Comment Regarding the hockey stick graph. (Score 1) 272
Regarding the "hockey stick" graph. (Taking absolutely no position on whether Mann was honest or not, competent or not, etc.)
I was under the impression that the Hockey Stick graph had been shown to be defective as an indicator of warming, primarily because it took tree ring data as one of its proxies for temperature, but carbon dioxide concentration increases alone have been shown to substantially promote tree growth even in the absence of temperature increases. So how much of the sudden rise in the graph is from temperature increase (if any) and how much just from increased CO2 levels is unknown.
But I don't have any links to reliable scholarly articles examining this issue. Do any of you?