You’re just barking up a totally irrelevant tree, posing a big fat red herring and kicking a dead horse, since we can totally skip all of Mann’s studies and it won’t do squat to undermine the tremendous evidence that AGW is happening. I’m not saying Mann was wrong. You and your nefarious sources are the ones who are dead wrong. But we really don’t need Mann’s work to prove AGW.
Proxy data is never quite as good as instrumental data – they only use it (after mashing it up with instrumental data for a validity check) bec they don’t have instrumental data for those earlier time periods. Furthermore all the other non-tree-ring proxies match up well enough, and as mentioned (you didn’t read my entire post), there may be good reasons why trees are not doing as well during this period of greenhouse effect induced global warming – AGW may be negatively impacting them.
Mann’s studies came out in the late 1990s & early 2000s, but climate scientist had already proven AGW a 95% confidence well before that (.05 on the null). And since his studies there have been numerous other studies from all sorts of angles supporting AGW, so that now the evidence is quite “robust.”
The gist is Mann did not explain in the graph itself that these were 2 spliced datasets; however, he did do that in his paper associated with the graph. (Problem: people are too lazy to read.) He has since recognized that he made a mistake in not putting that info in a footnote to his graph.
But for heaven’s sake, he replaced the proxy data in the more recent decades with
more accurate instrumental data. That is a good thing, not a bad thing, and people are just plain crazy or on some weird mission against life on earth not to recognize that.
Here is a graph of several proxies – they are not exact replicas of each other, but scientists do the best they can with the information they can extract from the proxies. And the do a lot of very hard work, and do NOT deserve to be abused and slandered by y’all, or harassed by or receive death threats from AGW denialists on an evil mission that contradicts what the Pope is asking of us.
http://www.skepticalscience.com/pics/Hockey_League_spaghetti.gif