( – promoted by buhdydharma )
Just over the weekend, my inbox was filled with a discussion attacking climate science with assertions that “none of the models predicted the current cooling period” and, therefore, the entire concept of Global Warming rests on very shaky grounds.
Those involved in that discussion have now received links to an excellent article by AP science reporter Seth Borenstein. That article, Impact: Statisticians reject global cooling, merits praise because it is an excellent of inventive investigative journalism on a very public issue.
In the face of claims of cooling appearing in multiple venues and gaining visibility (such as via the truthiness-laden pages of Superfreakonomics (see here and here and, well, tens of other sites/posts )), being a centerpiece of misrepresentations by George Will and others, Borenstein decided to put metereological data under the searing examination of statisticians unaware of the data stream that they were seeing.
Berenstein (okay, “the AP”) gave the data to four statisticians and asked them to analyze the data. The result:
the experts found no true temperature declines over time.
Without knowing what the data referred to, one statistician called it “cherry-picking” to assert that there was any sort of statistically meaningful ‘cooling trend’.
“If you look at the data and sort of cherry-pick a micro-trend within a bigger trend, that technique is particularly suspect,” said John Grego, a professor of statistics at the University of South Carolina.
The statisticians’ basic point: the starting date is key. If you play games and have 1998 as “the” starting point, there is a minor cooling in the intervening years. (Actually, not a cooling but a slight retreating, writ large, from very high temperatures.)
choosing a starting date can alter perceptions. Using the skeptics’ satellite data beginning in 1998, there is a “mild downward trend,” But doing that is “deceptive.” The trend disappears if the analysis starts in 1997. And it trends upward if you begin in 1999
Borenstein almost certainly will receit hateful (vitriolic) notes from deniers, self-proclaimed skeptics, and other anti-science syndrome sufferers who are unhappy with the results of a scientifically-sound path toward testing a hypothesis. Their loudly proclaimed hypothesis of a cooling globe since 1998 has, yet again, been tested and found wanting of a substantive basis.
See also: Brenden Demelle, DeSmogBlog, Statisticians Confirm: No Global Cooling Despite Skeptic Spin; Joe Romm, Must Read AP Story,