Topic: Man’s Impact on the environment

It mainly due to: Population explosion

Population(in Hong Kong) HK will face its largest population pressure from outside its borders. Population could reach 11 million if past trends continue.

In the World World population is forecast to approximately double before stabilizing by the year Fair shares of global resources will thus be about half of what they are today.

Resource Exploitation 1.renewable resources 2.non-renewable resource

Renewable resources 再生資源 They can be growth again after they are used. Example: 1. Oxygen 2. Water 3. Food

1.Oxygen Human takes in oxygen and give out carbon dioxide for energy by respiration. Then, plant take in carbon dioxide for making food by photosynthesis.

Problems Most of the Earth's rainforests are destroyed each year for farming and ranching

As deforestation is very serious. A lot of the tree/ plant were killed. The balance of oxygen and carbon dioxide content is lost. Resulting in carbon dioxide content increase.

Graph showing the change in CO2 content

The increase in carbon dioxide content will lead to green house effect.

Green House Effect

The effect of green house effect Global warming

If greenhouse gases continue to rise at the current rate, between 2030 and 2050, the average temperature on Earth will rise by about 1.5 o C to 10 o C. If the temperature should rise 4 o C, these scientists forecast massive changes in weather and ocean currents.

2. Water More than 70% of our body are composed of water

The use of water is increased in past few years

Water and the coming crisis Our total water supply. Most freshwater is frozen in glaciers and ice caps. A minuscule amount(0.003% of the to total) exists as vapor in the atmosphere.

Example of effect of exploitation of water The dry reservoir at Kensico, New York, poignantly illustrates the Earth's continuing problem with a dependable supply of freshwater. Perhaps such problems would be of less magnitude if we realized just how much water we actually use.

3. Food Food is essential for supporting human life. However, the food in the earth are unequally divided.

In developed countries In some developed countries, people prefer better food such as “organically grown”or “natural “food

Increasing rate in overweight in developed countries the rate of obesity among all children rose to 9% from 5% and the rate of overweight rose to 24% from 15% between 1989 and 1998.

In some developing countries As people in developed countries do not treasure food at all– even wasting the food. It leads to inadequate food supply for people developing countries

Nearly one billion people suffer from hunger and malnutrition on this planet. Over 40 million die each year of starvation, and most of them are children.

Result of lacking of food The first stored food he draws on is the readily available stored glycogen in his liver and muscle. Then to use stored fat. At about this time, the starving body begins to break down protein. Finally, the body's muscle begin to wither, including the heart muscle.

On the average, people are considered to be starving when they have lost about 33 % of their body weight. When they have lost 40 %, death is almost inevitable. Children are often permanently affected since improved diet cannot straighten bones or build normal brain cells, but adults can largely recover.

Our increasing efficient fishing technology has resulted in more fish being taken each year. We must now ask how long it can go on.

Non-renewable resources 不可再生的資源 Nonrenewable resources exist in a fixed amount. When we're out, we're out; They cannot be replaced. Normally, a nonrenewable resource is considered depleted when 80% of its estimated supply is gone. Example: 1.metal 2.energy

1. Metal Aluminium can more than 80 billion aluminum cans made in the United Sates each year If the cans Americans throw away in a single year were attached end to end, they would reach to the moon and back about eight times. If the metals are continuous used, they will eventually be used up.

2.Energy Estimated average daily per capita energy use at various stages

Energy from fossil fuels The oil is pumped from the ground which is non- renewable.

conclusion It seems that the resource exploitation of human is so strong, so we must try our best to protect our environment. Here are some suggestions: 1. Follow 3 “R” 2. Plant more trees/reduce deforestation 3. Be self- discipline to save all the resources