system
Given the following post, respond as if you're commenting on Reddit:
human
Why does CO2 only reflect heat back at the earth?

Shouldn't CO2 also reflect heat back at the sun, as well as back at the planet? Or is there something else?
gpt
The energy coming from the sun comes at frequencies that can pass through the atmosphere (visible light, UV, etc.). The earth re-emits the energy, but at a lower frequency (infrared). The lower frequency radiation is absorbed by the atmosphere.