Posted on 10/15/2004 2:39:25 AM PDT by Goat Locker Freeper
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. <>
In the scientific and political debate over global warming, the latest wrong piece may be the “hockey stick,” .... 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....
-SNIP-
But now a shock: independent Canadian scientists... 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!
-SNIP-
Suddenly the hockey stick, the poster-child of the global warming community, turns out to be an artifact of poor mathematics.
(Excerpt) Read more at technologyreview.com ...
to marktwain
As I have been saying for years, there is no such thing as "earth sciences."
Thanks for the article. Here is the critical analysis http://www.uoguelph.ca/~rmckitri/research/fallupdate04/update.fall04.html
*cough* ice age *cough*
But apparently thats not enough evidence that the Earth has its own global cycle.
....and Haliburton's
The writer implies that those writing the program didn't know what they were doing, but perhaps they knew EXACTLY what they were doing, i.e., cooking the books in their favor.
But to get the results that fit the observations, there is something introduced called a "finagle factor", that when applied, voila!, the "right answer" magically appears. This is a universal practice that runs throughout ALL scientific endeavor, when there are more unknowns than knowns, the human tendency to build myth as an explanation.
In integral calculus, the process is the reverse of differential calculus, but to cover variations in outcome, there always has to be room for the "jigger factor", expressed as k, from the German word konstant.
and Cheney's
Marking for later reading.
Junk science at its best. One of our Objectivist or Sovietologist friends here ought to comment on the parallels with what Soviets did during the last century. Namely, trying to use political ideas to achieve scientific results.
IIRC, it had something to do with communist ideology and wheat crops. The result being failed crops and starving people. As the first premise was ideological rather than scientific, the failure was explained in communist ideological terms and the failures repeated.
The upshot here is that these moonbat "scientists" are in a headlong, mad rush to crush modernity and send us all back to their medievel agrarian society.
And, they'll lie, cheat, fudge facts, skew data, and whatever else is necessary to achieve the desired end result.
Anyone care to theorize on the nexus of fascist islam, radical environmentalists, and socialism?
These guys probably are NOT deliberately fudging the data. Although I only have the math necessary to finish a degree in chemistry, and not the PhD in stat alot of these people have, I DO have some experience with this type of programming, having mucked around in the financial markets for years, and having worked as an environmental engineer.
Normalizaton of data (or "curve fitting") is also a real problem when you are trying to analyze data from the financial markets or environmental trends. You are looking for patterns of linear regression (is there market price behavior there that repeats itself with enough regularity that I should buy/sell, say, soybean futures at THIS point in the graph?). I call it the technological equivalent of reading chicken entrails to determine the future.
Anyway, the problem comes from the following.
1) The data is random
2) Within that random data are clear patterns
These seemingly contradictory statements have led some of the best minds and fastest computers and biggest players in the markets to crunch MOUNTAINS of data looking for a way to disprove item #1 above.
The lure is so strong that one is always tempted to look for a mathematical formula that will explain and predict the future. The problem is, that usually the formula only explains PAST patterns and is totally worthless to predict future behavior.
Though some folks who hawk environmental models have the same level of sleazy technoshysterism as the hacks bawling out their wares in Techical Analysis magazine, most of em are just blind to their own prejudiced conclusions. Therefore, they find patterns that TRULY ARE THERE, they are just curve fitted and not very useful.
Peer review is a great way to shut this stuff down as noted here.
Hockey stick? I thought the NHL players were locked out.
As a fellow chemist, I must point out that "the data ARE random" is the correct usage.
Read Gross & Levitt's 'Higher Superstition' or 'Fight From Science and Reason' or Noretta Koertge's 'House Built on Sand' or, best of all, Alan Sokal's essay 'Transgresing the Boundaries'. It'll all be clear.
Environmental Wacko Ping!
What took MIT so long??
John Daly debunked Mann and his "Hockey Stick" more than four years ago. For his efforts, Daly was crucified by the global warming advocates. Too bad he didn't live to see this.
Well done John....
Is this what they are talking about with "fuzzy math"?
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