Which of the following sequences is correct in terms of the Global Warming Potential?
Show Hint
Fluorinated gases (such as \( \text{SF}_6 \), HFCs, and PFCs) have exceptionally high GWP values (in the thousands) because they are highly stable and trap heat effectively.
Carbon dioxide always has the lowest GWP as the baseline reference (\( \text{GWP} = 1 \)).
Step 1: Understanding the Concept:
Global Warming Potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere compared to a reference gas, typically carbon dioxide (\( \text{CO}_2 \)).
GWP values are calculated over a specific time horizon (usually 100 years) and depend on the gas's infrared absorption capacity and its atmospheric lifetime. Step 2: Detailed Explanation:
Let us compare the 100-year GWP values of the greenhouse gases listed in the options, as established by the Intergovernmental Panel on Climate Change (IPCC): Carbon Dioxide (\( \text{CO}_2 \)): This is the baseline reference gas. By definition, its GWP is assigned a value of \( 1 \). Methane (\( \text{CH}_4 \)): Methane is a potent short-lived greenhouse gas. Over a 100-year timescale, it has a GWP of approximately \( 28 \text{ to } 36 \).
This means that releasing one ton of methane has the same warming effect as releasing about 30 tons of carbon dioxide. Nitrous Oxide (\( \text{N}_2\text{O} \)): Nitrous oxide is a long-lived greenhouse gas with a high capacity to absorb heat. Its GWP is approximately \( 265 \text{ to } 298 \). Sulfur Hexafluoride (\( \text{SF}_6 \)): This is an extremely stable, synthetic fluorinated gas used in electrical equipment.
Because of its very long atmospheric lifetime and strong infrared absorption, it has a GWP of approximately \( 23,500 \).
Arranging these gases in descending order of their Global Warming Potential:
\[ \text{SF}_6 \ (23,500) > \text{N}_2\text{O} \ (\sim 273) > \text{CH}_4 \ (\sim 30) > \text{CO}_2 \ (1) \]
This matches the sequence shown in Option (B). Step 3: Final Answer:
The correct sequence in descending order of Global Warming Potential is $\text{SF}_6 > \text{N}_2\text{O} > \text{CH}_4 > \text{CO}_2$.
