UPSC CSE Prelims
Question 2
The scientific view is that the increase in global temperature should not exceed 2 °C above pre-industrial level. If the global temperature increases beyond 3 °C above the pre-industrial level, what can be its possible impact/impacts on the world?
- Terrestrial biosphere tends toward a net carbon source.
- Widespread coral mortality will occur.
- All the global wetlands will permanently disappear.
- Cultivation of cereals will not be possible anywhere in the world.
Select the correct answer using the code given below.
View correct answer and explanation
Correct answer: B
Correct Option: B
Explanation: Beyond roughly 3°C of global warming, some terrestrial ecosystems can become net carbon emitters and coral mortality becomes widespread. The two universal claims are unjustified.
Statement/Pair-wise Analysis:
Statement/Item 1: Correct - Heat, drought and fires can shift land ecosystems from carbon sinks to carbon sources.
Statement/Item 2: Correct - Marine heatwaves and bleaching can cause widespread loss of warm-water coral reefs.
Statement/Item 3: Incorrect - All wetlands worldwide will not necessarily disappear permanently; impacts vary by site.
Statement/Item 4: Incorrect - Cereal farming would be disrupted in many regions but not become impossible everywhere.
Option-wise Analysis:
A: Incorrect - omits correct statement/item 2.
B: Correct - includes all and only the correct items.
C: Incorrect - includes incorrect statement/items 3, 4; omits correct statement/item 1.
D: Incorrect - includes incorrect statement/items 3, 4.