I'm a little embarrassed that I don't know the answer to this.  What is the basic reasoning behind polar amplification?

I know this is what is predicted but I was just thinking about WV and CO2 and thinking, there is much less WV at the poles, so why would it not be the reverse?  Why wouldn't increased CO2 raise the level of WV and create more warming at the equator and less at the poles? 

Ah.  I found a good article about it at Real Climate.

http://www.realclimate.org/index.php/archives/2006/01/polar-amplification/ 

I was under the false impression before that polar amplification was both poles.  It's primarily the Arctic, with moderate Antarctic warming.  I was also getting stuck on the WV issue.  But, as you say Dana, polar amplification is about ice albedo.

Ari just tweeted this one yesterday:

Contribution of sea ice loss to Arctic amplification