The carbon footprint and its reduction: give reasons why actions may be limited.

The idea

Reducing a carbon footprint means cutting the greenhouse gases released by burning fossil fuels for electricity, heating and transport. Actions such as using renewable energy, driving less or insulating homes are often limited. Economic limits include the upfront cost of solar panels or an electric car, which many people cannot afford. Practical limits include living in a rented flat where insulation cannot be installed, or a rural area with no bus service. Scientific and technical limits include the intermittent output of wind and solar power, so storage or backup supply is needed. Political and social limits include government priorities, public habits and the time taken to build new infrastructure. A good answer names a specific action, then explains the barrier that stops it being fully adopted.

What earns the marks

• Identifies a named action to reduce a carbon footprint, such as installing solar panels, using public transport or improving home insulation.
• Explains an economic barrier, for example high installation cost or long payback time, so the action is not affordable for everyone.
• Explains a practical or lifestyle barrier, for example no local bus route, rented housing or a job that requires a car.
• Explains a scientific or technical barrier, for example renewable output varies with weather and needs storage or backup.
• Explains a political or social barrier, for example government policy, public opinion or slow infrastructure change.
• Links the barrier clearly to why the action is limited rather than simply listing disadvantages.

Common mistakes and how to put them right

• Writing that renewable energy is 'bad for the environment' instead of explaining a specific limit such as intermittency or cost.

  Put it right: Name the action and the exact barrier that restricts it.

• Listing barriers without linking them to an action, for example 'it is expensive' with no mention of what is expensive.

  Put it right: State the action first, then the barrier.

• Confusing the carbon footprint with the ozone layer or with acid rain.

  Put it right: Keep the answer focused on greenhouse gases such as carbon dioxide and methane.

Exam tips

• Use the command word: 'give reasons' needs a cause-and-effect link, not just a list of problems.
• Aim for two or three different categories of barrier, such as cost, practicality and technology, to show range.
• Use connectives such as 'because', 'so' and 'therefore' to make each reason explicit.
• Apply each reason to a real context, such as a family, a town or a country, to make the limitation concrete.