The Hockey Stick Graph - Do the Math
I just finished "State of Fear" by Michael Chrichton again. It was an excellent book. The lessons that I got from it remind of when I'm helping my daughter do her math homework. She always has questions about what to do next or how to check her work. My answer is always, "Do the math". Along those lines, the science behind global warming seems to get a pass when it comes to peer review.
One of those passes is the famous hockey stick graph of global temperatures. Kim du Toit has a post about this research that was published in 1998 by Mann, Bradley and Hughes in Nature (vol. 392: 779-787) or MBH98. This work was important because it attempted to proved that the increase in global temperature was manmade. The hockey stick graph represented flat global temperatures until the 1990's when there was a sharp increase. Hence the hockey stick.
In the post, Kim quotes from a National Business Review article. Michael Mann would not allow peer review of his work by putting obstacles in the path of McIntyre and McKitrick and not allowing the release of his computer code. When McIntyre and McKitrick were able to use his algorithm, they found that the hockey stick can be re-produced with random data. Not excactly re-producible or good science. This is a good reason to "do the math" yourself.
Here is a further quote that ties into the message of "State of Fear" from the article:
This paragraph frames the fundemental problem that I see with the Global Warming crowd. They have a political bent to their view and ignore contrary evidence that does not blame the United States. They ignore the heat island effect, fudge past temperature data, from the citations in "State of Fear", they ignore real sea level data. If they are working from a suspect hypothesis, that warming is man made, is any of the other work presented worth anything? I suspect that some of it is, in context. If we could take some of the leftward political leaning out of the science, we might get better science and understanding of what our real problems and possible solutions are. It would be nice if we could all "do the math".
The reason why the Hockey Stick is so important is the fact that it tries to do away with the Medieval Warm Period and the Little Ice Age (and further back with the Dark Ages Cold Period and the Roman Warm Period). Those natural climate fluctuations are an embarrassment to the hypothesis that mankind is mainly to blame for the present warming. In its first Scientific Assessment Report (1990), the IPCC still had a temperature graph showing the Medieval Warm Period and the Little Ice Age. It is now clear in the 2001 report that the IPCC has deliberately eliminated these natural climate fluctuations with sleight of hand.