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Don’t estimate acceleration by fitting a quadratic…

Filed under: — stefan @ 20 November 2012

… if your data do not look like a quadratic!

This is a post about global sea-level rise, but I put that message up front so that you’ve got it even if you don’t read any further.

The reputable climate-statistics blogger Tamino, who is a professional statistician in real life and has published a couple of posts on this topic, puts it bluntly:

Fitting a quadratic to test for change in the rate of sea-level rise is a fool’s errand.

I’d like to explain why, with the help of a simple example. Imagine your rate of sea-level rise changes over 100 years in the following way:
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ClimateDialogue: Exploring different views on climate change

Filed under: — group @ 15 November 2012

This is a guest posting from some Dutch colleagues on a new online experiment in fostering dialogue on climate change. Bart Verheggen has asked us to host this quick introduction. We are interested to hear if you think this is a good idea.

Guest Commentary by Bart Strengers (PBL)

ClimateDialogue.org offers a platform for discussions between invited climate scientists on important climate topics that have been subject to scientific and public debate. The goal of the platform is to explore the full range of views currently held by scientists by inviting experts with different views on the topic of discussion. We encourage the invited scientists to formulate their own personal scientific views; they are not asked to act as representatives for any particular group in the climate debate.

Obviously, there are many excellent blogs that facilitate discussions between climate experts, but as the climate debate is highly polarized and politicized, blog discussions between experts with opposing views are rare.

Background


The discovery, early 2010, of a number of errors in the Fourth IPCC Assessment Report on climate impacts (Working Group II), led to a review of the processes and procedures of the IPCC by the InterAcademy Council (IAC). The IAC-report triggered a debate in the Dutch Parliament about the reliability of climate science in general. Based on the IAC recommendation that ‘the full range of views’ should be covered in the IPCC reports, Parliament asked the Dutch government ‘to also involve climate skeptics in future studies on climate change’.

In response, the Ministry of Infrastructure and the Environment announced a number of projects that are aimed to increase this involvement. ClimateDialogue.org is one of these projects.


We are starting ClimateDialogue with a discussion on the causes of the decline of Arctic Sea Ice, and the question to what extent this decline can be explained by global warming. Also, the projected timing of the first year that the Arctic will be ice free will be discussed. With respect to the latter, in its Fourth Assessment Report in 2007, IPCC anticipated that (near) ice free conditions might occur by the end of this century. Since then, several studies have indicated this could be between 2030-2050, or even earlier.

We invited three experts to take part in the discussion: Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology; Walt Meier, research scientist at the National Snow & Ice Data Center (NSIDC) in Boulder, Colorado; and Ron Lindsay, Senior Principal Physicist at the Polar Science Center of the University of Washington in Seattle.

Future topics that will be discussed include: climate sensitivity, sea level rise, urban heat island-effects, the value of comprehensive climate models, ocean heat storage, and the warming trend over the past few decades.

Our format


Each discussion will be kicked off by a short introduction written by the editorial staff, followed by a guest blog by two or more invited scientists. The scientists will start the discussion by responding to each other’s arguments. It is not the goal of ClimateDialogue to reach a consensus, but to stimulate the discussion and to make clear what the discussants agree or disagree on and why. 
To round off the discussion on a particular topic, the ClimateDialogue editor will write a summary, describing the areas of agreement and disagreement between the discussants. The participants will be asked to approve this final article, the discussion between the experts on that topic will then be closed and the editorial board will open a new discussion on a different topic.

The public (including other climate scientists) are also free to comment, but for practical reasons these comments will be shown separately.

The project organization consists of an editorial staff of three people and an advisory board of seven people, all of whom are based in the Netherlands. The editorial staff is concerned with the day-to-day operation of researching topics, finding participants for the discussion and moderating the discussions between the experts. The main task of the advisory board is to guard the neutrality of the platform and to advise the editorial staff about its activities

The project leader is Rob van Dorland of the Royal Netherlands Meteorological Institute (KNMI), a senior scientist and climate advisor in the Climate Services section and is often active at the interface between science and society. The second member is Bart Strengers. He is a climate policy analyst and modeler in the IMAGE-project at the PBL Netherlands Environmental Assessment Agency (PBL) and has been involved in the discussion with climate skeptics for many years. The third member is Marcel Crok, an investigative science writer, who published a critical book (in Dutch) about the climate debate.

We welcome comments here and are happy to answer any questions regarding this project. You can also send an email to info [at] climatedialogue [dot] org.

PBS: Climate of Doubt

Filed under: — gavin @ 24 October 2012

The video of Tuesday’s PBS show on the politics of the climate debate is available – I make a minor appearance…

The PBS website has more background.

A sea level Golden Horseshoe nominee*

Filed under: — gavin @ 14 October 2012

I was reading a sign high on the wall behind the bar:

‘Only genuine pre-war British and American whiskeys served here’

I was trying to count how many lies could be found in those nine words, and had reached four, with promise of more …”

Dashiell Hammett, “The Golden Horseshoe”

Google News occasionally throws up some obscure postings that I would never otherwise come across. A recent example was a letter to an editor of a Scottish newspaper (not my usual reading material) declaring that “Climate change is not man-made”. The letter itself is uninteresting – a basic confusion between weather and climate seguing into a NIMBY-ish rant about windmills. Ho hum.

However, in one of the comments from a “Dr John Cameron, St Andrews” (posted 9/Oct/2012), there was this unrelated pseudo-factoid:

As regards the catastrophic sea level rise in the Pacific, it became obvious some 20 years ago that results from island tide gauges did not support computer predictions. Scientists from Flinders University in Adelaide set up new, modern, tide-gauges in 12 Pacific islands to test whether there was in fact any evidence of sinking. Recently the whole project was abandoned as there had been no sign whatsoever of a change in sea level at any of the 12 islands for the past 16 years.

Now this is specific enough to probably actually refer to something real, but doesn’t pass the sniff test for something that might actually be true. Scientists don’t set up monitoring stations only to get the answer they want and then stop monitoring if it doesn’t happen. This only happens in the fevered imaginations of conspiracy theorists. So I was intrigued enough to investigate what this actually referred to…
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Let the games begin!

Filed under: — gavin @ 4 August 2012

I picked a good weekend to be out of cell phone range and unconnected to the internet – and judging from how the rest of the week has gone, I’d have been minded to stay there…

As most readers are probably aware, there was an op-ed in the Saturday New York Times from Richard Muller announcing the Berkeley Earth team’s latest results. It was odd enough that a scientific paper was announced via an op-ed, rather than a press release, odder still that the paper was only being submitted and had not actually been accepted, and most odd of all was the framing – a ‘converted skeptic’ being convinced by his studies that the planet has indeed warmed and that human activity is the cause – which as Mike and Ken Caldiera pointed out has been known for almost 2 decades.

Not wanting to be upstaged, plenty of ‘unconverted skeptics’ – including Anthony Watts and Ross McKitrick decided to stage dramatic press events and release barbs of their own. This was followed by a general piling on of commenters and bloggers trying to spin the events in their preferred direction combined with plenty of cluelessness in the general media about exactly who these people are (no-one special), what earth-shattering discovery had been made (none) and what it all means (not a lot).

The ‘best’ response to this circus is to sit back and see how pretzel-like the logical justifications can become. I particularly like the recent twist to the “No true scotsman” post-hoc rationalisation. Since the ‘converted skeptic’/prodigal scientist meme is a very powerful framing for the media, the obvious riposte for the ‘skeptics’ is to declare that Muller was not a true skeptic. But since these terms have become meaningless in terms of any specific position, this ends up as a semantic argument that convinces no-one but the faithful.

The actual trigger for all this hoopla is the deadline for papers that can be cited in the Second Order Draft of the new IPCC report. They needed to have been submitted to a journal by Tuesday (31 July) to qualify. Of course, they also need to be interesting, relevant and known to the IPCC lead authors. But there seems to be far too much emphasis being put on this deadline. The AR5 report is pretty much 90% written, and the broad outlines have been known for ages. Very few of the papers that have been submitted this week are anything other than minor steps forward and only a small number will be accorded anything other than a brief mention in AR5, and most not even that.

Furthermore, once the SOD is finalised (Aug 10), Tuesday’s deadline becomes moot, and the only thing that matters for the final report is whether papers are accepted by March 2013. (In a spirit of full disclosure, I should mention that I was working on a couple of papers with an eye to making this deadline, but in the end decided it was preferable to take the time to do a good job on the papers than to submit something shoddy).

The only worthwhile substance to any of this is the work that has mostly been done by Robert Rohde on the Berkeley Earth code and database as we’ve noted previously – and once this week’s drama has faded into the distance overshadowed by some new blog-storm, this work will still be a useful advance.

But still the games go on. Senate hearings are one of the longest running games of political theatre going – where the Senators pretend to listen to the panelists and the panelists pretend that this is an efficient way to inform policymakers. This week’s was little different from the ones in the past – some earnest submissions from the mainstream, and a cherry-pickers delight of misinformation from the Republican invitee, John Christy, who even quoted the woefully inept first draft of the Watts paper as if it meant something.

To confuse the metaphor even further, Roger Pielke Sr loudly declared that whatever the results of the Watts paper it will end up being a game changer:

The TOB effect could result in a confirmation of the Watts et al conclusion, or a confirmation (from a skeptical source) that siting quality does not matter. In either case, this is still a game changing study.

If only people would change the games they play…

My inclination is just to sit back and watch the spectacle, admire the logic-defying leaps, marvel at the super-human feats of hubris and, in two weeks time, remark on how little actually changed.


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