Things absorb heat regardless of their physical state. Again how do you think hot air balloons work! it's because you heat the air and hot air rises! Besides since you accept that solids can absorb heat from the sun there's your answer anyway - heat energy is lost from sunlight in our atmosphere in a million different ways. if it wasn't we wouldn't be here!

Also if your theory is correct Punisher and global warming is due to the sun radiating more than it did before then we'd have to be even more careful of what we do since it's going to make an inevitable situation harder for us!

When there's a drought in Australia we have water restrictions to help make what we have last until we get enough rain again - we don't all go getting swimming pools in our back yards just because we figure we're screwed anyway!