Yes, Andrew Bolt is back. And yes, he still denies the evidence for global warming. In fact, he seems to have given up on equivocating:
Belief in man-made global warming will soon be laughed out of existence.
And yes, Andrew Bolt still relies on selective presentation, misrepresentation and absurdly poor reasoning to make it seem as if the scientific evidence fits his agenda-driven argument.
His latest global warming column is a classic example of Boltian logic and rhetoric. The world has cooled “these past eight years”. Bolt thinks (or, at the very least, wants his readers to think) that this short-term pattern somehow discredits this long-term one. (For a more detailed rebuttal of the idea that this short-term “pause” disproves global warming, see here.)
He even tries out the statement I thought nobody would be stupid enough to utter:
Arctic ice has grown these past two years, not shrunk.
But the main target of Bolt’s column is the “hockey stick”. In this attack, he draws on a controversy that has been all over the climate change blogosphere in the past week or so – beginning with this post by Steve McIntyre. That post set off a flurry of “HOCKEY STICK DEBUNKED; GLOBAL WARMING A LIE!!!1!” reporting in the media and on blogs; Tim Lambert has a good round-up of the coverage. With his column, Bolt has joined the club.
But Bolt, along with many others, manages to overstate and misinterpret the implications of McIntyre’s analysis. Lambert highlights one issue Bolt ignores:
We don’t need proxies to know that temperatures increased in the 20th century, so McIntyre’s black line doesn’t prove that temperatures have not increased, rather it shows that those trees aren’t good proxies for temperature.
It seems to me that Lambert is spot on. McIntyre’s analysis of the tree-cores suggests that, if anything, temperatures declined during the 20th century. All of the recorded temperature sources indicate that temperatures rose during that period. If it turns out that McIntyre’s analysis is correct then it suggests the tree-ring data is not a reliable indicator of temperatures – that would mean we shouldn’t rely on them as a way of estimating temperatures for periods when temperature was not directly recorded, but it doesn’t mean that temperatures didn’t rise during the 20th century, and it doesn’t mean that McIntyre’s analysis shows the “true” historical temperature pattern.
But the authors at RealClimate also highlight that many other methods of temperature reconstruction, which don’t rely on tree cores and certainly don’t draw on the same data set Briffa used, demonstrate the hockey stick pattern. While Bolt seems keen to suggest that a possible problem with this one data source raises doubts about all “hockey stick” data, this is false – and even if the result of McIntyre’s analysis is that this data source is discredited, the weight of the evidence still converges on the same pattern. RealClimate nicely describes the pattern of commentary:
The timeline for these mini-blogstorms is always similar. An unverified accusation of malfeasance is made based on nothing, and it is instantly ‘telegraphed’ across the denial-o-sphere while being embellished along the way to apply to anything ‘hockey-stick’ shaped and any and all scientists, even those not even tangentially related. The usual suspects become hysterical with glee that finally the ‘hoax’ has been revealed and congratulations are handed out all round. After a while it is clear that no scientific edifice has collapsed and the search goes on for the ‘real’ problem which is no doubt just waiting to be found. Every so often the story pops up again because some columnist or blogger doesn’t want to, or care to, do their homework. Net effect on lay people? Confusion. Net effect on science? Zip.
Andrew Bolt is back, and he has jumped right back into contributing to that confusion.