IB Biology HL 4.3.2 Climate Feedback
Practise analysing HL climate-feedback evidence, including albedo loss, polar melting and self-reinforcing warming cycles.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Explain how polar ice loss reduces albedo and amplifies warming.
- Analyse positive-feedback chains linking greenhouse gases, temperature and climate change.
D4.3.2—Positive feedback cycles question 1
[Maximum number: 1]
Average human internal (core) body temperature is 36.4∘C, with slight variations between day and night. The average surface temperature of the Earth in the 20th century was 13.9∘C. It has now risen to 14.8∘C.
Melting polar ice due to global warming is reducing reflection of sunlight from the Earth. Identify with a reason whether this will result in positive or negative feedback.
a. positive feedback because warming causes melting of polar ice;
b. positive feedback because less ice means less sunlight is reflected (lower albedo);
c. positive feedback because more heat is absorbed by the Earth's surface which becomes warmer;
1 max
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