Sea ice keeps the polar regions cool and helps moderate global climate. Sea ice has a much brighter surface compared to many other Earth surfaces, particularly the surrounding ocean. The darker ocean reflects only 6 percent of the sun’s energy and absorbs the rest, while sea ice reflects 50 to 70 percent of the incoming energy.

-- https://nsidc.org/learn/parts-cryosphere/sea-ice/quick-facts-about-sea-ice

[–] [email protected] 3 points 1 year ago

Thank you very much, i was looking for this comment. The issue with 1°, 1.5°, 2° C of warming is that at some point you will break a critical level where the process is greatly accelerated because less/no sunlight is reflected by the ice caps, further increasing the energy absorption. This is especially apparent in Greenland and the Alps (and probably other glaciers), where the uncovered earth now absorbs WAY more light than the sheets of ice did, thus essentially making the melting process irreversible (at least in our comprehension).

[–] [email protected] 1 points 1 year ago (1 children)

I suppose but if you are reflecting it into greenhouse gases then the air temperatures go up instead.

[–] [email protected] 2 points 1 year ago (1 children)

Not really. Greenhouse gases don't absorb all wavelengths of light. Generally they only absorb parts of the IR spectrum. The 50-70% of light reflected isn't absorbed by greenhouse gasses because it's not in a wavelength that it can absorb, it mostly radiates back into space.

[–] [email protected] 1 points 1 year ago (1 children)

Ah, and much of that energy would be absorbed on the way in. So the additional energy absorbed on the way out depends on how the surface material changes the reflected light or later radiates the absorbed energy.

[–] [email protected] 1 points 1 year ago

Kinda. Most of the light from the sun is in the visible spectrum and the atmosphere does not absorb those frequencies well. Incoming light that gets reflected (snow/ice) stays in the same wavelengths so it passes back out just as easily. However the light that is absorbed by the ground is re-radiated mostly as IR and the atmosphere, specifically greenhouse gases are really good at absorbing those.

There's a lot more going on though, it's really complicated. Here are 2 vids that do a good job at explaining it:

https://www.youtube.com/watch?v=hUFOuoD3aHw&ab_channel=SixtySymbols

https://www.youtube.com/watch?v=oqu5DjzOBF8&ab_channel=SabineHossenfelder