The origin of the claim of “consensus”> > David Miliband, the Environment Minister of the United Kingdom, was greeted by cries of “Rubbish!” when he told a conference on climate change at the Holy See in the spring of 2007 that the science of climate and carbon dioxide was simple and settled. Yet Miliband was merely reciting a mantra that has been widely peddled by politicians such as Al Gore and political news media such as the BBC, which has long since abandoned its constitutional obligation of objectivity on this as on most political subjects, and has adopted a policy of not allowing equal air-time to opponents of the imagined “consensus”. > The claim of “consensus” rests almost entirely on an inaccurate and now-outdated single-page comment in the journal Science entitled The Scientific Consensus on Climate Change (Oreskes, 2004). In this less than impressive “head-count” essay, Naomi Oreskes, a historian of science with no qualifications in climatology, defined the “consensus” in a very limited sense, quoting as follows from IPCC (2001) – > “Human activities … are modifying the concentration of atmospheric constituents … that absorb or scatter radiant energy. … most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.” > The limited definition of “consensus” > Oreskes’ definition of “consensus” falls into two parts. First, she states that humankind is altering the composition of the atmosphere. This statement is uncontroversial: for measurement has established that the concentration of carbon dioxide in the atmosphere has risen over the past 250 years to such an extent that CO2 now constitutes almost 0.01 per cent more of the atmosphere than in the pre-industrial era. However, on the question whether that alteration has any detrimental climatic significance, there is no consensus, and Oreskes does not state that there is. > The second part of Oreskes’ definition of the “consensus” is likewise limited in its scope. Since global temperatures have risen by about 0.4C in the past 50 years, humankind – according to Oreskes’ definition of “consensus” – may have accounted for more than 0.2C. > Applying that rate of increase over the present century, and raising it by half to allow for the impact of fast-polluting developing countries such as China, temperature may rise by 0.6C in the present century, much as it did in the past century, always provided that the unprecedented (and now-declining) solar activity of the past 70 years ceases to decline and instead continues at its recent record level. > There is indeed a consensus that humankind is putting large quantities of greenhouse gases into the atmosphere; that some warming has resulted; and that some further warming can be expected. However, there is less of a consensus about whether most of the past half-century’s warming is anthropogenic, which is why, rightly, Oreskes is cautious enough to circumscribe her definition of the “consensus” about the anthropogenic contribution to warming over the past half-century with the qualifying adjective “likely”. > There is no scientific consensus on how much the world has warmed or will warm; how much of the warming is natural; how much impact greenhouse gases have had or will have on temperature; how sea level, storms, droughts, floods, flora, and fauna will respond to warmer temperature; what mitigative steps – if any – we should take; whether (if at all) such steps would have sufficient (or any) climatic effect; or even whether we should take any steps at all. > Campaigners for climate alarm state or imply that there is a scientific consensus on all of these things, when in fact there is none. They imply that Oreskes’ essay proves the consensus on all of these things. Al Gore, for instance, devoted a long segment of his film An Inconvenient Truth to predicting the imminent meltdown of the Greenland and West Antarctic ice-sheets, with a consequent global increase of 20 feet (6 m) in sea level that would flood Manhattan, Shanghai, Bangladesh, and other coastal settlements. He quoted Oreskes’ essay as proving that all credible climate scientists were agreed on the supposed threat from climate change. He did not point out, however, that Oreskes’ definition of the “consensus” on climate change did not encompass, still less justify, his alarmist notions. > Let us take just one example. The UN’s latest report on climate change, which is claimed as representing and summarizing the state of the scientific “consensus” insofar as there is one, says that the total contribution of ice-melt from Greenland and Antarctica to the rise in sea level over the whole of the coming century will not be the 20 feet luridly illustrated by Al Gore in his movie, but just 2 inches. > Gore’s film does not represent the “consensus” at all. Indeed, he exaggerates the supposed effects of ice-melt by some 12,000 per cent. The UN, on the other hand, estimates the probability that humankind has had any influence on sea level at little better than 50:50. The BBC, of course, has not headlined, or even reported, the UN’s “counter-consensual” findings. Every time the BBC mentions “climate change”, it shows the same tired footage of a glacier calving into the sea – which is what glaciers do every summer. > What Oreskes said > Oreskes (2004) said she had analyzed – > “928 abstracts, published in refereed scientific journals between 1993 and 2003, and listed in the ISI database with the keywords ‘climate change’.” > She concluded that 75% of the papers either explicitly or implicitly accepted the “consensus” view; 25% took no position, being concerned with palaeoclimate rather than today’s climate; and –
Dr. Peiser has commented:> “The decision to publish Oreskes’ claim of general agreement (just days before an important UN conference on global warming, the Tenth Conference of the Parties to the UN Convention on Climate Change), was apparently made while the editors of Science were sitting on a paper that showed quite clearly the opposite. > > “It would appear that the editors of Science knowingly misled the public and the world’s media. > > “In my view, such unethical behaviour constitutes a grave contravention, if not a corruption of scientific procedure. This form of unacceptable misconduct is much worse than the editors’ refusal to publish the numerous letters and rebuttals regarding Oreskes’ flawed study.” > Furthermore, what of the countless research papers that show global temperatures were similar or even higher than today’s during the Holocene Climate Optimum and the Medieval Warm Period, when atmospheric CO2 levels were much lower than at present? > What of the papers showing that solar variability is a key driver of recent climate change, and that in the past 70 years the Sun has been more active, for longer, than at almost any comparable period in the past 11,400 years? > What of the papers echoing Lorenz (1963), who, in the paper that founded chaos theory, stated and demonstrated his famous theorem that the climate is a mathematically-chaotic object that is by its nature unpredictable unless one fully understands not only all the relevant evolutionary processes but also the initial state of the global climate to a precision that is in practice altogether unattainable? > There are hundreds of learned papers, many of them written by the world’s leading experts in climatology and related fields, that have raised serious reservations about the notion of a “consensus” as to the alarmist presentation of climate change. Many of these papers explicitly reject the “consensus”, even in the limited sense used by Oreskes. > There is no such thing as a “scientific consensus”, except in a very limited sense. This may be readily demonstrated by quotation from dozens of papers casting doubt on the “consensus”. > Some examples of papers which fell within Oreskes’ search criteron and within her chosen timeframe but which she regarded as supportive of her imagined “unanimous” consensus: > Ø AMMANN et al. (2003) detected evidence for close ties between solar variations and surface climate. > Ø REID (1997) found that “the importance of solar variability as a factor in climate change over the last few decades may have been underestimated in recent studies”. > Ø KONDRATYEV and Varotsos (1996) criticize “the undoubtedly overemphasized contribution of the greenhouse effect to the global climate change”. > Two abstracts reviewed by Oreskes directly and bluntly rejected the “consensus” as she had defined it, but she counted them as “consensual” nevertheless: > GERHARD and Hanson (2000): > “The American Association of Petroleum Geologists’ Ad Hoc Committee on Global Climate Issues has studied the supposition of human-induced climate change since the committee’s inception in January 1998. This paper details the progress and findings of the committee through June 1999, At that time there had been essentially no geologic input into the global climate change debate. The following statements reflect the current state of climate knowledge from the geologic perspective as interpreted by the majority of the committee membership. The committee recognizes that new data could change its conclusions. The earth’s climate is constantly changing owing to natural variability in earth processes. Natural climate variability over recent geological time is greater than reasonable estimates of potential human-induced greenhouse gas changes. Because no tool is available to test the supposition of human-induced climate change and the range of natural variability is so great, there is no discernible human influence on global climate at this time.”
FERNAU et al. (1993):
“This article examines the status of the scientific uncertainties in predicting and verifying global climate change that hinder aggressive policy making. More and better measurements and statistical techniques are needed to detect and confirm the existence of greenhouse-gas-induced climate change, which currently cannot be distinguished from natural climate variability in the historical record. Uncertainties about the amount and rate of change of greenhouse gas emissions also make prediction of the magnitude and timing of climate change difficult. Because of inadequacies in the knowledge and depiction of physical processes and limited computer technology, predictions from existing computer models vary widely, particularly on a regional basis, and are not accurate enough yet for use in policy decisions. The extent of all these uncertainties is such that moving beyond no-regrets measures such as conservation will take political courage and may be delayed until scientific uncertainties are reduced.”> Though Oreskes has challenged Dr. Peiser’s analysis by pointing out that the paper by Gerhard and Hansen was not peer-reviewed, her essay appears not to have been peer-reviewed either. It may even be the case that the authors of most or even all of the cited abstracts personally believe that humankind is responsible for more than half of the 0.4C observed warming of the past half century. Dr. Peiser accepts, as does the author of the present paper, that most climate scientists published in the journals probably believe that humankind has contributed more than 0.2C of the 0.4C observed warming over the past half century. But the published papers we have quoted, nevertheless, raise sufficient doubts about important aspects of the imagined “consensus” to demonstrate the falsity of Oreskes’ claim that not one of the abstracts was counter-consensual. > Nor is the explicit and implicit rejection of the "consensus" confined to individual research papers such as those mentioned above. Distinguished scientific organizations such as the Russian Academy of Science and the U.S. Association of State Climatologists have also stated that they are skeptical of the imagined “consensus”. > Dr. Peiser concludes: > “The stifling of dissent and the curtailing of scientific skepticism is bringing climate research into disrepute. Science is supposed to work by critical evaluation, open-mindedness and self-correction. There is a fear among climate alarmists that the very existence of scientific skepticism and doubts about their gloomy predictions will be used by politicians to delay action. But if political considerations dictate what gets published, it’s all over for science.” > After examining the erroneous essay by Oreskes, the unsatisfactory circumstances in which it was published, and the failure of Science to correct more than one of its numerous deficiencies, we may conclude as follows: > · That Oreskes’ essay provides no sound basis for the assertion that a unanimous scientific “consensus” exists on climate change, for, though most climate scientists probably believe that humankind has caused 0.2C of the past half-century’s 0.4C warming, there is no unanimity; > · That even in the limited sense defined by Oreskes, there were more scientific papers explicitly doubting or even rejecting the “consensus” than explicitly supporting it; > · That less than half of the papers which Oreskes said had implicitly endorsed the “consensus” had in fact done so; > · That more than half of the papers which Oreskes considered had not mentioned anthropogenic climate change at all; > · That the definition of “consensus” in Oreskes’ essay is so limited, and her findings as published so greatly at variance with the content of the papers she reviewed, that the essay provides no justification for her frankly-political contention that – > “our grandchildren will surely blame us they find that we understood the reality of anthropogenic climate change and failed to do anything about it”; and > · That Science, having been given evidence of Oreskes’ errors before publication, in the form of a direct survey of more than 500 climate scientists, and after it, in the form of several letters pointing out the material errors some of which we have reported here, refused to allow the survey, the letters, or any other correction to appear in print, save only the correction of the database search term which Oreskes had used. > Bringing the analysis of “consensus” up to date > Oreskes’ essay is now outdated. Since it was published, more than 8,000 further papers on climate change have been published in the learned journals. In these papers, there is a discernible and accelerating trend away from unanimity even on her limited definition of “consensus”. > Schulte (2007: submitted) has brought Oreskes’ essay up to date by examining the 539 abstracts found using her search phrase “global climate change” between 2004 (her search had ended in 2003) and mid-February 2007. Even if Oreskes’ commentary in Science were true, the “consensus” has moved very considerably away from the unanimity she says she found. > Dr. Schulte’s results show that about 1.5% of the papers (just 9 out of 539) explicitly endorse the “consensus”, even in the limited sense defined by Oreskes. Though Oreskes found that 75% of the papers she reviewed explicitly or implicitly endorsed the “consensus”, Dr. Schulte’s review of subsequent papers shows that fewer than half now give some degree of endorsement to the “consensus”. The abstract of his paper is worth quoting in full:
> Shaviv (2006) considers the cosmic-ray forcing posited by Svensmark et al. (2006), and concludes that, if the effect is real, natural climate variability rather than anthropogenic enhancement of the greenhouse effect has contributed more than half of the warming over the past century – > “The cosmic-ray forcing / climate link … implies that the increased solar luminosity and reduced cosmic-ray forcing over the previous century should have contributed a warming of ~0.47K, while the rest should be mainly attributed to anthropogenic causes.” > Zhen-Shan and Xian (2007) say that CO2 forcing contributes less to temperature change than natural climate variability, that the anthropogenic enhancement of the greenhouse effect – > “Could have been excessively exaggerated” … Therefore, if CO2 concentration remains constant at present, the CO2 greenhouse effect will be deficient in counterchecking the natural cooling of global climate in the following 20 years. Even though the CO2 greenhouse effect on global climate change is unsuspicious, it could have been excessively exaggerated. It is high time to re-consider the trend of global climate changes.” > Whatever “unanimity” may have been thought or claimed to exist before 2004 in the peer-reviewed literature, there is certainly none in the peer-reviewed journals that have been published since. > Is there a scientific “consensus” wider than that defined by Oreskes? > We have established that Oreskes’ essay does not really lend any scientific credibility to the panicky predictions of a small minority of scientists many of whom have Left-leaning political opinions or connections. > The outright scaremongers are led by James Hansen, a donor of thousands of dollars to the re-election campaigns of Al Gore and John Kerry. He showed Congress a graph in 1988 that set the trend for wildly-exaggerated projections of future global temperature. The graph presented three scenarios, the most extreme of which had no basis in the scientific literature or in previously-observed trends. > Politicians at that time treated the graph with respect because it had been generated by a computer. Yet the model which generated the graph, still in use by Hansen and the UN today, continues to contain “flux adjustments” – i.e. fudge-factors – many times greater than the very small perturbations which the model is supposed to predicting.
Officials inserted this table after the scientists had finalized the draft of the 2007 reportalign=”center”>
Conclusion> One has only to cut away the alarmist rhetoric and the media distractions, one has only to focus on the central question in the climate-change debate, and at once the fact that there is no scientific consensus about climate change is laid bare. The central question is this: By how much will global temperature increase in response to any foreseeable increase in the atmospheric concentration of carbon dioxide? On that question, which the bureaucrats call the “climate sensitivity question”, there is no consensus whatsoever among the scientific community. We have seen how Hansen’s initial attempt at prediction, albeit using one of the largest computer models of the climate on the planet, turned out to contain an unfortunate element of exaggeration. It is inevitably the extreme scenarios that attract the attention of politicians and the media. > The UN’s own attempts to reach “consensus” on the climate sensitivity question demonstrate all too clearly not only that it cannot perform simple additions credibly but also that it does not even agree with itself. The internal inconsistencies in the UN’s documents are numerous and growing. We have already seen how it has changed its mind on sea level, as well as performing incorrect addition sums for what appears to have been a political purpose. On the climate sensitivity question, too, the IPCC does not agree with itself. In 2001, it said that the sum of the major climate “forcings” that contribute to temperature change was approximately 2.4 watts per square meter. Now it has decided that the “forcing” from carbon dioxide is largely canceled out by the negative “forcing” from the pollution that accompanies fossil-fuel burning, particularly in China and India, preventing sunlight from reaching the Earth. > Likewise, if one aggrgates up the UN’s central estimates of the contributions of all climate “forcings” and temperature “feedbacks” to the projected warming from increased greenhouse gases, the total comes to just half the UN’s published central estimate of a 3.2C temperature increase in response to a doubling of the atmospheric CO2 concentration. Once again, a large exaggeration is evident, right at the heart of the alarmist case. If the UN’s documents do not even agree with themselves, how can any kind of “consensus” be claimed? > The Russian Academy of Sciences and the US Association of State Climatologists are just two of the scientific organizations that have trenchantly expressed serious doubts about the imagined “consensus” on climate change. They have recently been joined by the Administrator of NASA, who has said that it is arrogant to make the Panglossian assumption that today’s climate is the best of all possible climates, and still more arrogant to assume that any of the more or less futile remedial measures which have been advocated will make any significant climatic difference. The Administrator ought to know: for it is his organization that gathers much of the weather data via satellite upon which the rickety edifice of the climate-change “consensus” is constructed.
A growing number of scientists who had previously subscribed to the alarmist presentation of the “consensus” are no longer sure. They are joining the numerous climatologists – many of them with outstanding credentials – who have never believed in the more extreme versions of the alarmist case. Indeed, many scientists now say that there has been no discernible human effect on temperature at all. For instance, Buentgen et al. (2006) say: “The 20th-century contribution of anthropogenic greenhouse gases and aerosol remains insecure.”Let the last word go to Mike Hulme, Director of the Tyndall Centre for Climate Change Research in the UK, who has himself undergone something of a conversio morum on climate change, and has written:> > “The IPCC is not going to talk about tipping points; it’s not going to talk about five-meter rises in sea level; it’s not going to talk about the next ice age because the Gulf Stream collapses; and it’s going to have none of the economics of the Stern Review. It’s almost as if a credibility gap has emerged between what the British public thinks and what the international science community think. … > > “Over the last few years a new environmental phenomenon has been constructed … – the phenomenon of ‘catastrophic’ climate change. It seems that mere ‘climate change’ was not going to be bad enough, and so now it must be ‘catastrophic’ to be worthy of attention. The increasing use of this pejorative term – and its bedfellow qualifiers ‘chaotic’, ‘irreversible’, ‘rapid’ – has altered the public discourse around climate change. >
“This discourse is now characterised by phrases such as ‘climate change is worse than we thought’, that we are approaching ‘irreversible tipping in the Earth’s climate’, and that we are ‘at the point of no return’. I have found myself increasingly chastised by climate change campaigners when my public statements and lectures on climate change have not satisfied their thirst for environmental drama and exaggerated rhetoric. It seems that it is we, the professional climate scientists, who are now the (catastrophe) sceptics. How the wheel turns!”>
*The views and opinions expressed in this paper are those of the author, and not necessarily those of SPPI. >