Atmosphere, climate and the natural greenhouse effect
Describe the atmosphere's layers and clean-air composition, define climate and explain how the natural greenhouse effect keeps Earth warm enough for life.
This original StudyForA sequence supports Cambridge IGCSE Environmental Management 0680 Topics 1–4 for exams in 2027, 2028 and 2029. Named local examples are chosen by the learner and centre; verify current conditions and local context with reliable sources. It is not a Cambridge paper, official grade or complete course.
Before you begin
- Use the 2027–2029 syllabus and check your exam year and centre's entry arrangements. Topics 1–4 are taught on this page; Topics 5–7 are still being built.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which sequence goes upward from Earth's surface?
What you will learn
- Describe the atmosphere's layers and clean-air composition, define climate and explain how the natural greenhouse effect keeps Earth warm enough for life.
- Use evidence from an unfamiliar case to explain a cause-and-effect link and justify a suitable response.
Locate the atmospheric layers and ozone layer
From Earth's surface upward, the syllabus layers are the troposphere, stratosphere, mesosphere and thermosphere. The ozone layer is in the lower stratosphere.
Keep the order and location distinct: the atmosphere is not one uniform layer, and the ozone layer is not at the surface.
Describe clean air and climate
Clean air is about 78% nitrogen and 21% oxygen, with carbon dioxide, argon and water vapour making up the remainder. Water vapour varies with place and conditions.
Climate means the weather conditions of a location based on weather observed over many years. A short spell of weather is not enough to establish a climate pattern.
Trace the natural greenhouse effect
Solar radiation passes through the atmosphere. Some is absorbed by land and oceans, heating Earth; some is reflected back into space.
Greenhouse gases and clouds absorb some radiation and re-emit it toward Earth's surface. This natural process warms Earth enough to support life; it is different from the enhanced effect caused by higher greenhouse-gas concentrations.
Sources for this lesson
Pause and explain
What does the natural greenhouse effect do?
Worked example
A learner says that a cold week disproves a warming climate trend. Correct the reasoning and state where the ozone layer is found.
Show the worked solution
- Climate describes weather conditions based on observations over many years, so one week is not enough to establish a climate pattern.
- The atmospheric layers from the surface upward are troposphere, stratosphere, mesosphere and thermosphere.
- The ozone layer is in the lower stratosphere; it is separate from the natural greenhouse effect explanation.
Answer A short weather event cannot establish or disprove a long-term climate pattern. The ozone layer is located in the lower stratosphere.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A diagram shows solar radiation passing through the atmosphere, warming land and oceans, and some energy being re-emitted toward the surface by greenhouse gases and clouds. Explain the sequence.
Give me a hint
Follow incoming energy, surface absorption, reflection and re-emission in order.
Compare my reasoning
- Solar radiation passes through the atmosphere; some is reflected back into space.
- Some radiation is absorbed by land and oceans, which heats Earth's surface.
- Greenhouse gases and clouds absorb and re-emit some radiation toward the surface, helping to keep Earth warm enough for life.
The natural greenhouse effect involves energy passing through the atmosphere, surface absorption and reflection, and some energy being re-emitted toward Earth by greenhouse gases and clouds.
Look for these in your work
- Incoming and reflected energy distinguished
- Surface absorption explained
- Natural warming stated
Clean air contains 78% nitrogen and 21% oxygen. Identify the gases in the remaining approximate 1% and explain why a single day's weather cannot define climate.
Give me a hint
Use the syllabus composition and the many-years basis in the climate definition.
Compare my reasoning
- The remainder includes carbon dioxide, argon and water vapour.
- Climate is based on weather conditions in a location over many years.
- Therefore, a single day's temperature or rainfall is too brief to represent a climate pattern.
The remaining approximate 1% includes carbon dioxide, argon and water vapour. Climate is based on many years of weather, so one day is not sufficient evidence.
Look for these in your work
- Three remaining components named
- Climate defined by long-term observations
- Weather and climate distinguished
A student draws the ozone layer below the troposphere and labels the natural greenhouse effect as 'ozone trapping heat'. Correct both labels using the syllabus.
Give me a hint
Separate the lower-stratosphere ozone layer from greenhouse gases and clouds in the natural effect.
Compare my reasoning
- Place the ozone layer in the lower stratosphere, above the troposphere.
- The natural greenhouse effect involves greenhouse gases and clouds absorbing and re-emitting some radiation toward Earth's surface.
- Explain that this natural warming supports life; ozone-layer location is a separate syllabus fact.
The ozone layer belongs in the lower stratosphere. Greenhouse gases and clouds help produce the natural greenhouse effect by absorbing and re-emitting some radiation toward the surface.
Look for these in your work
- Ozone location corrected
- Greenhouse mechanism accurately described
- Two concepts separated
Common mistakes
- Confusing daily weather with climate
- Putting the ozone layer in the troposphere
- Treating the natural greenhouse effect as entirely harmful
- Adding up the atmospheric layers as if their proportions were required
What can you explain now?
Which layer contains the ozone layer?
Compare with the explanation
The lower stratosphere
The correct answer is “The lower stratosphere”. The alternatives “The troposphere” and “The thermosphere” do not match the syllabus concept. Describe the atmosphere's layers and clean-air composition, define climate and explain how the natural greenhouse effect keeps Earth warm enough for life.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Name and order the four atmospheric layers, define climate and describe the natural greenhouse effect.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.