Environmental Challenges and Urban Development

Environmental Challenges

Air Pollution: Primarily caused by industrial emissions, air pollution has several consequences:

  • Global warming, due to increased CO2 and other greenhouse gases.
  • Thinning of the ozone layer, caused by Chlorofluorocarbons (CFCs).
  • Urban air pollution, resulting from human activities, traffic, and industries.

Water Exploitation:

  • Excessive water consumption.
  • Freshwater pollution from untreated agricultural and urban discharges.
  • Ocean and sea pollution from oil spills and ship activities.

Deforestation: Caused by burning or logging of forests. This leads to a massive increase in carbon dioxide emissions and decreases humidity.

Erosion: Caused by deforestation and unsustainable agricultural practices, depleting the soil.

Contamination: Due to chemical dumping from agriculture and industry, resulting in toxic products.

Biodiversity Loss: Biodiversity, the variety of living species, is threatened by:

  • Habitat alteration and overexploitation of resources.
  • Poaching.

These factors result in a dangerous simplification of ecosystems.

Farming: Contributes to water and soil contamination, and overuse of groundwater and surface water.

Energy Activities: Emit harmful substances into the environment.

Urban Activities: Cause pollution, generate noise, and pollute water sources.

Specific Environmental Issues:

  • Air pollution affects large cities and areas near industrial zones.
  • Soil alteration occurs through erosion and desertification.
  • Waste production is a growing problem affecting all regions, due to steadily increasing consumption.

Environmental Policy and Protection

Environmental Policy: Consists of guidelines determined by environmental concerns.

Protection of Natural Areas: Achieved through the establishment of protected natural areas.

Prevention: Implemented through mandatory environmental impact studies prior to project approval.

Environmental Standards: Impose concrete measures to reduce pollution, such as air pollution limits.

Urban Development Through History

Quantitative Criterion: Based on population figures.

Qualitative Criterion: Classifies settlements as cities based on certain physical characteristics.

Early Cities (Mesopotamia): The first cities arose in Mesopotamia around 7,000 years ago, along the Tigris and Euphrates rivers. Shortly after, cities emerged along the Nile and Indus rivers.

Classical Era: During the first millennium BC, cities spread throughout the Mediterranean due to Greek colonization and the Roman Empire.

Middle Ages: European Christian cities reemerged from the 11th century onward, thanks to booming trade. Muslim cities also experienced significant development.

Modern Age: In the 15th and 16th centuries, geographical discoveries led to urbanization spreading through Africa and America.

Developed Countries: Urban growth increased from the late 18th century until the economic crisis of 1975.

Underdeveloped Countries: Urban growth began in the early to mid-20th century.

Urban Morphology

Site: The physical space on which the city is built.

Situation: The city’s position relative to its surrounding areas.

Plan: The layout consisting of built-up areas (houses, monuments) and free spaces (streets, etc.).

Plot: The arrangement of buildings within the city:

  • Open Weave: Buildings are separated by open spaces.
  • Closed Weave: Buildings are connected to each other.

Building Types:

  • Single or low-rise buildings (often single-family homes).
  • Collective or high-rise buildings.

Urban Center: The area where the main commercial and business activities are concentrated.

Periphery: Contains the more recently built urban areas.

City Classifications (by population)

  • National Metropolis: Over 3,000,000 inhabitants.
  • Regional Metropolis: Between 500,000 and 1,500,000 inhabitants.
  • Subregional Metropolis: Between 250,000 and 500,000 inhabitants.
  • Medium-Sized Towns: Between 50,000 and 250,000 inhabitants.
  • Small Towns: Between 10,000 and 50,000 inhabitants.

Preferred Sites: Historically, favored locations were on hills and along roads.

Old Town: The part of the city urbanized from its origins up to 19th-century industrialization.