(1) Mann and Wegman have nothing do to with anything in the article, or, for that matter future predictions of Global Warming.
(2) The Wegman Report was commissioned by Joe Barton and Ed Whitfield., from the Energy and Commerce Committee of the House of Representatives, not the Senate.
(3) Neither Barton (who recently gained further notoriety by apologizing to the CEO of BP), nor Whitfield were the chairman of the relevant committee at the time. The Republican chairman of the committee and the rest of the Republican and Democratic members commissioned a real report from the National Academy of Sciences. That report was by a team of real researchers, chosen by the normal, careful practices of the National Academy of Sciences. It was then sent out for a formal peer review. It found that while the statistical methods used by Mann et al had a minor problem, correcting the problem made no substantial difference. Moreover, Mann's results had been validated by being repeated by several different researchers that found the same results, using completely different proxies for past temperatures and mathematical analyses.
(4) In contrast, Wegman was chosen by Barton, whose opinions on climate change were already well known at the time, and Wegman was given material by Barton's staff to include in his report. He has said in interviews that he was under pressure to complete the report faster than he wanted.
(5) Wegman's report was *not* peer reviewed. Wegman claims to have sent it to 6 people to look at, but of course even if this is true, they were chosen by *him*, not by any normal process of peer review.
(6) Wegman's report is now known to have been plagiarized and Wegman is now under formal investigation for it by George Mason University.
(7) Wegman has refused to release supporting code or data for his report. Prof. David Ritson of Stanford University made such a request in 2006, shortly after the Wegman report was released. Wegman's report called for disclosure of supporting materials and openness generally, but he has himself refused to comply, citing the technicality that his report was not federally funded.
The Wegman report is a piece of crap and it's pretty amusing that people who want to deny the reality of Global Warming keep citing it.
Do you really think that the members of the National Academy of Sciences haven't thought of these obvious questions?
If you really want to know the answers, you could start by reading articles on Wikipedia:
"Well, it don't make the sun shine, but at least it don't deepen the shit." -- Straiter Empy, in _Riddley_Walker_ by Russell Hoban