Skip to main content
Biology LibreTexts

1.2: Introduction to Sustainability

  • Page ID
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    Cities in today’s modern world are struggling to balance a sustainable society, economy, and environment. According to a 2016 report that rated sustainability across 32 indicators, Zurich, Switzerland, was ranked number one. Zurich invests in renewable energies, sustainable public transport, public green space, and public education. One of the most notable ways Zurich is leading global sustainability efforts is their dedication to keeping their carbon dioxide emissions low. Figure \(\PageIndex{1}\) below shows the difference in emissions for the United States and Switzerland:

    Per capita carbon dioxide emissions between the United States (high) and Switzerland (low). The United States emmissions overall are more erratic and high compared to Switzerland through the years. The last few years has seen a downward trend in the United States.

    Figure \(\PageIndex{1}\): Per capita emissions of carbon dioxide between the United States and Switzerland. Graph by Our World in Data (CC-BY4.0)


    Sustainability is derived from two Latin words: sus which means up, and tenere which means to hold. Thus, sustainability is essentially about holding up human existence by meeting the needs of the present without compromising the ability of future generations to meet their needs.

    There are three dimensions that sustainability seeks to integrate: economic, environmental, and social (including sociopolitical).

    • Economic interests define the framework for making decisions, the flow of financial capital, and the facilitation of commerce, including the knowledge, skills, competences and other attributes embodied in individuals that are relevant to economic activity.
    • Environmental aspects recognize the diversity and interdependence within living systems, the goods and services produced by the world’s ecosystems, and the impacts of human wastes.
    • Social/Socio-political refers to interactions between institutions/firms and people, functions expressive of human values, aspirations and well-being, ethical issues, and decision-making that depends upon collective action.

    The intersection of social and economic elements can form the basis of social "equitability". In the sense of enlightened management, "viability" is formed through consideration of economic and environmental interests. Between environment and social elements lies “bearability,” the recognition that the functioning of societies is dependent on environmental resources and services. At the intersection of all three of these lies sustainability (figure \(\PageIndex{2}\)).

    Sustainability paradigm venn diagram composed with environment, economy, and social components.
    Figure \(\PageIndex{2}\): Venn diagram of defining the components of sustainability. Image by Andrew, Sunray, based on "File:Sustainable development.svg" by Johann Dréo in Wikimedia Commons (CC-BY-SA4.0)

    The three main elements of the sustainability paradigm are thought of as equally important, however, tradeoffs occur depending on the local/global objective. For example, in some instances it may be deemed necessary to degrade a particular ecosystem in order to facilitate commerce, or food production, or housing. In reality, the extent to which tradeoffs can be made before irreversible damage results is not always known, and in any case there are definite limits on how much substitution among the three elements is wise (to date, humans have treated economic development as the dominant one of the three). This has led to the notion of strong sustainability, where tradeoffs among natural, human, and social capital are not allowed or are very restricted, and weak sustainability, where tradeoffs are unrestricted or have few limits. Whether or not one follows the strong or weak form of sustainability, it is important to understand that while economic and social systems are human creations, the environment is not. Rather, a functioning environment underpins both society and the economy.

    The Evolution of Sustainability

    Our Common Future (1987), the report of the World Commission on Environment and Development, is widely credited with having popularized the concept of sustainable development. It defines sustainable development in the following ways…

    • …development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
    • … sustainable development is not a fixed state of harmony, but rather a process of change in which the exploitation of resources, the orientation of the technological development, and institutional change are made consistent with future as well as present needs.

    The concept of sustainability, however, can be traced back much farther to the oral histories of indigenous cultures. For example, the principle of inter-generational equity is captured in the Inuit saying, ‘we do not inherit the Earth from our parents, we borrow it from our children’. The Native American ‘Law of the Seventh Generation’ is another illustration. According to this, before any major action was to be undertaken its potential consequences on the seventh generation had to be considered. For a species that at present is only 6,000 generations old and whose current political decision-makers operate on time scales of months or few years at most, the thought that other human cultures have based their decision-making systems on time scales of many decades seems wise but unfortunately inconceivable in the current political climate.

    Environmental Equity

    While much progress is being made to improve resource efficiency, far less progress has been made to improve resource distribution. Currently, just one-fifth of the global population is consuming three-quarters of the earth’s resources. If the remaining four-fifths were to exercise their right to grow to the level of the rich minority it would result in ecological devastation. So far, global income inequalities and lack of purchasing power have prevented poorer countries from reaching the standard of living (and also resource consumption/waste emission) of the industrialized countries.

    Countries such as China, Brazil, India, and Malaysia are, however, catching up fast. In such a situation, global consumption of resources and energy needs to be drastically reduced to a point where it can be repeated by future generations. But who will do the reducing? Poorer nations want to produce and consume more. Yet so do richer countries: their economies demand ever greater consumption-based expansion. Such stalemates have prevented any meaningful progress towards equitable and sustainable resource distribution at the international level. These issue of fairness and distributional justice remain unresolved.

    Ecological Footprint

    The ecological footprint (EF), developed by Canadian ecologist and planner William Rees, is basically an accounting tool that uses land as the unit of measurement to assess per capita consumption, production, and discharge needs. It starts from the assumption that every category of energy and material consumption and waste discharge requires the productive or absorptive capacity of a finite area of land or water. If we (add up) all the land requirements for all categories of consumption and waste discharge by a defined population, the total area represents the Ecological Footprint of that population on Earth whether or not this area coincides with the population’s home region.

    Land is used as the unit of measurement for the simple reason that, according to Rees, “Land area not only captures planet Earth’s finiteness, it can also be seen as a proxy for numerous essential life support functions from gas exchange to nutrient recycling … land supports photosynthesis, the energy conduit for the web of life. Photosynthesis sustains all important food chains and maintains the structural integrity of ecosystems.”

    WHAT IS YOUR CARBON FOOTPRINT? There are many personal calculators available on the internet. Here are a few to try:

    What does the ecological footprint tell us? Ecological footprint analysis can tell us in a vivid, ready-to-grasp manner how much of the Earth’s environmental functions are needed to support human activities. It also makes visible the extent to which consumer lifestyles and behaviors are ecologically sustainable calculated that the ecological footprint of the average American is – conservatively – 5.1 hectares per capita of productive land. With roughly 7.4 billion hectares of the planet’s total surface area of 51 billion hectares available for human consumption, if the current global population were to adopt American consumer lifestyles we would need two additional planets to produce the resources, absorb the wastes, and provide general life-support functions.

    For more information on ecological footprints see the Living Planet Report by the World Wildlife Fund, Zoological Society of London, and The Global Footprint Network. You can find the 2020 Living Planet Report as well as summaries on the Global Footprint Network website.

    The IPAT Equation

    As attractive as the concept of sustainability may be as a means of framing our thoughts and goals, its definition is rather broad and difficult to work with when confronted with choices among specific courses of action. Here we introduce one general way to begin to apply sustainability concepts: the IPAT equation. As is the case for any equation, IPAT expresses a balance among interacting factors. It can be stated as:


    where I represents the impacts of a given course of action on the environment, P is the relevant human population for the problem at hand, A is the level of consumption per person, and T is impact per unit of consumption. Impact per unit of consumption is a general term for technology, interpreted in its broadest sense as any human-created invention, system, or organization that serves to either worsen or uncouple consumption from impact. The equation is not meant to be mathematically rigorous; rather it provides a way of organizing information for a “first-order” analysis.

    The Precautionary Principle

    The precautionary principle is an important concept in environmental sustainability. A 1998 consensus statement characterized the precautionary principle this way: “when an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically”. For example, if a new pesticide chemical is created, the precautionary principle would dictate that we presume, for the sake of safety, that the chemical may have potential negative consequences for the environment and/or human health, even if such consequences have not been proven yet. In other words, it is best to proceed cautiously in the face of incomplete knowledge about something’s potential harm.

    Natural Resources

    All natural resources (also known as natural capital) can be divided into two categories: non-renewable and renewable.


    Non-renewable resources are present in a finite quantity and do not regenerate after they are harvested and used. Consequently, as non-renewable resources are used, their remaining stocks in the environment are depleted. This means that non-renewable resources can never be used in a sustainable fashion – they can only be “mined” (figure \(\PageIndex{3}\)). Examples of non-renewable resources include metal ores, petroleum, coal, and natural gas. Although continuing exploration may discover additional stocks of non-renewable resources that can be exploited, this does not change the fact that there is a finite quantity of these resources present on Earth. For example, the discovery of a large amount of metal ore in a remote place may substantially increase the known, exploitable reserves of those non-renewable materials. That discovery does not, however, affect the amounts of the metal present on Earth.

    Metals are often used to manufacture parts of buildings and machinery. To some degree, the metals can be recovered after these uses and recycled back into the economy, effectively extending the lifespan of their reserves. However, due to the growth and increasing industrialization of the economy, the demand for metals is accelerating. Because recycling cannot keep up with the increasing demands for metals, large additional quantities must be mined from their known reserves in the environment. For valuable metals, such as gold and platinum, there is a high efficiency of recycling, but it is much less so for iron and other less-costly metals.

    Fossil fuels are the other major category of non-renewable resources. They are mostly combusted to provide energy for transportation and heating, which converts their organic compounds into carbon dioxide and water, which are released into the environment. Some of that CO2 and H2O may be absorbed by plants and other photosynthetic organisms and be converted back into organic materials, a process that might be interpreted as being a kind of recycling. However, the rate at which this happens is insignificantly small compared with the release of the CO2 and H2O by the combustion of fossil fuels, so these materials should be viewed as being as non-renewable as metals are. A more minor use of fossil fuels is to manufacture various kinds of plastics. These synthetic materials can be recycled after initial uses, which does help to extend the lifespan of the reserves of fossil fuels. Nevertheless, because the dominant use of fossil fuels is as sources of energy, they essentially flow through an industrial economy, with little new recycling.

    Figure \(\PageIndex{3}\): Non-renewable resources can only be mined. This is a view of the Etaki open-pit diamond mine in the Northwest Territories. Three open pits can be seen as a cluster, plus another at the top-left of the image, along with an extensive tailings-disposal area and other infrastructure. Source: Jason Pineau, Wikimedia Commons; .


    Renewable resources are capable of regenerating after harvesting, so potentially their stocks can be utilized forever. Most renewable resources are biological (Figure \(\PageIndex{4}\), although some are non-biological. Biological Renewable Resources Renewable resources that are biological in nature (bio-resources) include the following:

    • wild animals that are hunted as food or for bio-materials, such as deer, moose, hare, ducks, fish, lobster, and seals
    • forest biomass that is harvested for lumber, fiber, or energy
    • wild plants that are gathered as sources of food
    • plants cultivated as sources of food, medicine, materials, or energy
    • the organic-based capability of soil to sustain the productivity of agricultural crops

    Figure \(\PageIndex{4}\): Renewable resources, such as timber and fish, are capable of regenerating after they are harvested. Provided they are not over-harvested or managed inappropriately, renewable resources can be harvested in a sustainable fashion. This photo shows a load of timber that was harvested on Vancouver Island. Source: B. Freedman.

    Non-Biological Renewable Resources The following are renewable resources that are non-biological:

    • sunlight, of which there is a continuous input to Earth
    • surface water and groundwater, which are renewed through the hydrologic cycle
    • winds, which are renewed through the heat-distribution system of the atmosphere
    • water currents and waves, which are renewed through the heat-distribution system of the oceans, as well as the tidal influence of the Moon

    Many renewable resources can be managed to increase their rates of recruitment and productivity and to decrease mortality. In the following section we explain how management practices can be used to increase the productivity of biological resources. Although a renewable resource can regenerate after harvesting, it can also be badly degraded by excessive use or by inappropriate management. These practices can damage the ability to regenerate and may ultimately cause a collapse of the stock. If this happens, the renewable resource is being “mined”, or used as if it were a non-renewable resource. As such, it becomes depleted by excessive use. For this reason, ecologists commonly use the qualified term: potentially renewable resources.

    Sustainable Living

    Sustainable living describes a lifestyle that attempts to reduce/eliminate an individuals (or societies) use of resources so as to be as close as possible to "net zero living". As such, an individual (or society) focuses on reducing their footprint (ecologically, carbon, socially, etc) through their choices/methods of:

    • Use of resources (energy/diet/transportation/water/etc)
    • Support of people/companies (voting/economic/social/etc)
    • Practices of reducing, reusing, and recycling
    • Consciousness of priority and focus for local concerns/needs versus global concerns/needs
    • Sharing knowledge with their community (all ages)

    The thought of getting started with sustainable living can be overwhelming! However, it is important to note that although we can acknowledge all the things that need to be accomplished, that that entire burden does not lie with just one individuals control (Figure \(\PageIndex{5}\)). It takes a multi-layerd approach to appropriately take action at the individual, societal, and political levels (Figure \(\PageIndex{6}\)).

    Venn diagram illustraing the focus point for what one cares about versus what one can control
    Figure \(\PageIndex{5}\): Focus for individual sustainability lifestyle goals. Image by Rachel Schleiger (CC-BY-NC)
    Goals for sustainability based priority, scale, focus on timelines, and approach
    Figure \(\PageIndex{6}\): Considerations for sustainable living goals. Image by Sustainability Week Switzerland in Wikimedia Commons (CC-BY-SA)

    References Cited and Further Reading

    Begon, M., R.W. Howorth, and C.R. Townsend. 2014. Essentials of Ecology. 4th ed. Wiley, Cambridge, UK.

    Brown, L.R. 2001. Eco-Economy: Building an Economy for the Earth. W.W. Norton and Company, New York, NY.

    Brown, L.R. 2003. Plan C: Rescuing a Planet Under Stress and a Civilization in Trouble. W.W. Norton and Company, New York, NY.

    Chambers, N., C. Simmons, and N. Wackernagel. 2001. Sharing Nature’s Interest: Ecological Footprints as an Indicator of Sustainability. Earthscan Publications, London, UK.

    Chiras, D.D. and J.P. Reganold. 2009. Natural Resource Conservation: Management for a Sustainable Future. 10th ed. Prentice Hall, Upper Saddle River, NJ.

    Clark, W.C. 1989. Clear-cut economies: Should we harvest everything now? The Sciences, Jan./Feb.: 16-19.

    Clark, W.C. and R.E. Munn (eds.). 1986. Sustainable Development of the Biosphere. Cambridge University Press, New York, NY.

    Costanza, R. 1991. Ecological Economics: The Science and Management of Sustainability. Columbia University Press, New York, NY.

    Costanza, R. and H.E. Daly. 1992. Natural capital and sustainable development. Conservation Biology, 6: 37-46.

    Daly, H.E. 1997. Beyond Growth: The Economics of Sustainable Development. Beacon Press, Boston, MA.

    Diamond, J.M. 1982. Man the exterminator. Nature, 298: 787-789.

    Diamond, J. 2004. Collapse: How Societies Choose to Fail or Succeed. Viking, East Rutherford, NJ.

    Ehrlich, P.R. 1989. Facing the habitat crisis. BioScience, 39: 480-482.

    Faber, M.M., R. Manstetter, and J. Proops. 1996. Ecological Economics: Concepts and Methods. Edward Elgar Publishers, New York, NY.

    Farley, J. and H.E. Daly. 2003. Ecological Economics: Principles and Applications. Island Press, Washington, DC.

    Freedman, B. 1995. Environmental Ecology. 2nd ed. Academic Press, San Diego, CA.

    Freedman, B. 2010. Environmental Science. A Canadian Perspective. 5th ed. Pearson Education Canada, Toronto, ON.

    Freedman, B., J. Hutchings, D. Gwynne, J. Smol, R. Suffling, R. Turkington, R. Walker, and D. Bazeley. 2014. Ecology: A Canadian Context. 2nd ed. Nelson Canada, Toronto, ON.

    Hardin, G. 1968. The tragedy of the commons. Science, 162: 1243-1248.

    Holechek, J.L., R.A. Cole, J.T. Fisher, and R. Valdez. 2003. Natural Resources: Ecology, Economics, and Policy. 2nd ed. Prentice Hall, East Rutherford, NJ.

    Martin, P.S. 1984. Catastrophic extinctions and late Pleistocene blitzkrieg: two radiocarbon tests. pp. 153-589 In: Extinctions (M.H. Nitecki, ed.). University of Chicago Press, Chicago, IL.

    Martin, P.S. and H.E. Wright (eds.). 1967. Pleistocene Extinctions: The Search for a Cause. Yale University Press, New Haven, CT.

    Meadows, D.H., D.L. Meadows, and J. Randers. 1992. Beyond the Limits: Global Collapse or a Sustainable Future. Earthscan, London, UK.

    Meadows, D.H., J. Randers, and D.L. Meadows. 2003. Limits to Growth: The 30-Year Update. Chelsea Green Publishing Co., White River Junction, VT.

    Mowat, F. 1984. Sea of Slaughter. McClelland & Stewart, Toronto, ON.

    Ponting, C. 1991. A Green History of the World. Penguin, Middlesex, UK.

    Rees, W.E. 1990. The ecology of sustainable development. Ecologist, 20(1): 18-23.

    Statistics Canada. 2014. Gross domestic product, expenditure-based, provincial and territorial. Cansim Table 384-00384.

    Thirgood, J.V. 1981. Man and the Mediterranean Forest: A History of Resource Depletion. Academic Press, New York, NY.

    Tietenberg, T. 2005. Environmental and Natural Resource Economics. 9th ed. Addison Wesley Boston, MA.

    Tristram, H.B. 1873. The Natural History of the Bible. Society for Promoting Christian Knowledge, London, UK.

    White, L. 1967. The historical roots of our ecological crisis. Science, 155: 1203-1207.

    World Commission on Environment and Development (WCED). 1987. Our Common Future. Oxford University Press, Oxford, UK.

    Contributors and Attributions

    This page titled 1.2: Introduction to Sustainability is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Melissa Ha and Rachel Schleiger (ASCCC Open Educational Resources Initiative) .