Lecture Notes: Urbanization (Topic 5.10)

Overview of Urbanization

• Definition: Conversion of natural landscapes (forests, wetlands) into urban areas (cities, towns).
• Focus of Lecture:
  • Environmental issues caused by urbanization.
  • Causes and expansion in developed nations, especially the USA.
  • Solutions to urbanization issues.

Environmental Effects of Urbanization

• Objectives:
  • Describe the environmental effects.
  • Discuss saltwater intrusion, increased fossil fuel combustion.
  • Understanding of pervious vs. impervious land.
  • Explore urban sprawl and its causes.

Key Environmental Issues

• Impervious Surfaces:

  • Replaces natural soil and vegetation.
  • Includes concrete and asphalt (roads, sidewalks, buildings).
  • Leads to increased runoff, disturbed water cycle, limited groundwater recharge.

• CO2 Emissions:

  • Cement and asphalt production releases CO2.
  • Construction machinery emits CO2 (fossil fuels).
  • Deforestation impacts carbon sequestration.
  • Increased landfills contribute to CO2 and methane emissions.

• Saltwater Intrusion:

  • Problems in coastal cities due to groundwater overuse.
  • Lowered water table reduces pressure, allowing seawater to infiltrate groundwater.
  • Sea level rise due to thermal expansion and melting ice caps exacerbates the issue.

Population Movement Trends

• Shift from Rural to Urban/Suburban:
  • Driven by job opportunities, entertainment, cultural attractions.
  • Urban areas: more walkable, potentially lower per-person environmental impact.
  • Suburbs: highest growth, leading to urban sprawl due to cheaper properties, car affordability.

Urban Sprawl

• Definition: Movement from dense urban areas to less dense suburbs.
• Causes:
  • Cheaper property in suburbs.
  • Affordability of cars and gasoline.
  • Domino effect of neighbors leaving urban areas, leading to reduced city services.
  • Businesses and residents move out due to declining tax base, services, and increased blight.

Solutions to Urban Sprawl

• Urban Growth Boundary:

  • Zoning law to limit city expansion.
  • Encourages efficient land use and vertical building.

• Efficient Public Transportation:

  • Increases likelihood of city residency if affordable and reliable.

• Mixed Land Use:

  • Combines residential, business, entertainment in one area.
  • Encourages people to stay in urban areas.

Practice Task

• Science Skill Practice:
  • Describe advantages, disadvantages, or unintended consequences of urban sprawl solutions.
  • Example task: Propose a solution and identify an economic consequence.

Conclusion:

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