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Science at the bleating edge

7 Jul 2009 by Gavin

Many of you will remember our pioneering discussion of the Sheep-albedo hypothesis, where we suggested that increasing numbers of sheep would cause a cooling climate because of their impact on the ground reflectivity. Well, new observations have now added significantly more complexity to this seemingly understood situation. It has just been reported that as well as the original sheep-albedo effect, there is now evidence of a second sheep-albedo effect (smaller sheep as the world warms). That would be a amplifying effect in general, but the actual population of sheep concerned come in many colours, so the overall affect is uncertain. (There is even speculation about a third effect (the sheep lifetime albedo impact), which could go either way depending the Lamb Marketing Board advertising campaign).

Yet more evidence that the science is very woolly.

*Title taken from a comment from glen

Filed Under: Climate Science

Science at the bleeding edge

6 Jul 2009 by Gavin

The vast majority of mainstream media items about science are related to new hot-off-the-press studies, often in high profile journals, that report a new breakthrough, or that purportedly overturn previous ideas. However, while these are exciting news items, this preponderance of coverage given to these state-of-the-art studies compared to assessments such as from the National Academies, can give a misleading impression about the state of a scientific knowledge. The more mature and solid a field, the less controversy there is, and thus the fewer news stories. Ironically, this means the public is told the least about the most solid aspects of science.

One effect of this tendency is that quite often news stories are focused on claims that turn out to be wrong, or if not actually wrong, heavily reduced in importance by the time the dust settles. This is not deliberate, but merely how science works at the frontier. People push measurements to the limit of their accuracy (and sometimes beyond) and theories are used slightly out of their domain of applicability. In recognition of that, Richard Feynman had a useful rule of thumb that the last data point on any graph should be discounted because, if it had been easy to obtain, there would have been another one further along.

[Read more…] about Science at the bleeding edge

Filed Under: Climate Science, Reporting on climate

More bubkes

1 Jul 2009 by group

Translations: (Chinese (simplified)) (English)

Roger Pielke Sr. has raised very strong allegations against RealClimate in a recent blog post. Since they come from a scientific colleague, we consider it worthwhile responding directly.

The statement Pielke considers “misinformation” is a single sentence from a recent posting:

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.

First of all, we are surprised that Pielke levelled such strong allegations against RealClimate, since the statement above merely summarises some key findings of the Synthesis Report of the Copenhagen Climate Congress, which we discussed last month. This is a peer-reviewed document authored by 12 leading scientists and “based on the 16 plenary talks given at the Congress as well as input of over 80 chairs and co-chairs of the 58 parallel sessions held at the Congress.” If Pielke disagrees with the findings of these scientists, you’d have thought he’d take it up with them rather than aiming shrill accusations at us. But in any case let us look at the three items of alleged misinformation:

[Read more…] about More bubkes

Filed Under: Climate Science

Bubkes

26 Jun 2009 by Gavin

Translations: (Chinese (simplified)) (English)

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…

[Read more…] about Bubkes

Filed Under: Climate Science, Greenhouse gases

A warning from Copenhagen

21 Jun 2009 by Stefan

Translations: (Deutsch) (Chinese (simplified)) (English)

Una traducción está disponible aquí.

Filed Under: Climate Science, Reporting on climate

Winds of change

11 Jun 2009 by group

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?
[Read more…] about Winds of change

Filed Under: Climate modelling, Climate Science, Instrumental Record

Groundhog day

7 Jun 2009 by Gavin

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.

Filed Under: Climate Science, Communicating Climate

On overfitting

1 Jun 2009 by eric

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).
[Read more…] about On overfitting

Filed Under: Arctic and Antarctic, Climate Science, Instrumental Record, Paleoclimate, Tutorials

Of tempests, barren ground and a thousand furlongs of sea

21 May 2009 by group

Guest commentary by Ron Miller, NASA GISS

Several studies have shown that hurricane activity is generally reduced during years when there is a thick aerosol haze over the subtropical Atlantic. The haze is comprised mainly of soil particles, stripped by wind erosion from the barren ground over the Sahara and Sahel. These particles are lifted into the atmosphere and carried by the Trade winds as far as the Caribbean and Amazon basin. Plumes of dust streaming off the African coast are easily recognized in satellite imagery, and were even described by Charles Darwin during his voyage on the Beagle.

[Read more…] about Of tempests, barren ground and a thousand furlongs of sea

Filed Under: Aerosols, Climate Science, Hurricanes

The tragedy of climate commons

7 May 2009 by Gavin

Translations: (Svenska) (English)

Imagine a group of 100 fisherman faced with declining stocks and worried about the sustainability of their resource and their livelihoods. One of them works out that the total sustainable catch is about 20% of what everyone is catching now (with some uncertainty of course) but that if current trends of increasing catches (about 2% a year) continue the resource would be depleted in short order. Faced with that prospect, the fishermen gather to decide what to do. The problem is made more complicated because some groups of fishermen are much more efficient than the others. The top 5 catchers, catch 20% of the fish, and the top 20 catch almost 75% of the fish. Meanwhile the least efficient 50 catch only 10% of the fish and barely subsist. Clearly, fairness demands that the top catchers lead the way in moving towards a more sustainable future.

[Read more…] about The tragedy of climate commons

Filed Under: Climate Science

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