If you're interested in following up the rebuttals of all that (and other - what they call climate contrarian arguments) you can find it here:
http://www.realclimate.org/index.php/archives/2004/12/index/#Responses
For example, here's what the consensus science says about the Hockey Stick opponents
The claims of McIntyre and McKitrick, which hold that the "Hockey-Stick" shape of the MBH98 reconstruction is an artifact of the use of series with infilled data and the convention by which certain networks of proxy data were represented in a
Principal Components Analysis ("PCA"), are
readily seen to be false , as detailed in a
response by Mann and colleagues to their rejected Nature criticism demonstrating that (1) the Mann et al (1998) reconstruction is robust with respect to the elimination of any data that were infilled in the original analysis, (2) the main features of the Mann et al (1998) reconstruction are entirely insensitive to whether or not proxy data networks are represented by PCA, (3) the putative 'correction' by McIntyre and McKitrick, which argues for anomalous 15th century warmth (in contradiction to all other known reconstructions), is an artifact of the censoring by the authors of key proxy data in the original Mann et al (1998) dataset, and finally, (4) Unlike the original Mann et al (1998) reconstruction, the so-called 'correction' by McIntyre and McKitrick fails statistical verification exercises, rendering it statistically meaningless and unworthy of discussion in the legitimate scientific literature.
The claims of McIntyre and McKitrick have now
been further discredited in the peer-reviewed scientific literature,
in a paper to appear in the
American Meteorological Society journal, "
Journal of Climate" by Rutherford and colleagues (2004) [and by yet
another paper by an independent set of authors that is currently "under review" and thus cannot yet be cited--
more on this soon!]. Rutherford et al (2004) demonstrate nearly identical results to those of MBH98, using the same proxy dataset as Mann et al (1998) but addressing the issues of infilled/missing data raised by Mcintyre and McKitrick, and using an alternative
climate field reconstruction (CFR) methodology that does not represent any proxy data networks by PCA at all.