Review: The Discovery of Global Warming, by Spencer Weart, Harvard, 1st edition, 2003
Climate Change Science as it is known today is a very young science. Many of those that first raised the alarm about our bringing upon ourselves catastrophic global warming, like Schneider and Hansen, are still with us today. In the late 1960s and 70s concern was mounting about the possible local and then global affect of pollution on climate, including cooling and warming. But it was not until the 1980s that the alarm over carbon dioxide driven warming really began.
Of the most recent past, can one really write a history? The closer an account of events moves towards the present the more recedes the special virtues we seek in history, and so it is hard to pick out which recent developments really matter in the long run. With such caveats Spencer Weart begins the final chapter of his The Discovery of Global Warming (2003), but they might just as well apply to the entire subject, and this is all the more so from the sceptic’s point of view; for the question of want has been discovered, if anything at all, may well be revealed to all in good time.
But in different ways for the advocate and the sceptic, the subject is too important to leave alone. For Weart, it is by tracing how scientists, politicians, journalists, and ordinary citizens pushed and pulled at one another in the past, we can be better prepared to deal with the fatal issues that confront us. Whereas for the sceptics, the value in examining the history of the global warming scare is to discover just how it was that this came to be seen as a fatal issue – threatening no less the survival of humanity – so as to understand the phenomenon of alarmism as it manifests in modern society (see eg Scared to Death by Booker & North).
At this blog, our particular interest is in how this scare was manifest and propagated by scientists, and through the great institutions and organs of sciences, upon a grotesque distortion of conventional scientific practice. And one thing that is well demonstrated, acknowledged and even promoted in Weart’s history is that the development of the science (and so its corruption) is almost inextricable from – in fact it thrived upon – the very scare it generated across the politique.
The Discovery of Global Warming story begins by taking us back beyond the doomsayers of our time, to the early 19th century, when the French scientist Joseph Fourier discovered that it is greenhouse warming – the trapping of heat by the reflection of infra-red radiation – that explains the retention of the sun’s heat in the atmosphere. Next it was a contemporary of Darwin and Lyell, John Tyndall, who measured the reflective qualities of specific gasses, only to find that the main atmospheric gasses, oxygen and nitrogen, were transparent to this radiation, and so performed no such reflective warming. Tyndall soon discovered methane and CO2 to be greenhouse gasses, but as there were only traces of these in the atmosphere it could not be these that are keeping us warm. Soon he had the answer, that it is in fact water vapour that is the predominant greenhouse warmer of our planet. So, by the late 19th century, with the greenhouse life-nurturing effect of our moisture-laden air well establish, the next question was of climate stability and the cause of its known variation.
Right up until the late 1960s, if you were discussing the question of ‘Climate Change’ you would most likely be considering one of the great questions of geology, namely, What caused the Ice Ages? In fact, Weart identifies a 1965 conference in Boulder Colorado on ‘The Causes of Climate Change’ as a turning point. At a conference convened to discuss paleo-climate variation across millions of years, the discussion noticeably shifted towards contemporary change and the human influence. Weart shows us just how much the contemporary discussion of prospective climate change emerged out of discussion of climate change across deep geological time, and in various ways he shows how the one discussion explains characteristics of the other that are otherwise perplexing. One of these is the eagerness to confirm processes of positive feedback. This grew out of the need to explain the large shifts in climatic condition that caused the advance and the retreat of massive ice sheets, when it was found that the candidates for their causation could have only affected much slighter perturbations.
In the 1870s James Croll proposed that variations in the earths orbit (as noted in the procession of the equinox) could trigger Ice Ages. As he saw it, these changes in themselves were not sufficient to cause the dramatic changes in temperature, and so he proposed amplification by positive feedback due to the greater albedo (reflection) of snow and ice cover and due to changes in the ocean currents. Similarly, in 1896, Svante Arrhenius accounted for inter-glacial warmth by volcanic CO2 causing a little warming….and this causes more humidity,…which causes more warming…and so. Thus, an Ice Age could be triggered by a period of low volcanic activity.
Now consider the problem of accounting for recent climate variation during, say, the last decade, century or millennium. And consider a scientific problematic where we propose solar changes, volcanic influences and other atmospheric changes to cause direct but minor shifts in the global climate, while also noting relatively minor fluctuations (say, + or – 2 degrees) in temperature record of these recent times. In this case we would tend to be looking for feedback that maintained the over-all stability of our climate and dampening these perturbations. However, if we saw it otherwise, with dramatic climatic shifts in these recent times, then we would have a problem similar to the problem of the geological Ice Ages in that we would be looking for positive feedbacks. The point is that alarmists and sceptics sometimes seem to occupy these two different problematics. While in the sceptic camp the former view tends to prevail, the idea of inherent instability in the system pervades alarmist Climate Change Science. It is not so much that they observe great climatic shifts in the climate record, but that they propose the system in a precarious balance easily tipped over into a cascade of dramatic change in the future.
Climatic instability is a theme of Weart’s whole narrative, and we will return to this theme below, but the specific influence of the Ice Age problematic is also evident in his history where it becomes easy to forget (and Weart often pauses to remind the reader) that an influential earlier theory is attempting to explain the slow advance and retreat of gigantic ice sheets, and not the relatively brief and small variations in the global climate of historical times.
Croll and Arrhenius’s feedback theories of Ice Ages had very different lives and influences. Croll’s orbital theory lingered until a variation was eventually confirmed by the matching of Milankovitch cycles with sediment and ice core data in the 1960s and 70s. Arrhenius’s CO2 theory was subject to harsh criticism over the next few decades. Some said that Arrhenius had not accounted for the flux of the carbon cycle and the potential for the oceans to absorb the excess CO2. Nor had he considered the negative feedback in the albedo of the greater cloud cover that one would expect in a more humid air. But, as Weart describes, the most damaging criticism came only a few years after the theory was proposed, when it was discovered that CO2 absorbed infrared in much the same band regions as water, thus with the air already opaque to those bands, changes in CO2 concentration could not even affect the small difference Arrhenius had proposed.
It was not until the late 1930s that these conclusions upon simple laboratory experiments were re-examined and found to over-simplify the actual atmospheric effect (see Weart’s discussion of further developments). And so the CO2-forcing argument was revived, but this time not as affected by volcanic emissions, and not to explain the Ice Ages. The interest this time was to consider the impact of the CO2 emissions of human industry, and to explain the creeping rise evident across temperature records which had begun in the 1880s and was continuing through the 1930s.
The proponent of this harbinger of what is now simply called ‘Climate Change’ was not a geophysicist or a meteorologist but a steam engineer who practiced climatology as something of a hobby. Guy Stewart Callendar saw this warming effect of anthropogenic CO2 as desirable, and especially in that it might offset the slow inevitable decline into the next Ice Age. His critics argued that he had not demonstrated the signature of the human impact, and that the more likely explanation is that the recent warming is but an up-cycle of the natural fluctuations in climate evident throughout history. And sure enough, in the 1950s the warming was found to have reversed. After some harsh winters of the early 1960s concern about the cooling world overwhelmed any interest in a warming theory. Alas, after two false starts, the theory of CO2-forced climate change would have to wait for the warming to begin again in the 1980s. Meanwhile, popular concern that the world was cooling during the 1970s, was not, as some have supposed, a beat-up by the media. Rather, it was sourced, as Weart explains, from just such speculation among the scientists.
Weart covers well the quiet and less memorable period of the early 1980s, including congressional hearings in 1981 orchestrated by Al Gore and others, with Schneider and Ravelle giving testimony. In the same year an important AGW paper was published by the newly appointed head of NASA’s Goddard institute, a young James Hansen. While Hansen’s paper made nothing of the splash of his more famous paper and sweaty congressional testimony of 1988, he did win the beach-head of the first global warming front-page report in the New York Times, and this was even follow by an editorial discussing the implications. The political breakthroughs of 1988, including the establishment of the IPCC, coincided with the 2nd consecutive ‘warmest year on record,’ but then the heat was off again, and there ensued another lull for climate alarmism through the early 1990s. This was not helped by the release in 1990 of the remarkably sober IPCC’s First Assessment, which found no conclusive evidence that greenhouse gas emissions were causing the recent warming; warming that anyway had not yet returned us to the balmy heights of the early middle ages.
After all the attention-grabbing drama of the congressional hearings, not the least Hansen testifying his 99% certainty, other activist-scientist (notably Schneider and Haughton) seemed genuinely confounded by the problem of how to argue the necessity of government action to mitigate catastrophe upon the grounds of scientific predictions that are inherently and somewhat irreducibly uncertain. These activists had by this time irrevocably politicised the debate, causing a deepening sceptic/alarmist divide to block the normal to & fro of scientific debate. Here Weart makes no mistake about which side he is on by providing us with the now familiar authority of the peer-view process to support the alarmist science, while questioning the science of the sceptics upon its motivation and its financing. Furthermore, Weart claims that the sceptical arguments that emerged in the public debate at this time were little more than industry propaganda and misleading ‘junk’ science. (Recently, moderates such as Judith Curry have also made similar claim of early scepticism — for her it was 2000-2006 — to excuse the slow acceptance of recent more valid sceptical auditing.)
This depiction of un-scientific trashiness of early scepticism is challenged by a range of documentation from this time. These includes the profoundly scientific grounds for scepticism given by the founding director of CRU, Hurbert Lamb, a case which he developing upon the available evidence from the 1970s through to the 1990s. As for the public debate, there is the well structured scientific case made in the 1990 BBC documentary The Greenhouse Conspiracy. And Weart himself reports further evidence that alarmism has not yet taken hold among the ranks of climate science when he points to surveys of the scientist at this time detecting little restive concern. Indeed, the main narrative of the triumph of Climate Change Science runs somewhat in contradiction to these slurs on early scepticism, for this was still a time when legitimate doubts remained, for we had not yet arrived at the ‘confirmation’ of the science upon which the scientific ‘consensus’ would be built.
The talk of ‘confirmation’ and ‘consensus’ only really began with the triumphant
release news of the IPCC 2nd Assessment late in 1995. It’s Official the Science journal headline declared, the first glimmer of greenhouse warming seen. The Science article did at least refer to the ‘war of words’ at the final meeting of (IPCC Working Group I) lead authors and political representatives in Madrid. And it did point to the remaining ‘uncertainties’ behind the headline-grabbing conclusion that the balance of evidence suggests that there is a discernible human influence on global climate. Weart provides no such qualifications. In quoting these same words he reports: It was page-one news everywhere, immediately recognised as a landmark. And then he glosses the ensuing scandal with an oblique reference to a nasty controversy casting doubt upon the personal integrity of some IPCC scientists. In fact, the controversy was over just how these and other conclusive statements were inserted into the report after the scientific review was complete. The long-sought breakthrough — that the ‘fingerprint’ of the human influence on the warming had finally been discovered — was claimed upon the authority of the yet-to-be-published research of the very lead author who was accused of drafting these modifications during the Madrid meeting.
One must wonder, if these late changes were not made, and the 2nd Assessment was released just as inconclusive as the 1st Assessment, would its fate have been much the same? And then what of the fate of the Climate Change movement at this critical time on the eve of Kyoto? We can only imagine, for the changes were made, and the discovery of global warming was broadly accepted, and the momentum achieved in the winter of 1995-6 was maintained through the political breakthrough of Kyoto, and towards the even more conclusive 3rd Assessment of 2001.
With the release of this 3rd IPCC report, the story of The Discovery of Global Warming comes to its close, but not without giving due emphasis to the startling new evidence of unprecedented recent warming. It had been discovered that 1998 had been not just the warmest year of the century, but of the millennium. And the final chapter, entitled ‘Discovery Confirmed,’ bares witness to just how important was this (now discredited) evidence by the fact that the 3rd and final image of this entire book is none other than Michael Mann’s iconic Hockey Stick graph.
That Weart is writing from within the AGW camp has some obvious disadvantages, but he is not entirely one-sided, and, even where he is, there are interesting revelation. For example, while there is not much discussion of the measurement of global temperature and how it has change and progressed over time, Weart does show how the advocates of AGW progressively dealt with the problem of the apparent fluctuations in 20th century warming, notably the warming up to the 1930s, the cooling of the 1970s and cooling of the early 1990s.
Hansen’s 1981 paper removes the ‘common misconception’ that the 1970s cooling is a global phenomenon by showing that (as per with the Medieval Warm Period) it was mostly restricted to the Northern Hemisphere (and so attributable to hemisphere bound industrial aerosol pollution). More obscure is Weart’s claim that by the 1990s most scientists now thought it likely that the warming trend from the 1880s to the 1940s, when greenhouse emissions were not yet great, had been caused at least in part by increased solar activity. Indeed, while some were still talking of AGW since the industrial revolution, there was now a retreat to have AGW kicking in only after the 70s – which, we might note, keeps that hobbyist, Callendar, out in the cold. When the 1990s cooling was attributed to the Mt Pinatubo eruption, all that was left to explain was the warming trend across the 80s and 90s, which, by a process of elimination, must be due to greenhouse gas emissions. In recognising the long hard labour to get to this position by the end of the millennium, one can begin to appreciate the frustration of long-time campaigners, when, as the new millennium progressed the warming appeared to stall yet again. As Keith Trenberth famously put it: The fact is that we can’t account for the lack of warming at the moment, and it is a travesty that we can’t.
Weart is also frank about the funding cycle, and especially how drumming up public alarm causes the politicians to listen and to open their purse to fund more research. War, the Cold War, the Arms Races and the Space Race all drove funding by public fear. He shows how the scientists in the anti-war movement also used the authority of science to drive up fear. In a carefully orchestrated political manoeuvre staged on the eve of Halloween 1983, Carl Sagan, and others, announced the theory of Nuclear Winter, an instant cooling far deeper than an Ice Age that would likely extinguish the entire human species. That the science was tenuous, with all the appearance of pseudo-scientific propaganda, this does not much concern Weart. Moreover, there is a recurring theme in the book that any science that affects public alarm is a good thing, irrespective of its validity and irrespective of the damage a beat-up might do to the integrity of scientific institutions and practices.
This attitude emerges when Weart discusses a catastrophic theory of Ice Age onset offered in the 1950s by Ewing and Donn. They proposed that an ice-free Arctic sea would trigger runaway cooling. As an ice-free Arctic was widely speculated during the 1950s, this theory would be the cause for some immediate concern if it were true. Indeed, taking it on face value, a contemporary US government meteorologist concluded that the human race is poised precariously on a thin climate knife-edge. But despite the enthusiasm of its proponents, the theory quickly fell apart under examination. Weart concludes: Like mistaken data, a mistaken idea can have valuable consequences. Ewing and Donn’s model of the ice ages gave the public for the first time a respectable scientific backing for images of swift, disastrous climate change. Later he writes:
Only a few [climatologists] like Brooks, Ewing, and Donn imagined that the entire climate system might be so delicately balanced that a relatively minor perturbation could trigger a big shift.
The implication is that such scary scenarios are a good thing, irrespective of the evidence for whether or not such instability might be true. And it does make one wonder that if Weart did ever accept that the science behind the Hockey Stick graph had collapsed (he’s not there yet — see this recent discussion), would it be of any consequence, or would he continue to support it as mistaken data nonetheless helpful in raising alarm. Weart does not appear concerned that the hard-won respectability of science might be tarnished by such summary alarmism repeatedly exploiting this respectability for its authority and the attention it demands. Instead, he blames the bad luck of a cooling spell for tarnishing the reputation of Climate Science:
The temporary northern cooling from the 1940s through to the 1960s had been bad luck for climate science. By feeding scepticism about the greenhouse effect, and by provoking some scientists and many journalists to speculate publicly about the coming of a new ice age, the cool spell gave the field a reputation for fecklessness that it would not soon live down.
Later, Weart expresses a similar attitude to the alarmism generated by dubious science when discussing an erroneous computer model (by Moller) that gave a temp rise of 10C with the doubling of CO2. While it caused Moller to doubt his whole theory, Weart says that some (unspecified) scientists found it fascinating…
Was the mathematics trying to tell us something truly important? It was a disturbing discovery that a simple calculation (whatever problems it might have in detail) could produce a catastrophic outcome.
Indeed, many sceptics of climate modelling might agree! If the computer modellers were doing their bit, the world’s image makers have failed to do theirs, for (as Weart writes in 2003) novelist and moviemakers had not given the public a vivid picture of what climate change might truly mean…
The general public was never offered convincing and humanized tales of travails that might realistically beset us: the squalid ruin of the world’s mountain meadows and coral reefs, the mounting impoverishment due to crop failures, the invasion of tropical diseases, the press of millions of refugees from drowned coastal regions.
Of course, the call for more vivid depictions of scary scenarios was soon answered Al Gore and others.
An over-riding theme of The Discovery of Global Warming is that the progress of the science has been the progressive revelation that the climate system is not so stable as we all first thought, but it is instead teetering on the edge of a most delicate balance, and that the improving record of the past reveals more and more that it is yet an erratic beast prone to sudden and wild fluctuations that could, if pushed, be upon us once again. For example, Weart says that when the ice and sediment proxies data became available it showed that the notion of radical climate instability was not absurd after all. Did it really? Evidence across timescales from decades to millennia to geological ages all show patterns of slowly developing cycles of cooling and warming within minor temperature ranges – that is slow relative to the human scale and minor relative to the time-scale. On a human timescale changes like sea level rise, or the descent into an Ice Age remain very slow. What we can say, and this is where some of the confusion lies, is that minor changes, if they were accelerated and unidirectional, then they would cause some significant disruption to modern civilisation. But even these should be compared to the disruption of familiar random/cyclic fluctuations of weather/climate that cause droughts, floods, famines and other devastating natural disasters.
By suggesting that the progress of the science is from an old view of climate stability to the new science of climate instability, Weart suggests that those who’s argument falls to the side of stability are retrogressive, even anti-science traditionalists. During those bad luck cool 1960s Weart applauds most of those experts who began to doubt AGW theory for at least not reverting to the traditional comfortable view that climate was regulated in a stable natural balance. Does this suggest that he regards the drumming of Ice Age alarm better than no alarm at all? Surely an advocate of science should support those who try to stay true to the evidence and not support the science according to whether it promotes alarm over comfort.
Earlier, after recounting Arrhenius’s theory of runaway positive feedback upon increased CO2, and then those objections that drew attention to the negative feedback (like increased cloud albedo), he has this to say:
These objections conformed to a view of the natural world that was so widespread that most people thought of it as plain common sense. In this view the way cloudiness rose or fell to stabilize temperature, or the way the oceans maintained a fixed level of gases in the atmosphere, were examples of a universal principle: the Balance of Nature. Hardly anyone imagined that human actions, so puny among the vast natural powers, could upset the balance that governed the planet as a whole. This view of Nature – suprahuman, benevolent, and inherently stable – lay deep in most human cultures.
We might object and say that the apocalypse of the doomsayer is also a recurrent theme throughout our cultural history, and we should be careful not to let these latter-day doomsayers re-write the history of Climate Science so easily. Weart himself shows that modern climatology emerged out of the plethora of ideas circulating during the time of Arrhenius to account for geological climate change. As for historical climate change, we soon find Brooks from the 1920s, and Lamb from the 1950s, mapping out the patterns of climate change that gave us the idea of the Roman Warming, the Medieval Warming the Little Ice Age, and many more ups and downs in rainfall and temperature. They were not proclaiming runaway change or wild fluctuations, but nor did they proclaiming a perfectly stable balance – for that is not what they found. It is one thing for Weart to support the current dogma that places us on the edge of a climatic tipping points, but his gloss of the commonly held views that preceded the triumph of this dogma appears as something of an extension of the aggressive efforts during the 1990s to erase the Medieval Warming from the millennium record. And there is no suggestion in Brooks nor Lamb that these fluctuations were not disruptive – rather, the disruption they caused constituted much of the first evidence of their existence – although they do both associate the warm-wet periods with prosperity. As for the human influence on climate, well surely it is best to let this case emerge upon the evidence, instead of promoting it as the modern view, or as worthy for the alarm it generates.
There is no doubt that The Discovery of Global Warming is a partisan history, but that is not to say that such histories have no value. Weart tells the story mostly as the partisan and advocate wants it to be told, even as the events are unfolding and well before the drama is complete. In this respect it reminds me of Sprat’s History of the Royal Society written to promote the Society while still in the throes of its tenuous institution in the even more tenuous Restoration. That History endorsed experimental science as a sobering remedy to the apocalyptic ‘enthusiasm’ that had of late torn the fabric of British society to shreds. Now, after three and a half centuries of state-sponsored science, we find The Discovery of Global Warming endorsing apocalyptic enthusiasm to exploit the hard-won respectability that science has earned for its every effort to resist the tendency to depart from a sober exploration of the available evidence.
Note: Weart has updated the story with a second edition which I have not read. Find additional and supporting documentation on his AIP website, including an extensive and useful bibliography. I hope to post shortly a review of Fleming’s Historical Perspectives on Climate Change.