Hello,
I am wondering why global warming is explained with heat bouncing back instead of going to space (that’s what I remember from school). However if that is the case should it not block alot or sunrays too?
Edit:
Just a clarification I am not a global warming denier, I just want to understand better.
In: 3
CO2 varies in transparency depending on the frequency of the light. This is true for many substances. For example you can see through a window just fine but glass tends to stop infrared light almost completely.
With sunlight the incoming light impacts Earth’s surface and the light emitted from those objects isn’t the same frequency. Trying to go back through the CO2 isn’t as easy because it is more opaque to that new frequency.
CO2 gets excited by (more or less) infrared. CO2 will absorb infrared, then disperse it in every direction. So only some of the infrared will continue to space and some will get bounced back. If there is no CO2 then everything will be shot to space (in an ideal scenario).
The sun emits electromagnetic radiation (light) in all wavelengths. Most of it passes freely through the atmosphere. CO2 only blocks a small part of electromagnetic spectrum.
When the light hits the earth it is absorbed and turns into heat. This heat is radiated away from earth as infrared radiation, which happens to be mostly in the same range of wavelengths that CO2 blocks.
The suns rays (visible and UV) light pass through the atmosphere, strikes the Earth. The Earth absorbs that light, then remits it at a lower frequency (e.g. infrared). It is this lower frequency that is reflected by green house gasses in the atmosphere.
Most of the heat energy delivered to Earth from the Sun is in the form of visible (optical) light. Most of the heat energy the Earth radiates into space is in the form of infrared radiation. CO2 is transparent to visible light, but opaque to infrared radiation.
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