Q: The scientific view is that the increase in global temperature should not exceed 2 °C above preindustrial level. If the global temperature increases beyond 3 °C above the pre-industrial level, what can be its possible impact/impacts on the world?
a) Terrestrial biosphere tends toward a net carbon source
b) Widespread coral mortality will occur.
c) All the global wetlands will permanently disappear.
d) Cultivation of cereals will not be possible anywhere in the world.
The correct answer is 1 and 2 only.
Terrestrial biosphere
- ⦁ It plays a significant role in regulating atmospheric composition and climate.
- ⦁ It can release or absorb the greenhouse gases, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).
- ⦁ It regulates fluxes of energy, water and aerosols between the earth surface and atmosphere.
- ⦁ Although a tiny amount of carbon leaves the terrestrial biosphere and enters the oceans as dissolved organic carbon, carbon is most quickly exchanged with the atmosphere. Hence, Statement 1 is correct.
Corals
- It is invertebrate animal belonging to a large group of colourful and fascinating animals called Cnidaria.
- ⦁ It is extremely diverse marine ecosystems hosting over 4,000 species of fish, massive numbers of cnidarians, molluscs, crustaceans, and many other animals.
- ⦁ As temperatures rise, mass coral bleaching events occur. If the temperature keeps on rising, widespread coral mortality will occur. Hence, Statement 2 is correct.
- ⦁ The temperate regions can still survive if the temperature increases. The temperate zones are where the widest seasonal changes occur. The vegetation can survive there. Hence, Statement 3 is not correct.
- ⦁ The weather should be warm and moist during the early stage of growth of cereals. Therefore, the cultivation of cereals would still be possible if the temperature rises. Hence, Statement 4 is not correct.
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