environmental change amplifies and creates pressures that shape human migration. In the 21st century, there has been increasing focus on the complexities of migration and environmental change, including forecasts of the potential scale and pace of so-called environmental migration, identification of geographic sites of vulnerability, policy implications, and the intersections of environmental change with other drivers of human migration. Migration is increasingly viewed as an adaptive response to climatic and environmental change, particularly in terms of livelihood vulnerability and risk diversification. Yet the adaptive potential of migration will be defined in part by health outcomes for migrating populations. There has been limited examination, however, of the health consequences of migration related to environmental change.
Migration related to environmental change includes diverse types of mobility, including internal migration to urban areas, cross-border migration, forced displacement following environmental disaster, and planned relocation—migration into sites of environmental vulnerability; much-debated links between environmental change, conflict, and migration; immobile or “trapped” populations; and displacement due to climate change mitigation and decarbonization action. Although health benefits of migration may accrue, such as increased access to health services or migration away from sites of physical risk, migration—particularly irregular (undocumented) migration and forced displacement—can amplify vulnerabilities and present risks to health and well-being. For diverse migratory pathways, there is the need to anticipate, respond to, and ameliorate population health burdens among migrants.
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.
V. Kerry Smith
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.
Enuvie G. Akpokodje
Deltas have played a significant role in the growth of human civilization because of their unique economic and ecological importance. However, deltas are becoming increasingly vulnerable because of the impact of intensive human developmental activities, high population and urban growth, subsidence, climate change, and the associated rise in sea level. The trapping of sediments by dams is another major threat to the long-term stability and sustainability of deltas. The emergence and global acceptance of the concept of sustainable development in the 1980s led to the advent of several multidisciplinary and applied fields of research, including environmental science, environmental geology, and sustainability science. Environmental geology focuses on the application of geologic knowledge and principles to broad-ranging environmental and socioeconomic issues, including the specific problems confronting deltas. The key environmental geologic challenges in deltas (especially urban delta areas) are: increasing exposure and vulnerability to geologic hazards (flooding, cyclones, etc.), rise in sea level, decreasing sediment load supply, contamination of soil and water resources, provision of adequate drinking water, and safe waste disposal. The application of geologic knowledge and principles to these challenges requires consideration of the critical geologic controls, such as the geological history, stratigraphy, depositional environment, and the properties of the alluvial sediments. Until recently, most of the traditional engineered solutions in the management of deltas were designed to keep out water (fighting nature), typically without adequate geological/hydrological input, rather than building with nature. Recent innovative approaches to delta management involve a paradigm shift from the traditional approach to a more integrated, holistic, adaptive, and ecologically based philosophy that incorporates some critical geological and hydrological perspectives, for instance, widening and deepening rivers and flood plains as well as constructing secondary channels (i.e., making more room for water). A key challenge, however, is the establishment of a close and functional communication between environmental geologists and all other stakeholders involved in delta management. In addition, there is growing global consensus regarding the need for international cooperation that cuts across disciplines, sectors, and regions in addressing the challenges facing deltas. Integrating good policy and governance is also essential.
Michael N. Moore
Humans have been exposed to naturally occurring toxic chemicals and materials over the course of their existence as a species. These materials include various metals, the metalloid arsenic, and atmospheric combustion particulates, as well as bacterial, fungal, algal, and plant toxins. They have also consumed plants that contain a host of phytochemicals, many of which are believed to be beneficial, such as plant polyphenols. People are exposed to these various substances from a number of sources. The pathways of exposure include air, water, groundwater, soil (including via plants grown in toxic soils), and various foods, such as vegetables, fruit, fungi, seafood and fish, eggs, wild birds, marine mammals, and farmed animals.
An overview of the various health benefits, hazards and risks relating to the risks reveals the very wide variety of chemicals and materials that are present in the natural environment and can interact with human biology, to both its betterment and detriment.
The major naturally occurring toxic materials that impact human health include metals, metalloids (e.g., arsenic), and airborne particulates. The Industrial Revolution is a major event that increased ecosystem degradation and the various types and duration of exposure to toxic materials. The explosions in new organic and organometallic products that were and still are produced over the past two centuries have introduced new toxicities and associated pathologies. The prevalence in the environment of harmful particulates from motor-vehicle exhaust emissions, road dust and tire dust, and other combustion processes must also be considered in the broader context of air pollution.
Natural products, such as bacterial, fungal, algal, and plant toxins, can also have adverse effects on health. At the same time, plant-derived phytochemicals (i.e., polyphenols, terpenoids, urolithins, and phenolic acids, etc.) also have beneficial and potential beneficial effects, particularly with regard to their anti-inflammatory effects. Because inflammation is associated with most disease processes, phytochemicals that have antioxidant and anti-inflammatory properties are of great interest as potential nutraceuticals. These potentially beneficial compounds may help to combat various cancers; autoimmune conditions; neurodegenerative diseases, including dementias; and psychotic conditions, such as depression, and are also essential micronutrients that promote health and well-being. The cellular and molecular mechanisms in humans that phytochemicals modulate, or otherwise interact with, to improve human health are now known.
In the early 21st century, some of the current pollution issues are legacy problems from past industrialization, such as mercury and persistent organic pollutants (POPs). These POPs include many organochlorine compounds (e.g., polychlorinated biphenyls, pesticides, polychlorinated and polybrominated dibenzo-dioxans and -furans), as well as polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and others. The toxicity of chemical mixtures is still a largely unknown problem, particularly with regard to possible synergies. The continuing development of new organic chemicals and nanomaterials is an important environmental health issue; and the need for vigilance with respect to their possible health hazards is urgent. Nanomaterials, in particular, pose potential novel problems in the context of their chemical properties; humans have not previously been exposed to these types of materials, which may well be able to exploit gaps in our existing cellular protection mechanisms.
Hopefully, future advances in knowledge emerging from combinatorial chemistry, molecular modeling, and predictive quantitative structure-activity relationships (QSARs), will enable improved identification of the potential toxic properties of novel industrial organic chemicals, pharmaceuticals, and nanomaterials before they are released into the natural environment, and thus prevent a repetition of past disastrous events.
Russian environmental history is a new field of inquiry, with the first archivally based monographs appearing only in the last years of the 20th century. Despite the field’s youth, scholars studying the topic have developed two distinct and contrasting approaches to its central question: How should the relationship between Russian culture and the natural world be characterized? Implicit in this question are two others: Is the Russian attitude toward the non-human world more sensitive than that which prevails in the West; and if so, is the Russian environment healthier or more stable than that of the United States and Western Europe? In other words, does Russia, because of its traditional suspicion of individualism and consumerism, have something to teach the West? Or, on the contrary, has the Russian historical tendency toward authoritarianism and collectivism facilitated predatory policies that have degraded the environment? Because environmentalism as a political movement and environmental history as an academic subject both emerged during the Cold War, at a time when the Western social, political, and economic system vied with the Soviet approach for support around the world, the comparative (and competitive) aspect of Russian environmental history has always been an important factor, although sometimes an implicit one. Accordingly, the existing scholarly works about Russian environmental history generally fall into one of two camps: one very critical of the Russian environmental record and the seeming disregard of the Russian government for environmental damage, and a somewhat newer group of works that draw attention to the fundamentally different concerns that motivate Russian environmental policies. The first group emphasizes Russian environmental catastrophes such as the desiccated Aral Sea, the eroded Virgin Lands, and the public health epidemics related to the severely polluted air of Soviet industrial cities. The environmental crises that the first group cites are, most often, problems once prevalent in the West, but successfully ameliorated by the environmental legislation of the late 1960s and early 1970s. The second group, in contrast, highlights Russian environmental policies that do not have strict Western analogues, suggesting that a thorough comparison of the Russian and Western environmental records requires, first of all, a careful examination of what constitutes environmental responsibility.
The Mississippi River, the longest in North America, is really two rivers geophysically. The volume is less, the slope steeper, the velocity greater, and the channel straighter in its upper portion than in its lower portion. Below the mouth of the Ohio River, the Mississippi meanders through a continental depression that it has slowly filled with sediment over many millennia. Some limnologists and hydrologists consider the transitional middle portion of the Mississippi, where the waters of its two greatest tributaries, the Missouri and Ohio rivers, join it, to comprise a third river, in terms of its behavioral patterns and stream and floodplain ecologies.
The Mississippi River humans have known, with its two or three distinct sections, is a relatively recent formation. The lower Mississippi only settled into its current formation following the last ice age and the dissipation of water released by receding glaciers. Much of the current river delta is newer still, having taken shape over the last three to five hundred years.
Within the lower section of the Mississippi are two subsections, the meander zone and the delta. Below Cape Girardeau, Missouri, the river passes through Crowley’s Ridge and enters the wide and flat alluvial plain. Here the river meanders in great loops, often doubling back on itself, forming cut offs that, if abandoned by the river, forming lakes. Until modern times, most of the plain, approximately 35,000 square miles, comprised a vast and rich—rich in terms of biomass production—ecological wetland sustained by annual Mississippi River floods that brought not just water, but fertile sediment—topsoil—gathered from across much of the continent. People thrived in the Mississippi River meander zone. Some of the most sophisticated indigenous cultures of North America emerged here. Between Natchez, Mississippi, and Baton Rouge, Louisiana, at Old River Control, the Mississippi begins to fork into distributary channels, the largest of which is the Atchafalaya River. The Mississippi River delta begins here, formed of river sediment accrued upon the continental shelf. In the delta the land is wetter, the ground water table is shallower. Closer to the sea, the water becomes brackish and patterns of river sediment distribution are shaped by ocean tides and waves. The delta is frequently buffeted by hurricanes.
Over the last century and a half people have transformed the lower Mississippi River, principally through the construction of levees and drainage canals that have effectively disconnected the river from the floodplain. The intention has been to dry the land adjacent to the river, to make it useful for agriculture and urban development. However, an unintended effect of flood control and wetland drainage has been to interfere with the flood-pulse process that sustained the lower valley ecology, and with the process of sediment distribution that built the delta and much of the Louisiana coastline. The seriousness of the delta’s deterioration has become especially apparent since Hurricane Katrina, and has moved conservation groups to action. They are pushing politicians and engineers to reconsider their approach to Mississippi River management.
Agroforestry systems, the planting of perennial trees and/or shrubs with annual agronomic crops or pasture, have been proposed as more environmentally benign, alternative systems for agricultural production in both temperate and tropical regions of the world. Agroforestry provides a number of environmental benefits as confirmed by scientific literature. The four major environmental benefits of agroforestry are (1) climate change mitigation through carbon sequestration, (2) biodiversity conservation, (3) soil health enrichment, and (4) air and water quality improvement. In addition to environmental benefits, the economic benefits of multiple crops within agroforestry systems have also generated interest in their adoption by farmers the world over. The major negative impacts come from conversion or degradation of forests following certain traditional practices, which may not fit in the definition of modern agroforestry. Challenges remain for widespread adoption of agroforestry, particularly in the temperate world; however, a new resurgence of interest in this land-use practice among small-scale farmers has shed light on a path toward its possible success. Past evidence clearly indicates that agroforestry, as part of a multifunctional working landscape, can offer not only economic return, but also a number of ecosystem services and environmental benefits for a sustainable society.
Kimberly M. Carlson and Rachael D. Garrett
Oil crops play a critical role in global food and energy systems. Since these crops have high oil content, they provide cooking oils for human consumption, biofuels for energy, feed for animals, and ingredients in beauty products and industrial processes. In 2014, oil crops occupied about 20% of crop harvested area worldwide. While small-scale oil crop production for subsistence or local consumption continues in certain regions, global demand for these versatile crops has led to substantial expansion of oil crop agriculture destined for export or urban markets. This expansion and subsequent cultivation has diverse effects on the environment, including loss of forests, savannas, and grasslands, greenhouse gas emissions, regional climate change, biodiversity decline, fire, and altered water quality and hydrology. Oil palm in Southeast Asia and soybean in South America have been identified as major proximate causes of tropical deforestation and environmental degradation. Stringent conservation policies and yield increases are thought to be critical to reducing rates of soybean and oil palm expansion into natural ecosystems. However, the higher profits that often accompany greater yields may encourage further expansion, while policies that restrict oil crop expansion in one region may generate secondary “spillover” effects on other crops and regions. Due to these complex feedbacks, ensuring a sustainable supply of oil crop products to meet global demand remains a major challenge for agricultural companies, farmers, governments, and civil society.
David I. Stern
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.
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.
María E. Ibarrarán and Jerónimo Chavarría
In Mexico, the laws and norms that regulate the environment emerged at the end of the 19th century to standardize infrastructure construction and preserve nature. However, it was not until the early 1970s that the first formal government entity dedicated to promote environmental protection, the Vice-Ministry for Environmental Improvement, under the Ministry of Health, was founded, mostly responding to a government initiative rather than social pressure. Other laws were then issued and applied by the Secretariat of Urban Development and Ecology. However, in the 1980s, civil society pressed for more regulations aimed at protecting the environment.
In the 1990s, the Ministry of the Environment, Natural Resources and Fisheries (SEMARNAP) was created, focusing on natural resources, biodiversity, hazardous waste, and urban-industrial environmental problems. Its objective was to reduce the trends of environmental deterioration and to promote economic and social development under criteria of sustainability. This and other institutions have evolved since then, covering a larger set of topics and media. Nevertheless, degradation has not been stopped and is far from being reverted, because even though there is a toolbox of policies and instruments, many of them economic, they have not been fully implemented in some cases or enforced in others because of economic and political factors.
With the changes in institutions, legislation was also modified. Mexico became part of international environmental agreements and included the rights to a safe environment in the constitution. However, this legislation has not been enough to modify behavior because often the incentives either for regulators or for polluters themselves are not enough.
Environmental degradation is a market failure. It can be shaped as an externality that markets alone cannot solve either because of overproduction, abuse of open access resources, or underprovision of public goods. In any of these cases, resolution comes only through government intervention. Regulations must include consideration of the benefits and costs they impose to change behavior. However, regardless of formal regulation, there are still a host of environmental problems that affect both urban and rural communities and Indigenous and non-Indigenous populations, and there is a regulatory vacuum integrating environmental aspects with economic and social development issues. Examples of this are the Energy Reform of 2013 and the Law of Waters, as well as the Law of Biodiversity, where impacts on communities are often left aside, because of a de facto prevalence of economic activity over human rights. On the other hand, legal loopholes prevent adequate management of wildlife resources and sufficient treatment of hazardous waste discarded by industries, even if they are regulated. Furthermore, environmental regulations are based on corrective regulations, such as obligations, restrictions, and sanctions, but these have not strengthened their preventive character. It is still less expensive to pollute or degrade the environment than take measures not to. A shift in the paradigm toward policies that create incentives to protect the environment, both for polluters and regulators, may foster much better environmental quality.
George Morris and Patrick Saunders
Most people today readily accept that their health and disease are products of personal characteristics such as their age, gender, and genetic inheritance; the choices they make; and, of course, a complex array of factors operating at the level of society. Individuals frequently have little or no control over the cultural, economic, and social influences that shape their lives and their health and well-being. The environment that forms the physical context for their lives is one such influence and comprises the places where people live, learn work, play, and socialize, the air they breathe, and the food and water they consume. Interest in the physical environment as a component of human health goes back many thousands of years and when, around two and a half millennia ago, humans started to write down ideas about health, disease, and their determinants, many of these ideas centered on the physical environment.
The modern public health movement came into existence in the 19th century as a response to the dreadful unsanitary conditions endured by the urban poor of the Industrial Revolution. These conditions nurtured disease, dramatically shortening life. Thus, a public health movement that was ultimately to change the health and prosperity of millions of people across the world was launched on an “environmental conceptualization” of health. Yet, although the physical environment, especially in towns and cities, has changed dramatically in the 200 years since the Industrial Revolution, so too has our understanding of the relationship between the environment and human health and the importance we attach to it.
The decades immediately following World War II were distinguished by declining influence for public health as a discipline. Health and disease were increasingly “individualized”—a trend that served to further diminish interest in the environment, which was no longer seen as an important component in the health concerns of the day. Yet, as the 20th century wore on, a range of factors emerged to r-establish a belief in the environment as a key issue in the health of Western society. These included new toxic and infectious threats acting at the population level but also the renaissance of a “socioecological model” of public health that demanded a much richer and often more subtle understanding of how local surroundings might act to both improve and damage human health and well-being.
Yet, just as society has begun to shape a much more sophisticated response to reunite health with place and, with this, shape new policies to address complex contemporary challenges, such as obesity, diminished mental health, and well-being and inequities, a new challenge has emerged. In its simplest terms, human activity now seriously threatens the planetary processes and systems on which humankind depends for health and well-being and, ultimately, survival. Ecological public health—the need to build health and well-being, henceforth on ecological principles—may be seen as the society’s greatest 21st-century imperative. Success will involve nothing less than a fundamental rethink of the interplay between society, the economy, and the environment. Importantly, it will demand an environmental conceptualization of the public health as no less radical than the environmental conceptualization that launched modern public health in the 19th century, only now the challenge presents on a vastly extended temporal and spatial scale.
Paolo Vineis and Federica Russo
While genomics has been founded on accurate tools that lead to a limited amount of classification error, exposure assessment in epidemiology is often affected by large error. The “environment” is in fact a complex construct that encompasses chemical exposures (e.g., to carcinogens); biological agents (viruses, or the “microbiome”); and social relationships. The “exposome” concept was then put forward to stress the relatively poor development of appropriate tools for exposure assessment when applied to the study of disease etiology. Three layers of the exposome have been proposed: “general external” (including social capital, stress and psychology); “specific external” (including chemicals, viruses, radiation, etc.); and “internal” (including for example metabolism and gut microflora). In addition, there are at least three properties of the exposome: (a) it is based on a refinement of tools to measure exposures (including internal measurements in the body); (b) it involves a broad definition of “exposure” or environment, including overarching concepts at a societal level; and (c) it involves a temporal component (i.e., exposure is analyzed in a life-course perspective). The conceptual and practical challenge is how the different layers (i.e., general, specific external, and internal) connect to each other in a causally meaningful sequence. The relevance of this question pertains to the translation of science into policy—for example, if experiences in early life impact on the adult risk of disease, and on the quality of aging, how is distant action to be incorporated in biological causal models and into policy interventions? A useful causal theory to address scientific and policy question about exposure is based on the concept of information transmission. Such a theory can explain how to connect the different layers of the exposome in a life-course temporal frame and helps identify the best level for intervention (molecular, individual, or population level). In this context epigenetics plays a key role, partly because it explains the long-distance persistence of epigenetic changes via the concept of “epigenetic memory.”
The animal world is under increasing pressure, given the magnitude of anthropogenic environmental stress, especially from human-caused rapid climate change together with habitat conversion, fragmentation, and destruction. There is a global wave of species extinctions and decline in local species abundance. To stop or even reverse this so-called defaunation process, in situ conservation (in the wild) is no longer effective without ex situ conservation (in captivity). Consequently, zoos could play an ever-greater role in the conservation of endangered species and wildlife—hence the slogan Captivity for Conservation.
However, the integration of zoo-based tools and techniques in species conservation has led to many conflicts between wildlife conservationists and animal protectionists. Many wildlife conservationists agree with Michael Soulé, the widely acclaimed doyen of the relatively new discipline of conservation biology, that conservation and animal welfare are conceptually distinct, and that they should remain politically separate. Animal protectionists, on the other hand, draw support from existing leading accounts of animal ethics that oppose the idea of captivity for conservation, either because infringing an individual’s right to freedom for the preservation of the species is considered as morally wrong, or because the benefits of species conservation are not seen as significant enough to overcome the presumption against depriving an animal of its liberty.
Both sides view animals through different lenses and address different concerns. Whereas animal ethicists focus on individual organisms, and are concerned about the welfare and liberty of animals, wildlife conservationists perceive animals as parts of greater wholes such as species or ecosystems, and consider biodiversity and ecological integrity as key topics. This seemingly intractable controversy can be overcome by transcending both perspectives, and developing a bifocal view in which zoo animals are perceived as individuals in need of specific care and, at the same time, as members of a species in need of protection.
Based on such a bifocal approach that has lately been adopted by a growing international movement of “Compassionate Conservation,” the modern zoo can only achieve its conservation mission if it finds a morally acceptable balance between animal welfare concerns and species conservation commitments. The prospects for the zoo to achieve such a balance are promising. Over the past decade or so, zoos have made serious and sustained efforts to ensure and enhance animal welfare. At the same time, the zoo’s contribution to species conservation has also improved considerably.
Juha Merilä and Ary A. Hoffmann
Changing climatic conditions have both direct and indirect influences on abiotic and biotic processes and represent a potent source of novel selection pressures for adaptive evolution. In addition, climate change can impact evolution by altering patterns of hybridization, changing population size, and altering patterns of gene flow in landscapes. Given that scientific evidence for rapid evolutionary adaptation to spatial variation in abiotic and biotic environmental conditions—analogous to that seen in changes brought by climate change—is ubiquitous, ongoing climate change is expected to have large and widespread evolutionary impacts on wild populations. However, phenotypic plasticity, migration, and various kinds of genetic and ecological constraints can preclude organisms from evolving much in response to climate change, and generalizations about the rate and magnitude of expected responses are difficult to make for a number of reasons.
First, the study of microevolutionary responses to climate change is a young field of investigation. While interest in evolutionary impacts of climate change goes back to early macroevolutionary (paleontological) studies focused on prehistoric climate changes, microevolutionary studies started only in the late 1980s. The discipline gained real momentum in the 2000s after the concept of climate change became of interest to the general public and funding organizations. As such, no general conclusions have yet emerged. Second, the complexity of biotic changes triggered by novel climatic conditions renders predictions about patterns and strength of natural selection difficult. Third, predictions are complicated also because the expression of genetic variability in traits of ecological importance varies with environmental conditions, affecting expected responses to climate-mediated selection.
There are now several examples where organisms have evolved in response to selection pressures associated with climate change, including changes in the timing of life history events and in the ability to tolerate abiotic and biotic stresses arising from climate change. However, there are also many examples where expected selection responses have not been detected. This may be partly explainable by methodological difficulties involved with detecting genetic changes, but also by various processes constraining evolution.
There are concerns that the rates of environmental changes are too fast to allow many, especially large and long-lived, organisms to maintain adaptedness. Theoretical studies suggest that maximal sustainable rates of evolutionary change are on the order of 0.1 haldanes (i.e., phenotypic standard deviations per generation) or less, whereas the rates expected under current climate change projections will often require faster adaptation. Hence, widespread maladaptation and extinctions are expected. These concerns are compounded by the expectation that the amount of genetic variation harbored by populations and available for selection will be reduced by habitat destruction and fragmentation caused by human activities, although in some cases this may be countered by hybridization. Rates of adaptation will also depend on patterns of gene flow and the steepness of climatic gradients. Theoretical studies also suggest that phenotypic plasticity (i.e., nongenetic phenotypic changes) can affect evolutionary genetic changes, but relevant empirical evidence is still scarce. While all of these factors point to a high level of uncertainty around evolutionary changes, it is nevertheless important to consider evolutionary resilience in enhancing the ability of organisms to adapt to climate change.