They're referring to the ludicrous vapor-canopy theory, which holds that a sizable portion of the waters of the flood were suspended in the clouds above. Of course, they ignore that for this to occur, Earth would have to be one giant pressure cooker, because vapor suspended in the atmosphere gets added to atmospheric pressure. They also have some bizarre fantasies about what this would do to longevity that defy every single thing known to zoology. They might as well just attribute the longevity to pixie dust while they're at it, it takes about an equal amount of speculation.
"Illuminant light,
illuminate me."