You're going to have to explicitly point out to me what scientific improprieties you found because I'm not aware of any.
Since you are claiming unfamiliarity with the whole hockey stick fraud situation, here's a nice, short and sweet treatment of Mann and the hockey stick controversy. It's just an internet blog, but then so is Slashdot. I'll quote one paragraph:
In doing this research McIntyre and McKitrick had legitimately accessed Mann’s public college web site server in order to get a lot of the source material, and whilst doing this they found the data that provoked them to look at the bristlecone series in a folder entitled “Censored”. It seems that Mann had done this very experiment himself and discovered that the climate graph loses its hockey stick shape when the bristlecone series are removed. In so doing he discovered that the hockey stick was not an accurate chart of the recent global climate pattern, it is an artificial creation that hinges on a flawed group of US proxies that are not even valid climate indicators. But Mann did not disclose this fatal weakness of his results, and it only came to light because of McIntyre and McKitrick'’s laborious efforts.
Regarding truncation of the Briffa series, it was Briffa that said that data should not be used and Mann simply followed his advice.
That's not how science works. Each person publishing a paper must be able to explain their own results, not point fingers at others.
But in the end you could throw out all of the paleoclimate data and everything that Michael Mann and Phil Jones have done
(resisting urge to make sarcastic remark here)
but it wouldn't make a difference to the finding of anthropogenic climate change which is based on physics. Paleo data is merely corroborating evidence.
Careful, if you don't know the climate variability of the past, how can you say whether measured 20th century variability is natural or anthropogenic? Paleoclimate studies (reliable or not) are the only way I know to explore that, wouldn't you agree?
Your comment about physics reflects a widely held assumption, but isn't factual. The complex feedback loops and chaotic behavior of our earth's atmosphere and oceans make it a fools errand to attempt to reduce it to a fundamental physics formula.