Environmental Science Exam III Notes

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Environmental Science Exam III Notes
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• Sustainable
• Agriculture
• Recall Information from Presentation

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About 38 of the worlds land is used for
agriculture

• Land use in the U.S. (not including Alaska and
  Hawaii).
• Of this, roughly 61 is used for agriculture
  either for crops or grazing.
• Of that, roughly 2/3 of agricultural land, or 40
  of all land is used for grazing animals to feed.

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• Also, according to the U.S. Department of
  Agriculture, farming and ranching are responsible
  for 69 of all species endangerment in the United
  States.
• So, looks like we're killing endangered animals
  in order to grow cows, pigs and chickens.

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Starvation

• There are more than 800 million people in the
  world afflicted with starvation. The reason for
  their hunger is not a global shortage of food,
  but a string of interconnected forces like
  poverty, population growth and lack of
  education.
• How many people starve to death each year?
• _at_ 5 million people per year.
• How many people starve to death each day?
• _at_ 30,273 per day !

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• The hunger trend is being combated by hundreds of
  global organizations and well-meaning
  governments, but the conditions of famine around
  the world are proving nearly impossible to
  eliminate.

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Kwashiorkor and marasmus are two types of
malnutrition that are the two extremes of
protein-calorie deficiency.
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Soil Formation I

• Physical events like fragmentation (by weathering
  e.g., by temperature changes and abrasion) of the
  parent material consisting of rocks or other
  geological deposits

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Soil Formation II

• Chemical weathering occurs when water and other
  substances react with parent material,

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Soil Formation III

• Biological events Organisms (e.g., lichens) also
  play a role in weathering, Humus is the resulting
  decaying organic matter that is formed and
  constitutes an important ingredient of the soil.

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Soil degradation is a serious threat to humans
2004
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Barriers to a Sustainable Agricultural System

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Erosion

• is the wearing away and transportation of soil by
  water or by wind. Worldwide 19 billion ha (47
  billion acres) suffer from erosion and other
  forms of degradation.

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• Desertification is the conversion of cropland,
  pasture, and rangeland into desert or land too
  arid to be farmed

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• The loss of fertile farmland to development
  (farmland conversion)

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• The amount of irrigated cropland is substantial
  and produces _at_ 33 of our food. There are many
  problems with irrigation including salinization
  (the buildup of salts in surface soil layers) and
  overuse of water resources.

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• Approximately 10 of the worlds irrigated
  cropland suffers from waterlogging

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• A loss of genetic diversity and a decline in
  species that are cultivated could result in great
  decreases in food production in the future.

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• The overapplication of fertilizers can also
  damage soil and plants

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Possible solutions to our problems with our
agricultural system Part I

• Protecting Soil and Water Resources.
• Farmland Conversion can be reduced by regulations
• Water should be used more efficiently
• Appropriate use of fertilizers is needed to
  replace nutrients in soil.

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Possible solutions to our problems with our
agricultural system Part II

• Crop rotation especially involving the periodic
  planting of legumes that replenish Nitrogen,
• A potential for increased food production is to
  increase the amount of land in use.
• Also eating lower on the food chain would
  increase total crop yields

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• Agriculture, Biotech,
• and the Future

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• Approximately 850 million people are malnourished
  and it plays a role in the death of 5 million
  deaths/year. The Green Revolution was supposed
  to have solved the problems, but instead it has
  resulted in other problems

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PESTS

• Pests consume or destroy _at_ 50 of the worlds
  crops. Pesticides - chemicals that are used to
  kill or control unwanted organisms or pests
  (e.g., fungi, animals, and plants).

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Pests

• The perfect pesticide would be inexpensive,
  affect only the target organism (narrow spectrum
  instead of broad spectrum), have a short
  half-life, and break down into harmless
  materials.
• B. Pesticides are widely used because their use
  increases crop yields, and profits as well as
  decreasing the incidence of insect-borne
  diseases. Annually _at_ 2.75 million tons of
  pesticides are used (22 in the U.S. and 57 in
  Europe and other developed areas).

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Problems associated with the use of pesticides
include

• Killing non-target species (e.g., beneficial
  insects, natural predators, wildlife and fish)
• Increasing genetically resistant species of
  pests.
• Biomagnfication and bioaccumulation
• Adverse affects to human health.
• Economic costs

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How might we reduce the use of pesticides

• Increased organic farming
• Integrated pest management involves the use of a
  variety of methods for pest control including
  the selective use of synthetic and natural
  pesticides, pheromones, the release of natural
  predators, and modifications of farming
  practices.
• Bans and registration
• Education

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• Resource Management
• is the practice of harvesting potentially
  renewable resources in ways that do not deplete
  them (Withgott and Brennan).

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Forests and Forest Management Recall the
Sustainable Forestry Presentation

• At one time, almost 50 of the US, 75 of Canada,
  and almost all of Europe were forested, but
  demand for wood has led to deforestation.
• Trees were harvested for fuel, building
  materials, and in order to clear land for
  farming. Negative impacts of the exploitation of
  the remaining forests include but are not limited
  to a further reduction in biodiversity, erosion,
  the loss of carbon sinks, regional and possibly
  global climate change, and changes in the water
  cycle.

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Forests Part II

• The root causes of deforestation include the
  developmentalist ethic, a lack of education
  concerning the benefits of forests, the growing
  human population, poverty, land ownership
  patterns, and government policies that promote
  overharvesting in several nations.
• Concern about deforestation has led to an
  interest in sustainable forestry.

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Rangelands and Range Management Protecting the
Worlds Grasslands

• Of the land that is in use for food
  production, 26 of that is used for grazing
  livestock and is called rangeland. It is mostly
  unsustainably managed.
• Despite that fact that leaves grow from the
  ground up and can regrow if the lower ½ of the
  plant (metabolic reserve) is left after grazing
  and thus are resistant to limited grazing, many
  ranglelands are overgrazed. This metabolic
  reserve is destroyed by overgrazing

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Consequences of overgrazing
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Range Management involves the following
techniques

• The carrying capacity of rangeland needs to be
  taken into consideration
• Sectioning the land and using only one area at a
  time for grazing and letting the other rest
  (deferred grazing)
• The distribution of the animals spreading them
  out
• Restoration efforts for deteriorated land
• Government policies to help achieve
  sustainability of rangeland.

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• According to the World Resources Institute (WRI,
  1992) "overgrazing is the most pervasive cause of
  soil degradation . . . . In Africa and Australia,
  overgrazing causes 49 and 80 percent,
  respectively, of soil degradation, mainly in
  semi-arid and arid regions." Although the share
  of responsibility on the part of other influences
  (the introduction of exotic species, fuel-wood
  harvesting, the suppression of the natural fire
  cycle, wildlife degradation and the conversion of
  rangelands to croplands or human settlements,
  etc.) has been emphasized in subsequent UNEP
  publications (WRI, 1994), overgrazing has always
  been considered the most important factor (Figure
  3).

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Wilderness and Remote Areas.

• According to the US Wilderness Act of 1964 a
  wilderness is defined as an area where the earth
  and its community of life are untrammeled by man,
  where man himself is a visitor who does not
  remain There has been increasing pressure to
  explore the remaining wilderness areas of the US
  for oil and mineral exploration (current
  situation in the Pacific Northwest involving gold
  and national forests).

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There are four traditional reasons for the
establishment of protected lands

• Land that is enormous, beautiful, or has unique
  features are favored because of monumentalism
• Land with recreational value
• Land that provides utilitarian benefits (like
  protected water sheds and water sources)
• Land that lacks economically valuable resources
• A fifth reason has recently been added, saving
  land in order to preserve biodiversity.

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• Urbanization
• and
• Livable Cities

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Urbanization involves people shifting from living
in rural areas to urban areas.

• Occurred due to the Industrial Revolution and has
  increased in the past 50 years, from 30 of the
  worlds people living in urban areas to 48
  living there currently.
• However, in developed countries, people like to
  escape the city and have developed suburbs in
  order to have larger homes with lawns.
• Despite the growing suburbs in developed nations,
  urban living continues to increase worldwide.
• Two reasons for the growth of urbanization are
  that more people are moving from the rural areas
  into the cities and the overall growth of the
  human population.

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• The desire to live in a suburban environment has
  increased what is called sprawl in developed
  countries (especially in the U.S.)
• One definition of sprawl - the spread of
  low-density urban or suburban development outward
  from the city center.
• Another definition of sprawl - the physical
  spread of development at a rate greater than the
  rate of population growth.

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Two causes of sprawl

• Human population growth
• The per capita land use- each person takes up
  more land

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Problems associated with sprawl Part I

• Increased need for fossil fuels to support
  transportation into the cities where jobs,
  entertainment, shopping opportunities exist.
• Pollution associated with transportation and
  water pollution related to runoff from homes,
  driveways, roads and other impervious surfaces.

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Problems associated with sprawl Part II

• Health problems that are promoted by people using
  cars too much and developing very sedate lives.
• Short-sighted land use and decreases in natural
  areas. Farmland conversion is a serious problem
  that may come back to haunt future generations,
  and as humans continue to spread out they
  displace other endemic species (e.g., bears and
  cougars) from the land that they need for
  existence.

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So what can help humans promote sustainability as
far as housing goes.

• City and County Growth Management Plans allow for
  zoning sections of available land for particular
  uses. This would help control sprawl by creating
  urban growth areas for housing, industrial areas,
  and natural lands.
• Unfortunately these Plans are the sources of
  controversy and different ideas on land use.
  While conservationists promote such plans,
  developers (housing etc.) prefer to be able to
  continue to add low density housing and continue
  sprawl.
• Smart growth and the new urbanism
• Alternative methods of transportation especially
  mass transit
• An important part of planning for smart growth
  is including open space and recreation areas.

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• Environmental Health
• and
• Toxicology

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Environmental Hazards

• Physical. Natural processes can negatively
  affect human health. Disasters, UV light
  exposure etc. can have major even life ending
  affects. Although some of these processes are
  natural, human activities may also influence the
  frequency and severity of some of these
  phenomena. For example, the hole in the ozone
  allows more UV light to penetrate the atmosphere.

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• Chemical hazards. Many chemicals that are used
  by humans are hazardous or toxic to us and/or
  organisms in the environment. Pesticides for
  example are used to increase crop yields but many
  of these cause serious health problems if humans
  come in contact with them.

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• Biological hazards. Infectious diseases would
  fall into this category. These are caused by
  various microbes, but humans may play roles
  outbreaks, epidemics, or even pandemics due to
  our activities such as deforestation of tropical
  rain forests and encountering emerging viruses
  (e.g., Ebola). See figure 14.2 (both texts) for
  the leading causes of death across the world in
  2004 and the leading causes of death by
  infectious disease

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• Cultural hazards. Some are choices (smoking,
  overeating etc.) and others are related to
  socioeconomic standings (we talked earlier about
  Environmental Justice and often toxic waste can
  be located in areas close to predominately poor
  people).

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• According to the US Resource Conservation and
  Recovery Act of 1976 wastes are considered as
  toxic if they
• cause or significantly contribute to an increase
  in mortality or an increase in serious
  irreversible, or incapacitating reversible,
  illness or pose a substantial present or
  potential hazard to human health or the
  environment when improperly treated, stored,
  transported, disposed of, or otherwise managed.
• To be precise toxic a narrow group of
  poisonous substances which may cause serious
  injury or death and hazardous a wider group of
  dangerous wastes that present health or
  environmental risks (immediate or long-term).

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• Heath Risks include immediate negative effects
  (poisoning), cancer, birth defects, and genetic
  damage.
• http//www.youtube.com/watch?vfD4-jSZamTo

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Sustainable solutions to the presence of toxins.

• Preventing the release of toxins is better than
  dealing with cleanup. Regulations and market
  incentives are methods that reduce the production
  of these chemicals.
• Previously toxic chemicals were dealt with after
  they were produced by various methods Deep-well
  injection into porous geological formations or
  salt caverns, discharge of liquids (treated and
  untreated) into municipal sewers, rivers, and
  streams, placement of liquids or sludges into
  surface pits, ponds or lagoons, storage in lined
  dumps, and dumping into sanitary landfills.
• Alternative methods include destroying hazardous
  wastes and immobilization (putting it into a
  solid form that is easier to deal with and less
  likely to contaminate the environment).

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• END OF NOTES For EXAM III