Ozone depletion Cambridge IGCSE Environmental Management revision
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In plain words
High above the weather is a thin layer of gas that absorbs most of the Sun's harmful rays. In the 1980s scientists found a hole in it. The cause was a gas used in spray cans and fridges, and within a few years the world had agreed to ban it. It is the best example there is of an environmental problem being fixed.
9 things to know
- The ozone layer, in the lower stratosphere, absorbs much of the harmful ultraviolet radiation from the Sun.
- Chlorofluorocarbons (CFCs), used in aerosols and refrigerants, are the cause of ozone depletion. In the stratosphere they break down and destroy ozone.
- With less ozone, higher levels of solar radiation reach the Earth's surface.
- In people, this increases the rates of cancer, especially skin cancer, and of cataracts, a clouding of the lens of the eye.
- Vegetation is damaged, which results in reduced crop yields.
- International agreement and policies: countries agreed to phase out CFCs. Because the atmosphere is shared, a ban in a single country would not have worked.
- CFC ban and alternatives: other gases are now used in aerosols and refrigerators.
- Safe disposal of CFCs: the gas in old refrigerators and air conditioners is collected, so it is not released when they are scrapped.
- Limitations. CFCs last for many decades in the atmosphere, so recovery is slow. Some alternatives are greenhouse gases. Old equipment is not always disposed of safely, and some CFCs are still produced illegally.
Worked example
CFCs were banned decades ago, yet the ozone layer has still not fully recovered. Explain why.
- CFCs already released stay in the atmosphere for many decades and go on destroying ozone.
- Old refrigerators still contain CFCs, which leak out if they are not disposed of safely.
- Recovery is therefore slow, even though very little new CFC is being made.
Tips and tricks
- Ozone depletion and global warming are different problems. Ozone depletion lets more harmful radiation in. It is not the cause of global warming.
- The health effects to learn are cancer and cataracts. The effect on plants is reduced crop yield.
It lands in your notebook with its questions as flashcards.
Ozone depletion: 6 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What causes ozone depletion?
Chlorofluorocarbons, from aerosols and refrigerants.
Where were CFCs used?
As the propellant in spray cans and the coolant in fridges.
Which health problem increases with ozone depletion?
More harmful radiation damages eyes and skin.
How does ozone depletion affect crops?
The extra radiation damages vegetation.
What is meant by safe disposal of CFCs?
The gas is removed before the appliance is scrapped.
Why is the ozone layer recovering only slowly?Stretch
The damage continues long after the releases stop.
Quiz
6 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 7 marks. Write your answers on paper, then check them.
Ozone depletion
Cambridge IGCSE Environmental Management 0680 · 7 marks · papermunch.org
Name ______________________________ Date ______________
State the cause of ozone depletion and two uses of the substance responsible.[2]
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Chlorofluorocarbons (CFCs). They were used in aerosols and as refrigerants.
Describe three impacts of ozone depletion.[3]
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Higher levels of solar radiation reach the Earth's surface. Rates of cancer and cataracts increase. Vegetation is damaged, so crop yields are reduced.
Explain why an international agreement was needed to deal with ozone depletion.[2]
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The atmosphere is shared by all countries, and CFCs released anywhere spread around the world. A ban works only if all countries stop using them.
Answers: Ozone depletion
- 1. Chlorofluorocarbons (CFCs). They were used in aerosols and as refrigerants.
- 2. Higher levels of solar radiation reach the Earth's surface. Rates of cancer and cataracts increase. Vegetation is damaged, so crop yields are reduced.
- 3. The atmosphere is shared by all countries, and CFCs released anywhere spread around the world. A ban works only if all countries stop using them.