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Analyzing the social and environmental problems that arise when cities grow too quickly.
Imagine a city growing so fast that a new neighborhood appears every single week. How do you keep the lights on, the water flowing, and the air clean when millions of people arrive at once?
When cities grow faster than planners can keep up, two things happen. First, Urban Sprawl occurs—this is the uncontrolled expansion of housing and shopping centers into the surrounding countryside. This eats up valuable farmland and destroys habitats. Second, because formal housing is often too expensive, many new arrivals build their own homes on land they don't own. These are called Informal Settlements (or slums). These areas often lack basic safety standards and legal recognition, making life precarious for millions of residents.
Quick Check
What is the main difference between urban sprawl and informal settlements?
Answer
Urban sprawl is the outward spread of a city into rural land, while informal settlements are unplanned housing areas built without legal permission or basic services.
Cities are environmental 'hotspots.' Because of all the concrete and asphalt, cities experience the Urban Heat Island effect, where they become significantly warmer than surrounding rural areas. Furthermore, Solid Waste Management becomes a nightmare. If a city of 10 million people each produces just 1 kg of trash a day, that is 10,000 tons of waste daily! Without proper systems, this waste ends up in 'mega-dumps' or local waterways, leading to toxic leaching into the soil.
Imagine a city where the population grows by every year. If the current waste is tons: 1. Next year's waste will be . 2. tons. 3. In just 10 years, the waste would be tons. This shows why infrastructure must grow faster than the population.
Quick Check
Why do cities feel hotter than the countryside?
Answer
Due to the Urban Heat Island effect, where concrete and asphalt absorb and trap heat more than natural landscapes do.
Providing Infrastructure—the basic physical systems of a city—is the greatest social challenge. This includes Potable Water (safe to drink), electricity, and sewage. In crowded cities, the demand for water often exceeds the supply, leading to 'water rationing.' Additionally, Traffic Congestion isn't just annoying; it causes massive economic loss and respiratory illnesses due to concentrated air pollution. When transport fails, people can't get to jobs, trapping them in a cycle of poverty.
A city decides to build a new subway to reduce smog. 1. Currently, 200,000 cars travel 20 km daily, emitting of per km. 2. Total daily (or 600 tons). 3. If the subway moves half those people and produces only 10% of the emissions per person, the city saves nearly 270 tons of every single day!
Which term describes the uncontrolled expansion of cities into the surrounding countryside?
If a city has a population () of 500,000 and an area () of 100 , what is its density ()?
Informal settlements are usually planned by the government to help new residents.
Review Tomorrow
In 24 hours, try to explain the 'Urban Heat Island' effect and the difference between sprawl and informal settlements to a friend or family member.
Practice Activity
Look at a satellite map (like Google Earth) of a major city like Mexico City or Lagos. Can you see where the 'sprawl' meets the green countryside?