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.