The Abused Science of Climate Change

THE EXTENT of anthropogenic global warming caused by carbon dioxide from the burning of fossil fuels is a controversial and politicised issue and there certainly is no scientific consensus. However, some conclusions (and some important gaps) can be listed with a reasonable degree of certainty:

• The concentration of carbon dioxide in the atmosphere is increasing due to combustion of fossil fuels.
• The basic spectroscopy (the science of the interaction of electromagnetic radiation with matter) of the atmosphere and the existence (and critical importance) of the misnamed “greenhouse effect” is beyond doubt, as is the fact that the principal “greenhouse gas” is water vapour, which is responsible for well over 90 per cent of the total effect. However, the estimation of the contribution of carbon dioxide is not straightforward, due to the non-linearity of absorption with increasing concentration and the fact that the absorption bands of carbon dioxide may already be saturated.
• The climate has always varied and there is evidence that we are passing through a warming period. The measurement of average surface temperatures is not straightforward; personally I consider that the widely observed retreat of mountain glaciers and melting of arctic ice constitute the most significant bits of evidence. The exact degree of warming is uncertain, but it is not unprecedented even in recorded history.
• Atmospheric carbon dioxide, although present in minute concentration, is not a “pollutant” but the very basis of life. The photosynthesis of carbohydrates by plants (including algae) from carbon dioxide, water and solar radiation, catalysed by pigments such as chlorophyll, is by far the most important process on earth for the continuation of life. What is more, the present concentration of carbon dioxide in the atmosphere is not optimal for plant growth, as experiments show that dramatic improvement accompanies increasing amounts of carbon dioxide. It thus appears that the positive effects of increasing the concentration of atmospheric carbon dioxide are better established than the negative (global warming) effects.

You can deduce from the above that I put myself in the “sceptics” rather than in the “alarmist” column, as I do not believe that any of the catastrophic predictions are well-based. There is, however, a caveat: the alarmist case has one argument going for it, the “precautionary principle”, which essentially amounts to avoiding risks if potential consequences are dire. This however always requires a quantitative judgment, as otherwise we would never cross roads, sit in a bus or even get out of bed. My considered judgment in this case is that the climate–anthropogenic carbon dioxide nexus justifies watching and research, but it does not justify the currently proposed expensive, probably unnecessary, disruptive and probably futile measures. And yes, I have a stake in the future: three children and seven grandchildren as well as the rest of mankind.

My scepticism is based on three independent areas of weakness in the alarmists’ case:

Computer modelling. Even a nodding acquaintance with the science of climatology uncovers an obvious problem: the Earth’s climate is a very complex, imperfectly understood and “chaotic” system. In non-technical language, this means that the climate is subject to numerous influences which act and interact in imperfectly understood ways and where the response to a change in a variable may not be “linear”, that is, proportional to input. In a situation like this, researchers cannot rely on straightforward calculations—remember the Gas Laws you enjoyed, or suffered, in high school or Chemistry 101?—and given the difficulty of direct experimentation in this case, they are reduced to computer modelling, which is subject to uncertainty in both the algorithms (how the variables interact) and inputs.
If that was not bad enough, the most alarming of the alarmists’ predictions are based on the operation of secondary effects, the “feedbacks”. The most obvious one runs as follows: increased concentration of carbon dioxide will result in global warming. This will cause an increase in the temperature of the oceans. This in turn will cause a decrease in solubility of carbon dioxide in the oceans, which will give up some of the dissolved carbon dioxide to the atmosphere. This will result in further global warming—you can see where this “positive feedback” leads. However, negative feedbacks are also likely—for example, an increase in the amount of carbon dioxide is associated with increased cloud cover, which reflects the sun’s radiation (higher albedo) and this results in cooling. In sum, computer modelling is a desperate research tool and not the sort of thing one should lightly accept as some sort of cast-iron scientific conclusion.

Credibility. To put it bluntly, the alarmists have made claims which damage their credibility, and we are not talking here about peripheral issues. The most egregious case is the so-called “hockey stick” which was a plot of average temperature against time and which purported to demonstrate that the earth’s climate was warming at an unprecedented rate, thus giving a graph of the “hockey stick” shape. This formed the very centre of the alarmists’ case and was inter alia just what you saw in Al Gore’s film. It has since been shown, mainly through the work of a Canadian academic, Steve McIntyre, that this effect was an artefact. Well, you might say, anybody can make a mistake. However, no alarmist has conceded that a huge (perhaps fatal) hole has been blown through their arguments— they just threw the hockey stick into an Orwellian memory hole but kept their now largely baseless conclusions. Furthermore, we are talking about high-profile people and high-profile institutions.
An even more clear-cut case is the fictitious claims that global warming has already caused an increase in catastrophic events, such as hurricanes. Such claims are tendentious at best and fictitious at worst, as are claims for catastrophic melting of the Antarctic ice sheet (only a very small bit appears to be affected; the bulk of the ice-cover seems to be actually growing).
Data get tendentiously reported—“the last x years in location z have been the warmest since y”—and, worst in my view, successful debunking is never acknowledged. Other data which are irrelevant (in particular, normal variations in the weather) are routinely presented as evidence for global warming, and the credulous believe this nonsense because “the evidence is before their eyes”. This goes all the way up to our Prime Minister, who has repeatedly connected the recent Australian drought to global warming. No serious climatologist claims this—go to the back of the class, young Kevin. Equally, the apparent global cooling experienced since 1998 is not a disproof of the global warming theory, even though no such predictions were apparent before its advent in any computer models. Weather and climate are related, but they are certainly not the same thing.
Other data, for example, the analyses of gases trapped in ice cores, which give a uniquely valuable picture of paleo-climate, get tendentiously reported with inconvenient bits ignored. All in all, by the time the arguments have percolated through to the public, they have been heavily “massaged” in favour of the alarmist case. The principal villains here are the media, with their irrelevant and downright misleading pictures of droughts, floods, hurricanes and a general weakness for the Hieronymus Bosch style of journalism.

No longer science. Once a subject has become politicised, it becomes difficult to determine “what is the case”, which is what scientists normally do, and the argument becomes about “making a case”, which is what lawyers do. The global warming “debate” is a reductio ad absurdum example of the above and the majority of the alarmists (but not many sceptics) invest their undoubtedly sincere arguments with an unmistakably religious tinge. One of the results of this is the nasty ad hominem tone they tend to adopt, which is quite justified from their point of view, seeing that they are fighting evil.

ON PURELY logical grounds the above three weaknesses of the alarmist case (inherent problems with their computer simulations, poor credibility and departure from scientific norms) do not “disprove” their case, although they do appear to weaken it considerably. The problem for a non-specialist (and I include myself in this category) making an independent judgment, is the complexity of climatology: if you get hold of even an unbiased standard work, you will find it indigestible.

I suggest two internet sites which have contributed to my scepticism: the most important one is Climate Debate Daily, an offshoot of the well-known Arts and Letters Daily, which simply lists in two parallel columns the alarmists’ and sceptics’ publications as they appear, without comment. Clearly, one could accuse any such listings of a selection bias either way, but in this case the sheer number of items makes this unlikely. The offerings are of variable quality and accessibility to laypeople, but any reader with a general familiarity with scientific literature can judge the “weight” of the individual entries. One overall impression is striking: the sceptics’ papers are full of graphs, maps, maths and descriptions of observational methods, while the alarmists’ papers appear to be more emotioncharged and devoted to the descriptions of various catastrophic scenarios rather than to arguments demonstrating how these scenarios would come about. Climate Debate Daily also lists numerous valuable links for both sides.

If you are willing to concentrate just a little, I also suggest you consult the site JunkScience, edited by Steve Molloy, and look for The Real Inconvenient Truth, which has some discussion of the basic physics involved in the “greenhouse” effect among some other reasonably digestible science. If you scour the internet you will also realise that whatever is the case, no scientific consensus exists. You will also discover thousands of alarmists’ postings dismissing sceptics for “being on the pay of oil companies” and so on, a nice example of the alarmists’ quasi-religious fervour. Best of luck.

Sev Sternhell is Emeritus Professor of Chemistry at the University of Sydney. His research interests have been in organic chemistry and molecular engineering. He served on the sub-panel of the Australian Research Council and is the author of numerous research publications.