Chapter 13 Human Impacts on Natural Systems

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Chapter 13 Human Impacts on Natural Systems

• Climates and biomas global warming, acid rain,
  and ozone
• Abuses of land and vegetation deforestation,
  desertification, and soil erosion
• Problems of water supply and water quality
• Disposal of solid and toxic wastes.

http//www.usatoday.com accessed date 4/21/08
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Physical Environments and Cultural Impacts

• Modest and substantial modifications of of nature
  (13.1), shopping mall/office buildings - new
  cultural creations
• Biosphere atmosphere, hydrosphere and
  lithosphere.
• Climate, Biomes, and Change
• Global climate patterns - determined by solar
  energy (13.2a and b), land and water
  distribution, ocean/atm. currents - controls
  biomes (major communities of plants and animals
  occupying extensive areas of the earths surface
  in response to climatic conditions).
• Ecosystems - self-regulating adapted to local
  combinations of climate, topography, soil, and
  drainage conditions.

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Global Cooling/Warming..

• Icebox effect - Global Cooling? - aerosols
  reradiate incoming solar energy back to space.
  Aerosols from dust storms, forest fires, or
  volcanoes. Two cool summer cases 1) 1815 due to
  Tambora, Indonesia, volcano eruption and 2) Mt.
  Pinatubo, Philippines, in 1991. Aerosols also
  produced from human activities (power plants,
  vehicles, factories). global cooling became
  noticeable in 1940.
• Cooling trends found in large industrial cities
  in China.
• This fear was replaced by other concerns in 80s
  1) Global Warming, 2) Acid Rain, and 3) Ozone
  depletion

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Global Warming

• Started in Industrial Revolution, burning coal,
  petroleum, gas, vehicle emission produce CO2 and
  water vapor. Deforestation cause less trees to
  trap CO2
• Greenhouse Effect - is needed, but it is too
  much with increased CO2. (13.5)
• 2.5 - 10.4 oF increase in temperature predicted
  in this century. Climate prediction is not an
  exact science.
• Current CO2 level 388.79 ppmv

• Arctic ice melt (might disappear by the middle
  of 21st century)
• Continental ice melt will cause sea level rise
  0.5 to 3 meters, (Maldives - 80 of land are less
  than 1 meter above sea level), http//www.guardian
  .co.uk/environment/2008/nov/10/maldives-climate-ch
  ange

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Global Warming?

• Carbon can be reduced by sinks - forest, soils
  and oceans.
• A 40 decrease of precipitation in corn belt is
  predicted, reducing productivity. Such reduction
  of precip will have water supply disasters in
  western states.
• Beneficial effects to northern countries, such as
  parts of Russia, Scandinavia, and Canada. Longer
  growing season in the north (12 days longer in
  45oN), latitudinal temperature difference is
  reduced.
• Impact on developing countries is high but
  uncertain. Global productivity could increase by
  up to 30 due to the doubling of CO2, in terms of
  fertilization effect. But, lower latitude
  developing countries have higher impact due to
  increased heat and higher evaporation rates.
  Impact of climate change on diversified developed
  countries are likely to be small.
• Kyoto Protocol - two goals 1) clean development
  credits 2) emissions trading. If fully
  implemented, would not slow warming trend too
  much, according to Climate Change Panel
• Increased precipitation in upper-latitude
  (recorded in Antarctica) would increase fresh
  water flux to sea water which, then dilute the
  density of seawater. This will affect the
  circulation of heat globally. Polar temperature
  can drop dramatically.
• Greenhouse Gases and Health EPAs report

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GWP (Global Warming Potential)
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Land-3800 Gt, Atm 762 Gt, Oceans 38,271 Gt.
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Lighter lighting
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Renewable Power
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Idaho wind power map http//www.inl.gov/wind/idah
o/i/idaho_map.jpg
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Acid Rain

• The average pH of normal rainfall is 5.6.
• The taller chimneys only creates more problems of
  acid rain (13.7) - Sulfur dioxide and nitrogen
  oxides mixed with water creates sulfuric and
  nitric acid carried to distant areas
• Mostly in developed countries. Its corrosive
  effects on marble and limestone buildings and
  metals (13.8). Trees at higher elevations,
  disappearing fish, increased heavy metals in
  drinking water supplies, loss of aquatic life
• Crop damage decrease yields of food production,
  death of soil microorganism
• US and Canada, 2,000 lakes totally dead to fish
  life and another 15,000 in danger (13.9)

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Ozone Depletion

• Ozone in troposphere block UV reaching earth,
  destruction in higher atmosphere will cause DNA
  and other skin cancers.
• 1986, ozone hole was found in Antarctica. (occur
  in late August and October), Hole spread to S
  America and Australia. Mostly from CFC (winter in
  Antarctic lack of sunlight, CFC destroying O3
  easily
• 1987 Montreal Protocol- developed country stopped
  using CFC and 2010 for developing countries.
• Surface Ozone - accumulation of ozone, harm to
  plants, reduced wheat yield - produced in
  photochemical smog by sunshine and vehicles
  emission. Destruction of forest in Europe caused
  by surface ozone.

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Land Use and Land Cover

• Minor LULC change - Methane gas increased by rice
  paddy, and increasing herds of cattle, fertilizer
  applications increase nitrous oxide, affecting
  the algae growth and water reflectivity and
  evaporation rates.
• Major LULC changes from deforestation and loss of
  grassland to farmland - alter temperature and
  water balance - increasing release of CO2 to the
  atmosphere.
• Growing pop. more agr. land needed, expanded
  demand for fuel and commercial wood, and
  midlatitude market for beef - cause loss of
  tropical rain forest in Asia, Africa and Latin
  America.
• 45 of original forest land was lost in these
  area. every year a size of Missouri are lost.
  Three global concerns are raised

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Tropical Deforestation

• Three global impacts
• 1) Forest act as carbon storage and oxygen
  replenishers
• 2) forest destruction change surface and air
  temperature, moisture content, and reflectivity.
  Estimated 3 to 5o C increase due to the clearing
  of S American forest.
• 3) loss of biodiversity of the planet. Food
  sources in rainforest and storehouse of
  drug-yielding plants and insects will be limited.
• Cutting trees in local area will increase
  flooding and soil erosion (13.11)

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Desertification - the expansion or
intensification of areas of degraded or destroyed
soil and vegetation cover.

• Climate variation, rather than human abuse of the
  land, is thought to be the major influence on
  dryland ecology and the shifting margins of
  deserts.
• 1/4 of the earths surface is qualified as
  degraded semi-desert
• 40 of the non-desert land is in danger of
  human-induced desertification.
• Food production drop 50 between 1950 and 1990 in
  area with most extensive desertification -
  Algeria, Ethiopia, Iraq, Jordan, Lebanon, Mali
  and Niger. Mali may be the first country in the
  world rendered uninhabitable by environmental
  destruction (13.14).
• Deforestation,farming, and grazing cause
  desertification

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Soil Erosion

• Soil - the top 1 ft of surface, is complex
  mixture of inorg/org matters, living organism,
  water and air formed from phy/chem decomposition
  of rock material and the decay of organic matter
• Under natural conditions, the rate of soil
  formation equals or exceeds the rate of soil
  erosion.
• Farmers practice to keep top soils
• Rotation to preserve fertility or to provide
  cover to protect soil
• Fallowing leaves a field idle in one year, a) in
  tropical wet regions, to renew soil fertility of
  the swidden plot, b) in semiarid areas , to
  accumulate soil moisture for next year.
• Terracing provide layers for cropland, and
  breaking speed of water flow

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Soil Erosion

• 40 of the worlds agr. land is seriously
  degraded - caused decreased yields of cultivated
  fields and in increased stream sediment loads and
  downstream deposition of silt.
• 15-17 million acres of existing arable land are
  lost to erosion each year.
• The most sediment-laden of any waterway on earth
  - Huang River in China - 50 silt by
  weight.(Yellow River)
• Terracing reduces soil erosion, but if farm on a
  15 slope, soil cover will be lost in 10 years.
• US lost 2 billion tons of soil each year to
  erosion. 1/3 land is in danger. 24 billion tons
  of sediments washed to the oceans each year. (fig
  13.15)
• Soil retention techniques contour plowing,
  terracing, strip cropping and crop rotation,
  construction of water diversion channels,
  erecting windbreaks, practicing no-till or
  minimum tillage
• Tennessees soil loss tolerance level 5
  tons/acre/year. Factors slope, rainfall, land
  cover.
• Quiet Crisis - Agricultural soil depletion due to
  soil erosion, salt accumulation, and
  desertification.

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Water Problems

• Problems in water distribution, availability, and
  its quality.
• Water is renewable resources, seen in hydrologic
  cycle (13.17)
• 13.18 Precipitation distribution, 13.19 Water
  supplies in relation to the demands of the
  vegetation cover.
• Irrigation accounts for 73 of freshwater use,
  90 in poorest countries. 21 industrial use.
  recreational and domestic use account for the
  remainder.
• Untreated sewer water pollute water in 90 of
  developing urban area.
• 70 surface water in India are polluted. Chinas
  80 river are polluted, untreated water will be
  the source of impounded water in Three Gorges Dam
  (not too many WWTP systems in China)

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Garbage Heaps and Toxic Wastes

• Middens - refuse piles containing the kitchen
  wastes, broken tools and other debris of human
  settlement. (Lebanese Garbage Mountain)
• Modern cultures differ in volume and character of
  their wastes, the more developed, the greater the
  volume and diversity of garbage.
• US produce 2 kg/person/day garbage and rate is
  increasing.
• Sanitary landfill site (13.24) - 75 of countrys
  municipal waste is disposed of.
• Incineration - reduce volume of waste, produce
  electricity and air pollution - burn out 1/6 of
  US garbage from 110 incinerators. Dioxin toxic
  release in Japan is 3 times higher than in the US
• Dioxin is formed by burning chlorine-based
  chemical compounds with hydrocarbons. (sources
  paper mills, PVC, pesticides manufactures..)

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Toxic /Hazardous Waste

• EPA classified more than 400 substance as
  hazardous.
• Groundwater is the most at risk of contamination
  from hazardous waste. 2 of US groundwater is
  polluted from hazardous wastes.
• e-Waste China, EU (not U.S.) proposed laws.
• U.S. Ship E-Waste
• China E-Waste
• E-waste youtube1, 2
• Facts and Figures on E-Waste and Recycling
• Radioactive Wastes (Yucca Mountain, pg.521)
• Half of low-level waste produced from nuclear
  power plants. (decay to safety level in lt 100
  years). Most in landfills.
• High-level waste - remain radioactive for 10,000
  years. Mostly from nuclear power plants spent
  fuel
• Major toxic waste exporters U.S., Germany,
  Australia, Britain, and Netherlands.
• In 2005, estimated 50-80 recyclable waste was
  shipped to China, India and Pakistan
• European waste to Baltic countries, Eastern and
  Central Europe
• U.S. waste to Latin America
• Britain waste to Asia

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Yucca Mountain

• In 1982, DOE (department of energy) was ordered
  to construct a permanent repository for spent
  fuel by 1998. Can it be open by 2010?
• Three concerns
• Volcano and earthquake may cause groundwater to
  flood the repository.
• Rainwater penetrate and dissolve waste which seep
  down to water table.
• Too close to air force bombing range.

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Denmark tiny island
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German town
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• Sugar Cane 40 fuel in Brazil, 90 less CO2

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