The carbon cycle and a warming atmosphere
Carbon is constantly moving between the air, living things, the oceans and the rocks. Human activity has added a new, one-way route into that cycle.
Part of your national curriculum
- Chemistry: Earth and atmosphere: Understand the carbon cycle and the production of carbon dioxide by human activity and the impact on climate
Lesson overview
What you'll learn in this lesson
Understand the carbon cycle and the production of carbon dioxide by human activity and the impact on climate
Key learning points
- • The natural cycle
- • What humans changed
- • The greenhouse effect
This lesson at a glance
- 25 minutes
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
The carbon cycle and a warming atmosphere
Carbon is constantly moving between the air, living things, the oceans and the rocks. Human activity has added a new, one-way route into that cycle.
In a nutshell
Understand the carbon cycle and the production of carbon dioxide by human activity and the impact on climate
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · The natural cycle
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
The natural cycle
Photosynthesis removes carbon dioxide from the air and locks carbon into plant tissue. Respiration, decay and natural combustion return it. The oceans dissolve and release carbon dioxide, and over very long timescales carbon is stored in rock and fossil fuels.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 20
Learn
What humans changed
Burning fossil fuels releases carbon that had been stored underground for millions of years. Deforestation removes photosynthesising plants that would have absorbed some of it. Together these raise the concentration of carbon dioxide in the atmosphere faster than natural processes remove it.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · The greenhouse effect
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
The greenhouse effect
Greenhouse gases let sunlight through but absorb infrared radiation leaving the Earth's surface, keeping the planet warm enough to live on. Increasing their concentration strengthens the effect, raising average global temperature and shifting weather and sea levels.
Quick check
Part 11 of 20
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 13 of 20
Explore the idea
Part 14 of 20
Worked example
Worked example: reading a carbon dioxide graph
A graph shows a saw-tooth line rising steadily from 1960 to today. Interpretation: the annual zig-zag is the northern hemisphere growing season, when photosynthesis briefly outpaces respiration. The upward trend beneath it is the human addition — the cycle is no longer balanced year to year.
Challenge round
Part 15 of 20
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 17 of 20
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Photosynthesis removes ____ dioxide from the air and locks carbon into plant tissue.
The oceans dissolve and release carbon ____, and over very long timescales carbon is stored in rock and fossil fuels.
Challenge round
Part 18 of 20
Game · Recall cards
Which human activity most directly adds extra carbon dioxide to the atmosphere?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: The carbon cycle and a warming atmosphere
4 questions, marked with the reasoning shown. No timer.
1. Which human activity most directly adds extra carbon dioxide to the atmosphere?
2. How does deforestation affect the carbon cycle?
3. Why is carbon dioxide called a greenhouse gas?
4. Which process removes carbon dioxide from the air?
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
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Understand the carbon cycle and the production of carbon dioxide by human activity and the impact on climate