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Title: Sustainable development 2


1
Sustainable development 2
2
  • Sustainable agriculture
  • Sustainable agriculture integrates three main
    goals environmental stewardship, farm
    profitability, and prosperous farming
    communities. These goals have been defined by a
    variety of disciplines and may be looked at from
    the vantage point of the farmer or the consumer.

3
  • Description
  • Sustainable agriculture refers to the ability of
    a farm to produce food indefinitely, without
    causing irreversible damage to ecosystem health.
    Two key issues are biophysical (the long-term
    effects of various practices on soil properties
    and processes essential for crop productivity)
    and socio-economic (the long-term ability of
    farmers to obtain inputs and manage resources
    such as labor).
  • The physical aspects of sustainability are partly
    understood (Altieri 1995). Practices that can
    cause long-term damage to soil include excessive
    tillage (leading to erosion) and irrigation
    without adequate drainage (leading to
    accumulation of salt in the soil). Long-term
    experiments provide some of the best data on how
    various practices affect soil properties
    essential to sustainability.
  • While air and sunlight are generally available in
    most geographic locations, crops also depend on
    soil nutrients and the availability of water.
    When farmers grow and harvest crops, they remove
    some of these nutrients from the soil. Without
    replenishment, the land would suffer from
    nutrient depletion and be unusable for further
    farming. Sustainable agriculture depends on
    replenishing the soil while minimizing the use of
    non-renewable resources, such as natural gas
    (used in converting atmospheric nitrogen into
    synthetic fertilizer), or mineral ores (e.g.,
    phosphate).

4
  • Possible sources of nitrogen that would, in
    principle, be available indefinitely, include
  • recycling crop waste and livestock or human
    manure
  • growing legume crops and forages such as,
    peanuts, or alfalfa that form symbioses with
    nitrogen-fixing bacteria called rhizobia
  • industrial production of nitrogen by the Haber
    Process uses hydrogen, which is currently derived
    from natural gas, but could instead be made by
    electrolysis of water using electricity (perhaps
    from solar cells or windmills) or
  • genetically engineering (non-legume) crops to
    form nitrogen-fixing symbioses or fix nitrogen
    without microbial symbionts.

5
  • The last option was proposed in the 1970s, but
    would be well beyond the capability of current
    (2006) technology, even if various concerns about
    biotechnology were addressed. Sustainable options
    for replacing other nutrient inputs (phosphorus,
    potassium, etc.) are more limited.
  • In some areas, sufficient rainfall is available
    for crop growth, but many other areas require
    irrigation. For irrigation systems to be
    sustainable they must be managed properly (to
    avoid salt accumulation) and not use more water
    from their source than is naturally replenished,
    otherwise the water source becomes, in effect, a
    non-renewable resource. Improvements in water
    well drilling technology and the development of
    submersible pumps have made it possible for large
    crops to be regularly grown where reliance on
    rainfall alone previously made this level of
    success unpredictable. However, this progress has
    come at a price, in that in many areas where this
    has occurred, such as the Ogallala Aquifer, the
    water is being used at a greater rate than its
    rate of recharge.
  • Socioeconomic aspects of sustainability are also
    partly understood. Regarding nonindustrialized
    farming, the best known analysis is Netting's
    (1993) study on smallholder systems through
    history.

6
  • Economics
  • Given the finite supply of natural resources,
    agriculture that is inefficient may eventually
    exhaust the available resources or the ability to
    afford and acquire them. It may also generate
    negative externality, such as pollution as well
    as financial and production costs. Agriculture
    that relies mainly on inputs that are extracted
    from the earth's crust or produced by society,
    contributes to the depletion and degradation of
    the environment. Despite this continuing
    practice, unsustainable agriculture continues
    because it is financially more cost-effective
    than sustainable agriculture in the short term.

7
  • In an economic context, the need for the farm to
    generate revenue depends on the extent to which
    it is market oriented and on government subsidy.
    The way that crops are sold must be accounted for
    in the sustainability equation. Fresh food sold
    from a farm stand requires little additional
    energy, aside from that necessary for
    cultivation, harvest, and transportation
    (including consumers). Food sold at a remote
    location, whether at a farmers' market or the
    supermarket, incurs a different set of energy
    cost for materials, labour, and transport.
  • To be sold at a remote location requires a
    complex economic system in which the farm
    producers form the first link in a chain of
    processors and handlers to the consumers. This
    practice allows greater revenue because of
    efficient transport of a large number of items,
    but because it produces externalities and relies
    on the use of non-renewable resources, shipping,
    processing, and handling, it is not considered
    sustainablecitation needed. Moreover, such a
    system is considered vulnerable to fluctuations,
    such as strikes, oil prices, and global economic
    conditions including labour, interest rates,
    futures markets, and farm product pricescitation
    needed.

8
  • In Third World agriculture, much of what is known
    about the social components of sustainability
    comes from anthropologist Robert Netting's work.
    In Smallholders, Householders Farm Families and
    the Ecology of Intensive, Sustainable
    Agriculture, he defines an important
    cross-cultural pattern of high-labor,
    high-production cultivation exemplified East
    Asian paddy rice cultivators, African cultivators
    such as the Kofyar, alpine peasants, and
    Mesoamrican farmers of raised fields. One key to
    socio-economic sustainability in such systems is
    that these farmers systems provide for much of
    their own subsistence and also participate in the
    market.
  • From a system's view, the gain and loss factors
    for sustainability can be listed. The most
    important factors for an individual site are sun,
    air, soil and water as rainfall. These are
    naturally present in the system as part of the
    larger planetary processes and incur no costs. Of
    the four, soil quality and quantity are most
    amenable to human intervention through time and
    labour. (The economic input depends solely on the
    price of labour and cost of machinery used).
  • Natural growth and outputs are also subject to
    human intervention. What grows and how and where
    it is grown are a matter of choice. Two of the
    many possible practices of sustainable
    agriculture are crop rotation and soil amendment,
    both designed to ensure that crops being
    cultivated can obtain the necessary nutrients for
    healthy growth.

9
  • Methods
  • Monoculture, a method of growing only one crop at
    a time in a given field, is a very widespread
    practice, but there are questions about its
    sustainability, especially if the same crop is
    grown every. Growing a mixture of crops
    (polyculture) sometimes reduces disease or pest
    problems (Nature 406718, Environ. Entomol.
    12625) but polyculture has rarely, if ever, been
    compared to the more widespread practice of
    growing different crops in successive years crop
    rotation with the same overall crop. For
    example, how does growing a corn-bean mixture
    every year compare with growing corn and bean in
    alternate years? Cropping systems that include a
    variety of crops (polyculture and/or rotation)
    may also use replenish nitrogen (if legumes are
    included) and may also use resources such as
    sunlight, water, or nutrients more efficiently
    (Field Crops Res. 34239)

10
  • Some pesticides, though sometimes useful in the
    short term, can harm the soil food web, a complex
    ecology of micro-organisms in soil that helps
    sustain the plant from the roots down.
    Experiments comparing plants grown in soil
    compared to plants grown through hydroponics have
    shown a thirty-three percent higher growth rate
    when there are beneficial soil microorganisms
    availablecitation needed.
  • Certain pesticides synthesized by chemical
    companies can impart a sometimes fatal toxicity
    to humanscitation needed, livestock and insect
    pollinators, such as bees and butterflies, which
    may be necessary for plant successcitation
    needed. Without insect pollinators, farm labor
    must be expended to manually pollinate each
    plant. Crops such as cacao beans and vanilla are
    examples of crops requiring highly
    labor-intensive practices in the absence of
    natural pollinators.

11
  • Throughout history, farmers seeking to grow crops
    usually confine themselves to growing only the
    fastest and most productive plants. Such
    practices can result in growing crops without the
    genetic diversity found in wildlifecitation
    needed. Without such diversity in the genes,
    crops may become more susceptible to disease and
    crop failurecitation needed. The Irish potato
    famine is a well-known example of the dangers of
    monocultural and mono-varietal crop
    cultivationcitation needed.

12
  • Many scientists, farmers, and businesses have
    debated how to make agriculture farming
    sustainablecitation needed. One of the many
    practices includes growing a diverse number of
    perennial crops in a single field, each of which
    would grow in separate season so as not to
    compete with each other for natural
    resourcescitation needed. This system would
    replicate the biodiversity already found in a
    natural environment, resulting in increased
    resistance to diseases and decreased effects of
    erosion and loss of nutrients in soilcitation
    needed. Nitrogen fixation from legumes, for
    example, used in conjunction with plants that
    rely on nitrate from soil for growth, will allow
    the land to be reused annuallycitation needed.
    Legumes will grow for a season and replenish the
    soil with ammonium and nitrate, and the next
    season other plants can be seeded and grown in
    the field in preparation for harvestcitation
    needed. This method is considered to require a
    minimal amount of outside resourcescitation
    needed.

13
  • In practice, there is no single approach to
    sustainable agriculture, as the precise goals and
    methods must be adapted to each individual case.
    There may be some techniques of farming that are
    inherently in conflict with the concept of
    sustainability, but there is widespread
    misunderstanding on impacts of some practices.
    For example, the slash-and-burn techniques that
    are the characteristic feature of shifting
    cultivators are often cited as inherently
    destructive, yet slash-and-burn cultivation has
    been practiced in the Amazon for at least 6000
    years (Sponsel 1986) serious deforestation did
    not begin until the 1970s, largely as the result
    of Brazilian government programs and policies
    (Hecht and Cockburn 1989).

14
  • Urban planning
  • There has been considerable debate about which
    form of human residential habitat may be a better
    social form for sustainable agriculture.
    Generally, it is thought that village communities
    can improve sustainability in that such
    communities tend to provide a cooperative
    environment that supports farmingcitation
    needed.
  • Many environmentalists pushing for increased
    population density to preserve agricultural land
    point out that urban sprawl is less sustainable
    and more damaging to the environment than living
    in the cities where cars are not needed because
    food and other necessities are within walking
    distancecitation needed. However, others have
    theorized that sustainable ecocities, or
    ecovillages which combine habitation and farming
    with close proximity between producers and
    consumers, may provide greater sustainabilitycita
    tion needed.
  • The use of available city space (e.g., rooftop
    gardens and community gardens) for cooperative
    food production is another way to achieve greater
    sustainabilitycitation needed.
  • One of the latest ideas in achieving sustainable
    agricultural involves shifting the production of
    food plants from major factory farming operations
    to large, urban, technical facilities called
    vertical farms. The advantages of vertical
    farming include year-round production, isolation
    from pests and diseases, controllable resource
    recycling, and on-site production that eliminates
    the need for transportation costscitation
    needed. While a vertical farm has yet to become
    a reality, the idea is gaining momentum among
    those who believe that current sustainable
    farming methods will be insufficient to provide
    for a growing global populationcitation needed.

15
  • References
  • Altieri, Miguel A. (1995) Agroecology The
    science of sustainable agriculture. Westview
    Press, Boulder, CO.
  • Jahn, GC, B. Khiev, C. Pol, N. Chhorn, S. Pheng,
    and V. Preap. 2001. Developing sustainable pest
    management for rice in Cambodia. pp. 243-258, In
    S. Suthipradit, C. Kuntha, S. Lorlowhakarn, and
    J. Rakngan eds. Sustainable Agriculture
    Possibility and Direction Proceedings of the 2nd
    Asia-Pacific Conference on Sustainable
    Agriculture 18-20 October 1999, Phitsanulok,
    Thailand. Bangkok (Thailand) National Science
    and Technology Development Agency. 386 p.
  • Lindsay Falvey (2004) Sustainability - Elusive or
    Illusion Wise Environmental Management.
    Institute for International Development, Adelaide
    pp259.
  • Hecht, Susanna and Alexander Cockburn (1989) The
    Fate of the Forest developers, destroyers and
    defenders of the Amazon. New York Verso.
  • Netting, Robert McC. (1993) Smallholders,
    Householders Farm Families and the Ecology of
    Intensive, Sustainable Agriculture. Stanford
    Univ. Press, Palo Alto.
  • Sponsel, Leslie E. (1986) Amazon ecology and
    adaptation. Annual Review of Anthropology 15
    67-97.

16
  • Sustainable industries
  • From Wikipedia, the free encyclopedia
  • Jump to navigation, search
  • The earliest mention of the phrase sustainable
    industries appeared in 1990 in a story about a
    Japanese group reforesting a tropical forest to
    help create sustainable industries for the local
    populace. (Dietrich, Bill. "Our Troubled Earth
    Japan." The Seattle Times. November 13, 1990.
    Page F-2.) Soon after, a study entitled Jobs in
    a Sustainable Economy by Michael Renner of the
    Worldwatch Institute was published, using the
    term sustainable industries. (1991)
  • This 1991 report concluded, "Contrary to the
    jobs-versus-owls rhetoric that blames
    environmental restrictions for layoffs, the
    movement toward an environmentally sustainable
    global economy will create far more jobs than it
    eliminates. The chief reason non-polluting,
    environmentally sustainable industries tend to be
    intrinsically more labour intensive and less
    resource intensive than traditional processes."
    While the conclusion may be subject to some
    debate, it nevertheless formed an important Among
    the features of sustainable industry offered in
    the paper were energy efficiency, resource
    conservation to meet the needs of future
    generations, safe and skill-enhancing working
    conditions, low waste production processes, and
    the use of safe and environmentally compatible
    materials. Some of the benefits, however would be
    offset by higher prices (due to labor costs) and
    a theoretically larger population needed to
    perform the same amount of work, increasing the
    agricultural and other loads on

17
  • Sustainable energy sources are energy sources
    which are not expected to be depleted in a
    timeframe relevant to the human race, and which
    therefore contribute to the sustainability of all
    species. This concept is termed sustainability.
    An additional criterion for strict
    sustainability, useful for short- and medium-term
    decisions is social and political sustainability
    of an energy technology.
  • Sustainable energy sources are most often
    regarded as including all renewable sources, such
    as solar power, wind power, wave power,
    geothermal power, tidal power, and others.
  • Fission power and fusion power meet the
    definition of sustainability, but there is
    controversy over whether or not they should be
    regarded as sustainable for social and political
    reasons

18
  • Renewable energy sources
  • Wind power is one of the most environmentally
    friendly sources of renewable energy
  • Main article renewable energy
  • Renewable energy sources are those whose stock is
    rapidly replenished by natural processes, and
    which aren't expected to be depleted within the
    lifetime of the human species. In most cases,
    these energy sources have technical challenges to
    overcome before they are economically competitive
    with conventional methods of electricity
    generation. Approaches to overcoming these
    challenges are a field of active research, and
    are described on the relevant generation method
    pages.

19
  • The well-known renewable energy options can be
    classified by the natural process that provides
    their energy
  • Direct solar energy
  • Solar cells use semiconductors to directly
    convert sunlight into electricity. Primary
    challenges with their use are low efficiency,
    energy-intensive manufacture, and power
    variability due to weather and nightfall.
  • Solar thermal plants use concentrated sunlight as
    a heat source to power a heat engine which
    generates electricity. Primary challenges with
    their use are manufacture and maintenance of
    large mirror arrays and power variability due to
    weather and nightfall.
  • Solar updraft tower plants use sunlight to heat a
    contained mass of air, setting up convection
    currents that cause air to exit through a chimney
    from which power is tapped. Primary challenges
    with their use are low efficiency, construction
    and maintenance of the large structures required,
    and power variability due to weather (a Solar
    updraft tower has enough heat capacity to
    function through night).

20
  • Indirect solar energy
  • Ocean thermal energy conversion uses the
    temperature difference between the warmer surface
    of the ocean and the cooler lower depths to drive
    a heat engine. The primary challenges with ocean
    thermal energy conversion's use are low
    efficiency and the construction and maintenance
    of large structures in a sea environment.
  • Wind power uses wind turbines to draw energy from
    large-scale motion of air. The primary challenges
    with wind power's use are the large areas
    required to produce useful amounts of
    electricity, and power variability due to
    weather.
  • Hydroelectricity uses dams to draw energy from
    the flow of water from high-altitude areas to
    areas with lower altitudes. Primary challenges
    with hydroelectricity's use are the environmental
    damage caused by the construction of dams, and
    the scarcity of remaining sites for power
    generation.
  • Wave power uses floats to extract mechanical
    energy from the motion of waves. Primary
    challenges with wave power's use are the large
    areas required to produce useful amounts of
    electricity, and disruption of coastal
    environments.
  • Biofuel uses products of plants, animals, or
    bacteria to provide fuels that can be used in a
    manner similar to fossil fuels. The primary
    challenge with biofuel's use is the availability
    of suitable feedstock in sufficient quantity for
    large-scale adoption. The environmental and
    economic benefits of non-cellulosic ethanol have
    been heavily critiqued by many, including Brad
    Ewing of Environmental Economics Sustainable
    Development1 and Lester R. Brown of Earth
    Policy Institute2

21
  • Radioactive decay within the Earth
  • Geothermal power uses the temperature difference
    between the earth's surface and its interior to
    drive a heat engine, generally at a location such
    as a hot spring where the heat has been
    transported most of the way to the surface by
    natural processes. The primary challenge with
    geothermal power's use is low power generation
    efficiency for most sites.
  • Rotation of the Earth
  • Tidal power uses dams to draw energy from the
    changes in water height due to tides produced by
    the gravitational influences of the moon and sun
    as Earth rotates. The primary challenges with
    tidal power's use are the large area required to
    produce useful amounts of electricity, and
    disruption of coastal environments.
  • Processes powered by solar energy will be renewed
    for as long as the sun remains on the main
    sequence (approximately 5 billion years).
    Processes powered by radioactive decay within the
    Earth will be renewed for time comparable to the
    half-life of uranium 238 (4.5 billion years) and
    thorium 232 (14 billion years). Processes powered
    by the Earth's rotation will last until the Earth
    becomes tidally locked to the Sun (though tidal
    acceleration would eject the moon from Earth
    orbit earlier). Both of these would take longer
    than the expected lifetime of the sun to occur.

22
  • Sustainable sources not considered renewable
  • Sustainable energy sources that aren't renewable
    are those whose stock is not replenished, but for
    which the presently available stocks are expected
    to last for as long as human civilization cares
    to use them.
  • These energy sources are derived from nuclear
    energy, as other forms of stored energy found on
    Earth do not have sufficient energy density to
    supply humanity indefinitely.

23
  • Fission power uses the nuclear fission of heavy
    elements to release energy that drives a heat
    engine. Primary challenges with the use of
    fission power are the production of small
    quantities of highly-radioactive waste in the
    form of spent fuel, larger quantities of
    less-radioactive waste in the form of activated
    structural material, and (for use as a long-term
    power source) the need to perform intensive
    processing of highly-radioactive fuel bundles,
    both to reclaim unused fuel in spent fuel rods,
    and to reclaim plutonium 239 and uranium 233 that
    have been bred from uranium 238 and thorium 232,
    respectively.
  • Fusion power uses the nuclear fusion of isotopes
    of hydrogen to release energy that drives a heat
    engine. Primary challenges with the use of fusion
    power are that the technology required to build a
    useful fusion power plant are still under
    development, and that substantial quantities of
    radioactive waste in the form of activated
    structural material is produced.
  • Fission power's long-term sustainability depends
    on the amount of uranium and thorium that is
    available to be mined. Estimates for fuel
    reserves vary widely, but if breeder reactors and
    fuel reprocessing are assumed, tend to be tens of
    thousands of years or longer (uranium is
    approximately as common in Earth's crust as tin
    or zinc (2 ppm), and thorium as common as lead (6
    ppm)).

24
  • Fusion power's long-term sustainability depends
    on the amount of lithium that is available to be
    mined (for deuterium-tritium fusion), or the
    amount of deuterium available in seawater (for
    deuterium-deuterium fusion). Lithium is a
    reasonably common component of Earth's crust,
    being about 10 times as common as thorium (65
    ppm). Deuterium (a hydrogen isotope) occurs
    wherever hydrogen is found (principally in
    water), at about 150 ppm. As it can be extracted
    easily from seawater, economically viable
    reserves of deuterium are for practical purposes
    unlimited.

25
  • Technical sustainability of nuclear power
  • Discussions are re-emerging on proper
    classification of nuclear energy under such
    umbrella terms as "renewable" and "sustainable"
    These attributes bring moral gains or eligibility
    for development aid under various jurisdictions.
  • The primary argument in favor of "renewable"
    status is the relatively inexhaustible supply of
    fuel available (uranium and thorium for fission
    or hydrogen for fusion). See also Renewable
    energy, Nuclear power section.

26
  • Proponents, such as environmentalists James
    Lovelock, Patrick Moore (Greenpeace co-founder),
    Stewart Brand (creator of The Whole Earth
    Catalog), and Norris McDonald (president of the
    AAEA), also claim that nuclear power is at least
    as environmentally friendly as traditional
    sources of renewable energy, making it the best
    future solution to global warming and the world's
    growing need for energy. They note that nuclear
    power plants produce little carbon dioxide
    emissions and claim that the radioactive waste
    produced is minimal and well-contained,
    especially compared to fossil fuels. 3

27
  • In 2001, professors Jan Willem Storm van Leeuwen
    and Philip Smith released a study which argued
    that, though nuclear plants don't produce any CO2
    directly, the energy required for the rest of the
    nuclear fuel cycle (uranium mining, enrichment,
    transportation) and power plant life cycle
    (construction, maintenance, decommissioning)
    leads to significant carbon dioxide emissions,
    especially as usage of lower-grade uranium
    becomes necessary.4 In 2000, however, Frans H.
    Koch of the International Energy Agency reported
    that, although it is correct that the nuclear
    life cycle produces greenhouse gases, these
    emissions are actually less than the life cycle
    emissions of other renewables, like solar and
    wind, and drastically less than fossil fuels.5

28
  • Political sustainability of nuclear power
  • This section is a stub. You can help by
    expanding it.Some critics of nuclear energy argue
    that deployment of nuclear reactors in many
    countries would accelerate the proliferation of
    nuclear weapons technology that has many links
    with civilian use of nuclear materials. Some
    nuclear reactors (especially heavy water
    moderated reactors) create the materials
    necessary for these weapons.
  • The issue of fuel reprocessing and/or long-term
    repository of nuclear waste materials also
    remains contentious. Very few coutries have
    developed waste depositories for high-level
    radioactive waste (see Yucca Mountain Repository
    USA Gorleben Germany Forsmark, Sweden).
  • Due to opposition to nuclear power many countries
    (Austria, Italy, Sweden, Germany) have
    effectively banned further development of nuclear
    energy showing a clear lack of political
    sustainability under present conditions.

29
  • Living machines
  • From Wikipedia, the free encyclopedia
  • Jump to navigation, search
  • The living machine at Oberlin College with a
    settlement tank in the foreground and filtering
    tanks in the background
  • Living Machines are a form of biological
    wastewater treatment designed to mimic the
    cleansing functions of wetlands. They are
    intensive bioremediation systems that can also
    produce beneficial by-products such as methane
    gas, edible and ornamental plants, and fish.
    Aquatic and wetland plants, bacteria, algae,
    protozoa, plankton, snails, clams, fish and other
    organisms are used in the system to provide
    specific cleansing or trophic functions. In
    temperate climates, the system of tanks, pipes
    and filters is housed in a greenhouse to raise
    the temperature, and thus the rate of biological
    activity. The initial development of living
    machines is generally credited to John Todd, and
    evolved out of the bioshelter concept developed
    at the now-defunct New Alchemy Institute. Living
    Machine is a trademarked term held by Living
    Designs Group, LLC of Taos, New Mexico. Living
    machines fall within the emerging discipline of
    ecological engineering, and many similar systems
    are built in Europe without being dubbed Living
    Machines.
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