Midterms

• Atmosphere


  Mixture of gases that surround the Earth
• Land


  The basis for agriculture and other rural and urban land uses, encompassing soils, climate, vegetation, topography, and other natural resources
• Land degradation


  The degradation or destruction of the Earth's surface and soil, directly or indirectly because of human activities
• Causes of land degradation


  • Deforestation
  • Desertification
  • Mining
  • Soil salinization
  • Urban sprawl
• Deforestation


  The massive removal of a forest or the clearing of vast forest areas either for lumber source, conversion to agricultural lands, or for urbanization
• Since 1960, over half of tropical rainforests have been destroyed (IUCN)
• Causes of Deforestation


  • Increase in human population
  • Agriculture
  • Urbanization
  • Timber extraction
  • Anthropogenic climate change
  • Social and political factors
• Effects of Deforestation


  • Anthropogenic climate change
  • Soil erosion and flooding
  • Reduced air humidity
  • Loss of habitat and biodiversity
• Reforestation


  The process of restoring forests by planting the same tree species that are native to that specific forest
• Afforestation


  Planting trees in areas that were never forests, converting (not restoring) an area into a forest
• Forest Landscape Restoration (FLR)

  Planting trees is not enough to restore forests, so IUCN has collaborated with FLR enthusiasts to bring people together to identify and implement the most appropriate restoration interventions in a landscape
• Desertification


  The conversion of a productive land to an unproductive barren land
• Causes of Desertification


  • Overgrazing
  • Anthropogenic climate change
  • Deforestation
  • Unsustainable farming methods
  • Overuse of groundwater
• Effects of Desertification


  • Decrease in crop yield
  • Loss of habitat and biodiversity
  • Migration and overpopulation
• Rotational Grazing


  1. Involves dividing an entire Pasteur to sub-pastures or paddocks

  2. Cattle grazing in these paddocks are done so by schedule, allowing time for Pasteur plants to rest, grow, and recover before being grazed again

  
• Dealing with Desertification


  • Rotational grazing
  • Better farming methods
  • Reforestation
  • Sustainable use of groundwater
  • Decrease greenhouse gas emissions
• Soil salinization


  Irrigating crops over several seasons causes the accumulation of salts in the upper layers of the soil
• Waterlogging


  Accumulation of saline water underground, gradually saturating the soil and resulting in damage and killing of plants as saline water surrounds the deep root
• Addressing soil salinization and waterlogging


  • Use less water for irrigation
  • Pump water in unlined ditches
  • Spray water across large areas with sprinklers or drip irrigation
  • Install drainage systems
• Mining


  The process of extracting precious minerals and other geological materials from the earth
• Types of Mining Methods

  • Surface mining
  • Underground mining

  
• Mining is one form of land degradation that requires strict monitoring and full compliance with mining laws and regulations
• Urban sprawl


  The rapid expansion of a city into the countryside around the city, resulting in the building of housing or suburbs and associated commercial buildings on the boundary of a larger town
• Effects of Urban Sprawl


  • Loss and fragmentation of habitat
  • Increase in energy demand and use of fossil fuels leading to global warming
• Dealing with Urban Sprawl

  • Practice sustainable development
  • Implement management strategies to direct urban growth
  • Build residential and commercial areas around mass transit networks (transit villages)
  • Develop ecovillages
• Atmosphere


  • Made up of 5 layers, the innermost two of which contain most of these gases
• Troposphere


  The atmospheric layer nearest the Earth's surface, contains most of the planet's air-the mixture of gases that people depend on to stay alive

  
• Composition of troposphere


  • 78% nitrogen
  • 21% oxygen
  • 1% mixture of other gases like carbon dioxide, nitrous oxide, helium, and argon

  
• Troposphere


  Contains water vapor in variable amounts depending on temperature
• Troposphere


  Responsible for maintaining the conducive temperature of the earth, allowing various organisms to thrive

  
• Stratosphere


  The Earth's second layer of air, contains much of the atmosphere's ozone gas (O3), which lies in a sub-layer of the lower stratosphere known as the ozone layer

  
• Ozone layer


  Serves as a sunscreen for the planet by filtering out about 95% of the sun's harmful ultraviolet (UV) radiation before it can reach the Earth's surface

  
• Anthropogenic activities are causing problems in the atmosphere, problems that are affecting us on a global scale
• Major problems involving the atmosphere


  • Global warming
  • Air pollution
  • Acid deposition
  • Ozone depletion

  
• Global warming


  The accelerating rate in the increase of the average global temperature

  
• This is due to the rapid increase in greenhouse gases found in the atmosphere due to anthropogenic activities
• Greenhouse effect


  Solar radiation that reaches the surface of the earth is absorbed and then re-emitted back by the heated surface as infrared radiation (IR)

  
• If there is no atmosphere, the infrared radiation freely escapes into space
• Greenhouse effect


  The heat absorbing components of the atmosphere prevent the IR from escaping, thus the heat is trapped on earth, much like the heat trapped in a farmer's greenhouse

  
• Components of the atmosphere

  • Nitrogen and oxygen (absorb little or no radiation)
  • Carbon dioxide and water vapor (effective absorbers of IR, responsible for the greenhouse effect)