Big news from the world of science: A major piece of evidence supporting the theory of global warming was based on flawed mathematics:
Progress in science is sometimes made by great discoveries. But science also advances when we learn that something we believed to be true isn?t. When solving a jigsaw puzzle, the solution can sometimes be stymied by the fact that a wrong piece has been wedged in a key place.
In the scientific and political debate over global warming, the latest wrong piece may be the ?hockey stick,? the famous plot (shown below), published by University of Massachusetts geoscientist Michael Mann and colleagues. This plot purports to show that we are now experiencing the warmest climate in a millennium, and that the earth, after remaining cool for centuries during the medieval era, suddenly began to heat up about 100 years ago–just at the time that the burning of coal and oil led to an increase in atmospheric levels of carbon dioxide. …
But now a shock: independent Canadian scientists Stephen McIntyre and Ross McKitrick have uncovered a fundamental mathematical flaw in the computer program that was used to produce the hockey stick. In his original publications of the stick, Mann purported to use a standard method known as principal component analysis, or PCA, to find the dominant features in a set of more than 70 different climate records.
But it wasn?t so. McIntyre and McKitrick obtained part of the program that Mann used, and they found serious problems. Not only does the program not do conventional PCA, but it handles data normalization in a way that can only be described as mistaken.
Now comes the real shocker. This improper normalization procedure tends to emphasize any data that do have the hockey stick shape, and to suppress all data that do not. To demonstrate this effect, McIntyre and McKitrick created some meaningless test data that had, on average, no trends. This method of generating random data is called ?Monte Carlo? analysis, after the famous casino, and it is widely used in statistical analysis to test procedures. When McIntyre and McKitrick fed these random data into the Mann procedure, out popped a hockey stick shape! (Emphasis added)
The author of the article is careful not to speculate, but I will: The error in the statistical analysis seems so blatant that it’s hard to imagine a university professor and his colleagues making it unintentionally.
I wonder if this revelation will make one bit of difference to environmental extremists.
McIntyre and McKitrick’s full analysis is available at their website.