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?

1. Terrestrial biosphere tends toward a net carbon source.
2. Widespread coral mortality will occur.
3. All the global wetlands will permanently disappear.
4. Cultivation of cereals will not be possible anywhere in the world.

Select the correct answer using the code given below.

[UPSC Civil Services Exam – 2014 Prelims]

(a) 1 only

(b) 1 and 2 only

(c) 2, 3 and 4 only

(d) 1, 2, 3 and 4

Answer: (b)        

Explanation:

• If the global temperature surpasses 3°C from the pre-industrial level, the terrestrial biosphere may become a carbon source instead of a sink, with taiga and temperate forests losing their ability to absorb carbon dioxide.
• As temperatures continue to rise, coral bleaching events become more frequent, eventually leading to the widespread death of coral reefs.
• Temperate regions have a better chance of surviving rising temperatures due to their greater capacity to tolerate seasonal changes and maintain vegetation.
• For cereal crops to grow, it is crucial to have warm and moist weather during the early stages of growth. Hence, if the temperature rises, cereal cultivation could still be possible.