What this lesson teaches
I can judge how well mitigation strategies, such as cutting emissions and storing carbon, build community resilience.
Syllabus K329, Topic 3.3, Key Question 3. How effective are mitigation strategies in building a community's resilience to climate change?
Make a guess
A factory halves the energy it uses for each product, then makes three times as many products. What happens to its total energy use?
- It rises, to 1.5 times what it was.
- It halves, because each product uses half as much.
- It stays the same, because the two changes cancel.
- It falls to zero, because the factory is efficient.
Show the answer
It rises, to 1.5 times what it was.
Half the energy per product times three times the products is 1.5 times the old total. Efficiency alone does not guarantee lower totals.
Cleaner energy, more efficient equipment and lower demand work together to cut total emissions.
Lower-carbon energy cuts emissions from electricity supply. Solar and wind generate power without burning fuel. Other options suit other places. But reliable supply still needs suitable sites, storage and power lines, and making the equipment uses materials and land.
Efficiency means using less energy for the same service. Efficient motors, lighting, buildings and public transport all help. Electrification replaces fuel-burning machines with electric ones; this helps more as electricity gets cleaner. Carbon capture can trap some emissions from hard-to-change industries, but it is costly, uses energy, misses some emissions and needs safe long-term storage.
Efficiency alone does not guarantee lower total emissions. If each product uses less energy but many more products are made, total energy use can rise. Cheaper running costs can also encourage people to use more. So check both emissions per unit and total emissions.
Put these in order
A factory becomes more efficient. Put the chain that can raise its total emissions in order.
- The factory makes many more products than before.
- Running costs per product fall.
- The factory fits efficient motors, so each product uses less energy.
- Total energy use and emissions can rise, despite the saving on each product.
Show the answer
- The factory fits efficient motors, so each product uses less energy. Less energy per product means each one is cheaper to run and make.
- Running costs per product fall. Cheaper production can make it worth making and selling more, so output grows.
- The factory makes many more products than before. Every extra product still uses some energy, so the savings per product are spread over a bigger total.
- Total energy use and emissions can rise, despite the saving on each product.
Barriers affect whether measures are taken up and work. Technological barriers include wind and solar output that varies, grid limits and a lack of maintenance skills. Economic barriers include high upfront costs and difficulty borrowing. Social barriers include affordability, public acceptance and habits. Institutional barriers include weak rules and poor coordination. For each, explain how it blocks the cut in emissions.
- Efficiency
- Less energy for the same job.
- Per unit vs total
- Total emissions = emissions per unit x amount made.
- Four barriers
- Technological, economic, social and institutional.
Step by step
Change the supply
Cleaner power cuts emissions from electricity.
Use energy well
Better equipment needs less energy.
Check the total
More production can cancel out the savings.
Real examples to use
Singapore's carbon tax
Singapore introduced a carbon tax in 2019 at S$5 per tonne of emissions and raised it to S$25 in 2024, to encourage firms to cut emissions.
Tengeh Reservoir floating solar farm
Opened in 2021, this large floating solar farm in Singapore generates clean electricity without using scarce land.
Worked example: An electric bus needs the full picture
Replacing a diesel bus with an electric one removes exhaust fumes. The climate benefit depends on how the electricity is made and how many car trips the bus replaces. Clean power plus a well-used bus service gives the biggest gain.
Watch out for this
Lower emissions per product always means lower total emissions.
Total emissions also depend on how much is made. Work out both.
Check your understanding
A factory cuts emissions per product from 2 to 1.5 units but raises output from 100 to 160 products. What happens to total emissions?
- They fall to zero because efficiency improved.
- They fall to 150 units.
- They rise from 200 to 240 units.
Show the answer
They rise from 200 to 240 units.
Yes. 2 x 100 = 200, and 1.5 x 160 = 240.