I discussed the ‘no statistically significant warming since 1995’ talking point on my blog recently This talking point has been around the delusionist blogosphere for some time, though with a lower profile than ‘global warming stopped in 1998’, and was put as question to Phil Jones of UEA in a BBC interview. Jones answered honestly, if a bit clumsily, that the data period since 1995 is marginally too short to derive a statistically significant trend, a response which was headlined by the Daily Mail as “Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995?” and became the talking point of the day. As has been widely noted, confusing not statistically significant’ with ‘not significant; in the ordinary sense indicates either deliberate dishonesty or ignorance of a point covered in excruciating detail in every introductory stats course.
But where did this silliness come from? I’d seen Janet Albrechtsen quote Lord Monckton on the point, and it seemed about right for him, an innumerate debating point that would take a fair while to refute, during which time he could move on to the next one.
Imagine my surprise, then, when I discovered the point being made (and apparently originated) by Richard Lindzen of MIT who is (or ought to be) by far the most credible figure on the delusionist side. In a piece published on “Watts Up With That” Lindzen says ‘There has been no warming since 1997 and no statistically significant warming since 1995’. Lindzen illustrates this claim with a graph he appears to have made up for the occasion, complete with unexplained error bars (I’ve appended a NASA graph with error bars for annual estimates).
In this piece for Quadrant he gives a variation, saying “has been no statistically significant net global warming for the last fourteen years” and “the fact that warming has ceased for the past fourteen years is acknowledged” . Note the slide from “has been no statistically significant net global warming for the last fourteen years ” to “warming has ceased”, committing the basic newbie error against which all budding stats students are warned.
Lindzen has published a couple of hundred papers in climatology, so I think we can assume he knows that the statement “there has been no statistically significant warming since 1995” means nothing more than “given the variability in the data, we need at least 15 observations to reject the null hypothesis at 95 per cent confidence”, a fact so trite as not to be worth mentioning.
It is sad to see a respected scientist reduced to this kind of thing. And as far as I can tell, all this is simply to avoid admitting that he backed the wrong horse back in 1990, when he bet that he was smarter than the majority of climate scientists who thought humans were (probably) causing global warming. The data since then has supported the majority view, but instead of revising his position, Lindzen has resorted to dishonest statistical trickery.
To quote The Economist, with respect to the Daily Mail
Since I’ve advocated a more explicit use of the word “lie”, I’ll go ahead and follow my own advice: that Daily Mail headline is a lie.But at least the Daily Mail headline writer could plead ignorance. Lindzen has no such excuse.
Update: More on this from Deep Climate