A fascinating and spirited conversation regarding past climates is underway at Climate Audit.
If you have issues with Climate Audit because it's allegedly a "global warming denialist site" (it's not, having read the site and Real Climate for several months now) then don't click the link. Or do, and learn something. Climate Audit is highly technical, and you may need a statistics textbook to understand what's going on.
For what it's worth, there was a time (after Katrina) that I considered this field for graduate work. Now, not so much, for a variety of reasons I'll get into in a future series of posts.