# Deforestation is one human activity linked to climate change. Explain how large-scale deforestation contributes to an increase in atmospheric carbon dioxide levels, and describe two possible effects of this increase on the Earth's climate.

> Pearson Edexcel A-Level Biology A (9BI0) — 3.3 Climate change · Explain · 5 marks

> Billions of trees are cut down each year worldwide. Forests store vast amounts of carbon in their wood, roots and surrounding soil. When trees are removed, this carbon store is affected in several ways.

## Mark scheme (5 marks)

1. Trees/plants normally absorb/remove carbon dioxide from the atmosphere through photosynthesis
2. When trees are burned or allowed to decompose after felling, the carbon stored in them is released as carbon dioxide
3. Carbon dioxide is a greenhouse gas that absorbs/traps infrared radiation (heat) that would otherwise escape into space
4. This leads to an enhanced greenhouse effect / global warming — an increase in average global temperatures
5. A named, described effect of rising temperatures on climate, e.g. melting of polar ice caps causing sea levels to rise / more frequent or intense extreme weather events / changes in rainfall patterns / disruption to seasons

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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-linked-f50d0ce1) · Published by Druglandscape Ltd.