Arrange the following gases in increasing order of their contribution towards global warming.

1.Methane

2.Chlorofluorocarbons

3.Nitrous oxide

4.Carbon dioxide

A1, 2, 3, 4

B3, 2, 1, 4 ✓ Correct

C3, 1, 2, 4

D1, 3, 2, 4

Correct answer: (B) 3, 2, 1, 4

Explanation

Ranked from smallest to largest share of warming, the order is nitrous oxide, chlorofluorocarbons, methane, then carbon dioxide.

Nitrous oxide contributes the least among these gases to overall warming.

Chlorofluorocarbons add a somewhat larger share despite being trace gases.

Methane contributes more, being far more potent per molecule than carbon dioxide.

Carbon dioxide dominates warming because of its huge and rising atmospheric volume.

Ranking by total contribution differs from ranking by per-molecule potency.

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