Footprints
Big idea: A footprint shows how much pressure human activities put on Earth’s systems.
Footprints help us understand whether the way we live can be supported by Earth in the long term.
Ecological footprint
The ecological footprint measures how much land and sea area is needed to provide the resources a population uses and to absorb the waste it produces.
- Includes cropland, grazing land, forests, and fishing grounds
- Measured in global hectares (gha)
- 1 gha is roughly the size of a football pitch
Biocapacity
Biocapacity is Earth’s ability to regenerate resources and absorb waste.
- If ecological footprint > biocapacity → biocapacity deficit (unsustainable)
- If ecological footprint < biocapacity → biocapacity reserve
- Countries with deficits often import resources or overexploit nature
Using resources faster than nature can replace them leads to unsustainability.
Earth Overshoot Day
Earth Overshoot Day is the date when humanity has used all the resources Earth can regenerate in one year.
- After this date, we are using future resources
- The date moves earlier if consumption increases
- Shows global ecological overshoot
Carbon footprint
A carbon footprint measures the amount of greenhouse gases released by human activities.
- Measured in tonnes of CO₂ per person per year
- Linked to energy use, transport, industry, and consumption
- Higher-income countries usually have higher carbon footprints
Water footprint
The water footprint measures the total amount of water used to produce the goods and services we consume.
- Measured in cubic metres per year
- Includes embedded (hidden) water in products
- Food and clothing often have very large water footprints
Products can use large amounts of water even if you don’t see it directly.
Citizen science
Citizen science involves non-scientists helping researchers collect environmental data.
- Allows large-scale data collection
- Used to track biodiversity, migration, and climate change
- Helps monitor whether Earth’s systems are being used sustainably
Exam focus
- Footprints measure human environmental impact
- Ecological footprint must be compared to biocapacity
- Biocapacity deficits show unsustainability
- Carbon and water footprints highlight specific pressures
- Footprints can be measured at local, national, and global scales
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
IB-style question — ecological footprint & biocapacity
(a) A region's ecological footprint is bigger than its biocapacity. State what this shows. [1] (b) Evaluate the ecological footprint as a model for measuring sustainability. [4]
How to answer it, step by step
- (a) One rule to know
• EF > biocapacity = unsustainable (using more than the land can renew)
• EF < biocapacity = sustainable - (b) Strengths vs Weaknesses + Judgement
• Strengths: simple, visual, easy to compare countries; raises awareness of overshoot
• Weaknesses: uses estimates; misses some impacts; less useful at local scale
• Judgement: 'useful for awareness but too rough for precise policy'
Final answer
Part (b) needs strengths + weaknesses + a conclusion — 'Evaluate' without a judgement loses the top mark.