Scared to Death?

February 9, 2010

As promised, I’ve read the section of North and Booker’s “Scared to Death” which deals with climate change and I’ll offer my thoughts. It’s a racy read – engagingly constructed and heavily biased – but it fails to back any of its contentions (that the IPCC is corrupt, anthropogenic climate change is a myth etc…) with peer reviewed evidence or convincing conjecture. For me, it fails to achieve what it sets out to do – which is to convince the reader that climate change is a scare story concocted by self-interested actors for personal profit (or other forms of gain). At best, it provides a corrective to the hubris of institutions like the IPCC and those who would happily politicize climate science to reinforce their personal goals, but it is a partial corrective – in more ways than one.

The core of North and Booker’s argument is that as the earth has experienced a history of climatic variations, including periods since the end of the last ice age which were hotter than the current warming period, forcing effects caused by greenhouse gases are not the prime mover behind modern day climate change.

As they cite no peer reviewed science which offers a critique of the role which such gases plays in regulating the climate, their argument is both historical and political. In the first place, they suggest that other factors must have influenced the climate to produce such warmer periods, and that such factors remain crucial. In the final part of their section on climate change, they suggest one alternative explanation – the role of sunspots and solar flux in hindering or promoting cloud formation.

In the second place, they list the ways in which the IPCC has alienated scientists and treated data in an unprofessional manner. They quote high profile dissenters from the view that carbon dioxide and other greenhouse gases are the major factor, such as Richard Lindzen, Fred Singer and Patrick Michaels. They also quote disgruntled scientists like Paul Reiter, who participated unhappily in the IPCC’s health impacts section, where his expertise (in malaria) was not matched by that of his colleagues (some of whom were experts only in the construction of motorcycle helmets). In this way, North and Booker seek to establish a circumstantial “guilt” (their work is basically a trial of the IPCC and the mythical “consensus” which it supposedly enforces).

But there are some significant problems with their approach. For one thing, there are factual errors. At one point, they claim that temperatures were higher between 7,000 B.C. And 3,000 B.C. Than they are today (the holocene climate optimum). Yet this is misleading. According to the U.S. National Oceanic and Atmospheric Administration, we now know that “there is no evidence to show that the average annual mid-Holocene temperature was warmer than today’s temperatures.” The northern hemisphere may have experienced warmer summers, but this effect was certainly not global.

Another misleading claim made by North and Booker concerns the Medieval Warm Period which, they argue, saw “generally higher” temperatures than the present period. This isn’t true. All peer reviewed studies converge around the finding that in many areas of the world temperatures between about 1000 and 1450 were comparable to today’s, but that the extremes were local – even if the warming was part of a global process. Some places in the northern hemisphere did warm significantly, but others did not, and the warming was certainly not felt across the world.

All of this then leads into a demolition of the so-called “Hockey Stick” graph, produced by climate scientist Michael Mann and used heavily by the Third IPCC Assessment Report, released in 2001. For North and Booker, Mann’s graph is simply fraudulent, produced by a computer program which was designed to produce the results that its creator desired i.e. a pronounced twentieth century warming following a millenium or more of relative stability.

Yet Mann himself has had much to say about such critics. Writing in his defense, he argues that the “claim that the 20th century on the whole is the warmest period of the past 1000 years” is a misrepresentation of his work. Instead, he writes that “Numerous studies suggest that hemispheric mean warmth for the late 20th century (that is, the past few decades) appears to exceed the warmth of any comparable length period over the past thousand years or longer, taking into account the uncertainties in the estimates.” Mann stands by his work showing an anomalous period of warming from the late twentieth century, which exceeds similar periods shown by historical data, including any within the Medieval Warm Period. Many studies have emerged subsequent to his “hockey stick” work which back it up, with modifications – showing a clear anomaly in recent times which can only be feasibly attributed to anthropogenic warming.

Moreover, Mann charges his critics (McKitrick and McIntyre) of misusing statistical data in seeking to discredit his work. In a powerful rebuttal to his critics, he has accused them of censoring the data, removing troublesome data sets (such as tree ring data from North America) that would suppress medieval warming and little ice age cooling effects. They subsequently came out with graphs showing exaggerated warmth and cooling in both periods, making current warming seem less anomalous.

North and Booker say nothing about Mann’s defense or potential problems with McKitrick and McIntyre’s own methods. For them, the Hockey Stick has simply been refuted and demolished – as have all similar reconstructions of temperatures which show recent times as exhibiting anomalous warming. This, while not necessarily dishonest, is the hallmark of polemic, which is precisely what their chapter on climate change represents.

There is no room for ambiguity. There is no mention, for example, of the work of Wally Broecker, who provides a far more realistic picture of the Medieval Warm Period and subsequent warming periods. Writing in Science, Broecker has argued that both the MWP and current warming can be fitted into a far longer term pattern of “oscillations” which work out over periods of some 1,500 years. For Broecker, these oscillations are caused by changes in the Atlantic’s thermohaline system (caused by the rise and fall of the salt content of seawater). But, crucially, his current concern is how present day anthropogenic forcings are interacting with longer term “natural” cycles, with potentially significant results.

Broecker has, to an extent, been welcomed by those who question the “consensus” surrounding anthropogenic warming – owing perhaps to his embrace of long cycles (which others refute, including Mann). But what they never discuss, is Broecker’s acceptance that anthropogenic forcing is a real causal factor behind present day warming.

North and Brooker like to have it both ways. On the one hand, they claim that an all-powerful consensus has developed which excludes dissident scientists (through withholding grants etc..) while on the other, no consensus has ever really existed, as there have been – and are – many such dissenters. But there aren’t, at least within the community of climate scientists.

North and Brooker make a seemingly convincing case that such a consensus took a long time to form, a process which occurred in parallel to the lionization of the UN’s IPCC as the “gold standard” of climate change research. For example, they quote a Gallup poll from 1991 which found that 49 percent of 118 scientists surveyed rejected the contention that climate change was a pressing threat to human societies.

Yet this is not what the survey actually found. In fact, 61 percent of respondents expressed agreement or strong agreement to the proposition that “there is little doubt among scientists that mean temperature would increase.” 50 percent of respondents agreed or strongly agred that most scientists would see the likely effects of climate change as “substantial.”
Moreover, the survey also asked respondents to name those scientists working in the field that they most respected. Richard Lindzen, quoted approvingly by North and Booker, came well below James Hansen and Stephen Schneider – derided as apostles of anthropogenic theory in their book. What it shows is that, in 1991, there was disagreement amongst scientists familiar with climate research. But the preponderance of those questioned did lean towards accepting the IPCC’s early findings.

Tellingly, the Gallup poll also commented on an earlier assessment by the Global Environmental Change Report Survey. The GECR found strongest agreement amongst scientists to the contention that increases in the concentration of greenhouse gases would “increase the atmosphere’s heat-trapping  capacity and warm the climate.” 95.8 percent agreed.

North and Brooker similarly distort the findings of a 1996 survey by the UN’s Climate Change Bulletin. In their version, only 10 percent of the scientists canvassed strongly agreed that global warming was underway, which was a true but extremely misleading point. 62 percent of those questioned placed themselves in the first three categories of a 1-6 spectrum from “strongly agree” to “strongly disagree.” Only 5 percent “strongly disagreed” while, by 2003, 32 percent described themselves as “strongly agreeing.”

As mentioned above, North and Booker have produced a polemic. It is a lively polemic, entertainingly written and narrating its tale adeptly. But it is a misleading account of climate change. North and Booker seek to portray “climate sceptics” as heroic outsiders breaching the walls of a fortress of consensus. They therefore exaggerate the level of disagreement before the IPCC process took off, and don’t even bother to provide evidence of how climate scientists think now. They quote no peer reviewed scientific papers, relying on the work of economists to criticise Mann’s “Hockey Stick,” for example, and at no point do they supply any evidence which challenges the theory of greenhouse gas fueled anthropogenic climate change.


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