IB ESS SL 6.3.2 Decarbonization Question Bank
Practise IB ESS SL/HL 006.003.002 by applying decarbonization concepts to exam-style environmental systems questions.
- Syllabus
- First assessment 2026
- Course
- ESS SL
- Level
- SL
Practise IB ESS SL/HL 006.003.002 by applying decarbonization concepts to exam-style environmental systems questions.

Figure:Planned changes in energy supply in Cape Town, 2025-2050
Evaluate how the planned changes in the energy supply, shown in Figure: Planned changes in energy supply in Cape Town, 2025-2050, are likely to influence carbon emissions in Cape Town.
Pros - reduce carbon emissions [2max]
a. decrease in use of coal with high emissions will tend to reduce carbon emissions / switch (from coal with high emissions) to coal with low sulfur emissions reduces overall carbon emissions;
b. decrease in overall use of coal (both low sulfur content and high emissions coal) will decrease carbon emissions / there is a slight decrease in carbon-producing sources;
c. increase in renewables/nuclear/wind/solar will tend to reduce carbon emissions;
Cons - increase carbon emissions [2max]
d. overall increase in energy supply will tend to increase carbon emissions due to construction/maintenance/extraction / production of batteries for renewable energies requires extraction of materials which produces carbon emissions;
e. use of coal with low sulfur content will still produce carbon emissions;
f. overall proportion of carbon producing sources remains fairly constant;
Note: For credit for either pros or cons, link must be made to carbon/carbon dioxide emissions.
For pros, do not accept only 'use of low sulfur coal will reduce emissions'.
Conclusion [1max] needs to be balanced considering both sides of the argument for credit and makes a clear value judgement e.g.: Although there is a planned increase in the use of renewable energies (associated with low carbon emissions) the majority of energy will still be generated using coal that releases carbon dioxide; Conclusion is not mandatory, and 3 marks can be achieved through consideration of both pros and cons