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about Gavin Schmidt

Gavin Schmidt is a climate modeler, working for NASA and with Columbia University.

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.

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.

New public opinion poll on global warming

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There is a new Zogby poll on public attitudes in the US towards global warming and the potential connection between severe weather events and climate change.

Unsurprisingly to us (but maybe not to others), most of the US public feel that global warming is happening (around 70%), and roughly the same amount of people report being more or much more convinced of this over the last two years.

More interestingly, the pollsters asked whether people believed that global warming was having an effect on intense hurricanes, droughts, heat waves and the like. Again, roughly 70% of people thought that global warming was having either some effect or a major effect on these weather extremes (note that the question was not phrased to ask whether any specific event was thought likely to have been caused by global warming (which was probably a good choice)).

This begs the question whether people’s experience of severe weather has convinced them that climate change is occuring. Televangelist Pat Robertson, for instance, said very recently that it was the latest heat wave that finally convinced him. I think this is likely to be true for most of the public who are not following the issue very carefully (which is most of them of course!). The most significant single event in this context was probably Katrina, regardless of how much climate change can or can’t be associated with Katrina the Hurricane (let alone Katrina the Disaster!).

I would guess that this is likely to be a very common way for public opinion to be formed across a whole number of issues. That is, when a dominant theme is very prevalent across a wide spectra of media, everyday occurrences or new information are often processed with that in mind, and given our extraordinary ability to see patterns in noisy data, we often end up associating the theme with our own experiences. Other examples surely abound in medical or political contexts.

Given that pattern, it is probably overly optimistic to expect scientists, who continually stress that single weather events can’t in general be attributed to climate change but that changes in statistics might be, to have much success in conveying these finer points to the public directly. Instead, their skills are probably best used in clarifying these points to those (e.g. journalists, policy-makers) that set the dominant themes in the first place.

Ocean heat content: latest numbers

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Net ocean heat content changes are very closely tied to the net radiative imbalance of the planet since the ocean component of the climate system has by far the biggest heat capacity. Thus we have often made the point that diagnosing this imbalance through measurements of temperature in the ocean is a key metric in evaluating the response of the system to changes in CO2 and the other radiative forcings (see here).
In a paper I co-authored last year (Hansen et al, 2005), we compared model results with the trends over the 1993 to 2003 period and showed that they matched quite well (here). Given their importance in evaluating climate models, new reports on the ocean heat content numbers are anticipated quite closely.

Recently, a new preprint with the latest observations (2003 to 2005) has appeared (Lyman et al, hat tip to Climate Science) which shows a decrease in the ocean heat content over those two years, decreasing the magnitude of the long-term trend that had been shown from 1993 to 2003 in previous work (Willis et al, 2004) – from 0.6 W/m2 to about 0.33 W/m2. This has generated a lot of commentary in some circles, but in many cases the full context has not been appreciated.
[Read more…] about Ocean heat content: latest numbers

The missing repertoire

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There was a small flurry of activity last week when the report “Warm words: How are we telling the climate story and how can we tell it better?” was released by the IPPR (a UK based left-leaning think tank). Most of the attention was focussed on their attention-seeking description of the more breathless media depictions of climate change as ‘climate porn’. However, the report was actually more interesting than just that, but possibly in ways that the authors didn’t intend.

[Read more…] about The missing repertoire

Amazonian drought

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Translations: (Slovenčina)

There has been a flurry of recent commentary concerning Amazon drought – some of it good, some of it not so good. The good stuff has revolved around a recently-completed interesting field experiment that was run out of the Woods Hole Research Center (not to be confused with the Woods Hole Oceanographic Institution), where they have been examining rainforest responses to drought – basically by using a very large rainproof tent to divert precipitation at ground level (the trees don’t get covered up). As one might expect, a rainforest without rain does not do well! But exactly what happens when and how the biosphere responds are poorly understood. This 6 year long field experiment may provide a lot of good new data on plant strategies for dealing with drought which will be used to improve the models and our understanding of the system.

The not-so-good part comes when this experiment is linked too directly to the ongoing drought in the southern Amazon. In the experiment, older tree mortality increased markedly after the third year of no rain at all (with around 1 in 10 trees dying). Since parts of the Amazon are now entering a second year of drought (possibly related to a persistent northward excursion of the ITCZ), the assumption in the Independent story (with the headline ‘One year to save the Amazon’) was that trees will start dying forest-wide next year should the drought continue. [Read more…] about Amazonian drought

The not-just-in-Copenhagen consensus

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Anyone who spends any time mixing with climate scientists or really looking at the literature knows that the scientific consensus on the reality of human-related climate change is almost universal. Thus it is not at all surprising that methods designed to assess this consensus objectively – such as that undertaken by Oreskes in 2004 and recently re-asserted in the LA Times (non-subscription version) come up with very conclusive results. Similar studies could be done by looking at abstracts at big meetings (AGU, EGU etc.) or simply by talking to us. One could of course argue about what this means, but the existence of this consensus is not really up for debate. That doesn’t stop some people from trying of course, but these attempts have been rather embarrassing at best.

However, that didn’t prevent the latest incoherent and highly misleading press release from the Senate EPW committee being issued to support the effort. I was recently in conversation with a journalist, who told me that she’d asked the ex-talk-radio author of these EPW releases, Mark Morano, what exactly they were suppposed to achieve. Morano replied that it was to ‘get their message out’. When asked what that message was, no clear answer was forthcoming. That politicians indulge in politics is not surprising, but these releases are really scraping along the bottom. The only consolation is that they are being completely ignored by the media. Long may that consensus remain!

Medieval warmth and English wine

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Never let it be said that we at RealClimate don’t work for our readers. Since a commenter mentioned the medieval vineyards in England, I’ve been engaged on a quixotic quest to discover the truth about the oft-cited, but seldom thought through, claim that the existence of said vineyards a thousand years ago implies that a ‘Medieval Warm Period‘ was obviously warmer than the current climate (and by implication that human-caused global warming is not occuring). This claim comes up pretty frequently, and examples come from many of the usual suspects e.g. Singer (2005), and Baliunas (in 2003). The basic idea is that i) vineyards are a good proxy for temperature, ii) there were vineyards in England in medieval times, iii) everyone knows you don’t get English wine these days, iv) therefore England was warmer back then, and v) therefore increasing greenhouse gases have no radiative effect. I’ll examine each of these propositions in turn (but I’ll admit the logic of the last step escapes me). I’ll use two principle sources, the excellent (and cheap) “Winelands of Britain” by geologist Richard C. Selley and the website of the English Wine Producers. [Read more…] about Medieval warmth and English wine

Runaway tipping points of no return

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Translations: (Slovenčina)

I wonder if any else has noticed that we appear to have crossed a threshold in the usage of the phrase ‘tipping point’ in discussions of climate? We went from a time when it was never used, to a point (of no return?) where it is used in almost 100% of articles on the subject. Someone should come up with a name for this phenomenon….

Regardless of the recent linguistic trends, the concept has been around for a long time. The idea is that in many non-linear systems (of which the climate is certainly one), a small push away from one state only has small effects at first but at some ‘tipping point’ the system can flip and go rapidly into another state. This is fundamentally tied to the existence of positive feedbacks and is sometimes related to the concept of multiple ‘attractors’ (i.e. at any time two different ‘states’ could be possible and near a transition the system can flip very quickly from one to another). Another ‘tipping point’ in non-linear systems occurs when as some parameter varies, the current attractor changes character or disappears. However it is currently being used interchangeably a number of potentially confusing ways and so I thought I’d try and make it a little clearer.

[Read more…] about Runaway tipping points of no return