I don't know about Carter, but Gray's just got his basic science wrong on just about every substantive point he tries to make, and the more we know, the more wrong he's got it.
See, for example:
http://www.realclimate.org/index.php/archives/2006/04/gray-on-agw/
Oh no, a global warming doubter is wrong, compared to almost all of the "global warming true believers" being wrong. Whatever shall we do?