Part of another thread of letters to The Canberra Times (posted here partly just as a record, because the CT’s site is so hopeless that most letters don’t even appear online), starting with this on 2 December:

Alan Barron and John Coochey (Letters, 30 November) appear to have been taken in by the misinformation that has been circulating around climate denial blogs: that the emails recently stolen from the Climate Research Unit at the University of East Anglia represent some kind of damaging blow to mainstream climate science.

Despite innumerable claims to the contrary, the emails contain no evidence whatsoever of scientific malpractice, nor of a corruption of the peer review process, nor of some cabal of malevolent individuals trying to manipulate results. And there is nothing that represents a credible scientific argument against the consensus picture of anthropogenic global warming.

The emails paint a picture of working scientists engaged in their discipline: battling disinformation, discussing interpretations of results, and in fact demanding scientific rigour. The worst charge that can be constructed from this collection of over a thousand emails (carefully selected and presented out of context to paint as damning a picture as possible) is that some ill-advised comments were made about an FOI request. If that’s the worst that the deniers can find in a decade of emails among a large number of scientists, that speaks volumes for their integrity and professionalism.

The emails do illustrate a culture which to some extent resisted openness with scientific information, and there is room in some circles for more openness on scientific data and methods, and discussion of the full range of opinion. Suggestions that contemporary climate science is based on secret data are deeply misinformed; for instance, the data and models used in NASA’s work are fully available.

Those who deny the evidence on climate change are seemingly so lacking in credible scientific evidence for their cause, and so unwilling to accept that they could be wrong, that there is now only one option left: conspiracy theories. They seem to be operating on the principle that, if you say it loud enough and often enough, enough people will believe it.

Matt Andrews

A reply appeared on 4 December:

If Matt Andrews (Letters, December 2) removes his head for a moment from his “cone of silence” he will see and acknowledge that there are many scientists who question the science of man-made climate change.

He would also know that the University of East Anglia, home of the Climatic Research Unit (the driver of man-made climate change and the IPCC) has announced the director of the unit will relinquish his position pending an investigation into allegations that he overstated the case for man-made climate change.

The reasons for the university’s action can be found in the released emails and documents that on any reading clearly show a course of extremely questionable scientific conduct by the unit.

The results of this conduct, when “cited”, has permeated through countless other scientific papers, resulted in Copenhagen and now forms the basis of the PM’s and Labor’s policy on climate change, ie ETS.

The debate on the science of man-made climate change, on what response if any is necessary or appropriate, is not over, it is just beginning.

Bob Edwards, Kambah

I then replied with this, published on 8 December:

Bob Edwards (Letters, 4 December) illustrates just how comprehensively many have been taken for a ride by the propaganda and disinformation surrounding the release of emails stolen from the Climate Research Unit in the UK.

Much of the controversy has surrounded this sentence in one email from Phil Jones, director of the the CRU: “I’ve just completed Mike’s Nature trick of adding in the real temps to each series […] to hide the decline”. Looks dodgy at first glance, right? But let’s look a bit deeper. This is part of a discussion of tree ring data, used to construct a long term temperature record over many centuries. There’s a well-known aspect of tree growth in high latitudes called the “divergence problem”: trees have grown more slowly than expected since around 1960, given the rising temperatures that we’ve observed. The slowdown seems to be due to air pollution and other regional factors. Consequently the tree ring data since around 1960 is of little statistical value in this context, and it is entirely correct practice that the recent portion (the “decline”) be removed (“hidden”) from the long term temperature reconstruction, since we have more reliable ways of measuring temperature in recent decades anyway.

The fact remains that there is overwhelmingly strong support among climate scientists for the basic observations that the world is warming and that human activity is primarily responsible. In fact, there is not a single credible and substantial line of evidence against those conclusions; the arguments usually promoted on denial blogs have been debunked over and over again.

Matt Andrews

Update, 9 December: this reply appeared in today’s edition:

Matt Andrews’ letter (December 8 ) refers to the “divergence problem” in tree ring data from 1960 onwards.

Trees grow faster when the climate is more favourable (ie, warmer and wetter), and form coarser rings than when they do when it is cold and dry. Usually, the finer rings are a product of winter, and the coarser rings, of summer. How can he or anybody else ignore observational data showing colder and dryer conditions at high latitudes, in order to make the data conform to the theoretical global warming concept?

This attitude of twisting or ignoring facts to suit a theory is why the leaked emails show such deplorable and unscientific treatment of the data, and make one wonder where the people who did this have any ethical sense at all. The first principle of science is that if the data don’t support your clever idea, then you think again and find an idea that fits the data – not the other way around.

Dr Marjorie Curtis, Kaleen

To which I replied:

Dr Marjorie Curtis (Letters, December 9) claims that the exclusion of high-latitude tree ring record since 1960 from long term temperature proxies constitutes a deliberate and unethical manipulation of the data to fit a theory, and that the recent narrow tree rings must indicate colder and dryer conditions in recent decades. It would serve Dr Curtis well to learn something about what the “divergence problem” really means.

We know that Arctic tree rings can reflect the temperature well, going back many centuries, as the tree ring data correlates strongly with a range of other indicators of temperature. Over the last century the tree ring record matches changes in temperature that we’ve directly measured via thermometers, ice area and many other indicators. The exception is that, since around 1960, tree rings in some Arctic regions have been unusually narrow relative to the dramatic warming that we’ve confirmed with satellites, thermometers and so on. We don’t know exactly why this divergence has happened in each region – in some cases it seems to be caused by increased air pollution. But the divergence is real, and very strongly established by the evidence. It would be statistically invalid to include this data since 1960 as part of a long term temperature reconstruction, and indeed such an error would almost certainly be criticised and corrected in peer review.

Accusing scientists of unethical behaviour seems to be par for the course for climate deniers these days. It’s a pity that these bold accusations are based on such profound scientific ignorance.

Matt Andrews