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Bubkes

Filed under: — gavin @ 26 June 2009 - (Chinese (simplified))

Some parts of the blogosphere, headed up by CEI (“CO2: They call it pollution, we call it life!“), are all a-twitter over an apparently “suppressed” document that supposedly undermines the EPA Endangerment finding about human emissions of carbon dioxide and a basket of other greenhouse gases. Well a draft of this “suppressed” document has been released and we can now all read this allegedly devastating critique of the EPA science. Let’s take a look…

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A warning from Copenhagen

Filed under: — stefan @ 21 June 2009 - (Deutsch) (Chinese (simplified)) (Español)

In March the biggest climate conference of the year took place in Copenhagen: 2500 participants from 80 countries, 1400 scientific presentations. Last week, the Synthesis Report of the Copenhagen Congress was handed over to the Danish Prime Minister Rasmussen in Brussels. Denmark will host the decisive round of negotiations on the new climate protection agreement this coming December.

The climate congress was organised by a “star alliance” of research universities: Copenhagen, Yale, Berkeley, Oxford, Cambridge, Tokyo, Beijing – to name a few. The Synthesis Report is the most important update of climate science since the 2007 IPCC report.

So what does it say? Our regular readers will hardly be surprised by the key findings from physical climate science, most of which we have already discussed here. Some aspects of climate change are progressing faster than was expected a few years ago – such as rising sea levels, the increase of heat stored in the ocean and the shrinking Arctic sea ice. “The updated estimates of the future global mean sea level rise are about double the IPCC projections from 2007″, says the new report. And it points out that any warming caused will be virtually irreversible for at least a thousand years – because of the long residence time of CO2 in the atmosphere.

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Winds of change

Filed under: — group @ 11 June 2009

Gavin Schmidt and Michael Mann

There was an interesting AP story this week about possible changes in wind speed over the continental US. The study (by Pryor et al (sub.)), put together a lot of observational data, reanalyses (from the weather forecasting models) and regional models, and concluded that there was some evidence for a decrease in wind speeds, particularly in the Eastern US. However, although this trend appeared in the observational data, it isn’t seen in all the reanalyses or regional models, leaving open a possibility that the trend is an artifact of some sort (instrumental changes, urbanization etc.). If the effect is real though, one would want to see whether it could be tied to anything else (such as forcing from greenhouse gas or aerosol increases), and indeed, whether it had any implications for wind-generated electricity, water evaporation etc.

Amusingly, both of us were quoted in the story as having ostensibly conflicting views. Mike was quoted as finding the evidence for a trend reasonably convincing, while Gavin was quoted as being unconvinced of the evidence for an anthropogenic climate change signal (note that the two statements are not in fact mutually inconsistent). As one should expect in any news story, these single lines don’t really do justice to the longlonger interviews both of us gave the reporter Seth Borenstein. So what is the bigger context?
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Groundhog day

Filed under: — gavin @ 7 June 2009

Alert readers will have noticed the fewer-than-normal postings over the last couple of weeks. This is related mostly to pressures associated with real work (remember that we do have day jobs). In my case, it is because of the preparations for the next IPCC assessment and the need for our group to have a functioning and reasonably realistic climate model with which to start the new round of simulations. These all need to be up and running very quickly if we are going to make the early 2010 deadlines.

But, to be frank, there has been another reason. When we started this blog, there was a lot of ground to cover – how climate models worked, the difference between short term noise and long term signal, how the carbon cycle worked, connections between climate change and air quality, aerosol effects, the relevance of paleo-climate, the nature of rapid climate change etc. These things were/are fun to talk about and it was/is easy for us to share our enthusiasm for the science and, more importantly, the scientific process.

However, recently there has been more of a sense that the issues being discussed (in the media or online) have a bit of a groundhog day quality to them. The same nonsense, the same logical fallacies, the same confusions – all seem to be endlessly repeated. The same strawmen are being constructed and demolished as if they were part of a make-work scheme for the building industry attached to the stimulus proposal. Indeed, the enthusiastic recycling of talking points long thought to have been dead and buried has been given a huge boost by the publication of a new book by Ian Plimer who seems to have been collecting them for years. Given the number of simply made-up ‘facts’ in that tome, one soon realises that the concept of an objective reality against which one should measure claims and judge arguments is not something that is universally shared. This is troubling – and although there is certainly a role for some to point out the incoherence of such arguments (which in that case Tim Lambert and Ian Enting are doing very well), it isn’t something that requires much in the way of physical understanding or scientific background. (As an aside this is a good video description of the now-classic Dunning and Kruger papers on how the people who are most wrong are the least able to perceive it).

The Onion had a great piece last week that encapsulates the trajectory of these discussions very well. This will of course be familiar to anyone who has followed a comment thread too far into the weeds, and is one of the main reasons why people with actual, constructive things to add to a discourse get discouraged from wading into wikipedia, blogs or the media. One has to hope that there is the possibility of progress before one engages.

However there is still cause to engage – not out of the hope that the people who make idiotic statements can be educated – but because bystanders deserve to know where better information can be found. Still, it can sometimes be hard to find the enthusiasm. A case in point is a 100+ comment thread criticising my recent book in which it was clear that not a single critic had read a word of it (you can find the thread easily enough if you need to – it’s too stupid to link to). Not only had no-one read it, none of the commenters even seemed to think they needed to – most found it easier to imagine what was contained within and criticise that instead. It is vaguely amusing in a somewhat uncomfortable way.

Communicating with people who won’t open the book, read the blog post or watch the program because they already ‘know’ what must be in it, is tough and probably not worth one’s time. But communication in general is worthwhile and finding ways to get even a few people to turn the page and allow themselves to be engaged by what is actually a fantastic human and scientific story, is something worth a lot of our time.

Along those lines, Randy Olson (a scientist-turned-filmmaker-and-author) has a new book coming out called “Don’t Be Such a Scientist: Talking Substance in an Age of Style” which could potentially be a useful addition to that discussion. There is a nice post over at Chris Mooney’s blog here, though read Bob Grumbine’s comments as well. (For those of you unfamiliar the Bob’s name, he was one of the stalwarts of the Usenet sci.environment discussions back in the ‘old’ days, along with Michael Tobis, Eli Rabett and our own William Connolley. He too has his own blog now).

All of this is really just an introduction to these questions: What is it that you feel needs more explaining? What interesting bits of the science would you like to know more about? Is there really anything new under the contrarian sun that needs addressing? Let us know in the comments and we’ll take a look. Thanks.

On overfitting

I don’t tend to read other blogs much, despite contributing to RealClimate. And I’m especially uninterested in spending time reading blogs full of ad hominem attacks. But a handful of colleagues apparently do read this stuff, and have encouraged me to take a look at the latest commentaries on our Antarctic temperature story. Since I happen to be teaching about principal component analysis to my graduate students this week, I thought it would be worthwhile to put up a pedagogical post on the subject. (If you don’t know what principal component analysis (PCA) is, take a look at our earlier post, Dummy’s Guide to the Hockey Stick Controversy).
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