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Archives for September 2006

Sachs’ WSJ Challenge

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Jeffery Sachs of the Columbia Earth Institute has an excellent commentary in Scientific American this month on the disconnect between the Wall Street Journal editorial board and their own reporters (and the rest of the world) when it comes to climate change. He challenges them to truly follow their interest in an “open-minded search for scientific knowledge” by meeting with the “world’s leading climate scientists and to include in that meeting any climate-skeptic scientists that that the Journal editorial board would like to invite”.

RealClimate heartily endorses such an approach and, while we leave it to others to judge who the ‘world leading’ authorities are, we’d certaintly be willing to chip in if asked. To those who would decry this as a waste of time, we would point to The Economist who recently produced a very sensible special on global warming and proposed a number of economically viable ways to tackle it, despite having been reflexively denialist not that many years ago. If the Economist can rise to the challenge, maybe there is hope for the Wall Street Journal….

The trouble with sunspots

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by Gavin Schmidt and Michael Mann

Solar forcing of climate is a subject that gets far more attention than any new observations or improved understanding would warrant. Two new articles appearing today attest to that. One is occasionally tempted to agree with Oscar Wilde when he said:

Why does not science, instead of troubling itself about sunspots, which nobody ever saw, or, if they did, ought not to speak about; why does not science busy itself with drainage and sanitary engineering?

Except in this case it’s Nature rather than Science who are troubling themselves…

A new review paper by Foukal et al does a reasonable job summarising the mainstream opinion on the issue. In particular, they outline quite clearly why some ideas related to long term solar variability (such as solar disk radius changes, or the difference between cycling and non-cycling stars) have recently fallen out of favor. Indeed, they assert that there is little evidence for any solar variability in irradiance that is not related to the shielding/enhancements of sunspots and faculae – which implies only a modest decrease in solar flux at the Maunder Minimum for instance. We could quibble with their use of paleo-reconstructions, their climate modeling approach, and the rather cursory treatment of the substantial body of work relating to amplyfying mechanisms due to UV/ozone links, but we’ve gone over this ground before and we refer readers to those earlier discussions.

Slightly more novel is the description in the News section of a new experiment at CERN that is attempting to test the cosmic-ray/cloud hypothesis by building a large cloud chamber mimicing the atmosphere and firing high energy particles at it. There’s nothing intrinsically wrong with the idea, but given the $11 million to spend on climate change research, we would have tended to favour projects that, unlike this one, have at least some empirical support within the observations….

Weekly Round-up

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A few scattered pieces that may be of interest:

The increasingly-odd behaviour of the American Association of Petroleum Geologists – who recently awarded Michael Crichton a journalism award (because his work apparently has the ‘ring of truth‘ as opposed to actually being true), aroused the ire of American Quaternary Association in a commentary in EOS.

Reason Magazine has a Roundtable discussing responses to global warming from their particular perspective. The second essay (by D. Boudreaux) has the remarkable subtitle “Why ignoring climate change isn’t a sign of scientific illiteracy or of ideologically induced stupidity”. His point appears to be that the science of climate change doesn’t specifically imply any particular actions in response (which is true – what action to take, if any, is a political, ethical and economic decision). However his conclusion that ignoring climate change is sensible postition to take is indeed pretty dim. Ignorance is never the answer.

And on a lighter note, the Union of Concerned Scientists has a cartoon competition.

Tropical SSTs: Natural variations or Global warming?

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by Michael Mann and Gavin Schmidt

Roughly a year ago, we summarized the state of play in the ongoing scientific debate over the role of anthropogenic climate change in the observed trends in hurricane activity. This debate (as carefully outlined by Curry et al recently) revolves around a number of elements – whether the hurricane (or tropical cyclone) data show any significant variations, what those variations are linked to, and whether our understanding of the physics of tropical storms is sufficient to explain those links.

Several recent studies such as Emanuel (2005 — previously discussed here) and Hoyos et al (2006 — previously discussed here) have emphasized the role of increasing tropical sea surface temperatures (SSTs) on recent increases in hurricane intensities, both globally and for the Atlantic. The publication this week of a comprehensive paper by Santer et al provides an opportunity to assess the key middle question – to what can we attribute the relevant changes in tropical SSTs? And in particular, what can we say about Atlantic SSTs where we have the best data? [Read more…] about Tropical SSTs: Natural variations or Global warming?

Why greenhouse gases heat the ocean

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Guest commentary by Peter Minnett (RSMAS)

Observations of ocean temperatures have revealed that the ocean heat content has been increasing significantly over recent decades (Willis et al, 2004; Levitus et al, 2005; Lyman et al, 2006). This is something that has been predicted by climate models (and confirmed notably by Hansen et al, 2005), and has therefore been described as a ‘smoking gun’ for human-caused greenhouse gases.

However, some have insisted that there is a paradox here – how can a forcing driven by longwave absorption and emission impact the ocean below since the infrared radiation does not penetrate more than a few micrometers into the ocean? Resolution of this conundrum is to be found in the recognition that the skin layer temperature gradient not only exists as a result of the ocean-atmosphere temperature difference, but also helps to control the ocean-atmosphere heat flux. (The ‘skin layer‘ is the very thin – up to 1 mm – layer at the top of ocean that is in direct contact with the atmosphere). Reducing the size of the temperature gradient through the skin layer reduces the flux. Thus, if the absorption of the infrared emission from atmospheric greenhouse gases reduces the gradient through the skin layer, the flow of heat from the ocean beneath will be reduced, leaving more of the heat introduced into the bulk of the upper oceanic layer by the absorption of sunlight to remain there to increase water temperature. Experimental evidence for this mechanism can be seen in at-sea measurements of the ocean skin and bulk temperatures. [Read more…] about Why greenhouse gases heat the ocean

Chinese whispers in Australia

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We decided months ago that we would not comment on leaks of the draft of the upcoming IPCC report (due Feb 2007) but we are prepared to correct obvious errors. The ongoing revisions of the text and the numerous drafts make any such commentary, let alone conclusions drawn from it, pretty pointless. This is even more true when the leaks are obviously confused about a central point. The principle error in the latest ‘exclusive’ is that the writer confuses a tightening of the estimate of climate sensitivity to 2xCO2 (as discussed here) with projections of climate change in 2100. These projections obviously depend on the uncertainties in the scenarios of future technology, economic progress and population (etc.) plus uncertainties in feedbacks related to the carbon or methane cycles. Unfortunately these have not been reduced since the last assessment report (and in some cases have actually increased).

That occasional stories will come out that get basic things wrong is unfortunate but not surprising. What is more troubling is that they subsequently get picked up by Reuters and UPI, and republished in places (such as Scientific American, though in their defence, it is simply a posting of the wire report) where the editors should know better. Worse still, the wire service stories are too brief to make the source of the error obvious, and thus the error gets propagated in an ever more confused state. As usual the blogsphere is playing a key role in amplifying and further muddying the story. The advantage of blogs is that errors can be corrected quickly, and the comments on Prometheus for instance, quickly revealed the confusion and the potential agenda of the original story.

There will be plenty of time to discuss the new IPCC report when it comes out and where everyone can read for themselves what has and what hasn’t changed since 2001. Until then, we would counsel against journalists and editors jumping at supposed ‘exclusives’ and – more dangerously – going ahead with them without even a basic sanity check of the details.

Nature’s press advisories

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Articles in Nature (or Science) are embargoed for the media until the day of publication. A week before publication, Nature sends out a press advisory describing the week’s upcoming papers that is separate from any press releases that the authors or their institutions might put out. Journalists read these, and if interested, spend the time before the actual publication talking to sources and doing background so that they have (hopefully) well-thought out stories ready to go when the embargo lifts. The resulting media splash for the most interesting papers is usually good for the magazine and the authors. But not always.

Last week, the press advisory for one paper gave a slightly misleading account of one apsect of the work described in the article. Normally this would probably not get much attention, but the paper in question dealt with the highly emotional and politicized topic of stem cell research. I don’t want to get into the specifics of this paper (comments on that should be directed elsewhere) but the New York Times reported on the clarification that Nature subsequently put out and noted that the principal author Robert Lanza, had neither seen nor approved the text of the press advisory.

This might seem strange, but this is actually the normal state of affairs. Nature‘s editors write the advisories, which only go out to journalists and are not in general ever seen by the public. Often though, these short blurbs set the tone for the subsequent media attention but, if there is a problem, it can lead to a very widespread mis-communication. Colleagues of mine have been in the odd position of having to ask the journalists to read out the release concerning their own work!

We have previously discussed the problems of getting the press release just right when dealing with articles on potentially controversial science topics, and we strongly urged scientists to be more aware of how press releases are crafted and the message they send. This is obviously very difficult to do if the scientists are not involved in the process.

Coincidentally, I recently had a casual conversation with one of the Nature editors concerning this exact issue (prior to last week’s kerfuffle) and learned that the magazine was thinking about making the advisories public at the time of publication. This would definitely be a step forward for openness. I would go further and also suggest that the principal authors be given a chance to comment on the advisories before they go out. Getting things wrong – even subtly – in contentious fields doesn’t help anyone and the slight extra effort to try and prevent mis-communication is well worth it.

In a similar vein, I have found that journalists who take the time to check back with scientists on their quotes or explanations of the science often catch ambiguities or errors at an early stage and this should be encouraged as much as possible.

At a time when science and science reporting is under pressure from many quarters, journals, press officers, editors and authors need to work more closely together on ensuring that science is reported accurately and effectively.