Which of the following gas is believed to cause temprature rise in the atmosphere?

Question

Accepted Answer

The correct option is 3:

Carbon dioxide is the gas most strongly associated with causing a temperature rise in the atmosphere, a phenomenon known as the greenhouse effect, which leads to global warming. $	ext{CO}_2$ is a greenhouse gas, meaning it has the ability to absorb and re-radiate infrared radiation (heat) that is reflected from the Earth's surface. When human activities, primarily the burning of fossil fuels (coal, oil, and gas), release massive amounts of $	ext{CO}_2$ into the atmosphere, this natural blanket thickens. This increased concentration traps more heat, preventing it from escaping into space, and thus raising the average global temperature. Carbon dioxide is the most significant anthropogenic (human-caused) greenhouse gas due to the sheer volume released and its long atmospheric lifetime.

The incorrect option is 1:
Hydrogen $\text{(H}\_2)$ is an extremely light gas that does not function as a primary greenhouse gas. Any $\text{H}\_2$ released quickly rises through the atmosphere and is not an effective absorber of infrared radiation, therefore it does not contribute to atmospheric temperature rise.

The incorrect option is 2:
Helium (He) is an inert noble gas and is chemically unreactive. Like Hydrogen, it is very light and escapes Earth's atmosphere over time. Helium is not considered a greenhouse gas and has no significant role in trapping heat or causing global temperature increases.

The incorrect option is 4:
Radon (Rn) is a heavy, naturally occurring radioactive gas. While it can be a health concern, especially when accumulated indoors, it is chemically inert and its concentration in the overall atmosphere is negligible. Therefore, Radon is not a greenhouse gas and is not a cause of atmospheric temperature rise.