# Describe the greenhouse effect and explain how greenhouse gases lead to an increase in the temperature of the Earth's atmosphere.

> Edexcel GCSE Chemistry (1CH0) — 8.2 Earth and atmospheric science · Describe · 4 marks

> Scientists have measured a steady rise in the average temperature of the Earth's atmosphere over the last century. This rise is linked to increasing concentrations of greenhouse gases such as carbon dioxide, methane and water vapour.

## Mark scheme (4 marks)

1. The Sun's radiation reaches the Earth's surface and warms it, causing the surface to emit infra-red radiation.
2. Greenhouse gases in the atmosphere absorb/trap the infra-red radiation emitted by the Earth's surface.
3. The absorbed infra-red radiation is re-emitted in all directions, including back towards the Earth's surface, raising the temperature of the atmosphere.
4. An increase in the concentration of greenhouse gases means more infra-red radiation is trapped, leading to a greater rise in atmospheric temperature / enhancing the greenhouse effect.

## Key terms

- [greenhouse effect](https://www.gradenine.co.uk/glossary/greenhouse-effect)
- [greenhouse gases](https://www.gradenine.co.uk/glossary/greenhouse-gases)

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-greenhouse-effect-and-explain-b82fc6dd) · Published by Druglandscape Ltd.