Thursday, January 21, 2010

Schiermeier in nature - quoting incorrectly

Quirin Schiermeier quotes me with "You need to be very circumspect about the added value of downscaling to regional impacts," agrees Hans von Storch in this week's issue of nature. And: he cautions, "planners should handle them with kid gloves. Whenever possible, they'd rather wait with spending big money on adaptation projects until there is more certainty about the things to come." I have not spoken with Mr Schiermeier about regional modelling, at least not recently; the term "kid gloves" is unknown to me, not part of my vocabulary. I have asked him for evidence that I have said these sentences to whom.

Indeed, I have been in contact with Quirin Schiermeier earlier this year, asking for "myths" about climate change. I have offered him three cases, none of them had any reference to regional modelling. He had told me that he would use the first of my myths, but obviously he decided to use my name differently.

Here are my three myths:

Myth #1: "Climate models provide decision makers with predictions."
   Here, "predictions" are understood as "probable developments", or even "most probable developments". However, the descriptions provided by climate models depend on a number of critical assumptions, first of all the amount of greenhouse gases emitted, or accumulated in the atmosphere. Thus they are conditional predictions – conditional upon social and economic developments. Most of these developments can not be predicted themselves but are described by "scenarios", so that the depictions of future climate itself are "scenarios", or is it often called, "projections".(Climate projections are distinguished from climate predictions in order to emphasize that climate projections depend upon the emission/concentration/radiative forcing scenario used, which are based on assumptions concerning, for example, future socioeconomic and technological developments that may or may not be realized. (see Baede, A. P. M. (Ed.) (n.d.). IPCC Annex I: Glossary. Retrieved February 9, 2009, from http://www.ipcc.ch/pdf/glossary/ar4-wg1.pdf)
   If all scenarios point to the same change, e.g., warming, this results in an unconditional prediction. Thus, a warming and a rise in sea level is predicted, but the rate of warming or sea level are given as scenarios i.e., possible developments.
   Unfortunately, according to a survey (Bray, D., and H. von Storch, 2009: 'Prediction' or 'Projection'? The nomenclature of climate science. Sci. Comm. 30, 534-543, doi:10.1177/1075547009333698), about 20% of scientists use the term "predictions" when speaking about "possible developments" (i.e., scenarios). 70% use it consistent with the IPCC terminology.

Myth #2: "In the course of man-made climate change, all extremes become worse."
   Here, "become worse" means "happen more often" and/or "get more intense". The statement is false: only some extremes will become "worse", while others will become rarer or less intense. An example of the first relates to heat waves, which in the course of warming will become more frequent and more intensely. An example of the latter is cold periods, which become less frequent and less intense.
   A popular argument is that mid-latitude wind storms must become "worse" because of elevated water vapour levels in the atmosphere. However, other effects influence the formation of storms such as vertical stability or horizontal temperature gradients, so that the European recovery from the little ice-age, which was associated with a warming, was not associated with a detectable intensification of storm activity in Northern Europe.
   Thus, some extremes will get "worse", while others they may become "better". Sometimes, the change will vary regionally.

Myth #3: "All changes of climatic conditions are related to human causes".
   This claim is usually not voiced explicitly, but implicit in numerous hints that certain events must be understood as "abnormal" and "consistent with" or even "due to man-made climate change". However, changes can be due to various causes, from natural variability, to changes in local conditions (e.g., urbanization), to changes in observational practices incl. instrumentation.
   Before attributing a change to global climate change, a "detection and attribution study" is needed. Such a study determines first how unusual the change is compared to the statistics of changes under undisturbed conditions. If so, then the different possible causes are screened which provides the most consistent explanation. This is usually only possible if the developments has been homogeneously be documented by observations for several decades.
 

6 comments:

Anonymous said...

Verb: handle with kid gloves

1.(idiomatic) (US) To treat something very delicately or carefully.
The campaign staff cautioned the candidate to handle the issue with kid gloves.

Anonymous said...

Schiermeier does not appear very concerned about accuracy. In his latest post on the Nature Climate feedback blog, about the IPCC error, I found 7 typos!

Richard Tol said...
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H Hak said...

Regarding myth nr 1 : also consider reliability of GCMs
Drs von Storch and Zorita,would you be willing to debate a mathematician and numerical annalist who has some basic questions on GCMs but has been unable to get any response from the climate modelers he approached?
The discussion is on Climate Audit under J Curry's review of Lindzen and Choi 2009. You could join there or reply here. The question is :
Gerald Browning
Posted Jan 19, 2010 at 5:58 PM | Permalink | Reply

Judith Curry,

Can you now give as careful a review of the problems with climate models?

No mathematician or numerical analyst would believe that a finite difference approximation of the atmospheric and oceanic equations with the real atmospheric and oceanic dissipation rates is accurate for more than a few
days. In this regard see the spread of error from an inaccurate approximation of the surface boundary layer to higher altitudes in a few days in Sylvie Gravel’s manuscript on this site. Note that this error growth is due to only one parameterization error. It is not hard to imagine the
problems due to other parameterization errors, especially in the tropics where the total (net) heating is dominant, but very poorly understood.

If a long time scale is crucial to understanding climate sensitivity, climate models have no mathematical or numerical justification for determining that sensitivity. They are basically a WPA project for
scientists that are dependent on them for publications without the use of rigorous mathematical analysis.

As one final note, can you please provide a rigorous mathematical explanation for convective adjustment, i.e., the artificial conversion of a small columnar feature (instability)into a large scale hydrostatic feature?
In particular, what impact does that adjustment have on the numerical
accuracy of the finite difference approximation of the continuous dynanical equations?

Jerry

Jason said...
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Hans von Storch said...

Following a demand by Mcmillan publishers I have deleted three posts in this thread - which were seen as "defamatory postings". Unfortunately I have also deleted my own one, which was not part of the complaint.
Therefore, I repost it here:

------------------
In some blogs it has been claimed that nature would have "invented" an interview with me - likely based on my statement "I have not spoken with Mr Schiermeier about regional modelling, at least not recently". This statement was insofar misleading that I had spoken with Quirin Schiermeier on December 8 (see my later post on this blog, which I actually had forgotten. I would, however, qualify a telephone conversation six weeks earlier not as "recent". Thus, claims that nature had "invented" a conversation are false, and I did not make such claims.
What I said was that the direct quotes were inaccurate, and indeed, Mr Schiermeier admits in the post, referenced above, that he failed to ask for authorization. When time limits are tights, this may be understandable, but I consider this inadequate journalistic practice – when first notes are scribbled down during a phone conversation, things may be have been said in ways, which may be understood in different ways, the notes are a short and possibly inadequate short version, and finally the translation into a different language may further move the original answer further away form what was meant. That is way direct quotes need to be authorized, also by a journal like "nature".
The request for authorization is directed only at direct quotes; if the journalist describes his or her perception – in indirect quotes – that is fine for me.
After I had an exchange with Quirin Schiermeier (see above posting), I cosnider the the episode as being clarified, and I have no bad feelings towards Quirin Schiermeier - even if I seriously hope that his journal and he himself will change the practice of using unauthorized direct quotes. I am, however, less than pleased that various blogs transformed my statement into the false claim of "invention".