Category Error or Cardinal Mistake?
Three telling opinion pieces on climate change have been published in the mainstream media in Australia in the past few days. One was alarming. One was fascinating. And one was unusually foolish.
On the Drum of 26 October, Stefan Rahmstorf, Professor of Physics at Potsdam University, pointed out that for the second time in four years the ice cover at the Arctic in September had been reduced to 4.4 million square kilometres, 40% less than it had been three or four decades earlier. In 2007 the reduction had been explained by odd wind patterns. There had been no odd winds this summer. The ice was also rapidly becoming thinner. There was now a prospect of an ice-free Arctic in summer, decades earlier than had once been believed remotely possible. Not only would several species in the area be in danger. The loss of the reflective mirror at the Arctic would further increase temperature in the northern regions. Already the pace of the Greenland ice shelf melt was becoming unnerving. If it was to melt entirely sometime in the future, ocean levels would rise by seven meters.
In the Sydney Morning Herald of October 28, Eugene Robinson, a columnist with the Washington Post, reported the findings of the most comprehensive study of the Earth’s temperature ever undertaken. The study had been conducted by the Professor of Physics at University of California, Berkeley, Richard Muller. His team had collated 1.6 billion temperature readings. Interestingly, Muller had begun his study as a climate change “sceptic”, mocking Michael Mann’s “hockey stick” graph; sympathetic to those responsible for hacking the University of East Anglia ‘Climategate’ emails. The “denialists” were confident that Muller’s study would produce results favourable to their cause. Muller even received a grant of $150,000 from the great sponsors of US denialism, the fossil fuel industry-based Koch brothers. As it turned out, however, the study confirmed earlier findings. Since the 1950s the Earth’s temperature has indeed risen by about 1°C. Muller argued in the Wall Street Journal: “When we began our study, we felt that sceptics had raised legitimate issues, and we didn’t know what we’d find. Our results turned out to be close to those published by prior groups.” He concluded: “You should not be a sceptic, at least not any longer.” Of course these results were immediately contested. Muller was once a climate change sceptic. His new enemies are climate change denialists. Nothing illustrates the distinction between climate change scepticism and denialism more neatly than the differences that are presently opening up between Muller and his critics.
Although the Australian is owned by the same corporation as the Wall Street Journal it chose not to publish Muller’s seminal opinion piece. Instead, on October 27, it published a somewhat less significant article by that well known climate scientist Cardinal George Pell. The article revealed that Pell presently regards himself as an authority on climate change. He informed his readers that, unlike him, many politicians had not investigated what he called “the primary evidence”. Had they done so they would have learned, as he had, about the inadequacies of both the “evidence” and the “explanations” being offered by the climate scientists with regard to global warming. Pell expressed strong disagreement with something I had written. “Recently”, he argued, “Robert Manne, following fashionable opinion, wrote that ‘the science is truly settled’ on the fundamental theory of climate change; global warming is happening; it is primarily caused by the emission of greenhouse gases, especially carbon dioxide; and it is certain to have profound effects in the future.” Pell complained about the fact that I appealed to something called “‘the consensual view among qualified scientists’”. For him, such an appeal was “a cop out, a way of avoiding the basic issues…” Indeed, to write of the core conclusions of the climate scientists as “settled science” or as the “consensual view” represented what he called “a category error, scientifically and philosophically.”
There are many ways of demonstrating the existence of this scientific core consensus, about whose non-existence the Cardinal seems to me entirely wrong. One obvious way is to provide a brief account of some of the statements released by some of the world’s most important scientific academies in recent years.
In 2007, the presidents of the Science Academies of Brazil, Canada, China, France, Germany, India, Italy, Japan, Mexico, Russia, South Africa, United Kingdom and the United States published a common statement. In part it read: “[C]limate change is happening …[A]nthropogenic warming is influencing many physical and biological systems. Average global temperatures increased by 0.74°C between 1906-2005 and a further increase of 0.2°C to 0.4°C in the next twenty years is expected. Further consequences are therefore inevitable, for example from losses of polar ice and sea-level rise.” In October 2009, the presidents of eighteen relevant scientific associations in the United States, led by the American Association for the Advancement of Science, signed a joint letter addressed to every member of the US Senate. “Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver. These conclusions are based on multiple lines of evidence, and contrary assertions are inconsistent with an objective assessment of the vast body of peer-reviewed science.” And in November 2009 in the United Kingdom, the Met Centre, Hadley Office; the Natural Environment Research Council; and the Royal Society released a joint statement. “Climate scientists from the United Kingdom and across the world are in overwhelming agreement about the evidence of climate change, driven by human input of greenhouse gases into the atmosphere.” The meaning of these statements seems clear.
The existence of a core scientific consensus on human-induced climate change has also been proven by surveys of climate scientists. The results have been published in three recent academic articles each using a different methodology. In Science in December 2004 Naomi Oreskes published an article that showed that of the 928 peer-reviewed articles published in relevant scientific journals between 1993 and 2003, not one “disagreed with the consensus position” on the reality of anthropogenic climate change. In 2009 Doran et al in EOS, The Transactions of the American Geophysical Union, asked 3146 Earth scientists whether they thought human activity was “a significant contributing factor in changing mean global temperatures”. While only 77% of non-climatologists thought it was, among the climatologists who published in the field of climate science, 97.4% agreed. In 2010 in PNAS, The Proceedings of the National Academy of the Sciences of the United States, Anderegg et al conducted a survey of the peer-reviewed articles of 1372 climate scientists who had signed public statement either for or against action on climate change. Their conclusion? “97%-98% of the climate researchers most actively publishing in the field support the tenets of anthropogenic climate change outlined in the Intergovernmental Panel on Climate Change.” The conclusion to be drawn from these academic studies is clear. About 97% of climate scientists actively publishing in peer reviewed journals support the idea that global warming is happening and that it is primarily caused by human activity. If that does not constitute a scientific consensus I am at a loss to know what would. Yet Cardinal Pell characterises all of this as something as frivolous and as politically determined as “fashionable opinion”.
Pell is not only wrong to deny the existence of a core consensus among the qualified climate scientists about global warming and its human cause. He is also wrong to believe that laypeople, like himself (and me), can arrive through uninstructed reasoning or speculation at our own conclusions about climate science. Commonsense ought to tell us that those without the requisite training or understanding have no rational alternative but to accept the conclusions of the scientists. In this area of highly sophisticated science, as in so many other similar examples, as Clive Hamilton once wisely put it, our problem is not what to believe but who. This situation of course is not without serious potential problem. If the climate scientists were divided on the core questions of climate change, laypeople would simply have no way of knowing what to believe. Fortunately, however, the scientists are not divided. They accept the fact of a rise in the temperature of the Earth in recent decades; the role played by human activity in that temperature rise through the burning of fossil fuels; and, in general, the kinds of grave potential danger posed. While concerning the precise pace at which the different outcomes of climate change will occur in the future there is no scientific consensus, on these core questions, consensus among the climate scientists undoubtedly exists. Consensus, of course, is not the same as unanimity.
If Cardinal Pell believed he was able, through intuition, to understand particle physics better than the particle physicists or evolutionary biology better than the evolutionary biologists, his hubristic self-confidence would be merely absurd. He is however living at a time when fossil fuel corporations and other vested interests are seeking to create public confusion about the likely impact of increasing greenhouse gas emissions and when people are searching rather desperately for rationalisations that will allow them, in good conscience, to preserve their way of life by denying the need for radical action to reduce emissions from the burning of fossil fuels. Climate scientists are telling us that the future for humans and other species is imperilled. In combination with the current deluge of similar pieces by the expanding army of climate change denialists, Pell’s pronouncements have influence on public opinion and thus the potential to do real harm. In my view, he has used the authority bestowed upon him by high office in the Roman Catholic Church imprudently and irresponsibly.
Cardinal Pell apparently believes that someone like himself – without scientific training; without scientific publications; without the capacity to read and understand academic scientific literature; without even the capacity to pass a first year university examination in one of the relevant climate science academic disciplines – is in a position to disregard the conclusions of 97% of climate scientists actively publishing in peer-reviewed journals which have been supported by the world’s major scientific academies. In denying the existence of a consensus among the climate scientists on core questions, and in arguing that laypeople without scientific understanding or expertise can come to their own conclusions on global warming, as if it were all merely a matter of opinion, Pell has committed what he might call a category error but which I prefer to call a cardinal mistake.