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Environmental Science Exam III Notes

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Title: Environmental Science Exam III Notes


1
Environmental Science Exam III Notes
2
  • Sustainable
  • Agriculture
  • Recall Information from Presentation

3
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.

6
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 !

7
  • 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.

8
Kwashiorkor and marasmus are two types of
malnutrition that are the two extremes of
protein-calorie deficiency.
9
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

10
Soil Formation II
  • Chemical weathering occurs when water and other
    substances react with parent material,

11
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.

12
Soil degradation is a serious threat to humans
2004
13
Barriers to a Sustainable Agricultural System

14
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.

15
  • Desertification is the conversion of cropland,
    pasture, and rangeland into desert or land too
    arid to be farmed

16
  • The loss of fertile farmland to development
    (farmland conversion)

17
  • 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.

18
  • Approximately 10 of the worlds irrigated
    cropland suffers from waterlogging

19
  • A loss of genetic diversity and a decline in
    species that are cultivated could result in great
    decreases in food production in the future.

20
  • The overapplication of fertilizers can also
    damage soil and plants

21
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.

22
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

23
  • Agriculture, Biotech,
  • and the Future

24
  • 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).

27
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).

37
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.

38
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.

39
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

40
Consequences of overgrazing
41
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).

48
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

52
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.

56
Two causes of sprawl
  • Human population growth
  • The per capita land use- each person takes up
    more land

57
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.

58
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.

59
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

62
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
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