Question

Which one of the following gases is not a greenhouse gas?

• A. Methane (CH$_4$)
• B. Carbon dioxide (CO$_2$)
• C. Nitrous oxide (N$_2$O)
• D. Oxygen (O$_2$)

Hint:

Greenhouse gases include CO$_2$, CH$_4$, and N$_2$O. These gases trap heat in the Earth's atmosphere.
Oxygen (O$_2$) does not contribute to the greenhouse effect.
Focus on gases that have heat-absorbing properties in the infrared spectrum to understand their impact on global warming.

Answer 1

The Correct Option is D

To determine which gas is not a greenhouse gas, let’s analyze each option.
Step 1: Understand the concept of greenhouse gases
Greenhouse gases trap heat in the Earth's atmosphere, which contributes to the greenhouse effect and global warming. Major greenhouse gases include carbon dioxide (CO$_2$), methane (CH$_4$), nitrous oxide (N$_2$O), and water vapor (H$_2$O). These gases absorb and emit infrared radiation, helping to keep the planet warm.
Step 2: Analyze Option A - Methane (CH$_4$)
Methane is a potent greenhouse gas with a much higher warming potential per molecule than CO$_2$. It is released through agricultural activities, waste management, and energy production.
Thus, option A is a valid greenhouse gas.
Step 3: Analyze Option B - Carbon dioxide (CO$_2$)
CO$_2$ is one of the most well-known greenhouse gases, primarily emitted through the burning of fossil fuels, deforestation, and other human activities. It plays a significant role in climate change.
Thus, option B is a valid greenhouse gas.
Step 4: Analyze Option C - Nitrous oxide (N$_2$O)
Nitrous oxide is another greenhouse gas that contributes to global warming. It is produced by agricultural activities, industrial processes, and the burning of fossil fuels.
Thus, option C is a valid greenhouse gas.
Step 5: Analyze Option D - Oxygen (O$_2$)
Oxygen is vital for life on Earth but does not function as a greenhouse gas. Unlike CO$_2$, CH$_4$, and N$_2$O, oxygen does not absorb and emit infrared radiation in a way that contributes to the greenhouse effect.
Thus, option D is not a greenhouse gas.
Step 6: Conclusion
Oxygen (O$_2$) is not a greenhouse gas, as it does not contribute to the warming of the Earth's atmosphere. Methane, carbon dioxide, and nitrous oxide all play significant roles in the greenhouse effect. Therefore, option D is the correct answer.