| What wavelengths of light would be reflected? My understanding is that the way greenhouse gas induced warming works is that we have incoming solar radiation over a broad range of wavelengths. Some of that ends up being absorbed by various things on the surface which heats them which causes them reradiate some of that absorbed energy as infrared. Greenhouse gases absorb infrared, and so some of that reradiated energy that would have been radiated back into space gets trapped by those gases. From a purely reducing warming perspective then it probably wouldn't matter much what wavelengths you are reflecting. Any light you stop from getting absorbed and turned into heat below would help. But incoming radiation often does useful things before or instead of getting turned into reradiated infrared. For example it may be used by plants for photosynthesis. It would seem then that if reflecting light in the stratosphere to reduce warming you'd want to try to avoid deflecting wavelengths that are important for photosynthesis or other useful things. You'd want to pick wavelengths that don't do much other than just end up getting absorbed at the surface. Does sulphur do this? |