Sec2notes

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What is Geography?

The Physical and Human Environment

Rivers and Environments

Weather and Climate

Natural Vegetation in the World

Overview of Lower Sec Geography Curriculum

Introduction to the Human Environment

Population

Settlements

Agriculture

Managing our Changing Environment

Land Supply

Water Resources

Global Warming and Ozone Depletion

Mapwork & Basic Technique

Human GeographyPhysical Geography

The Environments through Maps

Interpreting Topographical Maps

Environments through Photographs

Sec 1 Sec 2


CHAPTER 6CHAPTER 6Managing Our Changing EnvironmentManaging Our Changing Environment


Enduring Understanding

Students will be able to understand the impact of human activities on the environment at local, regional and global levels.


Essential Questions

Why is the environment constantly changing?

How do human activities affect the environment at local, regional and global levels?


Buzz with your partner

• Why is the physical environment being changed?

• What are the positive impacts of this change?

• What are the negative impacts of this change?


1. The activity in the photograph shows deforestation.

2. The physical environment would likely be changed into a human environment.

3. We clear forests for land -to build urban settlements like cities and

roads, -for useful resources like timber -and to create land for agriculture.


These changes have both positive and negative impacts.

Clearing forests enables us to expand our cities, land transport networks and improve our lives economically and socially by raising our standard of living (more space and less congestion).

However, deforestation can cause us to permanently lose the biodiversity in the forests.

Other problems?


Using the Earth’s Resources


Our Constantly Changing Environment

Cars and factories emit pollutants into the air.


Using the Earth’s Resources

We extract mineral resources, like coal, iron, copper and aluminium from the Earth’s crust and process them into useful materials to meet our needs.

In doing so, we make enormous changes to the physical environment.

It is also important to realise that the environmental effects of using these resources extend beyond its mining stage of extraction to its eventual use. Can you provide some examples of such effects?


Our Constantly Changing Environment

• We constantly change our environment as we find means to survive and make our lives more comfortable.

• As the world’s population continues to grow rapidly, the need for food, housing, amenities and other necessities will increase as well.

• In order to meet these needs, land has to be cleared for urban settlements and agriculture. As a result, we often make changes to the environment.


Growing world population

• Today, the world’s population stands at some 6.5 billion people.

• By 2050, it is expected to reach 9 billion.

• The rapid growth of the world’s population will cause an increase in the demand for natural resources.

• When more resources are consumed by people, more rubbish is generated.


SINGAPORE

• As Singapore’s population continues to grow, more waste is generated.

• To meet the future increasing demand for incineration of waste, more incineration plants are being built.

• For example, the Keppel Seghers Tuas Incineration Plant is scheduled for completion in early 2009.


Advances in technology



• As technology advances, the rate in which the environment changes also increases.

• For instance, today’s farmers depend on machinery like tractors and combine harvesters to cultivate large areas of land for agriculture within a shorter period of time and with less manpower.


The invention of container ships has greatly facilitated the growth of industrialisation and global international trade.



• Industrialisation has also increased due to advances in technology.

• With automation in factories, mass production of goods is possible.

• The integration of global transport networks has made it easier to transport goods between cities and countries.


Impact of Human Activities on the Environment

Problems caused by human activities

• Pollution

• Global warming

• Ozone depletion.


Problems caused by human activities


Most landfills release greenhouse gases like methane and carbon dioxide and eventually leak hazardous chemicals.


Coastal cities like Cancun, Mexico, are susceptible to flooding as global sea levels rise due to global warming.


Impact of human activities at various scales

• An environmental impact at a local scale affects only the area where a problem occurred.

• For example, studies have shown that waste disposed at landfills can contaminate groundwater and nearby water bodies.



• An environmental impact at a regional scale affects a few countries located in the same part of the world.

• An example is the occasional haze that engulfs parts of Southeast Asia caused by smoke from widespread burning of forests and agricultural plantations in Indonesia.

• Countries like Singapore, Malaysia and Thailand are affected by haze.



• An environmental impact at a global scale affects the whole world.

• The impact of human activities is the greatest at the global scale.

• Changes to the global atmosphere will result in global warming and ozone depletion which affect all life on Earth.

• Global warming will cause ice and snow-covered areas in the Poles to melt and cause sea-levels to rise.

• As a result, low-lying countries like Bangladesh are more susceptible to flooding.



• Ozone depletion damages crops and phytoplankton in the oceans

• and will cause increased incidence of skin

cancer and eye cataracts in people.



• The global impacts of global warming and ozone depletion are catastrophic.

• It is necessary for a worldwide coordinated effort where individuals and national, regional and international organisations work towards minimising these impacts.


Managing the environment to meet our needs

• With a growing world population and advances in technology, the use of natural resources is increasing.

• We have to manage the scarce resources wisely to meet our needs.


Managing the consequences of our actions

• Problems such as pollution, global warming and ozone depletion result as we change the environment to meet our needs.

• As all living things on the Earth are interdependent, ignoring these problems will cause a global environmental crisis.


Managing the consequences of our actions

• Hence, we need to practise environmental conservation

• where we use the Earth’s resources carefully to ensure that there are enough natural resources left for future use, and damage to the environment is kept to a minimum.

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