how do greenhouse gases trap heat in the atmosphere?
In: Physics
This came up in the most recent episode of [A Problem Squared](https://youtu.be/gXIh2GyIBXw).
Basically, different gasses are transparent to some light but opaque to others. This just means some light can get through but other light gets stuck.
Earth’s atmosphere is made up of a bunch of different gasses that let light through, predominantly in the visible and ultraviolet range (because evolution). Much of that light gets absorbed. The UV gets used by plants etc as food, and it gradually makes its way through the food chain. Ultimately, this eventually gets turned in to heat (as well as useful energy like movement etc.). Some of this heat gets emitted as infrared light.
The problem is, some of the gasses in the atmosphere (like CO2 and water) don’t let the infrared light through. These are the ones we call greenhouse gasses.
TLDR: greenhouse gasses let UV light in. Nature turns that in to heat in the form of IR light. The gasses don’t let the IR back out, so it gets stuck here.
Latest Answers