ScienceYear 9 Science: inheritance, energetics, climate, magnetism and space30 min★★★ difficulty

The carbon cycle and climate change

Carbon moves constantly between air, living things, oceans and rock. For thousands of years the flows roughly balanced. Human activity has tipped that balance, and the evidence sits in the data.

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
• Sinks and long-term stores
• What human activity added
• Consequences and responses

This lesson at a glance

30 minutes
19 parts to scroll through
4 quick checks
Marked quiz at the end
Gentle pace: short sittings with pauses

Words to know

carbonproductiondioxideactivityimpact

Scroll down — the lesson carries on below

Part 1 of 19 · Discover5%

Watch & discover

Part 1 of 19

Watch first

The carbon cycle and climate change

An English teaching video on this topic from LearnScienceWithB. Watch it, then scroll down for the lesson.

In a nutshell

Understand the carbon cycle and the production of carbon dioxide by human activity and the impact on climate

What you already know

Part 2 of 19

Before we start

What you already know

You should already know that respiration releases carbon dioxide and photosynthesis takes it in.

Recap: science-y8-photosynthesis Recap: science-y8-respiration

Key words

Part 3 of 19

Key words

Words you'll need today

Carbon sink: A store that absorbs more carbon than it releases.
Combustion: Burning a fuel, releasing carbon dioxide.
Greenhouse effect: Gases trapping energy re-radiated from Earth's surface.
Sequestration: Locking carbon away in a long-term store.

Learning cycle

Part 4 of 19

Learning cycle 1 of 2

How carbon moves

A short piece of teaching, then a check to make sure it has landed.

Explore the idea

Part 5 of 19

Learn

The natural cycle

Photosynthesis removes carbon dioxide from the air and locks carbon into glucose. Respiration by plants, animals and decomposers returns it. Some carbon is stored for far longer: in wood, in soil, dissolved in oceans, and in rocks and fossil fuels formed over millions of years. The cycle is a set of flows between stores, not a single loop.

Explore the idea

Part 6 of 19

Learn

Sinks and long-term stores

Oceans and forests are the largest carbon sinks. Cold water dissolves carbon dioxide, and marine organisms build shells that eventually form rock. Peatlands hold huge quantities of carbon in waterlogged soil. Damaging a sink matters twice: it stops absorbing and it can release what it already holds, which is why deforestation and peat drainage appear in climate data.

Quick check

Part 7 of 19

Quick check

Which process removes carbon dioxide from the air?

Quick check

Part 8 of 19

Quick check

A carbon sink is a store that...

Reset break

Part 9 of 19

Pause

That's sitting 1 of 2 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.

Stop here for now

Learning cycle

Part 10 of 19

Learning cycle 2 of 2

Why the balance has shifted

A short piece of teaching, then a check to make sure it has landed.

Explore the idea

Part 11 of 19

Learn

What human activity added

Burning fossil fuels releases carbon that was locked away for millions of years, adding it to the atmosphere far faster than natural processes remove it. Cement production, intensive agriculture and land-use change add more. Atmospheric carbon dioxide concentration has risen sharply since industrialisation, and the pattern is measured directly at monitoring stations and confirmed in ice cores.

Explore the idea

Part 12 of 19

Learn

Consequences and responses

More greenhouse gas means more energy retained near the surface, raising average global temperature. Consequences include sea level rise from melting ice and thermal expansion, shifting rainfall patterns, ocean acidification and more frequent extreme weather. Responses fall into reducing emissions and increasing sequestration; evaluating them means weighing effectiveness, cost and who is affected.

Quick check

Part 13 of 19

Quick check

Burning fossil fuels matters because it...

Quick check

Part 14 of 19

Quick check

Sea level rise is caused partly by...

Common mix-ups

Part 15 of 19

Common mix-ups

Things people often get wrong

People often confuse the greenhouse effect with ozone depletion. They are separate problems with different causes.
People often think weather disproves climate change. Climate is the long-term pattern, not a single cold week.

Challenge round

Part 16 of 19

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

Challenge round

Part 17 of 19

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 glucose.

Cold water dissolves carbon ____, and marine organisms build shells that eventually form rock.

Cement ____, intensive agriculture and land-use change add more.

Mastery quiz

Part 18 of 19

Marked quiz

End of lesson quiz: The carbon cycle and climate change

6 questions, marked with the reasoning shown. No timer.

1. Decomposers return carbon to the air through...
2. Peatlands are important because they...
3. Ice cores are useful because they...
4. Ocean acidification is caused by...
5. Which reduces atmospheric carbon dioxide?
6. Climate differs from weather because climate is...

Lesson round-up

Part 19 of 19

Lesson round-up

Ready when you are

Quiz score

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Games

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Points this lesson

Best run

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Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?

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Do the work

Your written work for this lesson

This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.

Case study

Why the school greenhouse failed

A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.

The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.

The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.

Written for Good Learning Co.

Reading questions

Name the variable the club changed the second time, and one variable they kept the same.
Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
Write a conclusion for the club's report, saying how far the evidence supports it.

Method and results
Writing
Write the aim, what you changed, what you measured and what you kept the same, then record your results in a table.
1 page + results table
Conclusion
Writing
Explain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.
6–8 sentences
Labelled diagram
Diagram
Draw the apparatus or the process in pencil, label it fully, and photograph it.
1 labelled diagram
Reading and notes
Reading
Read the lesson text again and write the key ideas in your own words.
Half a page of notes

Write your answer, notes or working here

Saved as you type.

Photos of paper work, diagrams or working outHow many minutes did the written work take?

Part 1 of 19 · Watch & discover

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