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Misinformation and the global warming debate

By Barry Maley - posted Tuesday, 15 August 2000

Sam van Rood posted a critique of an article of mine on global warming. My article summarised some of the key issues in measurement of global warming, the trend shown by measurements, the flaws in some surface measurements, the disparities between surface measurements and atmospheric measurements, the consequent invalidation of predictions implicit in the protocols of the Kyoto Treaty, and the signing of a petition by more than 17,000 American scientists (now some 19,000, I believe) recommending against ratification of the Kyoto Treaty on scientific grounds.

There are two central issues in the debate. First, whether the scientific evidence justifies the conclusion that human hydrocarbon and other emissions are causing significant global warming with disastrous potential; and, second, the massive and economically very costly industrial restructuring implied by Kyoto for all Australians. This latter issue revolves, of course, around the answers to the first question. If there is no credible and conclusive evidence that human emissions are causing significant global warming, then there is no case whatever, on that ground, for incurring huge and futile costs in reducing them.

Using methods that, regrettably, do the Australian Conservation Foundation no credit, he associates my article with "interest group tactics" and claims my arguments are "flawed and outdated", even though I was summarising acknowledged experts writing this year and in the knowledge of the latest measurement results. I have no affiliations with any "interest group"; unless a part-time association with an independent, wholly non-profit research and education organisation, without any industrial, political, religious or other affiliations or obligations meets that definition.


He refers to a Wall Street Journal article that I have never seen and then attacks the scientists’ petition referred to above and claims, falsely, that "The petition is full of fake non-scientists" such as "Perry S. Mason (the fictitious lawyer)". Now either Mr van Rood has never bothered to visit the petition’s website or, if he has, is concealing the fact that the petition’s organisers have taken extensive precautions against fraudulent tricksters’ and activists’ attempts to sabotage it and that the Perry Mason concerned is indeed a real person, a PhD chemist who has signed the petition. Rather than take my word about the importance and genuineness of the Petition, readers can judge for themselves by going to where a full listing of signers (including some 2,660 physicists, geophysicists, meteorologists, oceanographers, and environmental scientists) is available along with other relevant information.

Now for the science. There are three questions and they need to be separated. The first is whether there is evidence of global warming over the last 100 years. The answer is ‘yes’. Measurements of global surface air temperatures since the 1880s reveal an increase of about 1.0 degree C.

The second question is whether there has been a significant increase in human-caused output of greenhouse gases (mainly carbon dioxide and methane) in recent years. The answer is ‘yes’. About 80 per cent of the increase in carbon dioxide output has occurred since 1940.

The third question is whether it can be demonstrated that the temperature increase over the past century has been caused entirely or substantially by this increased output of greenhouse gases. The answer to this critical question is ‘no’, and the reasons follow. The objective reader must be constantly alert, in reading activist literature and statements, including those from the Australian Conservation Foundation, to the obfuscation caused when mention of ‘global warming’ is subtly implied to mean ‘human-caused global warming’.

It is worth noting that most of the increase over the past century in surface air measurements, referred to above, occurred before 1940; that is, before the large increase in output of greenhouse gases. There has been an upward trend in surface air temperature measurements, which began 120 years ago, and it cannot reasonably be explained as due to release of greenhouse gases by mankind and domesticated animals. In a moment, I will give some evidence that throws doubt upon the reliability of recent surface air measurements but, accepting their validity for the time being, what do they signify? The obvious answer is that they could signify a slight degree of global warming that has nothing to do with human action. Cores of polar ice, marine sediments, historical records, and other evidence, indicate large variations in temperature over the past tens of thousands of years. In his critique, Mr van Rood claims that the 1990s were the hottest decade in the last 1000 years. Yet it is likely that surface temperatures during the Middle Ages were at least as great then as now and possibly greater; to be followed by the ‘little ice age’ in the 17th century from which we have since been emerging, to reach temperatures today that may be still, so far as we can tell from the sort of evidence mentioned above, well below those of 3000 years ago. I am happy to supply the references for these and later claims.

The reliability of temperature measurements

The models employed to justify the Kyoto protocols to drastically reduce energy use predicted that atmospheric temperatures would show a rise of between one and two degrees Fahrenheit, or approximately 0.5 to 1.0 degree C over the past twenty years.


Surface measurements of temperatures reflect the averages of thousands of thermometers in every country. Most of them are located in cities and towns. Ocean surface temperatures are taken by ships using the same ‘Stevenson Screens’ (or boxes) that are used on land. It is these overall measurements that have shown the slight increase in surface temperature over the past century or more.

The surface measurements showed a global warming of 0.4 C between 1979 and the present.

Beginning in January, 1979, satellites began measuring the atmosphere between 1000 and 8000m altitude. Measurements by weather balloons have also been taken over this period. The satellites make many thousands of measurements each day and the orbit is constantly shifted so that the whole Earth is covered over a three-day period. The measurements are accurate and comprehensive.

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About the Author

Dr Barry Maley is a Senior Fellow at the Centre for Independent Studies.

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