Tuesday, October 19, 2004
Three weeks from next Friday: Just got finished watching the global warming disaster movie "The Day After Tommorrow." Al Gore and his cronies wanted us to watch this thing and be scared? I'd say the whole movie was overkill, but especially the computer-generated wolves. The special effects were impressive, but I kept thinking to myself as character after character said: "This can't be happening," that, you know, they're right.
On a related note: Spoons points to this Technology Review article that points out that one of the famous pieces of evidence of global warming is fatally flawed. It seems that one of those weather models that predicts doom and gloom to come predicts gloom and doom no matter what numbers you put in it.
But now a shock: 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!
Oops. It appears that the global warming enthusiasts got bitten by the Dan Rather bug -- they didn't examine their model critically because it produced a result that they expected.
On a not-so-related note: There may be something to this movie idea that global warming can cause a new ice age. The last photographic evidence I have of my niece, who was last reported to be in Rhode Island, is this:
While Maddie appears prepared for the extreme cold, it's now been nearly two weeks since I've received any photos and I'm very concerned. Any Dennis Quaid-type paleoclimatologists are directed to make every effort to locate Maddie.