IB ESS SL1.3 SustainabilityPaper 1 & 2Core idea~13 min read
Rethinking Economic Models
The economy we have was designed for a world that felt empty: endless materials in one end, endless space for waste at the other. That world has gone. This page is about what people are proposing instead, and why the arguments get so heated.
📚 What you need to know
A linear economy runs take → make → use → dispose. It needs constant inputs and produces constant waste.
A circular economy designs waste out, keeping materials in use through repair, reuse, remanufacture and recycling.
Cradle to cradle design treats every output as an input for something else.
GDP measures economic activity, not wellbeing and not sustainability.
Alternatives include the HDI, the Genuine Progress Indicator and Gross National Happiness.
Decoupling means growing the economy without growing resource use and emissions.
Steady-state and degrowth approaches question whether endless growth is possible at all.
From linear to circular
Recycling is the last loop, not the first one. Repairing and reusing keep far more value than melting something down and starting again.
Linear economy
Circular economy
Materials
Extracted, used once, discarded
Kept in use for as long as possible
Waste
An unavoidable end point
A design fault to be engineered out
Product design
Cheap to make, hard to repair, quick to replace
Durable, repairable, and made to be taken apart
Business model
Sell as many units as possible
Sell the service; lease, maintain and take products back
Effect on natural capital
Runs it down at both ends
Reduces extraction and reduces waste
Cradle to cradle
A design idea that goes further than recycling. Instead of asking how to dispose of a product, it asks what the product should become. Materials are kept in one of two cycles:
Biological cycle: materials that can safely return to the soil and feed natural processes.
Technical cycle: metals, polymers and components recovered and used again at the same quality.
The test is simple. If a material cannot go cleanly into either cycle, it should not have been in the product.
Be careful with recycling in exam answers. Most recycling is really downcycling: the material comes back at lower quality and eventually drops out of the loop anyway. It is much better than landfill, but it is not a closed circle, and saying so shows you understand the model rather than just liking it.
The problem with GDP
Look at the left column again. An oil spill raises GDP, because cleaning it up is economic activity. That is not a small flaw.
Alternatives to GDP
Measure
What it adds
Limitation
Human Development Index (HDI)
Combines income with life expectancy and education, so it measures development rather than output
Still ignores environmental cost and inequality
Genuine Progress Indicator (GPI)
Starts from consumption then subtracts pollution, resource depletion and inequality, and adds unpaid work
Requires many value judgements about what to count and what it is worth
Gross National Happiness
Measures wellbeing across health, culture, environment and governance, not just money
Hard to compare between countries and partly subjective
Ecological footprint
Shows whether the activity fits inside what the environment can supply
Says nothing about how well people are actually living
Growth, decoupling and degrowth
Here is the argument the whole topic has been building towards, and it is genuinely unsettled. You should be able to give both sides.
Position
The argument
The objection
Green growth
Growth can continue if it is decoupled from resource use, through renewable energy, efficiency and circular design
Absolute decoupling at the speed required has not been demonstrated at global scale
Steady-state economy
Keep the economy at a stable size within environmental limits, and improve quality rather than quantity
Modern economies and employment are built around growth, so the transition is hard
Degrowth
Wealthy economies should deliberately shrink resource use and consumption so poorer ones have room to develop
Politically very difficult, and risks harming the people it aims to protect if handled badly
Key termRelative decoupling means resource use per unit of output falls. Absolute decoupling means total resource use falls while the economy still grows. Only the second one solves the problem.
The link back to systems. An economy that grows its throughput forever inside a closed planet is a stock being drained by a flow that never stops. That is the natural capital diagram from the first page of this topic, drawn at global scale. Every model on this page is an attempt to close the loop or slow the flow.
🧠
Easy way to remember the three positions
Green growth: grow, but cleaner. Steady state: stop growing, get better. Degrowth: the rich part of the world shrinks so the rest has room.
Worked examples
WE 1
Compare linear and circular economies
Compare a linear economy with a circular economy, and explain why the circular model is considered more sustainable. (4 marks)
Point 1: linear
A linear economy takes resources, makes products, uses them and disposes of them, so it needs continuous inputs and produces continuous waste.
Point 2: circular
A circular economy keeps materials in use through repair, reuse, remanufacture and recycling, so waste becomes an input rather than an end point.
Point 3: why it is more sustainable
It reduces extraction of natural capital and reduces pollution, so the rate of use moves closer to the natural income.
Point 4: a limit
No loop is perfect — recycling loses quality and needs energy — so reducing consumption still matters.
Circular slows both ends: less taken in, less thrown outthe fourth point stops this reading like an advert and shows real understanding
WE 2
Criticise GDP as a measure
Explain why GDP is a poor indicator of sustainability. (3 marks)
Point 1: what it measures
GDP measures the total value of goods and services produced, so it records activity, not wellbeing.
Point 2: what it counts wrongly
Environmental damage can raise GDP, because clearing a forest or cleaning up a spill both count as economic activity.
Point 3: what it ignores
It ignores unpaid work, inequality, and the depletion of natural capital, so a country can grow while running its resources down.
GDP can rise while the things that keep people alive fallthe oil spill example is short, memorable and lands the point instantly
WE 3
Discuss endless growth
Discuss whether continued economic growth is compatible with sustainability. (4 marks)
Argument for
Growth funds renewable energy, efficient technology and circular design, and higher incomes can improve health and education. Relative decoupling has already been achieved in some economies.
Argument against
The Earth is a closed system for matter, so throughput cannot rise forever. Absolute decoupling at the required speed has not been shown globally.
Alternatives
Steady-state and degrowth approaches suggest stabilising or reducing resource use in wealthy economies, leaving room for poorer ones to develop.
Judgement
Growth may be compatible with sustainability only if it is absolutely decoupled from resource use; without that, it is not.
Not growth or no growth, but growth of whatusing the closed-system idea from 1.2 here is exactly the cross-topic linking that scores well
💡 Exam tips
Learn the linear chain as four words: take, make, use, dispose.
Use natural capital and natural income when explaining why circular is better. It ties the topic together.
Know the difference between relative and absolute decoupling.
Have one alternative to GDP ready with a strength and a limitation.
For growth questions, give both sides and then judge. Never just assert one.
Mention downcycling — it shows you know recycling is not a perfect loop.
⚠ Common mistakes
Treating circular economy as just recycling. Repair, reuse and redesign come first.
Saying GDP measures wealth or wellbeing. It measures activity over a period.
Assuming recycling closes the loop completely. Quality drops and energy is used every cycle.
Confusing relative and absolute decoupling. Only absolute decoupling actually reduces pressure.
Presenting degrowth as obviously right or obviously mad. Give the argument and the objection.
Forgetting fairness. Any growth answer has to deal with countries that still need to develop.
That completes 1.3 Sustainability, and with it the whole of Topic 1. You now have the toolkit: perspectives shape what people see, systems explain how things behave, and sustainability is the test you apply to any of it. Up next: 2.1 Individuals, Populations, Communities and Ecosystems, where you start using these tools on real ecology.
Want this explained one-to-one?
Book a free session with an experienced IB ESS tutor and get your trickiest topics made simple.
IB ESS SL1.3 SustainabilityPaper 1 & 2Core idea~13 min read
Rethinking Economic Models
The economy we have was designed for a world that felt empty: endless materials in one end, endless space for waste at the other. That world has gone. This page is about what people are proposing instead, and why the arguments get so heated.
📚 What you need to know
A linear economy runs take → make → use → dispose. It needs constant inputs and produces constant waste.
A circular economy designs waste out, keeping materials in use through repair, reuse, remanufacture and recycling.
Cradle to cradle design treats every output as an input for something else.
GDP measures economic activity, not wellbeing and not sustainability.
Alternatives include the HDI, the Genuine Progress Indicator and Gross National Happiness.
Decoupling means growing the economy without growing resource use and emissions.
Steady-state and degrowth approaches question whether endless growth is possible at all.
From linear to circular
Recycling is the last loop, not the first one. Repairing and reusing keep far more value than melting something down and starting again.
Linear economy
Circular economy
Materials
Extracted, used once, discarded
Kept in use for as long as possible
Waste
An unavoidable end point
A design fault to be engineered out
Product design
Cheap to make, hard to repair, quick to replace
Durable, repairable, and made to be taken apart
Business model
Sell as many units as possible
Sell the service; lease, maintain and take products back
Effect on natural capital
Runs it down at both ends
Reduces extraction and reduces waste
Cradle to cradle
A design idea that goes further than recycling. Instead of asking how to dispose of a product, it asks what the product should become. Materials are kept in one of two cycles:
Biological cycle: materials that can safely return to the soil and feed natural processes.
Technical cycle: metals, polymers and components recovered and used again at the same quality.
The test is simple. If a material cannot go cleanly into either cycle, it should not have been in the product.
Be careful with recycling in exam answers. Most recycling is really downcycling: the material comes back at lower quality and eventually drops out of the loop anyway. It is much better than landfill, but it is not a closed circle, and saying so shows you understand the model rather than just liking it.
The problem with GDP
Look at the left column again. An oil spill raises GDP, because cleaning it up is economic activity. That is not a small flaw.
Alternatives to GDP
Measure
What it adds
Limitation
Human Development Index (HDI)
Combines income with life expectancy and education, so it measures development rather than output
Still ignores environmental cost and inequality
Genuine Progress Indicator (GPI)
Starts from consumption then subtracts pollution, resource depletion and inequality, and adds unpaid work
Requires many value judgements about what to count and what it is worth
Gross National Happiness
Measures wellbeing across health, culture, environment and governance, not just money
Hard to compare between countries and partly subjective
Ecological footprint
Shows whether the activity fits inside what the environment can supply
Says nothing about how well people are actually living
Growth, decoupling and degrowth
Here is the argument the whole topic has been building towards, and it is genuinely unsettled. You should be able to give both sides.
Position
The argument
The objection
Green growth
Growth can continue if it is decoupled from resource use, through renewable energy, efficiency and circular design
Absolute decoupling at the speed required has not been demonstrated at global scale
Steady-state economy
Keep the economy at a stable size within environmental limits, and improve quality rather than quantity
Modern economies and employment are built around growth, so the transition is hard
Degrowth
Wealthy economies should deliberately shrink resource use and consumption so poorer ones have room to develop
Politically very difficult, and risks harming the people it aims to protect if handled badly
Key termRelative decoupling means resource use per unit of output falls. Absolute decoupling means total resource use falls while the economy still grows. Only the second one solves the problem.
The link back to systems. An economy that grows its throughput forever inside a closed planet is a stock being drained by a flow that never stops. That is the natural capital diagram from the first page of this topic, drawn at global scale. Every model on this page is an attempt to close the loop or slow the flow.
🧠
Easy way to remember the three positions
Green growth: grow, but cleaner. Steady state: stop growing, get better. Degrowth: the rich part of the world shrinks so the rest has room.
Worked examples
WE 1
Compare linear and circular economies
Compare a linear economy with a circular economy, and explain why the circular model is considered more sustainable. (4 marks)
Point 1: linear
A linear economy takes resources, makes products, uses them and disposes of them, so it needs continuous inputs and produces continuous waste.
Point 2: circular
A circular economy keeps materials in use through repair, reuse, remanufacture and recycling, so waste becomes an input rather than an end point.
Point 3: why it is more sustainable
It reduces extraction of natural capital and reduces pollution, so the rate of use moves closer to the natural income.
Point 4: a limit
No loop is perfect — recycling loses quality and needs energy — so reducing consumption still matters.
Circular slows both ends: less taken in, less thrown outthe fourth point stops this reading like an advert and shows real understanding
WE 2
Criticise GDP as a measure
Explain why GDP is a poor indicator of sustainability. (3 marks)
Point 1: what it measures
GDP measures the total value of goods and services produced, so it records activity, not wellbeing.
Point 2: what it counts wrongly
Environmental damage can raise GDP, because clearing a forest or cleaning up a spill both count as economic activity.
Point 3: what it ignores
It ignores unpaid work, inequality, and the depletion of natural capital, so a country can grow while running its resources down.
GDP can rise while the things that keep people alive fallthe oil spill example is short, memorable and lands the point instantly
WE 3
Discuss endless growth
Discuss whether continued economic growth is compatible with sustainability. (4 marks)
Argument for
Growth funds renewable energy, efficient technology and circular design, and higher incomes can improve health and education. Relative decoupling has already been achieved in some economies.
Argument against
The Earth is a closed system for matter, so throughput cannot rise forever. Absolute decoupling at the required speed has not been shown globally.
Alternatives
Steady-state and degrowth approaches suggest stabilising or reducing resource use in wealthy economies, leaving room for poorer ones to develop.
Judgement
Growth may be compatible with sustainability only if it is absolutely decoupled from resource use; without that, it is not.
Not growth or no growth, but growth of whatusing the closed-system idea from 1.2 here is exactly the cross-topic linking that scores well
💡 Exam tips
Learn the linear chain as four words: take, make, use, dispose.
Use natural capital and natural income when explaining why circular is better. It ties the topic together.
Know the difference between relative and absolute decoupling.
Have one alternative to GDP ready with a strength and a limitation.
For growth questions, give both sides and then judge. Never just assert one.
Mention downcycling — it shows you know recycling is not a perfect loop.
⚠ Common mistakes
Treating circular economy as just recycling. Repair, reuse and redesign come first.
Saying GDP measures wealth or wellbeing. It measures activity over a period.
Assuming recycling closes the loop completely. Quality drops and energy is used every cycle.
Confusing relative and absolute decoupling. Only absolute decoupling actually reduces pressure.
Presenting degrowth as obviously right or obviously mad. Give the argument and the objection.
Forgetting fairness. Any growth answer has to deal with countries that still need to develop.
That completes 1.3 Sustainability, and with it the whole of Topic 1. You now have the toolkit: perspectives shape what people see, systems explain how things behave, and sustainability is the test you apply to any of it. Up next: 2.1 Individuals, Populations, Communities and Ecosystems, where you start using these tools on real ecology.
Want this explained one-to-one?
Book a free session with an experienced IB ESS tutor and get your trickiest topics made simple.
