The scientific community has made the urgent need to mitigate climate change clear and, with the ratification of the Paris Agreement under the United Nations Framework Convention on Climate Change, the international community has formally accepted ambitious mitigation goals. However, a wide gap remains between the aspirational emissions reduction goals of the Paris Agreement and the real-world pledges and actions of nations that are party to it. Closing that emissions gap can only be achieved if a similarly wide gap between scientific and societal understanding of climate change is also closed.
Several fundamental aspects of climate change make clear both the need for education and the opportunity it offers. First, addressing climate change will require action at all levels of society, including individuals, organizations, businesses, local, state, and national governments, and international bodies. It cannot be addressed by a few individuals with privileged access to information, but rather requires transfer of knowledge, both intellectually and affectively, to decision-makers and their constituents at all levels. Second, education is needed because, in the case of climate change, learning from experience is learning too late. The delay between decisions that cause climate change and their full societal impact can range from decades to millennia. As a result, learning from education, rather than experience, is necessary to avoid those impacts.
Climate change and sustainability represent complex, dynamic systems that demand a systems thinking approach. Systems thinking takes a holistic, long-term perspective that focuses on relationships between interacting parts, and how those relationships generate behavior over time. System dynamics includes formal mapping and modeling of systems, to improve understanding of the behavior of complex systems as well as how they respond to human or other interventions. Systems approaches are increasingly seen as critical to climate change education, as the human and natural systems involved in climate change epitomize a complex, dynamic problem that crosses disciplines and societal sectors.
A systems thinking approach can also be used to examine the potential for education to serve as a vehicle for societal change. In particular, education can enable society to benefit from climate change science by transferring scientific knowledge across societal sectors. Education plays a central role in several processes that can accelerate social change and climate change mitigation. Effective climate change education increases the number of informed and engaged citizens, building social will or pressure to shape policy, and building a workforce for a low-carbon economy. Indeed, several climate change education efforts to date have delivered gains in climate and energy knowledge, affect, and/or motivation. However, society still faces challenges in coordinating initiatives across audiences, managing and leveraging resources, and making effective investments at a scale that is commensurate with the climate change challenge. Education is needed to promote informed decision-making at all levels of society.
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Addressing Climate Change Through Education
Tamara Shapiro Ledley, Juliette Rooney-Varga, and Frank Niepold
Article
Air Pollution and Weather Interaction in East Asia
Aijun Ding, Xin Huang, and Congbin Fu
Air pollution is one of the grand environmental challenges in developing countries, especially those with high population density like China. High concentrations of primary and secondary trace gases and particulate matter (PM) are frequently observed in the industrialized and urbanized regions, causing negative effects on the health of humans, plants, and the ecosystem.
Meteorological conditions are among the most important factors influencing day-to-day air quality. Synoptic weather and boundary layer dynamics control the dispersion capacity and transport of air pollutants, while the main meteorological parameters, such as air temperature, radiation, and relative humidity, influence the chemical transformation of secondary air pollutants at the same time. Intense air pollution, especially high concentration of radiatively important aerosols, can substantially influence meteorological parameters, boundary layer dynamics, synoptic weather, and even regional climate through their strong radiative effects.
As one of the main monsoon regions, with the most intense human activities in the world, East Asia is a region experiencing complex air pollution, with sources from anthropogenic fossil fuel combustion, biomass burning, dust storms, and biogenic emissions. A mixture of these different plumes can cause substantial two-way interactions and feedbacks in the formation of air pollutants under various weather conditions. Improving the understanding of such interactions needs more field measurements using integrated multiprocess measurement platforms, as well as more efforts in developing numerical models, especially for those with online coupled processes. All these efforts are very important for policymaking from the perspectives of environmental protection and mitigation of climate change.
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The Allocation of Groundwater: From Superstition to Science
Burke W. Griggs
Groundwater is a critical natural resource, but the law has always struggled with it. During the 19th and early 20th centuries, the common law developed several doctrines to allocate groundwater among competing users. The groundwater revolution of the mid-20th century produced an explosive growth in pumping worldwide—and quickly exposed the flaws of these doctrines. Legal rules predicated on land and on surface waters could not meet the challenges posed by the common-pool groundwater resource: those of understanding groundwater dynamics, quantifying the impacts of pumping on other water rights, and devising satisfactory remedies. Unfettered by received property restraints, pumping on an industrial, aquifer-wide scale depleted and contaminated aquifers, regardless of doctrine.
The groundwater revolution motivated significant legal developments. Starting in the 1970s, the Supreme Court of the United States adapted its methods for resolving interstate water disputes to include the effects of groundwater pumping. This jurisprudence has fundamentally influenced international groundwater law, including the negotiation of trans-boundary aquifer agreements. Advances in hydrogeology and computer groundwater modeling have enabled states and parties to evaluate the effects of basin-wide pumping. Nonetheless, difficult legal and governance problems remain. Which level of government—local, state, or national—should exercise jurisdiction over groundwater? What level of pumping qualifies as “safe yield,” especially when the aquifer is overdrawn? How do the demands of modern environmental law and the public trust doctrine affect groundwater rights? How can governments satisfy long-neglected claims to water justice made by Indigenous and minority communities? Innovations in groundwater management provide promising answers. The conjunctive management of surface and groundwater can stabilize water supplies, improve water quality, and protect ecosystems. Integrated water resources management seeks to holistically manage groundwater to achieve social and economic equity. Water markets can reward water conservation, attract new market participants, and encourage the migration of groundwater allocations to more valuable uses, including environmental uses.
The modern law of groundwater allocation combines older property doctrines with 21st-century regulatory ideals, but the mixture can be unstable. In nations with long-established water codes such as the United States, common-law Anglophone nations, and various European nations, groundwater law has evolved, if haltingly, to incorporate permitting systems, environmental regulation, and water markets. Elsewhere, the challenges are extreme. Long-standing calls for groundwater reform in India remain unheeded as tens of millions of unregulated tube wells pump away. In China, chronic groundwater mismanagement and aquifer contamination belie the roseate claims of national water law. Sub-Saharan nations have enacted progressive groundwater laws, but poverty, racism, and corruption have maintained grim groundwater realities. Across the field, experts have long identified the central problems and reached a rough consensus about the most effective solutions; there is also a common commitment to secure environmental justice and protect groundwater-dependent ecosystems. The most pressing legal work thus requires building practical pathways to reach these solutions and, most importantly, to connect the public with the groundwater on which it increasingly depends.
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Legal Regimes for Sharing Transboundary Water
Mara Tignino
The law applicable to transboundary waters is a corpus juris that dates back to the 19th century. It originally focused on regulating the uses of transboundary watercourses for navigation and commercial transport. It was crafted primarily on the European and North American continents, and it has gradually become universally applicable, thereby taking a new shape. The regulation of transboundary waters was rooted in a strict dynamic of coexistence between sovereign entities: each acted as it saw fit with respect to “its” portion of the watercourse, which was treated at the same time as the image of the territory to which it is attached.
The need for regulation only arose when uses affected the riparian states’ exercise of their “sovereign rights.” Since the 1990s, the law has tried to break away from this “classical” logic to make room for more community-based and even “ecosystem” notions based on aspects of joint management, and sometimes even pool of shared resources.
A number of treaties have been negotiated and adopted by states bordering transboundary watercourses in Europe, Asia, Africa, and the Americas. They reflect, and sometimes even develop, some of the principles and rules enacted in broader forums, such as the United Nations (UN) or its Economic Commission for Europe, or the European Union. These efforts show the steps taken in the field of transboundary waters management, but they also reveal some of its limits, as they do not always comprehend all facets of water management and protection.
Article
Arid Environments
Julie Laity
Arid environments cover about one third of the Earth’s surface, comprising the most extensive of the terrestrial biomes. Deserts show considerable individual variation in climate, geomorphic surface expression, and biogeography. Climatically, deserts range from dry interior environments, with large temperature ranges, to humid and relatively cool coastal environments, with small temperature ranges. What all deserts share in common is a consistent deficit of precipitation relative to water loss by evaporation, implying that the biological availability of water is very low. Deserts develop because of climatic (persistent high-pressure cells), topographic (mountain ranges that cause rain shadow effects), and oceanographic (cold currents) factors that limit the amount of rain or snowfall that a region receives. Most global deserts are subtropical in distribution.
There is a large range of geomorphic surfaces, including sand sheets and sand seas (ergs), stone pavements, bedrock outcrops, dry lakebeds, and alluvial fans. Vegetation cover is generally sparse, but may be enhanced in areas of groundwater seepage or along river courses. The limited vegetation cover affects fluvial and slope processes and results in an enhanced role for the wind. While the majority of streams in deserts are ephemeral features, both intermittent and perennial rivers develop in response to snowmelt in nearby mountains or runoff from distant, more well-watered regions. Most drainage is endoreic, meaning that it flows internally into closed basins and does not reach the sea, being disposed of by seepage and evaporation.
The early study of deserts was largely descriptive. More process-based studies commenced with the study of North American deserts in the mid- to late-1800s. Since the late 20th century, research has expanded into many areas of the world, with notable contributions coming from China, but our knowledge of deserts is still more compete in regions such as North America, Australia, Israel, and southern Africa, where access and funding have been more consistently secure. The widespread availability of high-quality remotely sensed images has contributed to the spread of study into new global field areas. The temporal framework for research has also improved, benefiting from improvements in geochronological techniques. Geochronological controls are vital to desert research because most arid regions have experienced significant climatic changes. Deserts have not only expanded or contracted in size, but have experienced changes in the dominant geomorphic processes and biogeographic environment. Contemporary scientific work has also benefited from improvements in technology, notably in surveying techniques, and from the use of quantitative modeling.
Article
Atmospheric Brown Clouds
Sumit Sharma, Liliana Nunez, and Veerabhadran Ramanathan
Atmospheric brown clouds (ABCs) are widespread pollution clouds that can at times span an entire continent or an ocean basin. ABCs extend vertically from the ground upward to as high as 3 km, and they consist of both aerosols and gases. ABCs consist of anthropogenic aerosols such as sulfates, nitrates, organics, and black carbon and natural dust aerosols. Gaseous pollutants that contribute to the formation of ABCs are NOx (nitrogen oxides), SOx (sulfur oxides), VOCs (volatile organic compounds), CO (carbon monoxide), CH4 (methane), and O3 (ozone). The brownish color of the cloud (which is visible when looking at the horizon) is due to absorption of solar radiation at short wavelengths (green, blue, and UV) by organic and black carbon aerosols as well as by NOx. While the local nature of ABCs around polluted cities has been known since the early 1900s, the widespread transoceanic and transcontinental nature of ABCs as well as their large-scale effects on climate, hydrological cycle, and agriculture were discovered inadvertently by The Indian Ocean Experiment (INDOEX), an international experiment conducted in the 1990s over the Indian Ocean. A major discovery of INDOEX was that ABCs caused drastic dimming at the surface. The magnitude of the dimming was as large as 10–20% (based on a monthly average) over vast areas of land and ocean regions. The dimming was shown to be accompanied by significant atmospheric absorption of solar radiation by black and brown carbon (a form of organic carbon). Black and brown carbon, ozone and methane contribute as much as 40% to anthropogenic radiative forcing. The dimming by sulfates, nitrates, and carbonaceous (black and organic carbon) species has been shown to disrupt and weaken the monsoon circulation over southern Asia. In addition, the ozone in ABCs leads to a significant decrease in agriculture yields (by as much as 20–40%) in the polluted regions. Most significantly, the aerosols (in ABCs) near the ground lead to about 4 million premature mortalities every year. Technological and regulatory measures are available to mitigate most of the pollution resulting from ABCs. The importance of ABCs to global environmental problems led the United Nations Environment Programme (UNEP) to form the international ABC program. This ABC program subsequently led to the identification of short-lived climate pollutants as potent mitigation agents of climate change, and in recognition, UNEP formed the Climate and Clean Air Coalition to deal with these pollutants.
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Biodiversity Generation and Loss
T.H. Oliver
Human activities in the Anthropocene are influencing the twin processes of biodiversity generation and loss in complex ways that threaten the maintenance of biodiversity levels that underpin human well-being. Yet many scientists and practitioners still present a simplistic view of biodiversity as a static stock rather than one determined by a dynamic interplay of feedback processes that are affected by anthropogenic drivers. Biodiversity describes the variety of life on Earth, from the genes within an organism to the ecosystem level. However, this article focuses on variation among living organisms, both within and between species. Within species, biodiversity is reflected in genetic, and consequent phenotypic, variations among individuals. Genetic diversity is generated by germ line mutations, genetic recombination during sexual reproduction, and immigration of new genotypes into populations. Across species, biodiversity is reflected in the number of different species present and also, by some metrics, in the evenness of their relative abundance. At this level, biodiversity is generated by processes of speciation and immigration of new species into an area. Anthropogenic drivers affect all these biodiversity generation processes, while the levels of genetic diversity can feed back and affect the level of species diversity, and vice versa. Therefore, biodiversity maintenance is a complex balance of processes and the biodiversity levels at any point in time may not be at equilibrium.
A major concern for humans is that our activities are driving rapid losses of biodiversity, which outweigh by orders of magnitude the processes of biodiversity generation. A wide range of species and genetic diversity could be necessary for the provision of ecosystem functions and services (e.g., in maintaining the nutrient cycling, plant productivity, pollination, and pest control that underpin crop production). The importance of biodiversity becomes particularly marked over longer time periods, and especially under varying environmental conditions.
In terms of biodiversity losses, there are natural processes that cause roughly continuous, low-level losses, but there is also strong evidence from fossil records for transient events in which exceptionally large loss of biodiversity has occurred. These major extinction episodes are thought to have been caused by various large-scale environmental perturbations, such as volcanic eruptions, sea-level falls, climatic changes, and asteroid impacts. From all these events, biodiversity has shown recovery over subsequent calmer periods, although the composition of higher-level evolutionary taxa can be significantly altered.
In the modern era, biodiversity appears to be undergoing another mass extinction event, driven by large-scale human impacts. The primary mechanisms of biodiversity loss caused by humans vary over time and by geographic region, but they include overexploitation, habitat loss, climate change, pollution (e.g., nitrogen deposition), and the introduction of non-native species. It is worth noting that human activities may also lead to increases in biodiversity in some areas through species introductions and climatic changes, although these overall increases in species richness may come at the cost of loss of native species, and with uncertain effects on ecosystem service delivery. Genetic diversity is also affected by human activities, with many examples of erosion of diversity through crop and livestock breeding or through the decline in abundance of wild species populations. Significant future challenges are to develop better ways to monitor the drivers of biodiversity loss and biodiversity levels themselves, making use of new technologies, and improving coverage across geographic regions and taxonomic scope. Rather than treating biodiversity as a simple stock at equilibrium, developing a deeper understanding of the complex interactions—both between environmental drivers and between genetic and species diversity—is essential to manage and maintain the benefits that biodiversity delivers to humans, as well as to safeguard the intrinsic value of the Earth’s biodiversity for future generations.
Article
Biodiversity Hotspots and Conservation Priorities
Peter Kareiva and Isaac Kareiva
The concept of biodiversity hotspots arose as a science-based framework with which to identify high-priority areas for habitat protection and conservation—often in the form of nature reserves. The basic idea is that with limited funds and competition from humans for land, we should use range maps and distributional data to protect areas that harbor the greatest biodiversity and that have experienced the greatest habitat loss. In its early application, much analysis and scientific debate went into asking the following questions: Should all species be treated equally? Do endemic species matter more? Should the magnitude of threat matter? Does evolutionary uniqueness matter? And if one has good data on one broad group of organisms (e.g., plants or birds), does it suffice to focus on hotspots for a few taxonomic groups and then expect to capture all biodiversity broadly? Early applications also recognized that hotspots could be identified at a variety of spatial scales—from global to continental, to national to regional, to even local. Hence, within each scale, it is possible to identify biodiversity hotspots as targets for conservation.
In the last 10 years, the concept of hotspots has been enriched to address some key critiques, including the problem of ignoring important areas that might have low biodiversity but that certainly were highly valued because of charismatic wild species or critical ecosystem services. Analyses revealed that although the spatial correlation between high-diversity areas and high-ecosystem-service areas is low, it is possible to use quantitative algorithms that achieve both high protection for biodiversity and high protection for ecosystem services without increasing the required area as much as might be expected.
Currently, a great deal of research is aimed at asking about what the impact of climate change on biodiversity hotspots is, as well as to what extent conservation can maintain high biodiversity in the face of climate change. Two important approaches to this are detailed models and statistical assessments that relate species distribution to climate, or alternatively “conserving the stage” for high biodiversity, whereby the stage entails regions with topographies or habitat heterogeneity of the sort that is expected to generate high species richness.
Finally, conservation planning has most recently embraced what is in some sense the inverse of biodiversity hotspots—what we might call conservation wastelands. This approach recognizes that in the Anthropocene epoch, human development and infrastructure are so vast that in addition to using data to identify biodiversity hotspots, we should use data to identify highly degraded habitats and ecosystems. These degraded lands can then become priority development areas—for wind farms, solar energy facilities, oil palm plantations, and so forth. By specifying degraded lands, conservation plans commonly pair maps of biodiversity hotspots with maps of degraded lands that highlight areas for development. By putting the two maps together, it should be possible to achieve much more effective conservation because there will be provision of habitat for species and for economic development—something that can obtain broader political support than simply highlighting biodiversity hotspots.
Article
Business Models for Sustainability
Nancy Bocken
Human activity is increasingly impacting the environment negatively on all scales. There is an urgent need to transform human activity toward sustainable development. Business has a key role to play in this sustainability transition through technological, product and service, and process innovations, as well as innovative business models. Business models can enable new technologies, and vice versa. These models are therefore important in the transition to sustainability. Business models for sustainability, or synonymously, sustainable business models, take holistic views on how business is operated in relation to its stakeholders, including the society and the natural environment. They incorporate economic, environmental, and social aspects in an organization’s purpose and performance measures; consider the needs of all stakeholders rather than giving priority to owner and shareholder expectations; treat “nature” as a stakeholder; and take a system as well as a firm-level perspective on the way business is conducted. The research field of sustainable business models emerged from fields such as service business models, green and social business models, and concepts such as sharing and circular economy. Academics have argued that the most service-oriented business models can achieve a “factor 10” environmental impact improvement if designed the right way.
Researchers have developed various conceptualizations, typologies, tools, and methods and reviews on sustainable business models. However, sustainable business models are not yet mainstream. Important research areas include the following: (a) tools, methods, and experimentation; (b) the assessment of sustainability impact and rebounds for different stakeholders; (c) sufficiency and degrowth; and (d) the twin revolution of sustainability and digital transition. First, a plethora of tools and approaches are available for inspiration and for creation of sustainable business model designs. Second, in the field of assessment, methods have been based on life cycle thinking considering the supply chain and how a product is (re)used and eventually disposed of. In the field of sufficiency, authors have recognized the importance of moderating consumption through innovative business models to reduce the total need for products, reducing the impact on the environment. Finally, researchers have started to investigate the important interplay between sustainability and digitalization. Because of the potential to achieve a factor 10 environmental impact improvement, sustainable business models are an important source of inspiration for further work, including the upscaling of sustainable business models in established businesses and in new ventures. Understanding how to design better business models and preempting their usage in practice are essential to achieve a desired positive impact. In the field of sufficiency, the macro-impacts of individual and business behavior would need to be better understood. In the area of digital innovation, environmental, societal, and economic values need scrutinization.
Researchers and practitioners can leverage the popularity of this field by addressing these important areas to support the development and roll-out of sustainable business models with significantly improved economic, environmental, and societal impact.
Article
Causes of Soil Salinization, Sodification, and Alkalinization
Elisabeth N. Bui
Driving forces for natural soil salinity and alkalinity are climate, rock weathering, ion exchange, and mineral equilibria reactions that ultimately control the chemical composition of soil and water. The major weathering reactions that produce soluble ions are tabled. Where evapotranspiration is greater than precipitation, downward water movement is insufficient to leach solutes out of the soil profile and salts can precipitate. Microbes involved in organic matter mineralization and thus the carbon, nitrogen, and sulfur biogeochemical cycles are also implicated. Seasonal contrast and evaporative concentration during dry periods accelerate short-term oxidation-reduction reactions and local and regional accumulation of carbonate and sulfur minerals. The presence of salts and alkaline conditions, together with the occurrence of drought and seasonal waterlogging, creates some of the most extreme soil environments where only specially adapted organisms are able to survive. Sodic soils are alkaline, rich in sodium carbonates, with an exchange complex dominated by sodium ions. Such sodic soils, when low in other salts, exhibit dispersive behavior, and they are difficult to manage for cropping. Maintaining the productivity of sodic soils requires control of the flocculation-dispersion behavior of the soil. Poor land management can also lead to anthropogenically induced secondary salinity. New developments in physical chemistry are providing insights into ion exchange and how it controls flocculation-dispersion in soil. New water and solute transport models are enabling better options of remediation of saline and/or sodic soils.
Article
Classification and Mitigation of Soil Salinization
Tibor Tóth
Soil salinity has been causing problems for agriculturists for millennia, primarily in irrigated lands. The importance of salinity issues is increasing, since large areas are affected by irrigation-induced salt accumulation. A wide knowledge base has been collected to better understand the major processes of salt accumulation and choose the right method of mitigation. There are two major types of soil salinity that are distinguished because of different properties and mitigation requirements. The first is caused mostly by the large salt concentration and is called saline soil, typically corresponding to Solonchak soils. The second is caused mainly by the dominance of sodium in the soil solution or on the soil exchange complex. This latter type is called “sodic” soil, corresponding to Solonetz soils. Saline soils have homogeneous soil profiles with relatively good soil structure, and their appropriate mitigation measure is leaching. Naturally sodic soils have markedly different horizons and unfavorable physical properties, such as low permeability, swelling, plasticity when wet, and hardness when dry, and their limitation for agriculture is mitigated typically by applying gypsum. Salinity and sodicity need to be chemically quantified before deciding on the proper management strategy. The most complex management and mitigation of salinized irrigated lands involves modern engineering including calculations of irrigation water rates and reclamation materials, provisions for drainage, and drainage disposal. Mapping-oriented soil classification was developed for naturally saline and sodic soils and inherited the first soil categories introduced more than a century ago, such as Solonchak and Solonetz in most of the total of 24 soil classification systems used currently. USDA Soil Taxonomy is one exception, which uses names composed of formative elements.
Article
Climate Change Impacts on Agriculture across Africa
Laura Pereira
Confidence in the projected impacts of climate change on agricultural systems has increased substantially since the first Intergovernmental Panel on Climate Change (IPCC) reports. In Africa, much work has gone into downscaling global climate models to understand regional impacts, but there remains a dearth of local level understanding of impacts and communities’ capacity to adapt. It is well understood that Africa is vulnerable to climate change, not only because of its high exposure to climate change, but also because many African communities lack the capacity to respond or adapt to the impacts of climate change. Warming trends have already become evident across the continent, and it is likely that the continent’s 2000 mean annual temperature change will exceed +2°C by 2100. Added to this warming trend, changes in precipitation patterns are also of concern: Even if rainfall remains constant, due to increasing temperatures, existing water stress will be amplified, putting even more pressure on agricultural systems, especially in semiarid areas. In general, high temperatures and changes in rainfall patterns are likely to reduce cereal crop productivity, and new evidence is emerging that high-value perennial crops will also be negatively impacted by rising temperatures. Pressures from pests, weeds, and diseases are also expected to increase, with detrimental effects on crops and livestock.
Much of African agriculture’s vulnerability to climate change lies in the fact that its agricultural systems remain largely rain-fed and underdeveloped, as the majority of Africa’s farmers are small-scale farmers with few financial resources, limited access to infrastructure, and disparate access to information. At the same time, as these systems are highly reliant on their environment, and farmers are dependent on farming for their livelihoods, their diversity, context specificity, and the existence of generations of traditional knowledge offer elements of resilience in the face of climate change. Overall, however, the combination of climatic and nonclimatic drivers and stressors will exacerbate the vulnerability of Africa’s agricultural systems to climate change, but the impacts will not be universally felt. Climate change will impact farmers and their agricultural systems in different ways, and adapting to these impacts will need to be context-specific.
Current adaptation efforts on the continent are increasing across the continent, but it is expected that in the long term these will be insufficient in enabling communities to cope with the changes due to longer-term climate change. African famers are increasingly adopting a variety of conservation and agroecological practices such as agroforestry, contouring, terracing, mulching, and no-till. These practices have the twin benefits of lowering carbon emissions while adapting to climate change as well as broadening the sources of livelihoods for poor farmers, but there are constraints to their widespread adoption. These challenges vary from insecure land tenure to difficulties with knowledge-sharing.
While African agriculture faces exposure to climate change as well as broader socioeconomic and political challenges, many of its diverse agricultural systems remain resilient. As the continent with the highest population growth rate, rapid urbanization trends, and rising GDP in many countries, Africa’s agricultural systems will need to become adaptive to more than just climate change as the uncertainties of the 21st century unfold.
Article
Containing Carbon Through Cap-and-Trade or a Per-Unit Tax
John A. Sorrentino
Carbon has been part of the Earth since its beginning, and the carbon cycle is well understood. However, its abundance in the atmosphere has become a problem. Those who propose solutions in decentralized market economies often prefer economic incentives to direct government regulation. Carbon cap-and-trade programs and carbon tax programs are the prime candidates to rein in emissions by altering the economic conditions under which producers and consumers make decisions. Under ideal conditions with full information, they can seamlessly remove the distortion caused by the negative externality and increase a society’s welfare. This distortion is caused by overproduction and underpricing of carbon-related goods and services. The ideal level of emissions would be set under cap-and-trade, or be the outcome of an ideally set carbon tax. The ideal price of carbon permits would result from demand generated by government decree meeting an ideal fixed supply set by the government. The economic benefit of using the ideal carbon tax or the ideal permit price occurs because heterogeneous decision-makers will conceptually reduce emissions to the level that equates their marginal (incremental) emissions-reduction cost to the tax or permit price. When applying the theory to the real world, ideal conditions with full information do not exist. The economically efficient levels of emissions, the carbon tax, and the permit price cannot be categorically determined. The targeted level of emissions is often proposed by non-economists. The spatial extent and time span of the emissions target need to be considered. The carbon tax is bound to be somewhat speculative, which does not bode well for private-sector decision-makers who have to adjust their behavior, and for the achievement of a particular emissions target. The permit price depends on how permits are initially distributed and how well the permit market is designed. The effectiveness of either program is tied to monitoring and enforcement. Social justice considerations in the operation of tax programs often include the condition that they be revenue-neutral. This is more complicated in the permit scheme as much activity after the initial phase is among the emitters themselves.
Based on global measurement of greenhouse gases, several models have been created that attempt to explain how emissions transform into concentrations, how concentrations imply radiative forcing and global warming potential, how the latter cause ecological and economic impacts, and how mitigation and/or adaptation can influence these impacts. Scenarios of the uncertain future continue to be generated under myriad assumptions in the quest for the most reliable. Several institutions have worked to engender sustained cooperation among the parties of the “global commons.” The balance of theory and empirical observation is intended to generate normative and positive policy recommendations. Cap-and-trade and carbon tax programs have been designed and/or implemented by various countries and subnational jurisdictions with the hope of reducing carbon-related emissions. Many analysts have declared that the global human society will reach a “tipping point” in the 21st century, with irreversible trends that will alter life on Earth in significant ways.
Article
Deforestation: Drivers, Implications, and Policy Responses
Christiane W. Runyan and Jeff Stehm
Over the last 8,000 years, cumulative forest loss amounted to approximately 2.2 billion hectares, reducing forest cover from about 47% of Earth’s land surface to roughly 30% in 2015. These losses mostly occurred in tropical forests (58%), followed by boreal (27%) and temperate forests (8%). The rate of loss has slowed from 7.3 Mha/year between 1990–2000 to 3.3 Mha/year between 2010–2015. Globally since the 1980s, the net loss in the tropics has been outweighed by a net gain in the subtropical, temperate, and boreal climate zones. Deforestation is driven by a number of complex direct and indirect factors. Agricultural expansion (both commercial and subsistence) is the primary driver, followed by mining, infrastructure extension, and urban expansion. In turn, population and economic growth drive the demand for agricultural, mining, and timber products as well as supporting infrastructure. Population growth and changing consumer preferences, for instance, will increase global food demand 50% by 2050, possibly requiring a net increase of approximately 70 million ha of arable land under cultivation. This increase is unlikely to be offset entirely by agricultural intensification due to limits on yield increases and land quality. Deforestation is also affected by other factors such as land tenure uncertainties, poor governance, low capacity of public forestry agencies, and inadequate planning and monitoring. Forest loss has a number of environmental, economic, and social implications. Forests provide an expansive range of environmental benefits across local, regional, and global scales, including: hydrological benefits (e.g., regulating water supply and river discharge), climate benefits (e.g., precipitation recycling, regulating local and global temperature, and carbon sequestration), biogeochemical benefits (e.g., enhancing nutrient availability and reducing nutrient losses), biodiversity benefits, and the support of ecosystem stability and resiliency. The long-term loss of forest resources also negatively affects societies and economies. The forest sector in 2011 contributed roughly 0.9% of global GDP or USD 600 billion. About 850 million people globally live in forest ecosystems, with an estimated 350 million people entirely dependent on forest ecosystems for their livelihoods. Understanding how to best manage remaining forest resources in order to preserve their unique qualities will be a challenge that requires an integrated set of policy responses. Developing and implementing effective policies will require a better understanding of the socio-ecological dynamics of forests, a more accurate and timely ability to measure and monitor forest resources, sound methodologies to assess the effectiveness of policies, and more efficacious methodologies for valuing trade-offs between competing objectives.
Article
Deforestation of the Brazilian Amazon
Phillip Fearnside
Deforestation in Brazilian Amazonia destroys environmental services that are important for the whole world, and especially for Brazil itself. These services include maintaining biodiversity, avoiding global warming, and recycling water that provides rainfall to Amazonia, to other parts of Brazil, such as São Paulo, and to neighboring countries, such as Argentina. The forest also maintains the human populations and cultures that depend on it. Deforestation rates have gone up and down over the years with major economic cycles. A peak of 27,772 km2/year was reached in 2004, followed by a major decline to 4571 km2/year in 2012, after which the rate trended upward, reaching 7989 km2/year in 2016 (equivalent to about 1.5 hectares per minute). Most (70%) of the decline occurred by 2007, and the slowing in this period is almost entirely explained by declining prices of export commodities such as soy and beef. Government repression measures explain the continued decline from 2008 to 2012, but an important part of the effect of the repression program hinges on a fragile base: a 2008 decision that makes the absence of pending fines a prerequisite for obtaining credit for agriculture and ranching. This could be reversed at the stroke of a pen, and this is a priority for the powerful “ruralist” voting bloc in the National Congress. Massive plans for highways, dams, and other infrastructure in Amazonia, if carried out, will add to forces in the direction of increased deforestation.
Deforestation occurs for a wide variety of reasons that vary in different historical periods, in different locations, and in different phases of the process at any given location. Economic cycles, such as recessions and the ups and downs of commodity markets, are one influence. The traditional economic logic, where people deforest to make a profit by producing products from agriculture and ranching, is important but only a part of the story. Ulterior motives also drive deforestation. Land speculation is critical in many circumstances, where the increase in land values (bid up, for example, as a safe haven to protect money from hyperinflation) can yield much higher returns than anything produced by the land. Even without the hyperinflation that came under control in 1994, highway projects can yield speculative fortunes to those who are lucky or shrewd enough to have holdings along the highway route. The practical way to secure land holdings is to deforest for cattle pasture. This is also critical to obtaining and defending legal title to the land. In the past, it has also been the key to large ranches gaining generous fiscal incentives from the government. Money laundering also makes deforestation attractive, allowing funds from drug trafficking, tax evasion, and corruption to be converted to “legal” money. Deforestation receives impulses from logging, mining, and, especially, road construction. Soybeans and cattle ranching are the main replacements for forest, and recently expanded export markets are giving strength to these drivers. Population growth and household dynamics are important for areas dominated by small farmers. Extreme degradation, where tree mortality from logging and successive droughts and forest fires replace forest with open nonforest vegetation, is increasing as a kind of deforestation, and is likely to increase much more in the future.
Controlling deforestation requires addressing its multiple causes. Repression through fines and other command-and-control measures is essential to avoid a presumption of impunity, but these controls must be part of a broader program that addresses underlying causes. The many forms of government subsidies for deforestation must be removed or redirected, and the various ulterior motives must be combated. Industry agreements restricting commodity purchases from properties with illegal deforestation (or from areas cleared after a specified cutoff) have a place in efforts to contain forest loss, despite some problems. A “soy moratorium” has been in effect since 2006, and a “cattle agreement” since 2009. Creation and defense of protected areas is an important part of deforestation control, including both indigenous lands and a variety of kinds of “conservation units.” Containing infrastructure projects is essential if deforestation is to be held in check: once roads are built, much of what happens is outside the government’s control. The notion that the 2005–2012 deforestation slowdown means that the process is under control and that infrastructure projects can be built at will is extremely dangerous. One must also abandon myths that divert efforts to contain deforestation; these include “sustainable logging” and the use of “green” funds for expensive programs to reforest degraded lands rather than retain areas of remaining natural forests. Finally, one must provide alternatives to support the rural population of small farmers. Large investors, on the other hand, can fend for themselves. Tapping the value of the environmental services of the forest has been proposed as an alternative basis for sustaining both the rural population and the forest. Despite some progress, a variety of challenges remain. One thing is clear: most of Brazil’s Amazonian deforestation is not “development.” Trading the forest for a vast expanse of extensive cattle pasture does little to secure the well-being of the region’s rural population, is not sustainable, and sacrifices Amazonia’s most valuable resources.
Article
Ecological Effects of Environmental Stressors
Bill Freedman
Regimes of environmental stress are exceedingly complex. Particular stressors exist within continua of intensity of environmental factors. Those factors interact with each other, and their detrimental effects on organisms are manifest only at relatively high or low strengths of exposure—in fact, many of them are beneficial at intermediate levels of intensity. Although a diversity of environmental factors is manifest at any time and place, only one or a few of them tend to be dominant as stressors. It is useful to distinguish between stressors that occur as severe events (disturbances) and those that are chronic in their exposure, and to aggregate the kinds of stressors into categories (while noting some degree of overlap among them).
Climatic stressors are associated with extremes of temperature, solar radiation, wind, moisture, and combinations of these factors. They act as stressors if their condition is either insufficient or excessive, in comparison with the needs and comfort zones of organisms or ecosystem processes. Chemical stressors involve environments in which the availability of certain substances is too low to satisfy biological needs, or high enough to cause toxicity or another physiological detriment to organisms or to higher-level attributes of ecosystems. Wildfire is a disturbance that involves the combustion of much of the biomass of an ecosystem, affecting organisms by heat, physical damage, and toxic substances. Physical stress is a disturbance in which an exposure to kinetic energy is intense enough to damage organisms and ecosystems (such as a volcanic blast, seismic sea wave, ice scouring, or anthropogenic explosion or trampling).
Biological stressors are associated with interactions occurring among organisms. They may be directly caused by such trophic interactions as herbivory, predation, and parasitism. They may also indirectly affect the intensity of physical or chemical stressors, as when competition affects the availability of nutrients, moisture, or space.
Extreme environments are characterized by severe regimes of stressors, which result in relatively impoverished ecosystem development. This may be a consequence of either natural or anthropogenic stressors. If a regime of environmental stress intensifies, the resulting responses include a degradation of the structure and function of affected ecosystems and of ecological integrity more generally. In contrast, a relaxation of environmental stress allows some degree of ecosystem recovery.
Article
Economics, Agriculture, and Famines
Noel Russell
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
Economics of Hazardous Waste Management
Hilary Sigman
Hazardous waste management involves treatment, disposal, or recycling of a wide range of different waste streams from industry, households, and others. The diversity of wastes and management methods means that many choices affect its environmental harms, which result from possible contamination of groundwater, surface water, soil, and air. Efficient public policies that would fully reflect such varied external costs are unlikely to be feasible. In practice, governments principally apply three policy approaches to hazardous waste: taxes on hazardous waste, liability for environmental damages, and standards-based regulation of waste management facilities. Hazardous waste taxes may help internalize environmental costs but do not reflect all the variability in these costs. By contrast, liability for environmental damage can make waste generators and managers confront environmental costs that vary with their particular choices. However, environmental liability is often linked to programs for cleanup of contaminated sites and may not create efficient incentives for active waste management because this liability does not reflect the social costs of the contamination. Regulation usually takes the form of technology and performance standards applied to treatment, storage, and disposal facilities (TSDFs) and affects generation decisions only indirectly. Research finds that public policies that raise costs of hazardous waste management, such as taxes and regulation, encourage less waste generation, but may also provoke detrimental responses. First, facilities may substitute illegal waste dumping for legal management and thus exacerbate environmental damage. Second, generators may ship waste to jurisdictions with weaker environmental protections, especially developing countries, giving rise to a “waste haven” effect. This effect may create offsetting environmental damage, facilitate destructive policy competition among jurisdictions, and worsen inequities in exposure to environmental harm from hazardous waste.
Article
Economics of Low Carbon Agriculture
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
Economics of the Biodiversity Convention
Joanne C. Burgess
Biological diversity refers to the variety of life on Earth, in all its forms and interactions. Biological diversity, or biodiversity for short, is being lost at an unprecedented rate. The International Union for Conservation of Nature (IUCN) Red List of Threatened Species estimates that 25% of mammals, 41% of amphibians, 33% of reef building corals, and 13% of birds are threatened with extinction. These biodiversity benefits are being lost due to conversion of natural habitat, overharvesting, pollution, invasive species, and climate change. The loss of biodiversity is important because it provides many critical resources, services, and ecosystem functions, such as foods, medicines, clean air, and storm protection. Biodiversity loss and ecosystem collapse pose a major risk to human societies and economic welfare.
The CBD was established in 1992 at the United Nations Conference on Environment and Development (the Rio “Earth Summit”) and enacted in 1993. The international treaty aims to conserve biodiversity and ensure the sustainable use of the components of biodiversity and the equitable sharing of the benefits derived from the use of genetic resources. The CBD has near universal global participation with 196 parties signatory to the treaty. The non-legally binding commitments established in 2010 by the CBD are known as the Aichi Targets. They include the goal of conserving at least 17% of terrestrial and inland water habitats and 10% of coastal and marine areas by 2020.
Biodiversity continues to decline at an unprecedented rate and the world faces “biological annihilation” and a sixth mass extinction event. There are several underlying causes of the continuing loss of biodiversity that need to be addressed. First, the CBD Aichi Targets are not ambitious enough and should be extended to protect as much as 50% of the terrestrial realm for biodiversity. Second, it is difficult to place an economic value on the range of direct, indirect, and nonuse values of biodiversity. The failure to take into account the full economic value of biodiversity in prices, projects, and policy decisions means that biodiversity is often misused and overused. Third, biodiversity is a global public good and displays nonrival and nonexcludable characteristics. Because of this, it is difficult to raise sufficient funds for conservation and to channel these funds to cover local conservation costs. In particular, much of the world’s biodiversity is located in (mainly tropical) developing countries, and they do not have the incentive or the funds to spend the money to “save” enough biodiversity on behalf of the rest of the world. The funding for global biodiversity conservation is $4–$10 billion annually, whereas around $100 billion a year is needed to protect the Earth’s broad range of animal and plant species. This funding gap undermines CBD’s conservation efforts. Governments and international organizations have been unable to raise the investments needed to reverse the decline in biological populations and habitats on land and in oceans. There is an important role for private-sector involvement in the CBD to endorse efforts for more sustainable use of biodiversity and to contribute funds to finance conservation and habitat protection efforts.
