kbsm bio form 4 chapter 9

1. CHAPTER 9
[ENDANGERED ECOSYSTEM]
GREENHOUSE EFFECT &
THE THINNING OF THE OZONE LAYER

2. EARTH
CARBON DIOXIDE LAYER
HEAT TRAPPED
IN ATMOSPHERE

3. Green house effect
• The main greenhouse gas is carbon dioxide
(from coal burning, vehicle exhaust and open
burning)
• Occurs when heat (infra red radiation) from
sunlight is trapped by carbon dioxide layer in
atmosphere.
• This can lead global warming.

4. Effects
• Increasing global temperature.
• Ice melting at north and south poles.
• Sea level increases.
• Flash flood.
• Loss of flora and fauna.
• Imbalance ecosystem.

5. OZONE LAYER
• Location : Stratosphere layer.
• Ozone layer is a protective shield that can
absorb ultraviolet radiation from Sun.
• Overexposure to UV radiations increase the
risk of skin cancer and eye disease (CATARACT)

6. Thinning of ozone layer
• Caused by CFCs (chlorofluorocarbons)
• Contains of chlorine, fluorine and carbons.
• Chlorofluorocarbon (CFC) from refrigerators, air
conditioner and aerosol can destroy ozone layer
in the atmosphere.
• Nowadays, CFCs is replaced by H CFCs that more
stable environmental friendly.