Which statement best describes the ‘Greenhouse Gas Effect’?
A) Greenhouse gases in the atmosphere cause sunlight to scatter so that the sky appears blue.
B) Greenhouse gases in the atmosphere trap the sun’s energy and do not let any of the energy radiate into space.
C) Greenhouse gases in the atmosphere lead to air pollution which is harmful to the environment.
D) Greenhouse gases in the atmosphere trap the infrared radiation and slow the loss of heat to space, therefore maintaining warm temperatures essential for life on Earth.
E) Greenhouse gases in the atmosphere have no effect on the Earth.
The correct answer and explanation is :
Correct Answer: D) Greenhouse gases in the atmosphere trap the infrared radiation and slow the loss of heat to space, therefore maintaining warm temperatures essential for life on Earth.
Explanation:
The Greenhouse Gas Effect, also known as the Greenhouse Effect, is a natural process that warms the Earth’s surface. When the Sun’s energy reaches the Earth, some of it is reflected back to space and the rest is absorbed, warming the planet. The Earth then emits this energy in the form of infrared radiation (heat). However, not all of this infrared radiation escapes directly into space.
This is where greenhouse gases—such as carbon dioxide (CO₂), methane (CH₄), water vapor (H₂O), nitrous oxide (N₂O), and ozone (O₃)—come into play. These gases are transparent to incoming solar radiation but absorb and re-radiate outgoing infrared radiation. This trapping of heat helps to slow down the loss of energy to space and maintains a relatively stable and life-supporting temperature on Earth.
Without the greenhouse effect, Earth’s average surface temperature would be about -18°C (0°F), far too cold to support most life forms. Instead, the actual average temperature is around 15°C (59°F)—thanks to the natural greenhouse effect.
However, human activities such as burning fossil fuels, deforestation, and industrial processes have significantly increased the concentration of greenhouse gases in the atmosphere. This has enhanced the greenhouse effect, leading to global warming and climate change. These changes manifest as rising sea levels, more frequent extreme weather events, and shifts in ecosystems.
To clarify other options:
- A refers to Rayleigh scattering, not the greenhouse effect.
- B is incorrect because energy still radiates to space, just at a slower rate.
- C confuses air pollution with the greenhouse effect.
- E is false; greenhouse gases have a significant effect.