Sustainability

Blue Marble composite images generated by NASA in 2001 (left) and 2002 (right).

Sustainability, in the broadest sense, is the ability to sustain a certain process or state at a certain rate or level, hence the term; sustain-ability.^[1] The concept of sustainability applies to all aspects of life on Earth and is commonly defined within ecological, social and economic contexts. Due to factors such as overpopulation, lack of education, inadequate financial circumstances and the actions of past generations, sustainability can be difficult to achieve.^[2][3]

In an ecological context, sustainability is defined as the ability of an ecosystem to maintain ecological processes, functions, biodiversity and productivity into the future.^[4] In a social context, sustainability is expressed as meeting the needs of the present without compromising the ability of future generations to meet their own needs.^[5] When applied in an economic context, a business is sustainable if it has adapted its practices for the use of renewable resources and is accountable for the environmental impacts of its activities.

To be sustainable, regardless of context, the Earth's resources must be used at a rate at which they can be replenished. There is now clear scientific evidence that humanity is living unsustainably, and that an effort is needed to keep human use of natural resources within sustainable limits.^[6][7] This has brought sustainability to the forefront of public consciousness and is seen by many as being a natural progression in human evolution as we develop the thought and means to sustain our own existence on Earth. Sustainability has become a complex term that can be applied to almost every facet of life on Earth, particularly the many different levels of biological organization, such as; wetlands, prairies and forests and is expressed in human organization concepts, such as; ecovillages, eco-municipalities, sustainable cities, and human activities and disciplines, such as; sustainable agriculture, sustainable architecture and renewable energy.

Scope and Definition

Sustainability can be a property of living systems, a manufacturing method, or a consideration as to a way of interpreting life. Although one definition of sustainable development given by the Brundtland Commission, is frequently quoted, it is not universally accepted and has undergone various interpretations. Difficulty in defining sustainability stems in part, that it may be seen to encompass all human activity. Although science forms the basis of sustainability concepts, it can be perceived also as a general concept like "liberty" or "justice", which is accepted as important, and can also be viewed as a "dialogue of values"^[8] that defies consensual definition.^[9] It is also open to political interpretation.

History

Further information: Environmentalism, Millennium Ecosystem Assessment, Ecological economics, Natural resource economics, Natural capital, and Environmental economics

The first book with the title Ecological Economics was published in Europe by Juan Martinez-Alier (Blackwell, Oxford, 1987). It traces the history of ecological critiques of economics since the 1880s to the 1950s. Connected European conceptual founders include Nicholas Georgescu-Roegen, William Kapp (1944) and Karl Polanyi (1950).^{[10] [11]} Furthermore, some key concepts of what is now ecological economics, the study of which is integrally linked to sustainability issues, are evident in the writings of E.F. Schumacher, whose book Small Is Beautiful – A Study of Economics as if People Mattered (1973) was published just a few years before the first edition of Herman Daly's comprehensive and persuasive Steady-State Economics (1977).^[12][13]

Some of the antecedents of current sustainability discussion track back to the Romantics of the 1800s as well as some Enlightenment political economists of that era. Concerns about overpopulation were expressed by Thomas Malthus (see Malthusian catastrophe), while John Stuart Mill hypothesized that the "stationary state" of an economy might be something that could be considered desirable, anticipating later insights of modern ecological economists, without having had their experience of the social and ecological costs of the dramatic post-World War II industrial expansion. The debate on energy economic systems can also be traced into the 1800s e.g. Nobel prize-winning chemist, Frederick Soddy (1877-1956).^[14]

In North America, economists of environmental focus such as Kenneth Boulding and Herman Daly, ecologists C.S. Holling, H.T. Odum and Robert Costanza, biologist Gretchen Daily and physicist Robert Ayres, discuss environment and sustainability concepts. Daly and Costanza were part of the institutional founding of the field - resulting in the establishment of the academic journal Ecological Economics and the International Society for Ecological Economics (ISEE). Some attribute origination of ecological economics as a specific field per se to professor Herman Daly, University of Maryland, a former economist at the World Bank. Ecological/Environmental economics has been popularized by ecologist and University of Vermont Professor Robert Costanza. CUNY geography professor David Harvey explicitly added ecological concerns to political economic literature. This parallel development in political economy has been continued by analysts such as sociologist John Bellamy Foster. One reason many environmental activists and information providers of sustainability concepts focus on ecological economics, is this disciplines claim, to put ecology first... rather than money.

The Romanian economist Nicholas Georgescu-Roegen (1906-1994), who was among Daly's teachers at Vanderbilt University, provided ecological economics with a modern conceptual framework based on the material and energy flows of economic production and consumption. His magnum opus, The Entropy Law and the Economic Process (1971), has been highly influential.^[15]

Hotelling's rule is a 1931 economic model of non-renewable resource management by Harold Hotelling. It shows that efficient exploitation of a nonrenewable and nonaugmentable resource would, under otherwise stable economic conditions, lead to a depletion of the resource. The rule states that this would lead to a net price or "Hotelling rent" for it that rose annually at a rate equal to the rate of interest, reflecting the increasing scarcity of the resource. The Hartwick's rule provides an important result about the sustainability of welfare in an economy that uses non-renewable resources.

Aldo Leopold's book A Sand County Almanac has been read by millions and has informed and changed the environmental movement and a widespread interest in ecology as a science. By the same token, The Wilderness Society and Leopold’s work in it were important precursors to the environmental movement that coalesced around the time of the first Earth Day.

Published in 1949, shortly after Leopold's death, A Sand County Almanac is a combination of natural history, scene painting with words, and philosophy. It is perhaps best known for the following quote, which defines his land ethic: "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise." The concept of a trophic cascade is put forth in the chapter Thinking Like a Mountain, wherein Leopold realizes that killing a predator wolf carries serious implications for the rest of the ecosystem..^[16]

Beginning with the environmental movement of the 1960s, heralded by Rachel Carson's Silent Spring (1962) and underlined by the Club of Rome’s Limits to Growth (1975), there has been an increasing awareness that human use of the Earth is approaching a range of environmental and resource limits and that this trend, rather than diminishing, is escalating at an alarming rate. ^{[17][18][7][19]}

Bina Agarwal is a prize-winning feminist economist who studies gender, development, and agriculture in India and throughout South Asia. Her work examines and urges political and group action for women. Her work, as well as her fellow compatriots work Vandana Shiva, has brought South Asia (especially India), South Asian women, and a more international perspective into the field of feminist economics as it relates to ecology and sustainability.

International concern over global environmental sustainability, strongly linked to health and poverty issues in the developing world, has resulted in the United Nations sustainable development programs. This has not always been supported by various environmental movements.

Environmental issues and the United Nations organization

Main articles: Earth Charter , Sustainable development, and Environmental science

United Nations General Assembly

Environmental science is the study of interactions among physical, chemical, and biological components of the environment. Environmental Science provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems.^[20] During the 1970s, while the developed world was considering the effects of the global population explosion, pollution and consumerism, the developing countries, faced with continued poverty and deprivation, regarded development as essential - to meet their need for the necessities of food, clean water and shelter. The 1972 United Nations Conference on the Human Environment, held in Stockholm was the UN's first major conference on international environmental issues and marked the beginning of global cooperation in developing environmental policies and strategies. In 1980 the International Union for Conservation of Nature published its influential World Conservation Strategy,^{[note 1]} followed in 1982 by its World Charter for Nature,^[21]which drew attention to the decline of the world's ecosystems. Confronted with the differing priorities of the developed and developing world, the United Nation's World Commission on Environment and Development (the Brundtland Commission) worked for two years to try and resolve the apparent conflict between the environment and development. The Commission concluded that the approach to development must change: it must become sustainable development. Development, in the Commission's view needed to be directed to meeting the needs of the poor in a way that no longer caused environmental problems, but rather helped to solve them or, in the words of the Commission in 1987:

Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.^[22][23]

In the same year the Commission's influential report Our Common Future was published. The 1992 UN Environmental Summit in Rio de Janeiro, Brazil produced the Rio Declaration on Environment and Development Earth Summit (1992) with an action agenda, Agenda 21, overseen by the Commission on Sustainable Development.^{[note 2]}. At Rio negotiations also began for an international agreement on climate change (which eventually led to the Kyoto Protocol); agreements on forestry were forged and the Convention on Biological Diversity was initiated. By the time of the World Summit on Sustainable Development (Earth Summit 2002), held in Johannesburg, delegates included representatives from the World Business Council for Sustainable Development and thousands of local governments reporting on how they had implemented Local Agenda 21 and the Cities for Climate Protection program.^[24] A broad-based consensus had been reached on what was to be done. This Summit, building on the 2000 United Nations Millennium Declaration, produced eight Millennium Development Goals for 2015 (adopted by 189 countries) and established the "WEHAB" targets for water, energy, health, agriculture, and biodiversity.^[25]The United Nations conducts global education programs as part of the International Decade of Education for Sustainable Development (2005-2014).

The 2005 World Summit on sustainable development in New York declared that, to be effective, action on sustainability must involve cooperation across three sustainability "pillars": environment, society and economy.^{[note 3]}

One formal study of sustainability recently emerging as an academic discipline is referred to as sustainability science. ^[26] This examines the broad, inclusive, and contradictory currents that humankind will need to navigate toward a just and sustainable future ^[27]This also references sustainability governance ^{[28] [29]} as a process to implement sustainability strategies and sustainability accounting. ^{[30] [31]}

Economic growth and the environment

Pollution can be a simple example of market failure. If costs of production are not borne by producers but are by the environment, accident victims or others, then prices are distorted.

Environmentalist disenchantment with some aspects of the global sustainability agenda can be attributed to the view that the environmental, social, and economic pillars (if accepted at all) cannot strictly be treated as equal. The notion of sustainable development is often resisted because many regard it as an oxymoron — that development is inevitably carried out at the expense of the environment.^[32] Environmentalists emphasize the global environment as the ecological and material basis of human existence that is being progressively degraded. If we were to live in acknowledgement of this fact then economies should address the goals of the societies they serve, and these societies, in turn, would recognize their dependence on natural resources.^[33] However, this ranking is often observed in reverse order. By placing strong emphasis on economic growth as a core human value, and investing so little effort in protecting the biosphere, we are setting ourselves on a trajectory of self destruction.^[34]Environmental science and Ecological economics both examine issues as they relate to Earths ecology.

Sustainability and development

Proponents( of sustainable development have been trying to reconcile the urgent needs of effective environmental protection and conservation of resources with economic development. While the concept has been politically successful at bringing sustainability into the mainstream, both in developed and developing countries, it remains controversial.^[35]

The skeptics( have pointed out that infinite economic growth is impossible on a finite planet, and that Earth’s limits also define the limits of all material-based activities. Some contend( that the term itself is an oxymoron, creating the impression that humans can "have their cake and eat it too."^[36] In reality, sustainable development has tended to mean nothing more than ecologically more sensitive growth — a slightly reformed status quo. Rebuttals involve, on one hand, the claims of expanding carrying capacity through human ingenuity, and on the other hand, a different conception of development.^[37]

Before flue gas desulfurization was installed, the air-polluting emissions from this power plant in New Mexico contained excessive amounts of sulfur dioxide.

Some of the advocates of sustainable development have argued it is best understood as qualitative improvement. In that case, development means “better” rather than “more” and an emphasis on quality of life, rather than material living standards. They call for better, not faster, lives and for a focus on values, not things. These advocates of a new paradigm urge a movement away from the dogma that the only wealth is material wealth, with the resulting development being recognized formally by an improvement in the quality of life indicators.^[38]

Environmental sustainability is the process of making sure current processes of interaction with the environment are pursued with the idea of keeping the environment as pristine as naturally possible.(

An "unsustainable situation" occurs when natural capital (the sum total of nature's resources) is used up faster than it can be replenished. Sustainability requires that human activity only uses nature's resources at a rate at which they can be replenished naturally. Inherently the concept of sustainable development is intertwined with the concept of carrying capacity. Theoretically, the long-term result of environmental degradation is the inability to sustain human life. Such degradation on a global scale could imply extinction for humanity.

Human impact on the biosphere

Land for all life forms - Catalonia

Land for humans - Chicago

Natural systems (often referred to as ecosystem services) are humanity's life-support system, providing the necessary conditions for humans to flourish. Over the last 50 years the rapidly escalating and potentially critical nature of human global impact on the biodiversity of these ecosystem services has become the source of major biological concern. ^{[39] [29]}

At a fundamental level human impact on the Earth is being manifest through changes in the global biogeochemical cycles of chemicals that are critical to life, most notably those of water, oxygen, carbon, nitrogen and phosphorus.

There is now clear scientific evidence that human activity is having a significant effect on all of these cycles.^[40]

Protecting the biosphere

There are two major ways of reducing human impact on the planet. The first is to monitor and respond to direct human impacts on the oceans and freshwater systems, the land and atmosphere (see direct impacts below). This approach is based on information gained from environmental science and conservation biology.^[39] However, this is management at the end of a long series of causal factors (known to ecologists as drivers) that are initiated by human consumption, our demand for food, energy, materials and water ^[41] (see indirect impacts below).

Direct global environmental impacts

Atmosphere

Main topic: climate change

Use of the atmosphere

Top of the atmosphere

The most obvious human impact on the atmosphere is the air pollution in our cities. The pollutants include toxic chemicals such as nitrogen oxides, sulphur oxides, volatile organic compounds and particulate matter that produce photochemical smog and acid rain. Anthropogenic particulates such as sulphate aerosols in the atmosphere reduce the direct irradiance of the Earth's surface. Known as global dimming the decrease is estimated at about 4% between 1960 and 1990 although the trend has subsequently reversed. Global dimming may have disturbed the global water cycle by reducing evaporation and rainfall in some areas: it also creates a cooling effect and this may have partially masked the effect of greenhouse gases on global warming.^{[42] [43]} However, it is now human-induced climate change and the carbon cycle that have become a major focus of scientific research because of the potential for catastrophic effects on both biodiversity and human communities (see Energy below).

Oceans

Thorsmork, Iceland

Main topics: overfishing, ocean acidification, marine pollution, bioeconomics.

Saltwater fish

Oceans and their circulation patterns have a critical effect on climate and the food supply for both humans and other organisms. Major environmental impacts occur in the more habitable regions of the oceans – the estuaries, coastline and bays. Because of their vastness oceans act as a dumping ground for human waste. Trends of concern include: ocean warming, reef bleaching and sea level rise, all due to climate change together with the possibility for a sudden alteration of present-day ocean currents which could drastically alter the climate in some regions of the globe; over-fishing (beyond sustainable levels); and ocean acidification due to dissolved carbon dioxide.^[7]

Remedial strategies include: more careful waste management, statutory control of overfishing, reduction of fossil fuel emissions, and restoration of coastal and other marine habitat.

Land

Main articles: Land use, land-use change and forestry, land cover, urbanization, deforestation.

Land use change is fundamental to the operations of the biosphere. This includes alteration to biogeochemical cycles, effects of agriculture, proportions of forest and woodland, grassland and pasture.^[7]

Forests

Main articles: forestry, deforestation, carbon sequestration, climate change.

Historically about 47% of the world’s forests have been lost to human use. Present-day forests occupy about a quarter of the world’s ice-free land with about half occurring in the tropics ^[44] In temperate and boreal regions forest area is gradually increasing (with the exception of Siberia), but deforestation in the tropics is of major concern.

Beech Forest - Grib Skov, Denmark

Forests can moderate the local climate and the global water cycle through their light reflectance (albedo) and evapotranspiration. They also conserve biodiversity, protect water quality, preserve soil and soil quality, provide fuel and pharmaceuticals, and purify the air. These free ecosystem services have no market value and so forest conservation has little appeal when compared with the economic benefits of logging and clearance which, through soil degradation and organic decomposition returns carbon dioxide to the atmosphere. The United Nations Food and Agriculture Organisation (FAO) has estimated that about 90% of the carbon stored in land vegetation is locked up in trees and that they sequester about 50% more carbon than is present in the atmosphere. Changes in land use currently contribute about 20% of total global carbon emissions (in heavily logged Indonesia and Brazil it is the greatest source of emissions).^[45] Climate change can be mitigated by sequestering carbon in reafforestation schemes, new plantations, and timber products. Wood biomass is a renewable carbon-neutral fuel.

The FAO has concluded that, over the period 2005–2050, effective use of tree planting could absorb about 10–20% of man-made emissions – so clearly we need to monitor the condition of the world's forests very closely (both reafforestation and deforestation) as they must be part of any coordinated emissions mitigation strategy.^[46]

Cultivated land

Main articles: agriculture, Green Revolution.

Rice Paddy

Feeding more than six billion human bodies takes a heavy toll on the Earth’s resources. This begins with the human appropriation of about 38% ^[47] of the Earth’s land surface and about 20% of its net primary productivity^[48]. Added to this are the resource-hungry activities of industrial agribusiness – everything from the initial cultivation need for irrigation water, synthetic fertilizers and pesticides to the resource costs of food packaging, transport (now a major part of global trade) and retail. The benefits of food production are obvious: without food we cannot survive. But the list of costs is a long one: topsoil depletion, erosion and conversion to desert from tillage for monocultures of annual crops; overgrazing; salinization; sodification; waterlogging; high levels of fossil fuel use; reliance on inorganic fertilisers and synthetic organic pesticides; reductions in genetic diversity by the mass use of monocultures; water resource depletion; pollution of waterbodies by run-off and groundwater contamination; social problems including the decline of family farms and weakening of rural communities.^[49]

Extinctions

Main articles: extinction, International Union for Conservation of Nature.

The Dodo (Raphus cucullatus)

In line with human migration and population growth, species extinctions have progressively increased to a rate unprecedented since the Cretaceous–Tertiary extinction event. Known as the Holocene extinction event this human-induced extinction of species ranks as one of the worlds six mass extinction events. Some scientific estimates indicate that up to half of presently existing species may become extinct by 2100.^[50][51]

Loss of biodiversity can be attributed largely to the appropriation of land for agroforestry. Current extinction rate are 100 to 1000 times their prehuman levels with more than 10% birds and mammals threatened, about 8% of plants and 5% of fish and more than 20% of freshwater species.^[7]

Biological invasions

Kudzu (Pueraria lobata) infesting trees in Atlanta, Georgia

Main articles: introduced species, invasive species.

Increasingly efficient global transport has facilitated the spread of organisms across the planet. The most stark examples are human diseases like HIV AIDS, mad cow disease and bird flu but invasive plants and animals are now, after climate change and land clearing, the greatest threat to native biodiversity.^[52] Non-indigenous organisms often quickly occupy disturbed land but can also devastate natural areas where, in the absence of their natural predators, they are able to thrive.

Freshwater

Main articles: freshwater, desalination, limnology, list of countries by freshwater withdrawal, list of countries by total renewable water resources, water resources, water crisis.

River Fluvia, Catalonia

Freshwater habitat is the world’s most vulnerable of the major biological systems due to the human need for potable water for food irrigation, industry and domestic use. Human freshwater withdrawals make up about 10% of global freshwater runoff. ^[18] and of this 15-35% is considered unsustainable - a proportion that is likely to increase as climate change worsens, populations increase, and water supplies become polluted and unsanitary.^[39]

In the industrial world demand management has slowed absolute usage rates but in the developing world water security, and therefore food security, remain among the most important issues to address. Increasing urbanization pollutes clean water supplies and much of the world still does not have access to clean, safe water.^[7]

Indirect global environmental impacts

People - our numbers and consumption patterns (resource use) relate directly to environmental impacts

Main article: appropriate technology

The direct impacts on the environment described above are the result of a long chain of causal factors, which is why managing direct human impacts on oceans, atmosphere and land is sometimes called "end of pipe" management; it does not manage the indirect "start of pipe" drivers of this impact which can be reduced to three fundamental factors:

• population numbers
• levels of consumption (affluence)
• impact per unit of resource use (which is a result of the technology used)

This has been expressed through an equation: ^[53]

I = PAT

where:

I = environmental impact

P = population

A = affluence

T = technology

This equation has been criticised, because it represents only a static picture without changes over time: rising affluence (A) may over time have a curbing effect on the environment due to the circumstance that a strong economy could provide the means to tackle environmental problems by changing technology (T). Also the equation does not include social considerations such as the development of efficient environmental governance; it is difficult to apply in a realistic and useful way. ^[54] Nevertheless, it provides a strong starting point for discussion. To detail the various direct and indirect environmental impacts per unit of consumption (T), the tool of Life Cycle Assessment is increasingly applied internationally.

Ecological analysis of CO-2 in an ecosystem

Addressing sustainability now focuses much of its attention on managing levels of consumption and resource impact by seeking, for example, to modify individual lifestyles, and to apply ideas like ethical consumerism, dematerialisation and decarbonisation, while at the same time exploring more environmentally friendly technology and methods through ecodesign and industrial ecology.

At present individual and household use of resources like energy and water is monitored through domestic water and energy bills and car fuel use – but much greater quantities of these resources are embodied in the goods and services we use. In the same way society as a whole tends to consider environmental management in terms of direct impacts rather than their driver - human consumption. Patterns of consumption must reflect the cleverer use of resources: e.g. using renewable energy rather than fossil fuels and fewer embodied resources in goods and services.^{[55] [56]}

Production, consumption, technology

Shopping

Main topics: consumption, primary production, simple living, consumerism, ethical consumerism, biotechnology.

There is a lively debate about the relationship between natural and human capital - whether we must live off the interest of our natural capital (strong sustainability).^[57]) or if it is possible to thrive indefinitely while taking more natural resources, provided total capital remains constant (weak sustainability).^[58] Consumerism focuses on the end-product. It tends to stay away from the focus on the production and transportation stage of the goods.

In coming to terms with human consumption sustainability science focuses on four interconected and basic human resource needs - for: water (agriculture, industry, domestic use), energy (industry, transport, tools and appliances), materials (manufacturing, construction) and food (horticulture, agriculture and agribusiness)^[41]. Each of these resources are discussed below.

Energy

Renewable energy
Biofuels Biomass Geothermal Hydro power Solar power Tidal power Wave power Wind power

Main articles: energy, climate change, decarbonisation, renewable energy.

Since the industrial revolution the concentrated energy of the Sun stored in fossilised plants as fossil fuels have been a major driver of technology and the source of both economic and political power.

In 2007, after prolonged skepticism about the human contribution to climate change, climate scientists of the IPCC concluded that there was at least a 90% probability that this atmospheric increase in CO2 was human-induced - essentially due to fossil fuel emissions and, to a lesser extent, the CO2 released from changes in land use.

Projections for the coming century indicate that a minimum of 500 ppm can be expected and possibly as much as 1000 ppm. Stabilising the world’s climate will require high income countries to reduce their emissions by 60-90% over 2006 levels by 2050. This should stabilise atmospheric carbon dioxide levels at 450-650 ppm from current levels of about 380 ppm. Above this level and temperatures would probably rise by more than 2^o C to produce “catastrophic” climate change. ^[59][60] Reduction of current CO2 levels must be achieved against a background of global population increase and developing countries aspiring to energy-intensive high consumption Western lifestyles.^[61]

Projecting climate into the future and forecasting regional impacts depends on our understanding of the exchange of carbon dioxide between the atmosphere, oceans and land ecosystems. NOAA (National Oceanic & Atmospheric Administration), is charged to provide the atmospheric measurements and analyses required to track the fate of carbon dioxide emissions caused by the burning of fossil fuels and biomass, and to reduce uncertainties in how the exchange of carbon responds to the variations and trends of climate and land use.^[62]

Water

Main articles: water, water cycle, water resources, wastewater, irrigation.

. Water covers 71% of the Earth's surface.
. The oceans contain 97.2% of the Earth's water.
. The Antarctic ice sheet (visible here at the South Pole) contains 90% of all fresh water on Earth.
. Condensed atmospheric water, as clouds, contributes to the Earth's albedo.

Awareness of the global importance of preserving water for ecosystem services has only just begun as, during the 20th century, more than half the world’s wetlands have been lost along with their valuable environmental services. Biodiversity-rich freshwater ecosystems are currently declining faster than marine or land ecosystems. ^[63]

In the decade 1951-60 human water withdrawals were four times greater than the previous decade. This rapid increase resulted from scientific and technological developments impacting through the economy - especially the increase in irrigated land, growth in industrial and power sectors, and intensive dam construction on all continents. This altered the water cycle of rivers and lakes, affected their water quality and therefore potential as a human resource, and altered the global water cycle. ^[64] Currently towards 35% of human water use is unsustainable, drawing on diminishing aquifers and reducing flows of major rivers. ^[7]

Over the period 1961 to 2001 there was a doubling of demand and over the same period agricultural use increased by 75%, industrial use by more than 200%, and domestic use more than 400%. ^[7] Humans currently use 40-50% of the globally available freshwater in the approximate proportion of 70% for agriculture, 22% for industry, and 8% for domestic purposes and the total amount is progressively increasing being about five times that at the beginning of the 20th century. ^[64]

The path forward appears to lie in improving water use efficiency through: demand management; maximising water resource productivity of agriculture; minimising the water intensity (embodied water) of goods and services; addressing shortages in the non-industrialised world; moving production from areas of low productivity to those with high productivity; and planning for climate change.^[63]

Materials

Materials – The Materials Science Tetrahedron

Main topics: ecolabelling, ecodesign, recycle, detoxification, extended producer responsibility.

Materials used by humans are still increasing in volume, number, diversity and toxicity. Synthetic chemical production is escalating and global transport systems accelerate distribution across the globe.^[65] Much of the sustainability effort is directed at converting the linear path of materials from one of extraction to production and disposal as waste, to a cyclical one that reuses materials indefinitely, much like the waste cycle in nature.

Waste

Main articles: dematerialization, zero waste, industrial ecology.

Household waste

International recycle symbol

As more materials are transported round the world material flow analysis is becoming widely accepted as an important part of sustainability accounting at the national level. The linear path of products (extraction, manufacture, disposal in rubbish tip) is being converted to a more circular material flow (like that in nature) as the world comes to grips with dematerialization, decarbonisation and zero waste.^[65] Industry, business and government are adopting the ideas of industrial metabolism, industrial ecology, ecodesign ^[66], ecolabelling, product stewardship, and extended producer responsibility. In addition to the well-established “reduce, reuse and recycle” shoppers are using their purchasing power for ethical consumerism.^[67]

Food

Main articles: sustainable agriculture, food security, environmental effects of meat production, environmental effects of fishing, food miles, environmental vegetarianism.

A vegetarian smorgasboard

The American Public Health Association (APHA) defines a "sustainable food system" as "one that provides healthy food to meet current food needs while maintaining healthy ecosystems that can also provide food for generations to come with minimal negative impact to the environment. A sustainable food system also encourages local production and distribution infrastructures and makes nutritious food available, accessible, and affordable to all. Further, it is humane and just, protecting farmers and other workers, consumers, and communities."^{[68][note 4]}

Concerns about the environmental impacts of agribusiness and the stark contrast between the obesity problems of the Western world and the poverty and food insecurity of the developing world have generated a strong movement towards healthy, sustainable eating as a major component of overall ethical consumerism. ^[69]

The environmental effects of different dietary patterns depend on various factors, including the proportion of animal and plant foods consumed and the method of food production.^{[70][71][72][73]} The World Health Organisation has published a Global Strategy on Diet, Physical Activity and Health which was endorsed by the May 2004 World Health Assembly. It recommends the Mediterranean diet which is associated with health and longevity and is low in meat, rich in fruits and vegetables, low in added sugar and limited salt, and low in saturated fatty acids; the traditional source of fat in the Mediterranean is olive oil, rich in monounsaturated fat. The healthy rice-based Japanese diet is also high in carbohydrates and low in fat. Both diets are low in meat and saturated fats and high in legumes and other vegetables; they are associated with a low incidence of ailments and low environmental impact.

At the local level there are various movements working towards more sustainable use of wastelands, peripheral urban land and domestic gardens. Included here would be permaculture, ^[74], urban horticulture, local food, slow food, organic gardening and the like.

Economic pillar

Main articles: Ecological economics, Natural resource economics, Natural capital, Energy economics, and Environmental economics

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The Great Fish Market, painted by Jan Brueghel the Elder

Ecological economics explores the interface between environmental issues and economics, especially in relation to how traditional market forces deal with diminishing natural resources. ^[75] In most circumstances, as commodity or service scarcity increases then the resultant increase in prices acts as a restraint that encourages technical innovation and alternative products. However, this principle applies only when the product or service falls within the market system. ^[76] Nature and natural resources are generally treated as economic externalities. While these services remain unpriced economic they will be overused and degraded, a situation referred to as the Tragedy of the Commons.

The economic importance of natural resources has been acknowledged by sustainability science through the use of the expression ecosystem services to indicate the market relevance of nature which can no longer be regarded as both unlimited and free. ^[77] Protecting the biological world is now becoming progressively subject to market strategies including environmental taxes and incentives, tradable permits for carbon, water and nitrogen use etc., together with an increasing willingness to accept payment for ecosystem services by these and other methods. Physical scientists and biologists were the first individuals to use energy flows to explain social and economic development.^[78]

Energy economics relating to thermoeconomics, is a broad scientific subject area which includes topics related to supply and use of energy in societies. Thermoeconomists argue that economic systems always involve matter, energy, entropy, and information.^[79]Thermoeconomics is based on the proposition that the role of energy in biological evolution should be defined and understood through the second law of thermodynamics but in terms of such economic criteria as productivity, efficiency, and especially the costs and benefits of the various mechanisms for capturing and utilizing available energy to build biomass and do work.^[80][81] As a result, thermoeconomics are often discussed in the field of ecological economics, which itself is related to the fields of sustainability and sustainable development.

Exergy analysis is performed in the field of industrial ecology to use energy more efficiently.^[82] The term exergy, was coined by Zoran Rant in 1956, but the concept was developed by J. Willard Gibbs. In recent decades, utilization of exergy has spread outside of physics and engineering to the fields of industrial ecology, ecological economics, systems ecology, and energetics.

Decoupling environmental degradation and economic growth

Main article: environmental economics, resource intensity, resource productivity. Over the second half of the 20th century, world population has doubled, food production has tripled, energy use quadrupled, and overall economic activity has quintupled. ^[83] Historically there has been a close correlation between economic growth and environmental degradation: as communities grow, so the environment declines. This trend is clearly demonstrated on graphs of human population numbers, economic growth, and environmental indicators.^[7]

Unsustainable economic growth has been compared to the malignant growth of a cancer^[84] because it eats away at the Earth's ecosystem services which are its life-support system. Mismanagement of finite natural resources by cultures such as the Maya, Anasazi and Easter Islanders eventually led to their demise by destroying their resource base ^{[85] [86]} and there is the concern that, unless growth is checked, our civilization will follow a similar path.

Part of the task for sustainability is to find ways of reducing (decoupling) the amount of resource (e.g. water, energy, or materials) needed for the production, consumption and disposal of a unit of good or service. In other words the goal of sustainability is to minimise resource use per unit of product or money spent (the resource intensity) and to maximise the output per unit of resource input or money spent (the resource productivity).^[87]

Peace and security

Main articles: war, peace, crime, corruption, security and environmental security.

War, crime and corruption divert resources from areas of greatest human need and generally threaten human well-being and the environment. Diminishing natural resources increase the likelihood of “resource wars”:^[88] this aspect of sustainability has been referred to as environmental security.

Population, migration, urbanization

Main topics: population, overpopulation, urbanization, megalopolis, migration, bioregionalism.

Human population from 10,000 BC – AD 2000.

The world population will likely increase by 2.5 billion over the next 43 years, passing from the current 6.7 billion to 9.2 billion in 2050. This increase is equivalent to the overall number of people in the world in 1950 and it will be absorbed mostly by the less developed regions, whose population is projected to rise from 5.4 billion in 2007 to 7.9 billion in 2050. In contrast, the population of the more developed regions is expected to remain largely unchanged at 1.2 billion and would have declined were it not for the projected net migration from developing to developed countries, which is expected to average 2.3 million persons a year after 2010. ^[89] Between-country migration and movement from rural to urban situations continues to increase. In some regions coalescence of urban centres has given rise to the term megalopolis. Emerging economies like those of China and India aspire to the living standards of the Western world as does the non-industrialised world. Long-term estimates suggest a peak at around 2070 of nine billion people, and then slowly decreases to 8.4 billion by 2100. ^[90][91]

Globalisation, and governments

Main articles: globalization, sustainability governance

An increase in globalization and trade and exchanges of technology, along with increased migration, and communication and some attendant global approaches to the management of environmental problems, frames many sustainability issues. The power of some national governments appears to have decreased in regard to transnational and non-government organizations.^[92]

The Sustainability Transition

Main articles: Ecological Footprint, Environmental Performance Index, Environmental Sustainability Index.

Almost all developed nations have an Ecological Footprint (the area of land needed to support a community and its waste) significantly larger than their geographic area - they are consuming more than they are producing. ^[93] The extra resources needed to maintain this level of consumption are gained in three ways: embedded in the goods and services of world trade; taken from the past (e.g. fossil fuels); or taken from the future as unsustainable resource usage.

The sustainable development goal is to raise the global standard of living without increasing the use of resources beyond globally sustainable levels; that is, to not exceed "one planet" consumption.(

At present the developing world per capita consumption is sustainable (as a global average) but population numbers are increasing and individuals are aspiring to high consumption Western lifestyles. The developed world population is stable (not increasing) but consumption levels are unsustainable. The task is to curb and manage Western consumption while raising the standard of living of the developing world without increasing its resource use and environmental impact. This must be done by using strategies and technology that decouple economic growth from environmental damage and resource depletion.^[94]

Cultural, psychological and behavioural change

Further articles: Precautionary Principle, cultural change, ecopsychology, environmental psychology, environmental sociology, social ecology.

Weight of scientific evidence is often insufficient to produce social change, especially if that change entails moving people out of their comfort zones. ^[95]

At present we have a cultural tradition that places a high value on possession of material goods and a relatively low value on the natural world.(

See also

Footnotes

1. ↑ An updated version entitled Caring for the Earth: A Strategy for Sustainable Living (IUCN/WWF, 1991) was published in 1991.
2. ↑ The Commission on Sustainable Development is the main implementation and action arm of the United Nations. Publications, news and information about sustainable development, by topic, are available on the Commission's web site at: [1]
3. ↑ The three pillars are not universally accepted: to these is sometimes added a fourth "institution" pillar, and indigenous peoples at UN summits have also advocated a "culture pillar"; the society pillar is sometimes replaced with "community".
4. ↑ Further reading on Sustainable food systems.

References

• Cothran, H. (Ed.). (2003). Global resources: opposing viewpoints. New York: Greenhaven Press.
• Dodds, W.K. (2008). Humanity’s footprint: Momentum, Impact, and our Global Environment. New York: Columbia University Press.
• Sitarz, D. (Ed.). (1998). Sustainable America: America’s Environment, Economy, and Society in the 21st century. Carbondale: EarthPress.
• Speth, J.G. (2008). The Bridge at the edge of the world: Capitalism, the Environment, and crossing from crisis to sustainability. Devon, PA: Yale University Press.

Further reading

External links

• Sustainability at the Open Directory Project
• Microdocs: Elements of sustainability