The biggest control knob: Carbon dioxide in earth’s climate history

[BPSDB] By Richard B Alley of Penn State University.

This was the keynote lecture at the American Geophysical Union meeting (a vast conspiracy of scientists to find out all they can about how the Earth works) last year.

It’s a good summary of what we know about the role of CO2 in the Earth’s climate, a proof that climate scientists really do take into account all the climate changes that have happened over the Earth’s history, and why that knowledge is still bad news for us as we belch huge amounts of buried carbon into the atmosphere.

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Countering disinformation on climate

[BPSDB] In the wake of the latest outrageously dishonest headlines misquoting Phil Jones, the excellent  Open Mind blog presented a good account of the error, and also initiated a civilised and productive discussion on how to present the facts to the general public. I urge you to read it. I hope to post some thoughts of my own on this in the near future.

Why should I make the data available to you

[BPSDB] In many comments on the CRU hack I’ve seen it alleged that Professor Phil Jones of the University of East Anglia Climate Research Unit denied his data to another researcher with the words, “Why should I make the data available to you, when your aim is to try and find something wrong with it?”

Whenever I’ve seen it quoted, it’s implied that  Jones made the comment in one of the emails. I finally got around to looking for it, in the file I downloaded soon after the hack was made public – and it ain’t there. Not perhaps surprising, as it really doesn’t sound like the sort of thing an academic would say, except jokingly or sarcastically.

Indeed, the words are there. In August 2007, a fellow researcher warns Jones that the words are being attributed to him by someone else. In October 2009, another colleague sends Jones a copy of the text of an article in the National Review of 23 September 2009. In this Patrick Michaels quotes Warwick Hughes as alleging that Phil Jones said, “We have 25 years or so invested in the work. Why should I make the data available to you, when your aim is to try and find something wrong with it?”.

So it doesn’t appear to be evidence that Jones actually wrote it.  Given the unreliability and political commitment of all the links in this chain, and that this was one of the main pieces of evidence for the supposed ‘conspiracy’, I think there is even less evidence of wrong-doing.

Conspiracy theories have a tendency to spawn new conspiracies: here’s a climate ‘sceptic’ who thinks the CRU staff may have leaked the emails themselves to make ‘sceptics’ look stupid. If so, they’ve succeeded.

Words: Correction, Compensation, Adjustment, Proxy, Trick

[BPSDB] Years ago, when I was a researcher, I used a technique called ‘infrared spectroscopy’ a lot.  It involves passing infrared radiation through a sample of a substance, then splitting the infrared radiation up into its various frequencies (a spectrum) and measuring which frequencies are absorbed by the substance. Most substances (though not all) absorb IR radiation.

The resulting pattern of peaks, called bands, can be used in analytical chemistry to identify compounds, if their IR spectra are known. Under favourable conditions, such as the vapours at low pressure I often worked with, you can get information that will help (along with other techniques) to discover the actual shapes of the molecules, and even to discover facts about the internal electronic structure.

So, in theory, all you do is pass the IR through the sample and record the spectrum, right? No. Between the lamp and the sample are other things that absorb IR. These could include the solvent (if you’ve had to dissolve the sample), but, in particular, there is carbon dioxide, which is a component of air that strongly absorbs IR. So your spectrum includes bands from the interfering substances, which will complicate matters and likely obscure details of the spectrum you want to see.

But there is a clever trick (that word came immediately to my mind writing this, in the sense of a clever thing to do). That is, you split the IR beam into two, and pass one half through the sample and the other through a path of the same length containing all the things (air, solvent, etc.) except the sample itself. Then you can electronically subtract the signal from the reference beam (the one without sample) from the signal from the sample beam. And you are left with the signal that comes from the sample alone. Clever, eh?

This is called correction or compensation. There is nothing dishonest about it. The result is a genuine spectrum. If anyone is being cheated, it is nature being tricked into giving up her secrets, as without the compensation or correction you would have much less, if any, information about the sample spectrum.

I mention this, as hordes of global warming ‘sceptics’ have been crying ‘fraud’ simply through seeing words like ‘correction’, ‘adjustment’ and even ‘trick’ in some otherwise unremarkable stolen emails containing informal correspondence between climate scientists. These words do not in themselves imply anything nefarious. Now there may have been improper behaviour on the part of the scientists, but that would require some contexts for these words, providing some actual evidence. But no evidence for serious wrong-doing (apart, apparently, from getting irritated with ignorant harassment) has been presented.

Corrections are not limited to the lab. Whenever you press the ‘tare’ button on a set of kitchen scales, you are making a correction, by subtracting the weight of the bowl from the flour you are weighing out. Without that correction you will have a less satisfactory cake. Corrections, or compensations, or adjustments, are an essential part of the tricks needed to extract real data from the raw data of the real world.

In science, most things are not measurable directly. Temperature is one of them. When you measure a temperature, you are actually measuring an electric current that changes numbers on a display or moves a needle on a dial. Or you are measuring the expansion of a liquid (alcohol or mercury) along a tube. Neither method measures temperature directly, which is, in fact, impossible. What you are measuring is a proxy for temperature: another measurable quantity that is related to temperature in a way that is known from theory and tested by practice. But the manufacturer still has to make corrections to ensure that the fixed points of the measuring device correspond to the fixed points of the standard temperature scale. Building these corrections in is called calibration.

Actual measurements of temperature, using thermometers, go back only a short time, at most a couple of centuries in relatively few places. That means that scientists trying to study temperature way back in history or beyond have to use proxies – whatever they can find, wherever they can find them. The proxies include annual tree-ring growth, ratios of isotopes of oxygen in ancient snow, and the patterns of annual deposition in lakes (varves). These may not vary in a straight line relationship with temperature. Also, nature may inconsiderately have placed the proxies in different places at different times, such as trees growing at different heights.

To try to make these separate items match up, you need to calibrate, or adjust, the data, so they represent the temperatures correctly. For example, you may need to allow for trees growing at different rates at different heights. You can imagine that a great part of research is given over to debate about these corrections. But there is nothing essentially dishonest about doing this. If you find that numerous different proxies, when compared over the same period of time, agree pretty well, then you can have reasonable confidence that the proxies are measuring the same thing. So it is with the so-called ‘hockey-stick’ graphs.

Trick or heat, continued

[BPSDB] 32,500,000 hits for ‘climategate’ on Google today, and I’m beginning to feel as if I’ve seen most of them. Lots of repetition there, but what I have yet to see is any actual evidence of climate data being suppressed or distorted to falsify conclusions. Only tendentious interpretations of selected quotes from emails that were themselves selected from what must have been ongoing conversations.

Possibly the scientists involved did not behave entirely correctly to other people, but I expect that will come out in the investigation.  I’m both a sceptical person and an old-fashioned believer in innocent till proven guilty, so I will wait for the results of the investigation before passing judgement on the scientists.

A  thousand emails out of a something like a decade and a half means that the emails have been drastically selected out of a very much larger number (and possibly redacted too). Whoever stole the emails is clearly manipulating his audience and rather a lot of commenters seem unaware of the possibility that they are being manipulated.

What is also clear that some people jumped to ‘obvious’ – just too obvious – and daft conclusions about what certain emails ‘meant’. For example, an email by Kevin Trenberth was widely taken to be a climate scientist expressing private doubts that global warming is happening, but it was actually a comment on short-term variability and was discussed openly in his publication here. Lots of people desperate to believe that global warming is  a hoax fell for this one, like Andrew Orlowski at The Register and the frankly begging-to-be-taken-to-the-cleaners James Delingpole.

How people are manipulated by sleazy lies

Obama misleading clip [BPSDB] Contrary to what many people believe, the camera and its still image always lie. Our visual perception of the world depends on a jerky series of images that the brain interprets as continual motion. This is especially important as we interpret other people’s faces, which are expressive through their unending mobility.

Stop that motion through the mechanism of a photograph, and we are left with something, motionless, flat and two-dimensional, that we cannot help but try to interpret as if it were part of the moving three-dimensional world. Wise people realise that they are being deceived and deliberately try to treat the impression with scepticism derived from their knowledge of the world and the weaknesses of the human eye and brain. But these weaknesses are easily exploited by the unscrupulous when the people viewing the picture are unwary. I have seen pictures taken of audience members at political party conferences showing fleeting facial expressions that are then “interpreted” to make implications about the relationship between the listener and the speaker.

A spectacular illustration of this manipulation is a recent still from a video taken of President Barack Obama, reported here by Angry Mob and discussed by the MSNBC reporters in the embedded video. Observe how fast the steps of the action take place, and how the moving scene leaves no room for the misinterpretation that seems almost obvious from the still. It is not just that the photo completely deceives us about the situation, but that the still was clearly selected from the original video to give a false interpretation.

The human brain is prone to cognitive errors, not only in interpreting visual information, but in processing other kinds of data too. It is noteworthy that the kind of sources actively promoting this lie are the kind that are likely to use other cognitive errors in order to promote denial of the existence of man-made global warming, a phenomenon firmly established by scientific research. Some of this manipulation is undoubtedly deliberate, but in most cases the misinformation is passed on by people who themselves are willingly and unsceptically manipulated, because it agrees with what they want to believe.