Don't get too excited until you see AR5. The IPCC community knew at the time of AR4 that the ice loss estimates were frankly crap, since they didn't include any ice sheet dynamics and were just completely simplified estimates. I attended a meeting recently for the IPCC physical sciences working group on the cryosphere, and there has been major progress since the last AR, so much so that it is getting its own chapter in AR5. Unfortunately, by the time any piece of science makes it into the IPCC it is already a few years old. Fortunately, if you read some of the current research you will have a sneak-peak into what is likely going to be included in AR5. Go to http://nsidc.org/ and look at "Publications" if you are interested in a sampling of the latest research.

I'm publishing a paper quite soon, hopefully, which examines cloud whitening and the dynamical responses. Previous researchers (eg Jones et al 2009, Rasch et al 2010) have examined the potential surface response, which gives a fairly rosy picture. I found that when you look more closely at the dynamical responses in the atmosphere, there are significant changes associated with this kind of geoengineering, including possible enhancement of Atlantic hurricanes. I hope Gates reads the literature on this before undertaking the proposed course of action. -- from a student in meteorology & climatology at Cornell University. Thesis work performed at Princeton University & Cornell, presented at AMS conference in January.

Water vapor isn't considered to have much radiative warming potential mainly because the Earth's emission spectrum is already saturated at the wavelengths at which water absorbs (See Houghton's Global Physical Climatology text for a detailed discussion). -- from a student in meteorology & climatology at Cornell