# Blocking of infrared radiation from the sun by $\rm CO_2$ [duplicate]

Why is the infrared heat from the sun not prevented from entering the earth's atmosphere by $\rm CO_2$ to the same extent that it is prevented from leaving the Earth's atmosphere?

• The second answer provided in the question link above provides a perfect explanation to the OPs question. Be sure to check it out. – Tausif Hossain Sep 10 '18 at 13:03
• Those words, "infrared heat," are leading you astray. About half of the heat delivered to the Earth by sunlight is delivered as visible light. Also, another big chunk of heat is delivered by shorter IR wavelengths that are not absorbed by atmospheric gasses. – user205719 Sep 10 '18 at 14:41

The radiation from sun is shorter wavelength than the radiation from earth. $\rm CO_2$ absorbs radiation mostly at wavelengths that the earth radiates. See this illustration of a publication.
So atmosphere acts as a big scatterer and atoms and molecules that absorb infrared like $CO_2$ scatter more and infinite absorbing and re-emitting traps the energy