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Q65 (IAS/2018) Environment & Ecology › Climate Change & Global Initiatives › Climate science and impacts Official Key

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

Result
Your answer: —  ·  Correct: A
Explanation

The correct answer is option A. Higher levels of carbon dioxide in the atmosphere can act as a fertilizer and increase plant growth.[4] This phenomenon is specifically known as the CO2 fertilization effect, which is the direct effect of increased atmospheric carbon dioxide concentration on crop yields.[6] Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals.[7] When atmospheric CO2 concentrations increase, plants have more of this essential raw material available for photosynthesis, leading to enhanced growth rates.

Option B is incorrect as it describes the greenhouse effect, not carbon fertilization. Option C refers to ocean acidification, which is a process where oceans absorb increasingly more carbon dioxide from the atmosphere, leading to lower pH and greater acidity[8]—a separate environmental phenomenon. Option D is too broad and vague, referring to general adaptation rather than the specific physiological effect on plant growth that defines carbon fertilization.

Sources
  1. [1] https://www.nasa.gov/earth-and-climate/nasa-at-your-table-climate-change-and-its-environmental-impacts-on-crop-growth/
  2. [2] https://www.nasa.gov/earth-and-climate/nasa-at-your-table-climate-change-and-its-environmental-impacts-on-crop-growth/
  3. [3] https://www.nasa.gov/earth-and-climate/nasa-at-your-table-climate-change-and-its-environmental-impacts-on-crop-growth/
  4. [4] https://www.nasa.gov/earth-and-climate/nasa-at-your-table-climate-change-and-its-environmental-impacts-on-crop-growth/
  5. [5] https://www.nature.com/articles/srep04978
  6. [6] https://www.nature.com/articles/srep04978
  7. [7] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
  8. [8] https://www.fisheries.noaa.gov/insight/understanding-ocean-acidification
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Q. Which of the following statements best describes "carbon fertilization" ? [A] Increased plant growth due to increased concentration of c…
At a glance
Origin: Mostly Current Affairs Fairness: Low / Borderline fairness Books / CA: 0/10 · 10/10
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This question masquerades as current affairs but is solvable via linguistic logic. 'Fertilization' implies growth/nutrients. While standard books explain photosynthesis, the specific term requires linking 'CO2 as food' to 'More CO2 = More Growth'. It tests mechanism over rote memory.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Does the term "carbon fertilization" refer to increased plant growth caused by higher atmospheric carbon dioxide concentrations?
Origin: Web / Current Affairs Fairness: CA heavy Web-answerable

Web source
Presence: 5/5
"higher levels of carbon dioxide in the atmosphere can act as a fertilizer and increase plant growth."
Why this source?
  • Explicitly states that higher atmospheric CO2 can act as a fertilizer and increase plant growth.
  • Directly links elevated CO2 concentrations in the air to increased crop growth, which matches the phrase 'carbon fertilization'.
Web source
Presence: 4/5
"Elevated atmospheric carbon dioxide (eCO2) can affect plant growth and physiology"
Why this source?
  • Refers to 'Elevated atmospheric carbon dioxide (eCO2)' and states it 'can affect plant growth and physiology', supporting that higher CO2 influences plant growth.
  • Uses the abbreviation eCO2 for elevated CO2 in experimental contexts, consistent with discussions of carbon fertilization effects.
Web source
Presence: 4/5
"Our results support this hypothesis and provide evidence that the interaction of warmer temperatures and eCO2 led to increased plant C inputs to SOC in the surface peat"
Why this source?
  • Reports evidence that elevated CO2 (eCO2) led to increased plant carbon inputs to soil, implying enhanced plant growth or productivity under higher atmospheric CO2.
  • Supports the idea that rising atmospheric CO2 can stimulate terrestrial plant carbon uptake, a core aspect of carbon fertilization.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
Strength: 5/5
“ENVIRONMENT Carbon is present in the atmosphere, mainly in the form of carbon dioxide (CO<sub>2</sub>). Carbon cycle involves a continuous exchange of carbon between the atmosphere and organisms. Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals. By process of respiration and decomposition of dead organic matter it returns back to atmosphere. It is usually a short term cycle. Some carbon also enters a long term cycle. It accumulates as un-decomposed organic matter in the peaty layers of marshy soil or as insoluble carbonates in bottom sediments of aquatic systems which take a long time to be released.”
Why relevant

Explains that carbon (as CO2) moves from the atmosphere into green plants via photosynthesis, linking atmospheric CO2 to plant carbon uptake.

How to extend

A student could infer that higher atmospheric CO2 might increase the raw substrate for photosynthesis and so could plausibly boost plant growth under some conditions.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 18
Strength: 5/5
“(L) The Carbon Cycle Carbon is a minor constituent of the atmosphere as compared to oxygen and nitrogen. However, without carbon dioxide life could not exist, because it is vital for the production of carbohydrates through photosynthesis by plants. It is the element that anchors all organic substances from coal and oil to DNA (deoxyribonucleic acid: the compound that carries genetic information). All Rights Reserved. No part of this material may be reproduced in any form or by any means, without permission in writing.”
Why relevant

States that CO2 is vital for production of carbohydrates through photosynthesis, emphasizing CO2 as a limiting input for plant organic matter production.

How to extend

Combine this with knowledge that photosynthesis rates can respond to CO2 concentration to judge whether extra CO2 could increase plant biomass.

Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > Activity 5.1 > p. 83
Strength: 4/5
“Now, let us study how the plant obtains carbon dioxide. In Class IX, we had talked about stomata (Fig. 5.3) which are tiny pores present on the surface of the leaves. Massive amounts of gaseous exchange takes place in the leaves through these pores for the purpose of photosynthesis. But it is important to note here that exchange of gases occurs across the surface of stems, roots and leaves as well. Since large amounts of water can also be lost through these stomata, the plant closes these pores when it does not need carbon dioxide for photosynthesis. The opening and closing of the pore is a function of the guard cells.”
Why relevant

Describes how plants obtain CO2 through stomata for photosynthesis, showing the physiological pathway by which atmospheric CO2 reaches plant photosynthetic machinery.

How to extend

A student could reason that if stomatal gas exchange supplies CO2 to leaves, higher atmospheric CO2 increases the gradient for uptake and may raise photosynthetic CO2 assimilation.

Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 7: Climate Change > 2. greenhouse gases > p. 10
Strength: 4/5
“But because of rapid growth of population and consumerism, the carbon dioxide is increasing signifcantly in the atmosphere. During the last century, it has increased by more than 30 per cent. Te doubling of the atmospheric CO2 concentration will enhance the planet's natural greenhouse efect to such an extent that”
Why relevant

Notes that atmospheric CO2 has increased substantially over the last century, providing the environmental change that would be necessary for any 'carbon fertilization' effect to occur.

How to extend

Use this trend plus known plant responses to higher CO2 to assess whether observed CO2 increases could drive detectable growth changes.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 21: Mitigation Strategies > zt.r.2. $rpes of Sequestration: > p. 281
Strength: 3/5
“• There are number of technologies under investigation for sequestering carbon from the atmosphere. These can be discussed under three main categories: • Ocean Sequestration: Carbon stored in oceans through direct injection or fertilization. • Geologic Sequestration: Natural pore spaces in geologic formations serve as reservoirs for long-term carbon dioxide storage. • Terrestrial Sequestration: A large amount of carbon is stored in soils and vegetation, which are our natural carbon sinks.”
Why relevant

Mentions 'fertilization' in the context of ocean carbon sequestration (ocean fertilization), showing that the term 'fertilization' is used in carbon-management contexts to mean adding carbon or nutrients to stimulate biological uptake.

How to extend

A student could extrapolate that 'carbon fertilization' might analogously denote stimulating biological (plant) growth by increasing available carbon (CO2) in the atmosphere.

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Statement analysis

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Statement analysis

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