Medium4 marksStructured
AQA GCSE · Question 02.5 · Ecology
Humans have destroyed large areas of peat bog to collect peat. The peat provides fuel and provides compost for gardeners. When peat is removed, it is often dried and the bog is drained.
Explain how the destruction of peat bogs and the use of peat affects the temperature of the Earth's atmosphere.
Humans have destroyed large areas of peat bog to collect peat. The peat provides fuel and provides compost for gardeners. When peat is removed, it is often dried and the bog is drained.
Explain how the destruction of peat bogs and the use of peat affects the temperature of the Earth's atmosphere.
How to approach this question
1. Start by identifying what is stored in peat bogs.
2. Explain what happens when peat is used as fuel. What gas is produced?
3. Explain what happens to the peat left in the drained bog. What process can now occur?
4. Link the gas(es) produced to the greenhouse effect and the impact on global temperature.
Full Answer
Peat bogs are significant carbon sinks, meaning they store more carbon than they release. This carbon is locked away in the organic matter that has built up over thousands of years due to the anaerobic (low oxygen) and acidic conditions preventing decomposition.
When humans destroy these bogs, this stored carbon is released.
1. **Combustion:** When peat is dried and burned as fuel, the carbon reacts with oxygen, releasing large amounts of carbon dioxide (CO₂), a greenhouse gas.
2. **Decomposition:** Draining the bog exposes the remaining organic matter to air (oxygen). This allows aerobic decomposers to thrive and break down the peat, releasing CO₂ through respiration. Methane (CH₄), another potent greenhouse gas, can also be released.
These greenhouse gases accumulate in the atmosphere. They absorb and re-radiate infrared radiation (heat) that would otherwise escape into space. This process, known as the enhanced greenhouse effect, leads to a gradual increase in the average temperature of the Earth's atmosphere, contributing to global warming and climate change.
Common mistakes
✗ Forgetting to mention that peat is a carbon store.
✗ Only mentioning burning and not the effect of draining the bog (decomposition).
✗ Vaguely stating "pollution" instead of naming carbon dioxide as a greenhouse gas.
✗ Not clearly linking greenhouse gases to trapping heat and increasing temperature.
Practice the full AQA GCSE Biology Higher Tier Paper 2
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