alexlockwood.net

In his Public Understanding of Science 2000 article ‘Knowledge, Ignorance and Popular Culture’, University of Toronto Professor Sheldon Ungar suggests the reason that public understanding and concern could coalesce around the ozone hole, where it has failed to do so for climate change, was in part due to two things: first, that the ozone hole argument found bridging metaphors from popular culture that were easily understood; and second, it engendered a ‘hot crisis’.

As Ungar suggests, these bridging metaphors for the ozone hole were simple and powerful:

The signal advantage of the ozone hole is that is can be encapsulated in a simple and widely familiar “penetration” metaphor. Stated succinctly, the hole leads to increased bombardment of the earth by lethal rays. The idea of rays penetrating a damaged ’shield’ meshes nicely with abiding and resonant cultural motifs, including Hollywood ‘affinities’, ranging from the Starship Enterprise to Star Wars.

Importantly, as Ungar notes, these metaphors are ‘pre-scientific’. That is, they’re kept simple, before they get into the scientific detail of the ways in which ‘ozone eater’ chemicals destroy the earth’s atmospheric protection.

In fact, these metaphors were so powerful, that both Ungar (2000) and Hargreaves, Lewis and Speers (2003) found that many people simply considered climate change to be a sub-set problem of/caused by the ozone hole problem. In a saturated media, people hold onto the main themes and frameworks of science stories, and not much more, with which to take educated guesses at what’s going on in the world (Hargreaves et al, 2003).

Hodel and the Hot Crisis
The second factor was the ‘hot crisis’. This happened when the depletion of the ozone hole was linked, without 100% proof, to skin cancer. It was the mid-80s, and President Reagan had just had two operations for skin cancer, and the issue was always part of the global psyche. Reagan’s Energy Minister, Donald Hodel, suggested that, rather than do something about the companies producing the chemicals, Americans should all wear hats as an adaptation measure. The Washington Post reported on it, and the issue went ‘hot’.

It’s interesting to note, of course, that Hodel claimed he never said this at all. But the power of the Washington Post’s message resonated, and amplified outwards, and the Reagan administration was forced to act by public pressure. It signed the Montreal Protocol and convinced DuPont and ICI, the largest chemical companies who were coincidentally the largest critics of the Montreal Protocol, that they would earn trillions fom developing new technologies (sound familiar?), and the rest is history. The Montreal Protocol has not bankrupted America; it has not given China and India huge relative gains. But then it is not about CO2.

The Hockey Stick’s own goal
The Hockey Stick then is one of the first bridging metaphors taken from popular culture and used to explain climate change. It is catchy, easily understood, and widespread. Although not as embedded as the idea of ‘penetration’ of a ’shield’, it’s shape is regular enough, from ice rink to street to field, and has links with other Hollywood favourites.

As such, the Hockey Stick graph of Mann, Bradley and Hughes, known as the MBH98 Reconstruction, is perhaps one of the most well known individual scientific studies of the epoch. Poor guys.

The Hockey Stick was in trouble from its inclusion in the IPCC TAR. It came under attack from Steve McIntyre, a retired statistician from Canada. McIntyre and McKitrick published a number of articles, first in Energy and Environment, and then in Geophysical Research Letters. Their papers stimulated two reviews, one comissioned by the Republican Joe Barton (the Wegman Report) and one commissioned by the National Research Council. The Barton commission came out in support of McIntyre and McKitrick. The NRC report was generally affirmative of Mann et al, but with some reservations.

As someone who is most interested in the coverage and representation of climate change, I’ll link to the summaries of the affair that I’ve come across (thanks to Dave Rado for many of these, and the commenters on my last post, Ron Cram, TonyN and Bishop Hill):

• Wikipedia overview of the controversy
• National Academic Press Surface Reconstructions
• The Wegman Report
• The Real Climate Wegman Paper commentary

The key points I have drawn from these sites, which may be different to your own, are:

• The instrumentally measured warming of about 0.6°C during the 20th century is also reflected in borehole temperature measurements, the retreat of glaciers, and other observational evidence, and can be simulated with climate models. From Page 2 of the NRC report.

• As Mann pointed out, not least in the full title of the paper, the study was ‘about the uncertainties‘ (the full title being: ‘Northern Hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations“. He is on record saying that he would not have conducted the study in the same way again.

And the IPCC has muted its treatment of the MBH paper from the 2001 Report. Its current SPM statement from 2007 (page 10) reads:

• ““Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1300 years. Some recent studies indicate greater variability in Northern Hemisphere temperatures than suggested in the TAR, particularly finding that cooler periods existed in the 12 to 14th, 17th, and 19th centuries. Warmer periods prior to the 20th century are within the uncertainty range given in the TAR.”

Why so much focus on this one graph and paper?
There are plenty of other graphs in the IPCC reports that show similar shapes, although perhaps not as dramatic, as the MBH paper. For example, Temperature in the Instrumental Record for Land and Oceans or from UK Met Office analyses (NMAT updated from Parker et al., 1995). Both are taken from the IPCC TAR, where the MRH98 Reconstruction first appeared. The IPCC TAR–or rather, the IPCC AND THEN the media that followed–made a bigger deal of the Hockey Stick than the authors intended: it was an easy metaphor to grab, and suits media simplicity. As the BBC suggests:

Over the years, the chart has gradually become a potent symbol of man’s impact on global climate in the post-industrial age.

However, when it really caught the mainstream attention was, as Bishop Hill says,

just a couple of years ago when it made a headlining appearance in Al Gore’s drama-documentary, An Inconvenient Truth. The revelation of the long, thin graph with its dramatic temperature rise in the last few decades, and the audience gasps that accompanied it, is something of a key moment for many environmentalists.

That’s when many people ‘got’ climate change. The Hockey Stick was the metaphor that carried the graph along far enough to be picked up and moulded into a superbly powerful presentation by one of the world’s, whatever else he is, great presenters.

Justified media attention?
In many ways, I understand the limpit-like attachment to this report for those who are more sceptical of the scientific basis of ‘very likely’ proof for AGW in the IPCC reports and elsewhere across scientific and academic establishments. There are issues with the data, issues with the methodology, that even the NRC report identifies and, as Mann agrees, would lead to it being conducted a different way next time. If the situation were reversed, and there was a report that was being held up as proof against something I strongly believed in, and there were potential holes in it which I could identify, then I’d be moving against it.

And also moving to defend it, if you feel it is being wrongly criticized. A scientific defence of the MBH paper appeard in Climatic Change in 2007, from Wahl and Ammann.

And then I came across this from Stefan Rahmstorf (scientist at the Postdam Institute for Climate Impact Research) which really contextualises how unwarranted the attacks on this paper have become, and why:

The MBH analysis suggests that, despite large error bars, twentieth-century warming is indeed highly unusual and probably was unprecedented during the past millennium. This result, presumably because of its symbolic power, has attracted much criticism, to some extent in scientific journals, but even more so in the popular media. The hockey-stick shaped curve became a symbol for the IPCC, and criticizing this particular data analysis because an avenue for some to question the credibility of the IPCC.

Three important things have been overlooked in much of the media coverage. First, even if scientific critics had been right, this would not have called into question the very cautious conclusion drawn by the IPCC from the reconstruction by MBJH… This conclusion has since been supported further by every single one of close to a dozen new reconstructions. [AL: for example, see this graph]

Second, by far the most serious scientific criticism raised against MBH was simply based on a mistake. The prominent paper of von Storch and others, which claimed (based on a model test) that the method of MBH systematically underestimated variability, “was itself based on incorrect implementation of the reconstruction procedure.”

Third, whether their reconstruction is accurate or not has no bearing on policy. If their analysis underestimated past natural climate variability, this would certainly not argue for a smaller climate sensitivity and thus a lesser concern about the consequences of our emissions… The [possible rise in global temperature to 2100] range given by the IPCC did not use the reconstruction of MBH or any other proxy records of the past millennium. (Rahmstorf, S. (2008) ‘Anthropogenic Climate Change: Revisiting the Facts’, in Zedillo, E. Global Warming: Looking Beyond Kyoto. Brookings institute Press: Washington, D.C.)

Final Word
I’m not a climate scientist and do not claim to be. My role is to assess and analyse power relations between media and society in relation to political economy, ideology and popular understanding of critical societal issues. I was drawn to look more closely at this issue because of some comments on my previous post, and I’m glad I have: anyone writing about climate change needs to be as informed as they can, while announcing their limitations.

The power of a symbol to both unite and divide is one of the unequivocal things about this debate. Truth often comes into it as a side issue in the media, especially when non-experts, including journalists and Republican Senators, get involved. As Anthony Watts has said, when politics and science mixes, it’s a messy outcome. But one which we need to get better at handling.

It’s also important to note that the Hockey Stick may never have been a binding metaphor for the scientific community itself–only the media, Al Gore, filmgoers and the sceptical lobby who didn’t like the power it was wielding in mobilizing action.

To be absolutely clear of my view as one of the non-experts, but writing about the media representation of climate change, having spent some time now reading through all the links, summaries, book chapters and web pages that I’ve found and been pointed to, it seems that there is some, minor argument with the statistical manner of the MBH article; the IPCC was right in its 4th AR to put the MBH paper in context of the other reconstructions; but that overall this debate in no way detracts from the experiences and evidences of anthropogenic climate change. As reported in Nature magazine, “National Council Affirms Hockey Stick”.

The next great climate change metaphor?
What, I wonder, will be the next metaphor for climate change? We’ve had the polar bears. (And as with Hodel’s remark, it’s been the power of the media and campaigning groups to amplify an image which has been taken out of context. Right or wrong? Many think wrong, e.g. here and here… but many of those use their own metaphors to make their points, e.g. remember Axis-of-Evil…? Next will be…?)

Blogs on the subject
But don’t take my word for it (as some of you already haven’t ). Occupying one position, I’ve tried to put across the different opinions on this subject, hopefully as fairly as I can being already in one camp. For me this is interesting as I’m getting a better picture of the complex role that the media and online plays in amplifying particular climate messages. There’s been a huge amount written on this over the years. Here are some of the main ones that I’ve come across in the past couple of days.

Climate Audit
Steve McIntyre’s collation of papers on what he and his social network have published about the subject.

Tamino: Open Mind
Science blog on Principal Components Analysis which I am still trying to understand, but is an incredibly useful and rich aid to understanding hockey stick graphs.

Bishop Hill’s latest entry
His article ‘Caspar and the Jesus paper’ is “not an attempt to rebut the hockey stick per se (I haven’t even mentioned principal components!), but rather to tell the story of Wahl and Ammann.” I’m impressed with the energy and commitment Bishop shows to his blog and to his audience. In that, fair credit. My person view is that this article is misplaced. Many disagree, as evidenced by the support on the Bishop’s blog. Viva la free speech. Updated: And here’s the Wahl and Ammann paper (PDF) again, as it’s relevant to the Bishop’s blog.

Real Climate: search for Hockey Stick
A whole plethora of articles dealing with northern hemisphere reconstructions. this one is the Dummy’s Guide from 2005.

Deltoid: bored with the hockey stick
A ribald riposte of McIntyre and McKitrick linking them with the right-wing think tanks responsible for most denial messages. Deltoid is one of the ScienceBlogs group, held in high esteem, and a strong watchdog on poor media reporting of climate change.

Stoat on the Hockey Stick
Another science blog that argues attacking the MBH paper is ‘pointless’ on the basis, as Rahmstorf says above, the IPCC were so cautious about it anyway.

And some extra links:

• Independent summary (very clear language)
• Natuurwetenschap & Techniek (PDF)
• Pielke on the Hockey Stick Graph here and here
• Briggs on why statisticians should get more involved
• The Zorita report
• Nature blog on Von Storch

For a more comprehensive link listing, see Wikipedia Exernal Links to papers.

References
Ungar, S (2000). ‘Knowledge, Ignorance and the popular culture’ in Public Understanding of Science, 9:3.
Hargreaves et al., (2003) Towards a Better Map, ESRC.