Previous Year Question

Argon is not considered a greenhouse gas. Greenhouse gases contribute to atmospheric warming by absorbing infrared radiation emitted by the Earth. According to NOAA, important greenhouse gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapour.

In contrast, argon is a noble gas and constitutes about 0.93% of Earth's atmosphere. NOAA lists it among the normal major constituents of the atmosphere but not among the greenhouse gases. Thus, among the given options, methane, CO2 and N2O are greenhouse gases, whereas argon is not.

An important point is that although argon is more abundant in the atmosphere than CO2, it does not produce significant greenhouse warming. This shows that the greenhouse effect of a gas depends not merely on its abundance but on its ability to absorb infrared radiation.