Geography Study Notes: Environmental Issues
Hello! Welcome to your study notes for Environmental Issues. This topic is super important, not just for your HKDSE exams, but for understanding the world we live in. We're going to look at some of the biggest challenges our planet faces, from problems in our own city to global issues affecting everyone. We'll break it all down into simple, easy-to-understand parts. Let's get started!
Part 1: Building a Sustainable City
Cities like Hong Kong are amazing places, but they face huge environmental challenges. How can a city keep growing and developing without harming the environment? That's the big question we'll explore.
What's Wrong with Our Growing City? - Urban Problems
When millions of people live close together, problems pop up. In Hong Kong, we see these every day:
Pollution: This isn't just one problem, but many!
Air pollution from traffic and factories next door in the PRD, water pollution in Victoria Harbour, noise pollution from construction, and waste pollution from all the things we throw away.Transport Problems: Ever been stuck in traffic in Central or squeezed onto a crowded MTR? That's traffic congestion. It’s a classic urban problem caused by too many people and vehicles trying to move around at once.
Housing Problems: Hong Kong is famous for its skyscrapers, but also for its housing issues. Problems include a lack of affordable housing and old, decaying buildings in areas like Sham Shui Po (this is called urban decay).
Urban Sprawl: This is when a city spreads outwards, eating up countryside and natural habitats. It happens as cities grow to make space for more people and industries.
Why Do Cities Keep Growing? - Causes of Urban Growth
Cities don't grow by accident. The main reasons are:
Natural Increase: When the birth rate is higher than the death rate.
Migration: People move from the countryside to the city to find jobs and a better life.
Economic Development: More businesses and industries attract more people.
Quick Review: Key Urban Processes
Urbanisation: The process of more and more people living in cities.
Suburbanisation: People moving from the city centre to the outskirts (suburbs).
Urban Renewal/Redevelopment: Rebuilding and improving old, run-down parts of a city. Example: The renewal projects in Wan Chai.
The Big Conflict: Development vs. Conservation
This is a classic tug-of-war. A developer might want to build new apartments on a piece of woodland, which creates homes and jobs (development). But environmental groups will want to protect the trees and wildlife (conservation). Finding a balance is really tricky.
Think about it: Should we build a new runway at the airport to boost our economy, even if it harms marine life like the Chinese White Dolphin? These are the tough choices cities have to make.
A Solution? The Concept of Sustainable Development
This is a super important key term! Don't worry, it's simpler than it sounds.
Sustainable Development means meeting the needs of people today without messing things up for people in the future (your children and grandchildren!).
Analogy Time! Imagine you have a big jar of cookies.
- Unsustainable: You eat all the cookies today. It's great now, but there are none left for tomorrow.
- Sustainable: You eat one or two cookies a day. You get to enjoy them now, AND there are still cookies left for the future.
A sustainable city tries to do this by balancing three things: a healthy economy, a fair society, and a clean environment.
How to make a city more sustainable?
Better Urban Planning: Designing the city smartly. For example, building new towns like Tung Chung with good public transport links so people don't need to drive as much.
Environmental Conservation Measures: Protecting nature. This includes creating country parks, managing waste better (like the new waste charging scheme), and reducing pollution.
Regenerating the City: Giving old areas a new life, like turning the old Central Police Station into the Tai Kwun arts centre.
Key Takeaway for Part 1
Growing cities face serious environmental problems like pollution and congestion. The goal is to achieve sustainable development, which is about finding a balance between economic growth, social needs, and protecting the environment for the future. This involves smart planning and conservation.
Part 2: The Disappearing Green Canopy - Deforestation
Let's zoom out from the city and look at one of the world's most important environments: the tropical rainforest. They are amazing, but they are under threat.
What Makes a Rainforest So Special?
A tropical rainforest is an ecosystem – a community of living things (biotic components like plants and animals) interacting with their non-living environment (abiotic components like sunlight, soil, and rain).
They are known for being complex but fragile.
Complex: They have the highest biodiversity on Earth, with millions of species of plants and animals all linked together.
Fragile: The whole system is in a delicate balance. Most of the nutrients aren't in the soil, but are locked up in the plants themselves. This is called rapid nutrient cycling. When trees are cut down, the nutrients are lost, the thin soil is washed away by heavy rain, and the whole system can collapse.
Did you know? Although tropical rainforests cover only about 6% of the Earth's surface, they are home to over half of the world's plant and animal species!
The Problem: Deforestation
Deforestation is the large-scale cutting down or clearing of forests for other uses. This is happening at an alarming rate in places like the Amazon and Southeast Asia.
Why is it happening? (Reasons for Deforestation)
Think of the acronym HEAD:
H - Hardwood Logging: Cutting down valuable trees like mahogany to sell for furniture.
E - Economic Development: Governments clearing land for mining, building dams for hydro-electric power, and building roads.
A - Agriculture: Clearing land to grow crops (like palm oil and soybeans) or for cattle ranching (raising cows for beef).
D - Dwelling (Population Growth): Clearing forest to build new settlements and towns for a growing population.
What are the Impacts of Deforestation?
The effects are massive, both locally and globally.
Impact on Climate: Trees absorb Carbon Dioxide (CO2). Fewer trees mean more CO2 in the atmosphere, which contributes to global warming. This is a global impact. Locally, it can lead to less rainfall.
Impact on Biosphere (Living things): Loss of biodiversity as animal and plant habitats are destroyed. Many species become extinct.
Impact on Lithosphere (Soil): Without tree roots to hold it together, the soil is easily eroded by rain, leading to landslides and ruining farmland.
Socio-Economic Impact: Indigenous tribes who live in the rainforest lose their homes and way of life. However, deforestation can also bring jobs and income to poor countries (this is why the issue is so complex!).
How Can We Protect the Rainforests?
This is tough because of conflicts of interest between different groups (e.g., logging companies vs. environmentalists vs. local people).
Some measures include:
Sustainable Management: Using the forest in a way that doesn't destroy it, like selective logging (only cutting down mature trees) instead of clear-cutting.
Afforestation: Planting new trees.
Setting up National Parks: Protecting areas of the forest by law.
Ecotourism: Creating jobs for local people through tourism that respects and protects the environment.
Key Takeaway for Part 2
Tropical rainforests are complex but fragile ecosystems threatened by deforestation. The main causes are related to economic and agricultural development. The impacts are severe, affecting climate, soil, and biodiversity globally. Solutions require sustainable management and balancing the conflicting interests of different groups.
Part 3: Our Warming World - Climate Change
This is probably the biggest environmental issue of our time. It connects to both cities and deforestation. Let's break down what it is and why it's happening.
First, The Basics: Weather vs. Climate
It's easy to mix these up! Here's a simple way to remember:
Weather is what's happening outside right now or over a short time. "It's rainy and cool today."
Climate is the average weather pattern in a place over a long time (usually 30 years or more). "Hong Kong has a hot and humid sub-tropical climate."
The Problem: Global Warming
Global Warming refers to the long-term heating of Earth’s climate system observed since the pre-industrial period due to human activities. It's not just a "fluctuation" - the evidence is strong:
Rising Global Temperatures: The planet's average temperature has been rising sharply.
Melting Glaciers and Ice Sheets: Ice at the poles and on mountains is melting at a rapid rate.
Sea-Level Rise: As ice melts and warmer water expands, the sea level is rising, threatening coastal cities.
More Frequent Extreme Weather: We are seeing more intense heat waves, droughts, floods, and powerful typhoons.
The Main Cause: The Enhanced Greenhouse Effect
Think of the Earth as being wrapped in a blanket of gases. This is the Greenhouse Effect, and it's natural and essential for life! These "greenhouse gases" (like CO2) trap some of the sun's heat, keeping our planet warm enough to live on.
The Problem: Human activities are making the blanket much thicker. We are releasing huge amounts of extra greenhouse gases. This is the enhanced greenhouse effect. It traps too much heat, causing global warming.
Human Activities Causing This:
Burning Fossil Fuels: This is the biggest one! Using coal, oil, and gas for electricity, factories, and transport releases massive amounts of CO2.
Deforestation: As we learned, fewer trees mean less CO2 is absorbed from the atmosphere.
Agriculture: Farming activities, especially raising livestock like cows, release methane, another powerful greenhouse gas.
A Local Problem: The Urban Heat Island Effect
Have you noticed it always feels hotter in urban areas like Mong Kok than in the New Territories countryside? This is the Urban Heat Island (UHI) Effect.
It happens because:
Dark Surfaces: Concrete and asphalt absorb and store more of the sun's heat than grass and trees.
Less Vegetation: Fewer trees mean less shade and less cooling effect from transpiration (when plants release water vapour).
Waste Heat: Air conditioners, vehicles, and factories all pump out heat into the city air.
The UHI effect is a local climate change, which adds on top of the effects of global warming, making our cities even hotter.
What Can We Do About Climate Change?
It's a huge global problem, and tackling it requires cooperation between all countries, which is very difficult to achieve.
There are two main strategies:
Mitigation: This means trying to reduce the cause of the problem. The goal is to lower greenhouse gas emissions.
Examples: Switching to renewable energy (solar, wind), driving electric cars, improving energy efficiency, and planting more trees.Adaptation: This means changing our lifestyles and infrastructure to cope with the effects of climate change that are already happening or unavoidable.
Examples: Building sea walls to protect against sea-level rise, developing drought-resistant crops, and creating better warning systems for extreme weather.
Key Takeaway for Part 3
Global warming is the long-term heating of the Earth, caused by the enhanced greenhouse effect from human activities like burning fossil fuels. On a local scale, cities experience the Urban Heat Island Effect. Tackling climate change requires both mitigation (reducing emissions) and adaptation (coping with the impacts).