It doesn't seem to.
environment.newscientist.com/channel/earth/climate-change/dn11652
It mentions that the effect of water vapour in the atmosphere will be significant when there is more water vapour in the atmosphere because of rising temperatures, but it doesn't mention water emissions. If that's the right link.
( Newington, Wed 27 Aug 2008, 10:01, archived)

nope, finally got the link to load
you're both right, the article maitains that human emissions won't matter. I still think it's wrong though. even at a basic thermodynamic level, temp isn't the only thing that effects a liquid/vapour equilibrium.
( the mighty badger Aphrodite, on a bar stool, by your side, Wed 27 Aug 2008, 10:04, archived)

Most of the earth's surface is water.
It's a fairly simple diffusion model: an(effectively) infinite supply of water and a finite volume of gas in a (sort of) closed box. So temperature pretty much _is_ the only important thing.

edit: is that right? where's the back of an envelope when you need one?

edit edit: yes ... I think that's right ... god it's a good job I don't do much science for a living any more
( Dr. Shambolic je suis charlie, Wed 27 Aug 2008, 10:10, archived)

not strictly
because that assumes atmospheric temperature is the only cause of water vaporisation, which isn't really the case. The atmosphere is capable of holding more water for short periods on a localised basis .. I dunno, it's quite difficult for me to explain my reasoning behind this on the internet, so I'm not really expecting anyone to be convinced. It's something I've looked into a fair bit (one of my students is working on fuel cells)

one problem with the temp equilibrium argument around global warming though is that it opens a tiny door for the twats that say "ah but see, look at temp equilibriums and solubility, CO2 levels are actually rising BECAUSE of temp increases nernenerneneeeer .. and then I have to kill them.
( the mighty badger Aphrodite, on a bar stool, by your side, Wed 27 Aug 2008, 10:21, archived)

Sorry. That's not quite what I meant.
Water will evaporate at the surface (pretty much irrespective of temperature). The water vapour will diffuse into the rest of the volume of gas until it equalises. In an entirely closed system that would mean that eventually you'd get 100% saturation. But the actual equilibrium will be considerably below that because there are sinks of water vapor. The temperature dependence is not in how much water enters the system from evaporation, it's in the position of that equilibrium. Pumping additional water vapor into the system won't affect that equilibrium point, it will just affect how you reach it.

It'll have local effects on the weather of course ... you'll probably get much prettier clouds above cities.
( Dr. Shambolic je suis charlie, Wed 27 Aug 2008, 10:33, archived)