Friday, December 18, 2009
I cannot condone some things that colleagues of mine wrote or requested in the e-mails recently stolen from a climate research unit at a British university. But the messages do not undermine the scientific case that human-caused climate change is real.
The hacked e-mails have been mined for words and phrases that can be distorted to misrepresent what the scientists were discussing. In a Dec. 9 op-ed, former Alaska governor Sarah Palin argued that “The e-mails reveal that leading climate ‘experts’ . . . manipulated data to ‘hide the decline’ in global temperatures.” Yet the e-mail she cites was written in 1999, just after the warmest year ever recorded (1998) to that date. It could not possibly have referred to the claim that global temperatures have declined over this decade — a claim that is false (the current decade, as has been recently reported, will go down as the warmest on record).
In the same e-mail, Jones uses the phrase “hide the decline” in reference to work by tree-ring expert Keith Briffa. Because tree-ring information has been found to correlate well with temperature readings, it is used to plot temperatures going back hundreds of years or more. Briffa described a phenomenon in which the density of wood exhibits an enigmatic decline in response to temperature after about 1960. This decline was the focus of Briffa’s original article, and Briffa was clear that these data should not be used to represent temperatures after 1960. By saying “hide the decline,” Jones meant that a diagram he was producing was not to show those data during the unreliable post-1960 period.