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wetterfrosch

L'ex ministre fait le clown!

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Cuckoo Science

http://www.realclimate.org/index.php/archi...cuckoo-science/

Par Gavin Schmidt

Sometimes on Realclimate we discuss important scientific uncertainties, and sometimes we try and clarify some subtle point or context, but at other times, we have a little fun in pointing out some of the absurdities that occasionally pass for serious 'science' on the web and in the media [Quelque fois nous discutons sur realClimate des absurdités que l'on peut trouver sur le web et dans les médias

]. These pieces look scientific to the layperson (they have equations! references to 19th Century physicists!), but like cuckoo eggs in a nest, they are only designed to look real enough to fool onlookers and crowd out the real science [ Ces papiers paraissent scientifiques. Comme les oeufs de coucous dans un nid. Ils sont désignées pour paraitre suffisemment scientifiques pour le lecteur idiot

]. A cursory glance from anyone knowledgeable is usually enough to see that concepts are being mangled, logic is being thrown to the winds, and completetly unjustified conclusions are being drawn - but the tricks being used are sometimes a little subtle. [un coup d'oeil par une personne bien informée est en général suffisant pour se rendre compte que les concepts sont déchiquetés, que la logique jettée au vent et que des conclusions injustiées sont dessinées

]

Two pieces that have recently drawn some attention fit this mould exactly. One by Christopher Monckton (a viscount, no less, with obviously too much time on his hands) which comes complete with supplematary 'calculations' using his own 'M' model of climate, and one on JunkScience.com ('What Watt is what'). Junk Science is a front end for Steve Milloy, long time tobacco, drug and oil industry lobbyist, and who has been a reliable source for these 'cuckoo science' pieces for years. Curiously enough, both pieces use some of the same sleight-of-hand to fool the unwary (coincidence?).

But never fear, RealClimate is here! [ Mais n'ayez crainte, RealClimate est là !

]

The two pieces both spend a lot of time discussing climate sensitivity but since they don't clearly say so upfront, it might not at first be obvious. (This is possibly because if you google the words 'climate sensitivity' you get very sensible discussions of the concept from Wikipedia, ourselves and the National Academies). We have often made the case here that equilibrium climate sensitivity is most likely to be around 0.75 +/- 0.25 C/(W/m2) (corresponding to about a 3°C rise for a doubling of CO2).

Both these pieces instead purport to show using 'common sense' arguments that climate sensitivity must be small (more like 0.2 W/m2, or less than 1°C for 2xCO2). [Au lieu de cela, ces deux papiers, en utilisant des "arguments de bon sens", veulent montrer que la sensibilité climatique devrait être plus faible (moins d'un degré pour un doublement du taux de C02 pré-industriel

) ] Our previous posts should be enough to demonstrate that this can't be correct, but it worth seeing how they arithimetically manage to get these answers. [Nos articles précèdants sur RealClimate devraient être suffisants pour montrer que ce n'est pas correct, mais ça à plus de valeur de voir comment ils arrivent mathématiquement à ces réponses

] To save you having to wade through it all, I'll give you the answer now: the clue is in the units of climate sensitivity - °C/(W/m2). Any temperature change (in °C) divided by any energy flux (in W/m2) will have the same unit and thus can be 'compared'. But unless you understand how radiative forcing is defined (it's actually quite specific), and why it's a useful diagnostic, these similar seeming values could be confusing. Which is presumably the point.

Readers need to be aware of at least two basic things. First off, an idealised 'black body' (which gives of radiation in a very uniform and predictable way as a function of temperature - encapsulated in the Stefan-Boltzmann equation) has a basic sensitivity (at Earth's radiating temperature) of about 0.27 °C/(W/m2). That is, a change in radiative forcing of about 4 W/m2 would give around 1°C warming. The second thing to know is that the Earth is not a black body! On the real planet, there are multitudes of feedbacks that affect other greenhouse components (ice alebdo, water vapour, c louds etc.) and so the true issue for climate sensitivity is what these feedbacks amount to.

[Commentaire : c'est la base, c'est fondamental]

So here's the first trick. Ignore all the feedbacks - then you will obviously get to a number that is close to the 'black body' calculation. Duh! Any calculation that lumps together water vapour and CO2 is effectively doing this (and if anyone is any doubt about whether water vapour is forcing or a feedback, I'd refer them to this older post).

As we explain in our glossary item, climatologists use the concept of radiative forcing and climate sensitivity because it provides a very robust predictive tool for knowing what model results will be, given a change of forcing. The climate sensitivity is an output of complex models (it is not decided ahead of time) and it doesn't help as much with the details of the response (i.e. regional patterns or changes in variance), but it's still quite useful for many broad brush responses. Empirically, we know that for a particular model, once you know its climate sensitivity you can easily predict how much it will warm or cool if you change one of the forcings (like CO2 or solar). We also know that the best definition of the forcing is the change in flux at the tropopause, and that the most predictable diagnostic is the global mean surface temperature anomaly. Thus it is natural to look at the real world and see whether there is evidence that it behaves in the same way (and it appears to, since model hindcasts of past changes match observations very well).

So for our next trick, try dividing energy fluxes at the surface by temperature changes at the surface. As is obvious, this isn't the same as the definition of climate sensitivity - it is in fact the same as the black body (no feedback case) discussed above - and so, again it's no surprise when the numbers come up as similar to the black body case.

But we are still not done! The next thing to conviently forget is that climate sensitivity is an equilibrium concept

[Commentaire : Importance du facteur temps, inertie du sytème etc.]. It tells you the temperature that you get to eventually. In a transient situation (such as we have at present), there is a lag related to the slow warm up of the oceans, which implies that the temperature takes a number of decades to catch up with the forcings. This lag is associated with the planetary energy imbalance and the rise in ocean heat content. If you don't take that into account it will always make the observed 'sensitivity' smaller than it should be. Therefore if you take the observed warming (0.6°C) and divide by the estimated total forcings (~1.6 +/- 1W/m2) you get a number that is roughly half the one expected. You can even go one better - if you ignore the fact that there are negative forcings in the system as well (cheifly aerosols and land use changes), the forcing from all the warming effects is larger still (~2.6 W/m2), and so the implied sensitivity even smaller! Of course, you could take the imbalance (~0.33 +/- 0.23 W/m2

in a recent paper) into account and use the total net forcing, but that would give you something that includes 3°C for 2xCO2 in the error bars, and that wouldn't be useful, would it? [ default_unsure.png ]

And finally, you can completely contradict all your prior working by implying that all the warming is due to solar forcing. Why is this contradictory? Because all of the above tricks work for solar forcings as well as greenhouse gas forcings. Either there are important feedbacks or there aren't. You can't have them for solar and not for greenhouse gases. Our best estimates of solar are that it is about 10 to 15% the magnitude of the greenhouse gas forcing over the 20th Century

. Even if that is wrong by a factor of 2 (which is conceivable), it's still less than half of the GHG changes. And of course, when you look at the last 50 years, there are no trends in solar forcing at all. Maybe it's best not to mention that

. [ Commentaire : Oui, il vaut mieux ! default_clover.gifdefault_blink.pngdefault_sorcerer.gif ]

There you have it. The cuckoo has come in and displaced the whole field of climate science. [Vous y êtes. Le coucou est entré et a supplanté l'ensemble du champs des sciences du climat

]

Impressive, yes? Errrr.... not really. [Impressionant, oui ? Errrrr......pas vraiment

.]

Plus d'infos sur les coucous ici :

/index.php?s=&showtopic=17453&view=findpost&p=349583'>http://forums.infoclimat.fr/index.php?s=&a...st&p=349583

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Il n'y a pas que des cuckoos dans le monde anglophone mais aussi dans le monde francophone...

NB - Le coucou (cuckoo) est un parasite et pond ses oeufs dans le nid d'autres espèces d'oiseaux.

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Posted

Location : Muret(180 m) et Font-Romeu (1760m)

Il n'y a pas que des cuckoos dans le monde anglophone mais aussi dans le monde francophone...

NB - Le coucou (cuckoo) est un parasite et pond ses oeufs dans le nid d'autres espèces d'oiseaux.

et en plus le coucou, il ne chante même pas bien.

Il ne sait faire que "cou-cou, cou-cou,...."

pas très varié! default_flowers.gif

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et en plus le coucou, il ne chante même pas bien. Il ne sait faire que "cou-cou, cou-cou,...."

pas très varié! default_flowers.gif

A propos de l'article cuckoo science de G Schmidt (climatologue de haut niveau de la NASA qui vient de recevoir un award de Scientific american), voici plusieurs sens pour le mot cuckoo :

- Nom commun :

1 - A grayish European bird (Cuculus canorus) that has a characteristic two-note call and lays its eggs in the nests of birds of other species. (oiseau grisâtre européen qui a un chant à deux notes caractéristique et qui pond ses oeufs dans les nids d'autres espèces d'oiseaux

)

2 - A person regarded as strange, eccentric, or crazy. A man who is a stupid fool. A foolish or crazy person. (une personne idiote ou folle

)

- Verbe : To cuckoo : To repeat incessantly, as a cuckoo does its call. (répèter sans cesse, comme le coucou le fait avec son cri

)

- Adjectif : Lacking in sense; foolish or crazy. Afflicted with or exhibiting irrationality and mental unsoundness

A propos de la négation organisée du réchauffement anthropique, l'expression cuckoo science est parfaitement adaptée.

NB - NASA Climatologists Named in Scientific American Top 50 Scientists

http://www.nasa.gov/vision/earth/everydaylife/sa_top50.html

" ...Dr. Gavin Schmidt is a computer climate modeler who works on developing large-scale models of the atmosphere-ocean climate system. He has worked on understanding climate variability both in past climates going back as far as 55 million years ago and forward to the possible future climates. He received a BA in Mathematics from Oxford University, U.K. in 1989 and a PhD in Applied Mathematics from University College London in 1994. He worked as a postdoctoral fellow at McGill University, Montreal until 1996, when he was awarded a NOAA Climate and Global Change Fellowship which allowed him to start working at NASA GISS.

Schmidt has over 30 papers in the scientific literature and is heavily involved in public outreach, most recently at the College de France in Paris, and among high school students in New York City, two of which he has mentored to the finals of the Intel International Science competition.

The scientists were selected by the magazine's Board of Editors with the help of distinguished outside advisors, the Scientific American 50 spotlights Research, Business and Policy Leaders of the Year. The list also recognizes research, business and policy leaders in various technological categories including Agriculture, Chemicals and Materials, Climate, Communications, Computing, Energy, Environment, Medical Treatments and more.

Founded in 1845, editorial contributors to Scientific American have included over 100 Nobel laureates, among them Albert Einstein, Neils Bohr, Francis Crick, Stanley Prusiner and Harold Varmus. Scientific American, Inc. is a division of Holtzbrinck Publishers, a U.S. subsidiary of Verlagsgruppe Georg von Holtzbrinck GmbH, a privately held International media corporation operating in more than 40 countries."

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Posted

Location : 34230 Paulhan - Centre Hérault

Il n'y a pas que des cuckoos dans le monde anglophone mais aussi dans le monde francophone...

NB - Le coucou (cuckoo) est un parasite et pond ses oeufs dans le nid d'autres espèces d'oiseaux.

Oui et c'est une sale bestiole qui n'hesite pas a balancer les oeufs des autres oiseaux par dessus bord, mais ce n'est pas un parasite pour tout, il a son utilité, en particulier c'est un grand prédateur des chenilles processionnaires qui envahissent les pinèdes.

http://www.oiseaux.net/oiseaux/cuculiformes/coucou.gris.html

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Oui et c'est une sale bestiole qui n'hesite pas a balancer les oeufs des autres oiseaux par dessus bord, mais ce n'est pas un parasite pour tout, il a son utilité, en particulier c'est un grand prédateur des chenilles processionnaires qui envahissent les pinèdes.

Oui, c'est vrai. Mais il n'est pas le seul à aimer les chenilles (pas que les processionnaires d'ailleurs). Et les pins acidifient les sols default_tongue.png/emoticons/tongue@2x.png 2x" width="20" height="20">

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Pour information, épilogue de cette longue histoire : Allègre a finalement été dégraissé de L'Express !

Précision d'après Le Monde daté de ce jour : cela n'a rien à voir avec sa récente prise de position climatique, le nouveau patron du magazine a simplement viré tous les éditorialistes externes à la rédaction, sauf l'inusable Jacques Attali.

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Posted

Location : La-Chapelle-Saint-Florent (49)

Virer jacques Attali, y'aurait eut des grêves dans les rues ^^

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Qui va s'en plaindre ?

Eh bien, peut-être les lecteurs de l'Express. Tu sais, les gens n'ont pas tous les mêmes goûts, ni les mêmes idées, ni les mêmes désirs.

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Eh bien, peut-être les lecteurs de l'Express. Tu sais, les gens n'ont pas tous les mêmes goûts, ni les mêmes idées, ni les mêmes désirs.

Allègre peut porter à la connaissance des chercheurs ses travaux scientifiques sur le climat, personne ne l'en empêche.

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Pour information, épilogue de cette longue histoire : Allègre a finalement été dégraissé de L'Express !

Il ne te reste plus qu'à candidater sur les postes laissés vacants par mammouth and Co. default_sleeping.gif

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Il ne te reste plus qu'à candidater sur les postes laissés vacants par mammouth and Co. default_sleeping.gif

Pas bête. Mais le scepticisme, en ce moment, ce n'est pas très vendeur. Ca ne l'est pas en général, d'ailleurs, les sceptiques sont presque toujours considérés comme des rabat-joie ou des briseurs de rêve ou des coupeurs de cheveux en quatre ou des agresseurs de mouche par voies non naturelles default_biggrin.png/emoticons/biggrin@2x.png 2x" width="20" height="20">

Il me semble que David ou toi auriez à tout prendre plus de chances en envoyant un CV.

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D'ailleurs, les sceptiques sont presque toujours considérés comme des rabat-joie ou des briseurs de rêve ou des coupeurs de cheveux en quatre ou des agresseurs de mouche par voies non naturelles default_smile.png/emoticons/smile@2x.png 2x" width="20" height="20">

Au contraire, les propos des "sceptiques" amateurs sont rassurants.

Ils sont comparés à des /index.php?s=&showtopic=16767&view=findpost&p=346844'>coucous quand ils parasitent le débat scientifique avec des propos infondés, biaisés ou carrément faux.

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Au contraire, les propos des "sceptiques" amateurs sont rassurants.

Ils sont comparés à des /index.php?s=&showtopic=16767&view=findpost&p=346844'>coucous quand ils parasitent le débat scientifique avec des propos infondés, biaisés ou carrément faux.

Heureusement qu'il y a les sceptiques pour te rassurer. Parce que les propos de G. Schmidt sur les aérosols suite aux demandes de précision de Météor sur RC, ce n'est pas très rassurant sur le modèle GISS. Et comme David Archer a finalement trouvé mieux de remplacer :

the warming in the last few decades can only be explained as a result of human-released greenhouse gases.

par
the warming in the last few decades cannot be explained without the impact of human-released greenhouse gases.

suite à une critique sceptique, j'en déduis que cette dernière n'est pas totalement inutile pour améliorer la précision du discours, histoire que les coucous alarmistes ne mésinterprètent pas les travaux des chercheurs qui leur donnent des graines à picorer.

Sinon, dans le texte de G. Schmidt auquel tu renvoies :

First off, an idealised 'black body' (which gives of radiation in a very uniform and predictable way as a function of temperature - encapsulated in the Stefan-Boltzmann equation) has a basic sensitivity (at Earth's radiating temperature) of about 0.27 °C/(W/m2). That is, a change in radiative forcing of about 4 W/m2 would give around 1°C warming. The second thing to know is that the Earth is not a black body! On the real planet, there are multitudes of feedbacks that affect other greenhouse components (ice alebdo, water vapour, c louds etc.) and so the true issue for climate sensitivity is what these feedbacks amount to. [Commentaire : c'est la base, c'est fondamental]

Je suis bien d'accord avec ton commentaire et avec l'esprit du propos de G. Schmidt. C'est la sensibilité climatique qui importe. Et je bloque toujours sur plusieurs points de GS dont celui-là :

Because all of the above tricks work for solar forcings as well as greenhouse gas forcings. Either there are important feedbacks or there aren't. You can't have them for solar and not for greenhouse gases.

Justement, je ne vois pas pourquoi la rétroaction à deux phénomènes physiques différents serait identique. Quand je lui avais posé la question pourquoi la sensibilité climatique du soleil serait la même que celle des GES, Schmidt me répond :

You don't expect it to be completely the same since there are differences: GHGs cause stratospheric cooling, solar irradiance increases cause warming there - GHGs have a very even effect across latitudes, solar is stronger in the tropics. GHGs are stronger at night, solar obviously isn't. However, in all modelling experiments so far done (and with many different models), the effects of equivalent GHG and solar forcings (defined as the forcing at the tropopause) are very similar (within about 10%).

Donc en fait, la réponse est : la sensibilité soleil / GES n'a pas de raison d'être la même, mais elle est pourtant la même parce que les modèles concluent ainsi. Ben, je ne suis pas toujours pas intellectuellement satisfait de ce genre de réponse circulaire.

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Heureusement qu'il y a les sceptiques pour te rassurer.

Ce qui me rassure c'est que dans 4 ou 5 ans ils auront complètement disparu.

Ce qui m'inquiète, c'est que la denial industry fait perdre du temps au monde entier.

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Un article hilarant sur RealClimate (effet des moutons blancs sur l'albedo terrestre...).

Par Raymond Pierrehumbert, Professeur in Geophysical Sciences at the University of Chicago, et qui ne manque pas d'humour ! :

"The already-reeling "consensus" supposedly linking climate change to CO2 is about to receive its final coup-de-grace from a remarkable new result announced in a press conference today by Dr. Ewe Noh-Watt of the New Zealand Institute of Veterinary Climatology [1]. Noh-Watt and his co-workers, describing work funded by a generous grant from the Veterinary Climate Science Coalition, declared "We have seen the future of climate -- and it is Sheep." Prof. Jean-Belliere Poisson d'Avril, star student of Claude Allegro Molto-Troppo (discoverer of the Tropposphere) reacted with the words, "Parbleu! C'est la meilleure chose depuis les baguettes tranchées!"

The hypothesis begins with the simple observation that most sheep are white ["L'hypothèse a commencé avec la simple observation que les moutons sont blancs"...C'est tellement évident que personne n'y avait pensé ! default_innocent.gif ], and therefore have a higher albedo than the land on which they typically graze (see figure below). (...)"

http://www.realclimate.org/index.php/archi...backi/#more-429

Claude Allègre, découvreur de la trop-posphère...Il est vraiment trop !

Poisson d'avril ! default_sleeping.gif

NB - Voir aussi : Con allegre, ma non troppo.

http://www.realclimate.org/index.php/archi...-ma-non-troppo/

mini-sheep.jpg

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