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.