To answer your chemistry question, once a molecule of CO2 absorbs infrared light, it then emits infrared light. On average it’s in a random direction, so some

To answer your chemistry question, once a molecule of CO2 absorbs infrared light, it then emits infrared light. On average it’s in a random direction, so some goes out into space eventually. But some goes straight toward the Earth’s surface, which also absorbs and then re-emits it. The result is that some IR energy is trapped bouncing back and forth between the surface and atmospheric greenhouse gases (there are a few, not just CO2). This is the so-called “greenhouse effect” that keeps the surface habitable. As you increase the amount of greenhouse gases, there are more molecules available to absorb and re-emit IR energy. So the total amount of energy that can be trapped bouncing back and forth goes up. More heat is trapped. CO2 is particularly worrisome because the carbon cycle is slow. Water vapor has a larger effect, but it varies on the order of weeks (when it rains, for example). CO2 can take hundreds of years to get fixed again once it is in the atmosphere.