Consider the following statements:[Physical Geography]

I. Without the atmosphere, temperature would be well below freezing point everywhere on the Earth’s surface.

II. Heat absorbed and trapped by the atmosphere maintains our planet’s average temperature.

III. Atmosphere’s gases, like carbon dioxide, are particularly good at absorbing and trapping radiation.

Which of the statements given above are correct?

The correct option is I, II and III.

Let us analyze each statement step-by-step to understand why they are all correct:

Statement I: Without the atmosphere, temperature would be well below freezing point everywhere on the Earth’s surface.
Without an atmosphere, Earth would lack the natural greenhouse effect that retains heat. The incoming solar radiation would strike the surface, and during the night, most of the heat would be radiated back into space immediately. It is calculated that without the atmosphere, the average temperature on Earth's surface would drop to approximately -18°C (which is well below the freezing point of water, 0°C), making the planet uninhabitable for most life forms. Thus, Statement I is correct.

Statement II: Heat absorbed and trapped by the atmosphere maintains our planet’s average temperature.
The atmosphere acts like a thermal blanket. It allows visible light from the Sun to pass through and warm the Earth's surface. The warmed surface then emits infrared radiation (heat). The atmosphere absorbs a significant portion of this outgoing infrared radiation and re-radiates it in all directions, including back toward the Earth's surface. This process of absorbing and trapping heat maintains Earth's average surface temperature at a hospitable 15°C. Thus, Statement II is correct.

Statement III: Atmosphere’s gases, like carbon dioxide, are particularly good at absorbing and trapping radiation.
Certain trace gases in the atmosphere, known as greenhouse gases, have molecular structures that allow them to absorb and emit infrared radiation (heat energy). Carbon dioxide (CO₂), water vapor (H₂O), methane (CH₄), and nitrous oxide (N₂O) are highly effective at absorbing this longwave thermal radiation emitted from the Earth's surface, thereby driving the greenhouse effect. Thus, Statement III is correct.

Since all three statements (I, II, and III) are correct, the correct option is I, II and III.