Which of the following statements best describes "carbon fertilization" ?

(a) Increased plant growth due to increased concentration of carbon dioxide in the atmosphere ✓ UPSC's answer
(b) Increased temperature of Earth due to increased concentration of carbon dioxide in the atmosphere
(c) Increased acidity of oceans as a result of increased concentration of carbon dioxide in the atmosphere
(d) Adaptation of all living beings on Earth to the climate change brought about by the increased concentration of carbon dioxide in the atmosphere

Why the answer is (a)

• 'Carbon fertilisation' (CO2 fertilisation effect) is the increase in photosynthesis and plant growth caused by higher atmospheric CO2 concentrations, since CO2 is a raw material for photosynthesis — option (a).

• Satellite data show a 'greening' of the Earth partly due to this effect, though gains are limited by water, nutrients and heat stress, and crops become less nutritious.

• Warming (b) is the greenhouse effect; ocean acidification (c) is a separate CO2 impact; option (d) is not a defined term.

• Hence option (a).

Why the other options are wrong

(b) Increased temperature of Earth due to increased concentration of carbon dioxide in the…: Warming is the greenhouse effect, not carbon fertilisation.
(c) Increased acidity of oceans as a result of increased concentration of carbon dioxide in…: Ocean acidification is a different CO2 effect.
(d) Adaptation of all living beings on Earth to the climate change brought about by the…: Adaptation is not what the term means.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2018, held on 3 June 2018. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.