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.
Mark V. Barrow
The prospect of extinction, the complete loss of a species or other group of organisms, has long provoked strong responses. Until the turn of the 18th century, deeply held and widely shared beliefs about the order of nature led to a firm rejection of the possibility that species could entirely vanish. During the 19th century, however, resistance to the idea of extinction gave way to widespread acceptance following the discovery of the fossil remains of numerous previously unknown forms and direct experience with contemporary human-driven decline and the destruction of several species. In an effort to stem continued loss, at the turn of the 19th century, naturalists, conservationists, and sportsmen developed arguments for preventing extinction, created wildlife conservation organizations, lobbied for early protective laws and treaties, pushed for the first government-sponsored parks and refuges, and experimented with captive breeding. In the first half of the 20th century, scientists began systematically gathering more data about the problem through global inventories of endangered species and the first life-history and ecological studies of those species.
The second half of the 20th and the beginning of the 21st centuries have been characterized both by accelerating threats to the world’s biota and greater attention to the problem of extinction. Powerful new laws, like the U.S. Endangered Species Act of 1973, have been enacted and numerous international agreements negotiated in an attempt to address the issue. Despite considerable effort, scientists remain fearful that the current rate of species loss is similar to that experienced during the five great mass extinction events identified in the fossil record, leading to declarations that the world is facing a biodiversity crisis. Responding to this crisis, often referred to as the sixth extinction, scientists have launched a new interdisciplinary, mission-oriented discipline, conservation biology, that seeks not just to understand but also to reverse biota loss. Scientists and conservationists have also developed controversial new approaches to the growing problem of extinction: rewilding, which involves establishing expansive core reserves that are connected with migratory corridors and that include populations of apex predators, and de-extinction, which uses genetic engineering techniques in a bid to resurrect lost species. Even with the development of new knowledge and new tools that seek to reverse large-scale species decline, a new and particularly imposing danger, climate change, looms on the horizon, threatening to undermine those efforts.
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.
Maria Cristina Fossi and Cristina Panti
A vigorous effort to identify and study sentinel species of marine ecosystem in the world’s oceans has developed over the past 50 years. The One Health concept recognizes that the health of humans is connected to the health of animals and the environment. Species ranging from invertebrate to large marine vertebrates have acted as “sentinels” of the exposure to environmental stressors and health impacts on the environment that may also affect human health. Sentinel species can signal warnings, at different levels, about the potential impacts on a specific ecosystem. These warnings can help manage the abiotic and anthropogenic stressors (e.g., climate change, chemical and microbial pollutants, marine litter) affecting ecosystems, biota, and human health.
The effects of exposure to multiple stressors, including pollutants, in the marine environment may be seen at multiple trophic levels of the ecosystem. Attention has focused on the large marine vertebrates, for several reasons. In the past, the use of large marine vertebrates in monitoring and assessing the marine ecosystem has been criticized. The fact that these species are pelagic and highly mobile has led to the suggestion that they are not useful indicators or sentinel species. In recent years, however, an alternative view has emerged: when we have a sufficient understanding of differences in species distribution and behavior in space and time, these species can be extremely valuable sentinels of environmental quality.
Knowledge of the status of large vertebrate populations is crucial for understanding the health of the ecosystem and instigating mitigation measures for the conservation of large vertebrates. For example, it is well known that the various cetacean species exhibit different home ranges and occupy different habitats. This knowledge can be used in “hot spot” areas, such as the Mediterranean Basin, where different species can serve as sentinels of marine environmental quality. Organisms that have relatively long life spans (such as cetaceans) allow for the study of chronic diseases, including reproductive alterations, abnormalities in growth and development, and cancer. As apex predators, marine mammals feed at or near the top of the food chain. As the result of biomagnification, the levels of anthropogenic contaminants found in the tissues of top predators and long-living species are typically high. Finally, the application of consistent examination procedures and biochemical, immunological, and microbiological techniques, combined with pathological examination and behavioral analysis, has led to the development of health assessment methods at the individual and population levels in wild marine mammals. With these tools in hand, investigators have begun to explore and understand the relationships between exposures to environmental stressors and a range of disease end points in sentinel species (ranging from invertebrates to marine mammals) as an indicator of ecosystem health and a harbinger of human health and well-being.
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.
Precipitation falling onto the land surface in terrestrial ecosystems is transformed into either “green water” or “blue water.” Green water is the portion stored in soil and potentially available for uptake by plants, whereas blue water either runs off into streams and rivers or percolates below the rooting zone into a groundwater aquifer. The principal flow of green water is by evapotranspiration from soil into the atmosphere, whereas blue water moves through the channel system at the land surface or through the pore space of an aquifer. Globally, the flow of green water accounts for about two-thirds of the global flow of all water, green or blue; thus the global flow of green water, most of which is by transpiration, dominates that of blue water. In fact, the global flow of green water by transpiration equals the flow of all the rivers on Earth into the oceans.
At the global scale, evapotranspiration is measured using a combination of ground-, satellite-, and model-based methods implemented over annual or monthly time-periods. Data are examined for self-consistency and compliance with water- and energy-balance constraints. At the catchment scale, average annual evapotranspiration data also must conform to water and energy balance. Application of these two constraints, plus the assumption that evapotranspiration is a homogeneous function of average annual precipitation and the average annual net radiative heat flux from the atmosphere to the land surface, leads to the Budyko model of catchment evapotranspiration. The functional form of this model strongly influences the interrelationship among climate, soil, and vegetation as represented in parametric catchment modeling, a very active area of current research in ecohydrology.
Green water flow leading to transpiration is a complex process, firstly because of the small spatial scale involved, which requires indirect visualization techniques, and secondly because the near-root soil environment, the rhizosphere, is habitat for the soil microbiome, an extraordinarily diverse collection of microbial organisms that influence water uptake through their symbiotic relationship with plant roots. In particular, microbial polysaccharides endow rhizosphere soil with properties that enhance water uptake by plants under drying stress. These properties differ substantially from those of non-rhizosphere soil and are difficult to quantify in soil water flow models. Nonetheless, current modeling efforts based on the Richards equation for water flow in an unsaturated soil can successfully capture the essential features of green water flow in the rhizosphere, as observed using visualization techniques.
There is also the yet-unsolved problem of upscaling rhizosphere properties from the small scale typically observed using visualization techniques to that of the rooting zone, where the Richards equation applies; then upscaling from the rooting zone to the catchment scale, where the Budyko model, based only on water- and energy-balance laws, applies, but still lacks a clear connection to current soil evaporation models; and finally, upscaling from the catchment to the global scale. This transitioning across a very broad range of spatial scales, millimeters to kilometers, remains as one of the outstanding grand challenges in green water ecohydrology.
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.
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.
Elisabet Lindgren and Thomas Elmqvist
Ecosystem services refer to benefits for human societies and well-being obtained from ecosystems. Research on health effects of ecosystem services have until recently mostly focused on beneficial effects on physical and mental health from spending time in nature or having access to urban green space. However, nearly all of the different ecosystem services may have impacts on health, either directly or indirectly. Ecosystem services can be divided into provisioning services that provide food and water; regulating services that provide, for example, clean air, moderate extreme events, and regulate the local climate; supporting services that help maintain biodiversity and infectious disease control; and cultural services.
With a rapidly growing global population, the demand for food and water will increase. Knowledge about ecosystems will provide opportunities for sustainable agriculture production in both terrestrial and marine environments. Diarrheal diseases and associated childhood deaths are strongly linked to poor water quality, sanitation, and hygiene. Even though improvements are being made, nearly 750 million people still lack access to reliable water sources. Ecosystems such as forests, wetlands, and lakes capture, filter, and store water used for drinking, irrigation, and other human purposes. Wetlands also store and treat solid waste and wastewater, and such ecosystem services could become of increasing use for sustainable development.
Ecosystems contribute to local climate regulation and are of importance for climate change mitigation and adaptation. Coastal ecosystems, such as mangrove and coral reefs, act as natural barriers against storm surges and flooding. Flooding is associated with increased risk of deaths, epidemic outbreaks, and negative health impacts from destroyed infrastructure. Vegetation reduces the risk of flooding, also in cities, by increasing permeability and reducing surface runoff following precipitation events.
The urban heat island effect will increase city-center temperatures during heatwaves. The elderly, people with chronic cardiovascular and respiratory diseases, and outdoor workers in cities where temperatures soar during heatwaves are in particular vulnerable to heat. Vegetation and especially trees help in different ways to reduce temperatures by shading and evapotranspiration. Air pollution increases the mortality and morbidity risks during heatwaves. Vegetation has been shown also to contribute to improved air quality by, depending on plant species, filtering out gases and airborne particulates. Greenery also has a noise-reducing effect, thereby decreasing noise-related illnesses and annoyances. Biological control uses the knowledge of ecosystems and biodiversity to help control human and animal diseases.
Natural surroundings and urban parks and gardens have direct beneficial effects on people’s physical and mental health and well-being. Increased physical activities have well-known health benefits. Spending time in natural environments has also been linked to aesthetic benefits, life enrichments, social cohesion, and spiritual experience. Even living close to or with a view of nature has been shown to reduce stress and increase a sense of well-being.
Fred Mackenzie and Abraham Lerman
The tendency to represent natural processes as cycles—from Latin cyclus and Greek κυκλος—is undoubtedly rooted in the human observations of repeating or periodic phenomena. The oldest notions of the water cycle, as water cycling between the Earth, air, and back to earth, are mentioned in the Old Testament and by Greek philosophers, from the 900s to 300s
The main “bioessential” chemical elements are carbon (C), nitrogen (N), phosphorus (P), oxygen (O), and hydrogen (H). These are represented in the mean composition of aquatic photosynthesizing organisms as the atomic abundance ratio C:N:P = 106:16:1 or as (CH2O)106(NH3)16(H3PO4). In land plants, estimates of mean composition vary from C:N:P = 510:4:1 to 2057:17:1. On land, the photosynthesizing organisms are much more efficient than in water by being able to incorporate more carbon atoms for each atom of phosphorus. The bioessential elements are coupled by the living organisms in the exogenic cycle, the processes at and near the Earth’s surface, and in the endogenic cycle of the processes that include subduction into the Earth’s interior and return to the surface. The main reservoirs of the bioessential elements are very different: although oxygen is the most abundant element in the Earth’s crust, most of it is locked in silicate minerals as SiO2, and the forms available to biogeochemical cycling are oxygen in water and, as a product of photosynthesis, as gas O2 in the atmosphere. Carbon is in the atmospheric reservoir of CO2 gas and dissolved in ocean and fresh waters. The main nitrogen reservoir is the molecular N2 in the atmosphere and oxidized and reduced nitrogen compounds in waters. Phosphorus occurs in the oxidized form of the phosphate-ion in crustal minerals, from where it is leached into the water.
The natural cycle of the bioessential elements has been greatly perturbed since the late 1700s by human industrial and agricultural activities, the period known as the Anthropocene epoch. The increase in CO2, CH4 and NOx emissions to the atmosphere from fossil-fuel burning and land-use changes has rapidly and strongly modified the chemical composition of the atmosphere. This change has affected the balance of solar radiation absorbed by the atmosphere—generally known as “climate change”—and the acidity of surface-ocean waters, referred to as “ocean acidification.” CO2 in water is a weak acid that dissolves carbonate minerals, biogenically and inorganically formed in the ocean, and it thus modifies the chemical composition of ocean water. Overall, a major anthropogenic perturbation of the biogeochemical cycles has been the faster increase in atmospheric concentration of CO2 than its removal from the atmosphere by plants, dissolution in the ocean, and uptake in mineral weathering.