# Explain how a positive feedback mechanism involving Arctic permafrost can amplify the effects of climate change.

> IB DP Biology Standard Level (2023 syllabus) — D4.3 Climate change · Explain · 4 marks

> Permafrost is frozen ground found across much of the Arctic. As global average temperatures rise, permafrost thaws and the organic matter within it begins to decompose.

## Mark scheme (4 marks)

1. Thawing permafrost allows decomposition of previously frozen organic matter by microorganisms/decomposers
2. Decomposition releases greenhouse gases (carbon dioxide and/or methane) into the atmosphere
3. Increased atmospheric greenhouse gas concentration enhances the greenhouse effect, causing further warming
4. This is a positive feedback loop because the initial warming causes further thawing, which releases more greenhouse gases, driving yet more warming

## Key terms

- [permafrost](https://www.gradenine.co.uk/glossary/permafrost)
- [positive feedback](https://www.gradenine.co.uk/glossary/positive-feedback)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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/explain-how-a-positive-feedback-mechanism-ebf1861a) · Published by Druglandscape Ltd.