Connect environmental systems and sustainability
Model interactions between living and physical environments and evaluate management decisions through sustainability, scale and trade-offs.
Section 1.3 · Sustainability
Exam scope and assessment notes
Original StudyForA teaching and practice, not Cambridge-authored questions, mark schemes or official grades. Cambridge expects candidates to study all eight topics, carry out investigative work and learn teacher-selected case studies. This course does not replace a centre's named case-study examples, current local environmental data, supervised fieldwork or the candidate's own investigation. Practice datasets are illustrative, not observations from a real place. No official assessment or certification is provided. The examples and practice datasets in these lessons are fictional and formative; learners must add their centre's verified case studies and current local evidence.
Before you begin
- Cambridge recommends prior environmental/science study equivalent to IGCSE or O Level. This is an AS-only qualification; use the exam-year syllabus and confirm centre entry details.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What makes environmental evidence useful?
What you will learn
- Distinguish biotic and abiotic components and explain their interactions
- Trace environmental pressures across local, regional and global scales
- Evaluate sustainability by weighing environmental, social and economic outcomes over time
Treat the environment as a connected system
Biotic components include producers, consumers and decomposers. Abiotic factors include light, water, temperature, oxygen, salinity and pH. A change to one factor can affect other components through food webs, cycles and population interactions.
Environmental management aims to protect systems while people depend on them. Trace the chain from human activity to a measured environmental effect, then identify which groups or places experience the benefit or cost.
Sustainability involves time and scale
Sustainable development meets present needs without compromising the ability of future generations to meet theirs. A management choice can create a short-term gain while shifting costs elsewhere or into the future.
Local actions can have regional or global consequences. State the scale and time period of each claim; a local boundary may omit supply chains, downstream effects or delayed impacts.
Sources for this lesson
Pause and explain
What should a sustainability judgement consider?
Worked example
A town restores wetlands upstream of a settlement. Explain one potential benefit and one trade-off to investigate.
Show the worked solution
- Trace a possible ecological or flood-management benefit.
- Identify a land-use or livelihood trade-off.
- State what evidence would be needed to judge sustainability.
Answer Restored wetlands may provide habitat and slow runoff, potentially reducing some downstream flood peaks. They may also compete with current land use and require long-term maintenance. A fair evaluation compares ecological and social outcomes over time and asks which groups are affected.
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 coastal project increases tourism income but disturbs nesting habitat. Frame a balanced management judgement.
Give me a hint
Separate stakeholders, scales and time horizons.
Compare my reasoning
- Identify the relevant data, place or process in the prompt.
- Apply distinguish biotic and abiotic components and explain their interactions to the stated context.
- Explain the inference and one limitation or trade-off.
Tourism may increase local income, while disturbance could reduce nesting success and damage the habitat that attracts visitors. Compare income, habitat indicators and community views over several seasons, then consider visitor limits, seasonal closures or alternative routes.
Look for these in your work
- Distinguish biotic and abiotic components and explain their interactions
- Uses relevant evidence and explains the environmental mechanism
- Distinguishes observation, inference and limitation
A river cleanup reduces visible litter for one month. What evidence is needed before claiming environmental improvement?
Give me a hint
Visible litter is one indicator at one time point.
Compare my reasoning
- Identify the relevant data, place or process in the prompt.
- Apply trace environmental pressures across local, regional and global scales to the stated context.
- Explain the inference and one limitation or trade-off.
Repeat comparable observations upstream and downstream and measure relevant water-quality or ecological indicators. Record methods, dates and rainfall. One month of visible litter counts cannot establish a sustained improvement or rule out seasonal change and upstream inputs.
Look for these in your work
- Trace environmental pressures across local, regional and global scales
- Uses relevant evidence and explains the environmental mechanism
- Distinguishes observation, inference and limitation
An energy plan lowers city emissions but depends on minerals extracted elsewhere. How should the assessment handle scale?
Give me a hint
Trace impacts across the supply chain.
Compare my reasoning
- Identify the relevant data, place or process in the prompt.
- Apply evaluate sustainability by weighing environmental, social and economic outcomes over time to the stated context.
- Explain the inference and one limitation or trade-off.
The city benefit is important but incomplete. Include extraction, processing and transport impacts in source regions, then compare life-cycle effects, rights and benefits across the supply chain rather than treating the city boundary as the whole system.
Look for these in your work
- Evaluate sustainability by weighing environmental, social and economic outcomes over time
- Uses relevant evidence and explains the environmental mechanism
- Distinguishes observation, inference and limitation
Common mistakes
- Calling any conservation action sustainable without examining trade-offs
- Treating an environmental impact as only local
- Inferring causation from a coincident change
What can you explain now?
What should a sustainability judgement consider?
Compare with the explanation
Environmental, social and economic effects over time and across affected scales
A short-term gain alone cannot show whether future options are protected.
After trying it yourself, choose your next review. This is your self-assessment.
Your review choice appears on Today. Sign in to sync it across devices.
Make it stick
Why should an environmental-management decision be assessed at more than one scale?
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.