I have been dismayed over the bogus science and media hype associated with the (dangerous) human-induced global warming hypothesis. My innate sense of how the atmosphere-ocean functions does not allow me to accept these scenarios. Observations and theory do not support these ideas.

Professor Emeritus William Gray - Colorado State University, 2006

Author’s note

This paper is an updated version of a paper invited for the AusIMM New Leaders’ Conference in Brisbane in May, 2007, and is republished with the permission of The Australasian Institute of Mining and Metallurgy.

The original publication is: Carter, R M, 2007. The Myth of Dangerous Human-Caused Climate Change, in Proceedings The AusIMM 2007 New Leaders’ Conference, pp 61-74 (The Australasian Institute of Mining and Metallurgy: Melbourne). Available from:  http://www.shop.ausimm.com.au/paperdetails.php?PaperID=2553.

Abstract

Human-caused global warming has become the environmental cause celebre of the early 21^st century. The strong warming alarmist camp currently includes the United Nations, most Western governments, most of the free press, many large corporations (including Enron, before it failed), the major churches, most scientific organizations and a large portion of general public opinion. This phalanx of support notwithstanding there is no scientific consensus as to the danger of human-induced climate change. There is, therefore, a strong conflict between the level of public alarm and its science justification. How can this be?

In a democracy, the media serve to convey to the public the facts and hypotheses of climate change as provided by individual scientists, governmental and international research agencies, and NGO and other lobby groups. In general, the media have promulgated an alarmist cause for climate change; they have certainly failed to convey the degree of uncertainty that is characteristic of climate science, or a balanced summary of the many essential facts that are relevant to human causation.

Climate change is as much a geological as it is a meteorological issue. Natural climate changes, both warmings and coolings, are indeed a societal hazard. We usually deal with geological hazards by providing civil defence authorities and the public with accurate, evidence-based, general information about events like earthquakes, volcanic eruptions, tsunamis and floods, and then by adapting to the effects when a damaging event occurs. As for other major natural disasters, the appropriate preparation for extreme climate events is to mitigate and manage the negative effects when they occur, and especially so for dangerous coolings. Attempting instead to “stop climate change” by reducing human carbon dioxide emissions is a costly exercise of utter futility. Rational climate policies must be based on adaptation to dangerous change as and when it occurs, and irrespective of its sign or causation.

The issue now is no longer climate change as such, the reality of which will always be with us. Rather, the issues are, first, the failure of the free press to inform the public about the true facts of human-caused climate change and of the dangers posed by natural climate change. And, second, the vested interests held by many of the groups of warming alarmists. These interests include not only the obvious commercial ones, but also the many scientists and science managers who have discounted or remained silent about the huge uncertainties of the human-caused global warming hypothesis because it suited them to do so. Public opinion will soon demand an explanation as to why experienced editors and hardened investigative journalists, worldwide, have melted before the blowtorch of self-induced guilt, political correctness and special interest expediency that marks the sophisms of global warming alarmists.

Introduction  

In a recent letter to European heads of state, British Prime Minister Tony Blair wrote: “We have a window of only 10-15 years to take the steps we need to avoid crossing a catastrophic (climate) tipping point”. In contrast, Emeritus Professor Gray, a distinguished climate scientist from the University of Colorado, said recently “Observations and theory do not support these ideas (of dangerous human-caused warming)”. These statements cannot both be true. Who is right, and how should members of the public make up their minds on the matter?

That climate changes frequently, rapidly and sometimes unpredictably has been conventional knowledge amongst earth environmental scientists since the early days of ocean drilling in the 1970s. Yet we do not read about such natural climate change in the everyday news. Instead, in 2007 the daily media, in pursuit of circulation needs, is full of doom and gloom about human-caused global warming. Climate alarmism is propagated by a diverse group of journalists, environmental lobbyists, scientific and business groups, church leaders and politicians, all of whom preach that we must “stop climate change” by severely reducing human carbon dioxide emissions, two propositions that compete in their impracticality.

There are many qualified persons who argue against such an alarmist interpretation of recent and likely future climate change. I am one. When referred to politely, such persons are badged as “climate sceptics”; nearly as often they are disparaged as “climate septics”, “climate deniers” or “flat earthers”. The denigration implicit in the word sceptic is interesting in itself, because virtually all scientists -  whether they support the alarmist views of the U.N.’s Intergovernmental Panel on Climate Change (IPCC) or are of more independent mind – accurately view themselves as professional sceptics, for that is what scientists are trained to be. A more appropriate term for persons who are critical (on balanced scientific grounds) of the IPCC's alarmism is either "climate agnostics" or "climate rationalists" - the latter term, in particular, reflecting the primacy that such persons give to empirical data and thinking. The climate rationalist approach contrasts markedly with the untestable worlds of computer virtual reality that so many climate alarmists now inhabit.

Much public discussion on global warming is underpinned by two partly self-contradictory assumptions. The first is that there is a “consensus” of qualified scientists that dangerous human-caused global warming is upon us; and the second is that although there are “two sides to the debate”, the dangerous-warming side is overwhelmingly the stronger. Both assertions are unsustainable. The first because science is not, nor ever has been, about consensus, but about experimental and observational data and testable hypotheses. Second, regarding the number of sides to the debate, reality is that small parts of the immensely complex climate system are better or less understood - depending upon the subject - by many different groups of experts. No one scientist, however brilliant, “understands” climate change, and there is no general theory of climate nor likely to be one in the near future. In effect, there are nearly as many sides to the climate change debate as there are expert scientists who consider it.

Some key questions and answers that are relevant to the climate change debate include the following. Is there an established Theory of Climate? Answer: no. Do we understand fully how climate works? No. Is carbon dioxide demonstrated to be a dangerous atmospheric pollutant? No. Can deterministic computer models predict future climate? Another no. Is there a consensus amongst qualified scientists that dangerous, human-caused climate change is upon us? Absolutely not. Did late 20^th century temperature rise at a dangerous rate, or to a dangerous level? No, in either case. Is global temperature currently rising? Surprisingly, no. And finally, is the IPCC a scientific or a political advisory body? Answer: it is both.

This paper provides an analysis of these questions and some related issues. It is intended to provide easy reading more than to be an exhaustive analysis of the published scientific research that underpins its conclusions. Readers interested in more detail and a more complete bibliography should consult publications such as Carter et al. (2006), de Freitas (2002), Gerhard et al. (2001), IPCC (2001), Khandekar et al. (2005), Khilyuk and Chilingar (2006), Kininmonth (2004), Lindzen (2006), Jaworowski (2007) and Philander (1998), or browse some of the web sites listed after the main references.

Theory of climate

There is no established theory of climate in the sense that there is a theory of Newtonian mechanics. It is part of the nature of established theories that they have been repeatedly tested against empirical data, from which derives their predictive power. Such theories have their birth in hypotheses.

The currently favoured hypothesis of dangerous global warming includes the presumption that late 20^th century warming was substantially caused by human emissions of the greenhouse gas carbon dioxide. As will be elaborated later, this theory has failed the three main tests to which it has been subjected. First, no close relationship exists between the 20^th century patterns of increasing carbon dioxide and changing temperature; second, 20^th century rates and magnitude of temperature change fall well within previous natural limits of change despite accompanying increases in human-sourced carbon dioxide; and, third, the deterministic computer models that are used to engender public alarm have proved unable to predict the course of temperature change over the period 1990-2006, let alone out to 2100. 

Richard Lindzen, the distinguished US atmospheric scientist, recently wrote in the U.K. Telegraph: “After all, like hurricane frequency or the price of oil, global mean temperature is as likely to go down as up”. This observation, which is accurate, suggests that if there is to be a theory of climate for frequencies shorter than Milankovitch-scale variations (100,000, 41,000 and 19,000/23,000 year climate cycles) then it might turn out to be that climate changes stochastically, as indeed has recently been suggested by Ditlevsen (2007) for the millennial cycles termed Dansgaard-Oeschger events. Instead, in place of such a theory at the moment there is a hypothesis of anthropogenic global warming (AGW). It has been tested, and fails.

How does climate work?

If there is no theory of climate, then how much do we know about how climate works? The answer - as detailed in such useful references as Philander (1998), IPCC (2001), Ruddiman (2001), Kininmonth (2004) and Singer and Avery (2006) - is “a very great deal, though not yet enough to predict its future with any certainty”. And we would certainly hope that the first part of this answer were true, because at least US$50 billion dollars has been expended on climate change research since 1990. As discussed in more detail later, it is noteworthy that this large expenditure, and the extended efforts of the many talented scientists supported by it, have in 2007 still not provided convincing evidence for a measurable human effect on global climate.

There are many subdisciplines of research relevant to climate change, including meteorology, climatology, atmospheric chemistry and physics, geology, palaeoceanography, Quaternary science, mathematics-statistics and modelling. So different groups of scientists know a lot about different parts of the climate jigsaw. The subdisciplines at the beginning of this list are concerned mostly with weather and climate processes, those in the middle with climate history, and the two at the end with data processing and virtual reality. The climate advice that governments receive, mostly through the IPCC, is heavily influenced by scientists whose prime interests are climate processes and imaginary virtual reality, and very light-on on information from experts in ancient climate change. And therein lies one of the fatal weaknesses of the IPCC.

Is carbon dioxide a dangerous pollutant?

Carbon dioxide (CO₂) is a colourless, odourless gas that has been present in earth’s atmosphere through time in trace amounts ranging from a few hundred to a few thousand parts per million (ppm). Average atmospheric values over the last few hundred thousand years are inferred from ice cores to have been about 180 ppm during glacials and 280 ppm during interglacials (e.g. Petit et al., 1999) (Fig. 1). Hurd (2006), Jaworowski (2007) and others have argued that these values are about 30-50% lower than the original atmospheric values that they purport to represent, because of the post-depositional diffusion and mixing that occurs within the compacting ice mass. Independent evidence from fossil plant stomata indicates that carbon dioxide levels during the Holocene were variable on a decadal-centennial scale compared with the monotonic curve delineated by the ice cores (Fig. 1, inset), and reached at least the present day (post-industrial) value of 380 ppm (Kurschner et al., 1996; Wagner et al., 2002; Kouwenberg et al, 2005) (Fig. 2). More support for decadal fluctuations of carbon dioxide comes from the compilation and summary of 90,000 historical atmospheric analyses back to the mid-19^th century by Beck (2007).

In any case, and irrespective of these uncertainties, all estimates of carbon dioxide levels during the recent past are very low by the standards of earlier geological history, for planetary carbon dioxide values have declined from around 1000 ppm in the early Cenozoic, 60 million years ago (Lowenstein and Demicco, 2006) (Fig. 3). It is therefore crystal clear that there is nothing inherently unusual, nor necessarily dangerous, about the “extra” carbon dioxide that is currently being contributed to the atmosphere by human activity, which anyway amounts annually to only about 3% of the natural flux. Together with oxygen, carbon dioxide is a staff of life for earth’s biosphere because the metabolism of plants depends upon its absorption. Increasing carbon dioxide in the range of about 200-1000 ppm has repeatedly been shown to be beneficial for plant growth, and to increase plants’ efficiency of water use (Eamus, 1996; Saxe et al., 1998; Robinson et al., 1998). Prima facie, therefore, there is no reason to assume that atmospheric carbon dioxide levels of 500-1000 ppm are dangerous, or that such levels would have dramatically adverse ecological effects. Rather, increasing atmospheric carbon dioxide over this range is mostly beneficial (Idso, 2001; and many papers listed at the website CO₂ Science).

Following from this discussion, that carbon dioxide is, by definition, not a pollutant has been a cause of constant exasperation to those environmental activists who fear global warming. This exasperation underlay a US Supreme Court case brought by the State of Massachusetts against the Environmental Protection Agency (EPA) which asked that the Court declare that carbon dioxide should come under the Clean Air Act, and thereby be defined as a “pollutant” and require regulation by the EPA. The Court handed down its decision on April 2^nd this year, ruling in a narrow 5 to 4 decision that the EPA must consider greenhouse gases as pollutants. The Court said that "Because greenhouse gases fit well within the Clean Air Act's capacious definition of 'air pollutant' we hold that EPA has the statutory authority to regulate the emission of such gases from new motor vehicles". The Court also said that the “harms associated with climate change are serious and well-recognized ” and that “EPA has offered no reasoned explanation for its refusal to decide whether greenhouse gases cause or contribute to climate change”.

Predictably, this decision was greeted with approval by environmental groups, and with dismay by those who question whether any court has the competence to determine a scientific, rather than a legal, matter. In a dissenting statement, Chief Justice John Roberts said the court lacked constitutional power to second-guess the EPA at the behest of states and environmental groups, adding that the majority's reasoning “has caused us to transgress the proper -- and properly limited -- role of the courts in a democratic society”. Justice Antonin Scalia said the court “has no business substituting its own desired outcome for the reasoned judgment of the responsible agency”.

The court judgement notwithstanding, unless Congress passes a new law it will be many years before carbon dioxide emissions are EPA-regulated, if ever, for the following reasons (David Wojick, pers. comm.). Prior to the court case, EPA denied a citizen petitition to regulate carbon dioxide from cars on the grounds that it was not scientifically established that carbon dioxide is an environmental harm. To now introduce a new rule to regulate, EPA is first required to do a cost benefit analysis that uses a realistic discount rate (usually 7%) to assess future benefits. This makes future net benefits almost impossible to demonstrate. If, before or after making such an analysis, EPA again denies the petition to regulate, then that decision will in turn be taken to court, where the EPA will likely win because they are the experts and courts seldom overturn agency expert findings. Alternatively, and even should the EPA regulate by setting what it determines is a dangerous national ambient concentration level of carbon dioxide, given the huge temporal and geographic fluctuations in gas concentration what level can they choose? If they pick 440 ppm then everyone will be in attainment; if they say 300 ppm then everyone will be out of attainment, but due to global factors that are beyond their control which is likely unconstitutional. As David Wojick observes – “the Supreme Court decision is just the first move, no more than pawn to Queen-4 in a chess game”.

Though not a pollutant, it is nonetheless the case that carbon dioxide absorbs space-bound infrared radiation, thereby increasing the energy available at Earth’s surface for warming or increased evaporation (e.g. de Freitas, 2002). Radiation theory thus accepted, there remain four problems with turning an increase in atmospheric carbon dioxide into global warming alarmism. First, the relationship between increasing carbon dioxide and increasing temperature is logarithmic, which lessens the forcing effect of each successive increment of carbon dioxide (Fig. 4). Second, in increasing from perhaps 280 ppm in pre-industrial times to 380 ppm now, carbon dioxide should already have produced 75% of the theoretical warming of ~1⁰ C that would be caused by a doubling to 560 ppm (Lindzen, 2006); as we move from 380 to 560 ppm, at most a trivial few tenths of a degree of warming remain in the system. Claims of greater warming, such as those of the IPCC (2001), are based upon arbitrary adjustments to the lambda value in the Stefan-Boltzmann equation, and untested assumptions about positive feedbacks from water vapour. Third, the ice core data show conclusively that, during natural climate cycling, changes in temperature precede changes in carbon dioxide by an average 800 years or so (Fischer et al., 1999; Indermuhle et al., 2000; Mudelsee, 2001; Caillon et al., 2003); similarly, temperature change precedes carbon dioxide change, in this case by 5 months, during annual seasonal cycling (Kuo et al., 1990). And, fourth, Boucot et al. (2004) have shown that over the Phanerozoic little relationship exists between the atmospheric concentration of carbon dioxide and necessary warming, including that extensive glaciation occurred between 444 and 353 million years ago when atmospheric carbon dioxide was up to 17 times higher than today (Chumakov, 2004).

In summary, there is almost universal agreement that significant carbon dioxide increases - human-caused or otherwise - will cause gentle planetary warming. But scientific opinion remains strongly divided as to how great a warming would accompany a real world doubling, and whether any such warming would on balance be beneficial or harmful.