Dec 7, 2009

Climategate on Front Page of Washington Post [LINK]

It's nice to see the climategate controversy reported prominently, in what is overall a very good article, at least considering the expanse of the scandal. Still, this sentence made me howl:

Phil Jones, the unit's director, wrote a colleague that he would "hide" a problem with data from Siberian tree rings with more accurate local air temperature measurements.
Jones didn't say that he hid data that was a problem simply because it was inaccurate; he said that he employed a "trick" suggested by Michael Mann specifically to "hide the decline." It's a well-known "divergence" problem: relatively recent tree-ring data over the past 50 years or so suggest declining temperatures, while presumably more accurate thermometer data indicate a warming trend. The problem is that Jones used tree rings before 1960 and thermometers afterwards, resulting in a dubious hockey-stick rise, one that conveniently matches other dubious hockey sticks Mann produced. If what you're measuring is the historical size of fruit, I expect you'd get much the same result if you started by measuring apples and ended up with oranges. This need to mix dissimilar data sets also raises the obvious question: if the tree-ring data offers such an inaccurate representation of recent climate, why would it offer a reliable proxy for past climate trends? If there's an honest answer, I'd like to hear it.

Also, this sentence:

These are the facts: After an increase in 1998, the world has been historically warm, but its average temperatures have not climbed steadily. Does that mean climate change has stopped?
it would be far more accurate to say that following an increase leading up to 1998 ... average temperatures have "flattened." Also, it begs the question: temperatures are "historically warm" compared to what? Perhaps we're in a warm period compared to the recent Little Ice Age, but not the Medieval Warm Period that immediately preceded it. And, of course, under no circumstances does climate change "stop." (We should "stop" using the meaningless term "climate change.")

As yet, no comments: