Question

red arrows pointing back towards earth. because this infrared radiation is trapped near earths surface, the average temperature of earths surface is warmer than it would be if all the infrared radiation escaped into space.
based on the information above, which of the following statements are true? select all that apply.
greenhouse gas molecules absorb but do not release infrared radiation.
after infrared radiation is trapped in the atmosphere, the infrared radiation may be absorbed by other greenhouse gas molecules.
greenhouse gas molecules gain energy after absorbing infrared radiation.
earths average temperature is warmer than it would be if earths atmosphere did not contain any greenhouse gases.

Explanation:

• For the first statement: Greenhouse gas molecules absorb and release infrared radiation. So the statement "Greenhouse gas molecules absorb but do not release infrared radiation" is false.
• For the second statement: After infrared radiation is trapped in the atmosphere (by greenhouse gases like \(CO_2\), \(H_2O\), \(CH_4\)), it can be re - absorbed by other greenhouse gas molecules. This is part of the greenhouse effect mechanism.
• For the third statement: When greenhouse gas molecules (e.g., \(CO_2\)) absorb infrared radiation (a form of energy), they gain energy (vibrational energy in the case of molecular - level energy absorption).
• For the fourth statement: The greenhouse effect (caused by greenhouse gases) warms the Earth. If there were no greenhouse gases, the average temperature of the Earth would be much colder (like the moon's surface temperature variation, since the moon has no significant atmosphere to trap heat).

Answer:

B. After infrared radiation is trapped in the atmosphere, the infrared radiation may be absorbed by other greenhouse gas molecules.
C. Greenhouse gas molecules gain energy after absorbing infrared radiation.
D. Earth’s average temperature is warmer than it would be if Earth’s atmosphere did not contain any greenhouse gases.