How is that a problem? Temperature changes for understood reasons. At the moment the reason is human emissions. Saying "it has changed in the past" is a pointless red herring when "the reasons that caused the changes in the past are not present now".
---------- Post added 2012-12-11 at 02:08 AM ----------
That cartoon is posted every single global warming thread, I won't expect it to do any good this time either...