# Describe the role of methane as a greenhouse gas and explain how the increasing amount of methane in the atmosphere may affect global climate.

> Cambridge International IGCSE Chemistry (0620) — 10.3 Air quality and climate · Describe and Explain · 4 marks

> Methane is produced from several natural and human-related sources. Its concentration in the atmosphere has more than doubled since pre-industrial times.

## Mark scheme (4 marks)

1. Methane is a greenhouse gas that absorbs infrared radiation (heat) from the Earth's surface
2. The absorbed energy is re-emitted back towards the Earth's surface, warming it
3. Higher concentration of methane means more infrared radiation is absorbed/trapped
4. This leads to an enhanced greenhouse effect / global warming / climate change, causing a rise in average global temperatures

## Key terms

- [methane](https://www.gradenine.co.uk/glossary/methane)
- [greenhouse gas](https://www.gradenine.co.uk/glossary/greenhouse-gas)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-role-of-methane-as-852c82dc) · Published by Druglandscape Ltd.