The first argument against anthropogenic global warming is that humans are not (and cannot) causing any changes to climate. Ian Plimer, Emeritus Professor of Earth Sciences at the University of Melbourne, argues (Plimer 2010, 30) that CO2 (carbon dioxide) is such an insignificant greenhouse gas that it cannot drive global warming. He states that human production of CO2 is too small (3% of the “annual exhalation”) to affect climate and, indeed, CO2 levels have been much higher in the past. In other words, any human contribution to climate change can simply be ignored.
The second argument considered here is that global climate is actually cooling, not warming. Bob Carter is a Research Professor at James Cook University. He stated in 2006 (Carter, 34) that global average temperature has “not changed significantly” for the period 1998-2005. He goes on to declare (35) that cooling and warming are equally likely probabilities, based on the view of experts that climate is always varying. Therefore it is far more prudent to take no action rather than waste money on an improbable event.
The third argument is most prominently put in Australia by David Archibald. He asserts that climate is fundamentally driven by the energy of the sun, and is directly correlated to the length of solar cycles (Archibald 2008, 1). These solar cycles vary a great deal and can lead to less or more energy entering the Earth’s atmosphere. Archibald predicts that temperature will drop 2.2o C as a result of the current cycle (in one location), and that “there will be a significant cooling very soon” (20). Thus there is, if anything, an urgency to actually emit more CO2 in order to avert a catastrophic ice age.
In considering whether these arguments are correct or persuasive, the first thing to notice is their contradictory natures. Plimer claims CO2 cannot affect climate, while Archibald encourages greater CO2 emissions in order to keep temperatures warm (tacitly admitting that humans can affect climate). Carter claims global climate is cooling, Archibald claims it will cool soon, and Plimer seems to accept that climate is warming (but that humans are not the cause). Clearly, not all of these arguments can be correct.
Plimer’s argument does not agree with the balance of evidence available. The IPCC (Intergovernmental Panel on Climate Change) in its 2007 report noted that, while CO2 may be low overall (as Plimer claims), production of CO2 has increased dramatically over the last decades (IPCC 2007, 5) and that global warming is due to these emissions with a “very high confidence” level since other climate factors would have led to cooling. Human emissions, particularly CO2 and methane, would appear to be the likely candidates in the observed warming. Plimer’s argument therefore is incorrect.
Carter’s argument, also, does not match the observed data. The IPCC note (2007, 2) that global warming is “unequivocal” based on multiple observations of the rising temperature of air and oceans, as well as decreasing snow cover and the rising of sea levels. Much of this data is publicly available, such as the sets provided by NASA’s Goddard Institute for Space Studies (NASA 2011). Global monthly and annual temperature anomaly data sets were downloaded and graphed to produce the results shown below. While it might be true to claim, as Carter does, that global temperatures fell between 1998 and 2005, it is clear that the fall was minor, particularly in the context of the long term trend. Global warming is evident, despite the noise of minor falls and rises, and shows that Carter is also incorrect.
Archibald’s argument can also be seen to be incorrect from the previous discussion. Global temperature is not falling, as he predicts, unless in the very limited sense of a short-term variation not affecting the long-term trend. The IPCC do, in fact, agree with Archibald that solar cycles would have been expected to lead to cooling (2007, 5). The fact that they have not indicates that global warming is occurring, and that there must therefore be some other driving force behind it. Human emissions of greenhouse gases are the most likely cause. Archibald’s claims thus ignore the full range of evidence and are also consequently wrong.
Taken as a whole, it is clear that these three arguments are not scientific. A scientific argument would be expected to be objective and factual. Where claims are made it is also expected that they are supported by observation or references to other research. The papers by Plimer and Carter, on the other hand, are full of emotive language and provide no citations in order to verify the claims being made. The intention of their papers is further made clear by the fact that they are published in a journal with an avowedly political aim (IPA n.d.), rather than a peer reviewed scientific journal. Archibald’s argument, on the other hand, at least includes some references but it is self-published rather than peer reviewed. That it also contains highly emotive language (accusing five scientific bodies of ‘alarmist projections’ and ‘scientific fraud’ (Archibald 2007, 6) for instance) indicates that this is not simply a scientific argument. Errors in each of the arguments have already been shown, but that they need to be presented in the context of an appeal to emotion indicates that the science itself is insufficient.
These arguments continue to be made, even when they are wrong. Scientists are in general agreement that global temperatures are increasing. Phil Jones at the University of East Anglia’s Climatic Research Unit in a 2010 co-authored paper (Jones and Wigley, 59) notes that there are multiple temperature data sets which are all in broad agreement. While acknowledging that there are many issues with these data sets (67) the broad picture remains clear. Whether the data is more or less reliable, global temperatures are consistently measured as increasing. This agreement has existed for some time, but the same counter-arguments continue to be made. Keller (2008, 644–645) discusses some of the counter-arguments, including the ones considered here, and observes that many of the critics of global warming have conflicting business or political interests. Their claims must be considered in isolation for them to work, whereas the complete body of climate science provides a clearer picture, with less doubt, of what is happening. He notes that one of the most contentious issues is the fact that dealing with global warming is a societal issue (671), and it is this that seems to be driving critics.
Doubt was an effective strategy used by the tobacco companies in order to delay action on a major health issue decades after the science was settled (Oreskes and Conway 2010, 14). The same strategy was used to combat moves to address acid rain (70), the ozone hole (125), and second hand smoke (139), and now against the science of global warming. In the populist debate where the science is difficult and poorly understood, however, it is emotion and rhetoric that sway public opinion and decision makers.
The arguments put by Carter, Plimer and Archibald are all essentially political, rather than scientific, even though they appear scientific at first glance. None of them presents an argument that would be acceptable in a scientific context, lacking evidence, data or citations that might support their various assertions. Their arguments are highly emotive and designed to promote doubt rather than provide answers. The fact that these arguments do not appear in the peer-reviewed scientific press but rather as essays in political journals is perhaps most telling about the intention these authors have – to make political rather than balanced scientific arguments.
The certainty of anthropogenic global warming is accepted scientifically, but the public continues to be presented with conflicting information leading to falling levels of acceptance of the science and consequent pressure on politicians to do nothing. While certainty about anthropogenic global warming directly correlates with scientific expertise in earth sciences (Doran and Zimmerman 2009, 22) a surprisingly high percentage of the public remains unconvinced (Hamilton 2010, 1). McCright and Dunlap (2010, 111) note how the countermovement distorts, manipulates and obfuscates the scientific evidence for political aims, while Oreskes and Conway (2010, 244) describe how the arguments they make appear scientific without having passed the fundamental first step of being peer reviewed. Plimer, Carter and Archibald each in their own way do exactly this, providing cherry-picked data, emotive contexts and apparently persuasive but ultimately flawed claims. Their arguments are incomplete and incorrect, and clearly intended to create doubt even though the overwhelming consensus is against them.
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