Navigation
Looking ahead at global population projections and the future of urban living in the 21st century.
By the time you are in your 40s, the world will hold nearly 10 billion people—but where will they all live, and who will be looking after whom?
According to the United Nations, the global population is projected to reach approximately billion by the year 2050. This growth isn't happening everywhere at the same rate. While many developed nations are seeing their populations shrink, more than half of the projected growth will be concentrated in just eight countries, mostly in Sub-Saharan Africa and Southern Asia. This shift means the world's 'center of gravity' is moving. We must consider how resources like water, food, and energy will be distributed when the human family grows by another billion members in just a few decades.
Quick Check
Which two geographic regions are expected to drive the majority of global population growth toward 2050?
Answer
Sub-Saharan Africa and Southern Asia.
While the total population is growing, the average age is also rising. This is known as an aging population. Due to better healthcare and falling fertility rates (the average number of children per woman), the segment of the population aged 65 and over is growing faster than any other. This creates a challenge for the Dependency Ratio. This ratio compares the number of 'dependents' (those under 15 or over 64) to the working-age population. As the ratio increases, fewer workers are available to support the economy and healthcare systems for the elderly.
To understand the pressure on an economy, we use this formula:
1. Suppose a town has 200 children, 200 seniors, and 600 working-age adults. 2. Add the dependents: . 3. Divide by workers: . 4. Multiply by 100: The Dependency Ratio is . This means for every 100 workers, there are roughly 67 people to support.
Quick Check
If fertility rates continue to drop, what happens to the median age of a country?
Answer
The median age increases, meaning the population becomes older on average.
By 2050, nearly of the world's population will live in cities. To manage this density, we are developing Smart Cities. These cities use the Internet of Things (IoT)—a network of sensors and software—to collect data in real-time. This data helps manage traffic flow, reduce energy consumption, and improve waste collection. Imagine a trash can that signals a truck only when it is full, or streetlights that dim when no one is around. These innovations aim to make high-density living sustainable and efficient.
In a Smart City, traffic lights aren't just on timers.
1. Sensors detect a backup of 50 cars on North Street. 2. The AI calculates the 'flow rate' of the intersection. 3. The system extends the green light by seconds automatically. 4. Result: Carbon emissions from idling cars decrease by and commute times drop.
As cities grow into Mega-cities (over 10 million people), they face the 'Urban Heat Island' effect.
1. Concrete absorbs heat, raising city temperatures by up to compared to rural areas. 2. Planners must use (reflectivity) calculations to choose building materials. 3. By installing 'Green Roofs' (gardens on top of buildings), a city can reduce its cooling energy needs by , where is the reduction factor of the plants. This requires balancing expensive technology with natural solutions.
What is the projected global population for the year 2050?
What does a high 'Dependency Ratio' usually indicate?
By 2050, the majority of the world's population is expected to live in rural, farming communities.
Review Tomorrow
In 24 hours, try to explain to someone else what a 'Smart City' is and why the 'Dependency Ratio' matters for the future economy.
Practice Activity
Research a city currently using 'Smart' technology (like Singapore or Barcelona) and identify one specific way they use sensors to save energy.