Question

Arrange the following atmospheric gases in terms of increasing global warming potential
(A) $\text{CH}_4$}
(B) $\text{N}_2\text{O}$}
(C) $\text{CO}_2$}
(D) $\text{SF}_6$}
Choose the correct answer from the options given below :

• A. (C), (A), (B), (D).
• B. (B), (A), (C), (D).
• C. (A), (B), (D), (C).
• D. (C), (B), (D), (A).

Hint:

While Carbon Dioxide ($\text{CO}_2$) has the lowest global warming potential, it is the most significant driver of climate change because it is emitted in far larger quantities than any other greenhouse gas.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Global Warming Potential (GWP) is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period (usually 100 years), relative to the emissions of 1 ton of carbon dioxide ($\text{CO}_2$).
It evaluates the relative radiative forcing and atmospheric lifetime of different greenhouse gases.

Step 3: Detailed Explanation:
Let us compare the 100-year GWP values of the given greenhouse gases:
1. (C) Carbon Dioxide ($\text{CO}_2$):
By definition, the GWP of $\text{CO}_2$ is set as the baseline reference value of $1$.
This is the lowest GWP value.
2. (A) Methane ($\text{CH}_4$):
Methane is much more effective at trapping infrared radiation than $\text{CO}_2$, but it has a relatively short atmospheric lifetime (about 12 years).
Its 100-year GWP is approximately $28 - 36$.
3. (B) Nitrous Oxide ($\text{N}_2\text{O}$):
Nitrous oxide has a long atmospheric lifetime (around 114 years) and is highly effective at absorbing heat.
Its 100-year GWP is approximately $265 - 298$.
4. (D) Sulfur Hexafluoride ($\text{SF}_6$):
This synthetic industrial gas is extremely stable, with an atmospheric lifetime of over 3,200 years.
It is the most potent greenhouse gas evaluated by the IPCC, with a massive 100-year GWP of approximately $23,500$.
Arranging these gases in order of increasing GWP:
(C) $\text{CO}_2$ ($1$) $\rightarrow$ (A) $\text{CH}_4$ ($\approx 28$) $\rightarrow$ (B) $\text{N}_2\text{O}$ ($\approx 265$) $\rightarrow$ (D) $\text{SF}_6$ ($23,500$).

Step 4: Final Answer:
The correct sequence of increasing global warming potential is (C), (A), (B), (D).
This matches Option (A).