# Deforestation is one human activity that contributes to climate change. Explain how large-scale deforestation leads to an increase in atmospheric carbon dioxide concentration and describe two consequences of this increase for the Earth's climate.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 3.3 Climate change · Explain · 5 marks

> Vast areas of tropical forest are cleared every year for agriculture and urban development. Scientists have recorded a steady rise in atmospheric carbon dioxide levels over the last century, which has been linked to both fossil fuel combustion and deforestation.

## Mark scheme (5 marks)

1. Trees absorb / fix carbon dioxide during photosynthesis, so removing trees reduces the uptake of carbon dioxide from the atmosphere.
2. When felled trees are burned or decay / decompose, the carbon stored in them is released as carbon dioxide.
3. Carbon dioxide is a greenhouse gas that absorbs / traps infrared radiation (heat) emitted by the Earth's surface.
4. This leads to global warming / an increase in average global temperatures (first climate consequence).
5. A second described consequence, e.g. more frequent / severe extreme weather events such as storms or droughts; OR melting of polar ice caps / glaciers causing sea level rise and flooding of low-lying land; OR changes in rainfall patterns causing habitat loss / desertification.

## Key terms

- [deforestation](https://www.gradenine.co.uk/glossary/deforestation)
- [carbon dioxide](https://www.gradenine.co.uk/glossary/carbon-dioxide)

## Related

- [Revision notes for Edexcel A-Level Biology A: Salters-Nuffield (9BN0)](https://www.gradenine.co.uk/learn)
- [How to answer "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/deforestation-is-one-human-activity-that-61d405cb) · Published by Druglandscape Ltd.