Emissions, transport and the environment

Words to know

Greenhouse gas

A gas that traps heat in the atmosphere, such as carbon dioxide and methane.

CO₂ equivalent

A way of adding different gases by the warming each one causes compared with carbon dioxide.

Territorial emissions

Emissions made inside a country's borders, not including goods made abroad and bought there.

Net zero

Balancing greenhouse gases released with those removed.

Negative externality

A cost to other people that the producer does not pay, such as pollution.

Decarbonise

Reduce the carbon dioxide released by an activity.

Charts

Greenhouse gas emissions by sector, year by year

Million tonnes of CO₂ equivalent, UK, final figures.

Questions

1. Calculate[3]

   UK greenhouse gas emissions were 791 million tonnes in 1990 and 373 million tonnes in 2024. Calculate the percentage change. Give your answer to the nearest whole number.

   GCSE Maths · AQA 8300 · Ratio, proportion and rates of change: percentage change
   Answer. -53%

   M1 for 373 − 791. M1 for ÷ 791 × 100. A1 for -53.

   Common error: Dividing by the later value.
2. Work out[3]

   In 2024, transport produced 110 million tonnes of the UK's 373 million tonnes of greenhouse gases. Work out the percentage from transport. Give your answer to 1 decimal place.

   GCSE Maths · AQA 8300 · Number: percentages of amounts
   Answer. 29.6%

   M1 for 110 ÷ 373. M1 for × 100. A1 for 29.6.
3. Calculate[2]

   Emissions fell from 531 to 373 million tonnes between 2014 and 2024. Work out the mean fall each year. Give your answer to 1 decimal place.

   GCSE Maths · AQA 8300 · Ratio, proportion and rates of change: rates
   Answer. 15.7 million tonnes a year

   M1 for 531 − 373 = 157 divided by 10 years. A1 for 15.7.
4. Work out[2]

   There were 34.49 million licensed cars and 69.5 million people in the UK. Work out the number of cars for every person. Give your answer to 2 decimal places.

   GCSE Maths · AQA 8300 · Ratio, proportion and rates of change: rates
   Answer. 0.50

   M1 for 34.49 ÷ 69.5. A1 for 0.50.
5. Calculate[3]

   Road deaths in Great Britain were 1,730 in 2015 and 1,556 in 2025 (the latest year is provisional). Calculate the percentage change.

   GCSE Maths · AQA 8300 · Ratio, proportion and rates of change: percentage change
   Answer. -10.1%

   M1 for 1,556 − 1,730. M1 for ÷ 1,730 × 100. A1 for -10.1.
6. Explain[4]

   Transport produced 110 million tonnes of greenhouse gases in 2024. Explain two ways in which emissions from transport could be reduced.

   GCSE Geography · The challenge of resource management; sustainable transport (check your board)
   Answer. Electric vehicles; public transport; walking and cycling

   B1+B1 for each way with an explanation, e.g. switching to electric vehicles removes exhaust emissions (if the electricity is low-carbon); better public transport or cycling infrastructure reduces car journeys; road pricing or fuel duty makes driving more costly.
7. Analyse[9]

   Greenhouse gas emissions were 373 million tonnes in 2024. Analyse how a carbon tax could reduce emissions, and one problem of using it.

   A-level Economics · AQA 7136, Edexcel 9EC0 · Market failure: negative externalities and environmental policy
   Answer. Tax internalises the external cost; shifts supply; problems of setting and distribution

   Levels: L1 (1–3) relevant points, little analysis; L2 (4–6) developed chains of reasoning; L3 (7–9) well-developed analysis, supported by the data, with a clear line of argument. Indicative: emissions are a negative externality, so private cost is below social cost; a tax raises firms' marginal cost, shifting supply left and quantity down; the right rate is hard to set; regressive impact on low-income households; competitiveness and leakage abroad; revenue can be used elsewhere.
8. Calculate[4]

   Model emissions as falling by a constant amount each year, using the fall between 2014 (531 million tonnes) and 2024 (373 million tonnes). (a) Find the yearly fall. [1] (b) Estimate how many years from 2024 until emissions reach zero. [2] (c) State one reason the model may be unreliable. [1]

   A-level Mathematics · Mathematical modelling: linear models (check your board)
   Answer. (a) 15.7; (b) about 24 years

   (a) B1 15.7 million tonnes a year. (b) M1 for 373 ÷ 15.7. A1 for about 24 years. (c) B1 real falls are not constant (easy cuts such as coal first, harder cuts in buildings and industry later) and emissions can be offset or removed.
9. Assess[9]

   Electricity supply produced 204 million tonnes in 1990 and 38 million tonnes in 2024, while buildings produced 82 and industry 46 million tonnes in 2024. Assess how far changes in electricity generation explain the fall in UK emissions.

   A-level Geography · Climate change: mitigation and the sources of emissions (check your board)
   Answer. Large fall in electricity; other sectors fell less

   Levels: L1 (1–3) relevant points, little analysis; L2 (4–6) developed chains of reasoning; L3 (7–9) well-developed analysis, supported by the data, with a clear line of argument. Indicative: electricity emissions fell by 82% from the end of coal and growth of renewables, a large part of the total fall; buildings and industry fell less and are harder to decarbonise; offshored production; data use.
10. Evaluate[12]

    Transport produced 110 million tonnes in 2024, with 34.5 million licensed cars and 2.07 million new cars registered a year. Evaluate the effectiveness of policies to reduce emissions from road transport.

    A-level Geography · Managing carbon emissions: transport and policy (check your board)
    Answer. A reasoned judgement on cost, speed and fairness

    Levels: L1 (1–3) a few relevant points; L2 (4–6) analysis, one-sided or unsupported; L3 (7–9) developed analysis with data and some judgement; L4 (10–12) balanced, evidence-based judgement that answers the question. Indicative: electric vehicle incentives and a phase-out of petrol and diesel, charging infrastructure, fuel duty and road pricing, public transport, active travel; costs, speed, who gains and loses, rural and low-income households; the electricity mix matters; judge with criteria.

Ideas for discussion

• Why have emissions from electricity fallen faster than from transport?
• Who should pay for cutting emissions: people who emit most, everyone through taxes, or companies?
• Should the UK count emissions from goods it imports? How would that change the picture?