A new peer reviewed study by McShane and Wyner 2010, published in Annals of Applied Statistics has falsified the Hockey Stick graph, as found in the UN’s Intergovernmental Panel on Climate Change (IPCC)’s Third Assessment Report' (TAR-2001). Why this graph is important is that it was touted as the very foundation of Anthropogenic Global Warming (AGW) theory.
The IPCC made the hockey stick the centrepiece of IPCC TAR 2001. This graph was plastered all over the report. It occupied a very prominent and central place in the Summary for Policymakers, it is shown twice in the Assessment Report in Chapter 2, it is shown twice in the Synthesis Report, and it leads to their conclusions: temperatures in the latter half of the twentieth century were unprecedented.
Because of the centrality of Hockey Stick graph in AGW, it made climate alarmism extremely vulnerable as once you falsify the graph, you falsify the whole theory of AGW.
There is a vital part of any science: replication. Do it again. If we observe something, and we describe what we did and other people can repeat our experiment and observe the same result, then we can conclude we have correctly observed what is true.
McShane and Wyner did just that - proved Mann’s experiment cannot be replicated using the same data and method. It not only falsified the experiment but since the hockey stick was central to the AGW theory, it also falsifies the latter. If the confidence in the science cannot match the pain of solution, then the AGW falls off the public agenda.