La Terre est ronde

Ray Pierrehumbert takes apart two French global warming skeptics, Claude Allègre and Vincent Courtillot. My favourite bit:

This flub is nothing compared to the trouble Courtillot's collaborator Le Mouël got into during the debates, when he was trying to show that the 1 Watt per square meter variation in the Solar irradiance over the solar cycle is fully half the greenhouse gas forcing. Well, there is the little matter that Le Mouël forgot to take into account the sphericity of the Earth (which means divide the solar irradiance by 4) or its reflectivity (which means take 70% of the result). As the Le Monde reporter archly noted, Le Mouël's calculation assumes a black flat Earth, but, "Hélas! La Terre est ronde" (zut alors!). Le Mouël seems eager to follow in Allègre's geometrically-challenged footsteps: In a 1988 book (12 clés pour la géologie, Belin:Paris), Allègre confidently stated that the pole to equator temperature gradient was due to snow albedo and atmospheric absorption, making no mention of the role of the Earth's spherical geometry, which is far and away the dominant factor (and the reason there's ice at the poles to make a high albedo). Messieurs, here's a little hint: What does the "G" stand for in "IPGP?"

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France has a national newspaper with a reporter who understands the difference between pi-r-squared and 4-pi-r-squared? It truly is a different culture.

Fair dues to Le Monde. If the NYT takes up the story we may yet see the headline foretold by Krugman: OPINIONS ON SHAPE OF EARTH DIFFER.

By Kevin Donoghue (not verified) on 18 Nov 2007 #permalink

I think Allègre once argued that the glacier retreat on Kilomanjaro was due to "geologic uplift". His theories are often quite unique.

Re #1
French media know there is a ratio 4 between sphere on disc surfaces but they don't know the difference between prediction made by unvalidated computers and reality. And they take their information from national climatologists nearly all of whom are from the CEA (of the 14 French authors of the IPCC, 12 are from the CEA). Not sure, it's better.

P.S. CEA means: "commissariat à l'énergie atomique" which in French means "Agency for Energy which emits-ZERO-greenhouse-gazes-likely-to-cause-cataclysmic-global-warming" ;)

Re #3
You "think" but you are not sure, aren't you ?
I read French and I am "virtually certain" your claim is unsustanciated.

Re #5 Since Pierrehumbert over at Realclimate also states that Allègre thinks glacier retreat on Kilomanjaro was due to "geologic uplift", and gives sources for the statement it seems plausible he has in fact said this. Have you read his column in L'Express or Ma vérité sur la planète?

I was at a talk given by (anthro global warming skeptic) Jan Veizer. (Mainstream climate scientist) Gavin Schmidt was in the audience and afterwards made some comments, including something along the lines of "and, Jan, you're missing a factor of 4 for solar irradiance". At the time I assumed it was a somewhat technical point. But -- at least if it was the same issue as above -- it turns out it was something easily explained to an intelligent middle schooler. It's just the fact that the formula for the surface area of a sphere is 4*pi*r^2 versus pi*r^2 for a disk. Yikes.

By David Kane's friend (not verified) on 19 Nov 2007 #permalink

I've seen said factor of four missed on more than one occasion. It's a dismayingly common mistake. The global mean solar constant to an earth scientist is exactly 1/4 of the solar constant to an astrophysicist. So any inconstancy is also frequently erroneously multiplied by 4.

If you see something on the order of 1300 W/m^2, it is the astronomical measure, whereas the number on the order of 330 is the earth science measure that is appropriate for most climate related discussions.

The error is not from a weak grasp of geometry, I think, but from looking up quantities that have similar names and different meanings.

But it would be shabby indeed coming from Veizer, who ought to know better.

The error is not from a weak grasp of geometry, I think, but from looking up quantities that have similar names and different meanings."

The real problem is that these people (the ones who are honest, at least) apparently never bother to check their answers -- against anything!

If they did, they would know that they had goofed big time.

A simple google search of the terms

solar radiation at earth's surface

turns up a link to a wikipedia article on (you guessed it) solar radiation, which explains the factor of 1/4 in the second paragraph.

For an earth science prof to make such a basic error is the equivalent of a high school student writing 2 + 2 = 5 on a math test.

It should be very embarrassing -- to say nothing of grounds for revoking their PhD -- but some of these people do not even seem to care.

JB said: "It should be very embarrassing -- to say nothing of grounds for revoking their PhD -- but some of these people do not even seem to care".

I suspect that they do care in the sense that these errors support the anti-AGW sentiments of their financial backers. I'm sure that they would have "found" the error if it had gone in the opposite direction i.e., discredited their financial masters.

By Ian Forrester (not verified) on 20 Nov 2007 #permalink

I forget the wording of the quote about when someone's paycheck depends on their makiing an error, expect them to make the same "error" over and over.

Thanks, Gavin.

By David Kane's friend (not verified) on 21 Nov 2007 #permalink

"For an earth science prof to make such a basic error is the equivalent of a high school student writing 2 + 2 = 5 on a math test."

Or confusing radians with degrees.

About post #4 suggesting that most French members of IPCC are bound to the nuclear industry. Labs in France have several affiliations, usually CNRS (National Basic Research Agency, say), one or several universities, and sometimes other specialized research/development agencies. CEA (the Atomic one) supports research in many areas, ranging from quantum computing to biology. The LSCE (Climate and Environment Sciences Lab) is affiliated to CNRS, a university and CEA. A bunch of French IPCC members (but not 12 out of 14!) are members of LSCE. Others are members of labs with no ties to CEA, or to non-French labs (see http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-annexes.pdf
for a complete list of autohrs).

Jean Jouzel for instance, a paleoclimatologist and one of the most respected French climate scientists, is head of LSCE and an employee of CEA (but others may be employees of CNRS or the university). He has been Flint Lecturer (Yale University, 1996), received the Milankovitch Medal (European Geophysical Society, 1997), the "Golden Medal" of the CNRS (the basic research one) in 2002, etc.
Now you are free to think he receives a percentage on sales of nuclear plants. If you want to.

See
http://www.cnrs.fr/cw/fr/pres/compress/medailleOr2002/Page01.html
http://www.lsce.ipsl.fr/

Why do scientists call it "climate change" or "the evolving climate" in French, instead of the Degenerating Climate, as is required by thermodynamics. Even without so called anthropogenic causes.

Two new trollpoints! Well, one plus one so old it might as well be new.

Okay, in order:

1. The climate is not a closed system. There are no thermodynamic reasons it has to degenerate.

2. It's been indisputably proven that human activity can lower the amount of available useful solar energy - that global dimming can come from human activity. It's been proven that C02 and methane are greenhouse gases, and that human activity can increase the net accumulation of such gases yearly. Hence, the expression "so called anthropogentic causes" is equivalent to "so called speed of light" or "so called genetic mutations" or "so called DNA" - either meaningless or simply dishonest. And that's why the French call it the changing or evolving climate.

By Marion Delgado (not verified) on 19 Dec 2007 #permalink