#engineerilyderiving

[neverendingaudit]

Arthur Sees the Problem

[In a post attacking (for a rare time) James Annan, Arthur Smith notices that the Auditor hopes to discuss at an engineer-level a very different beast.]

What’s the corresponding situation with climate? It’s definitely not an engineering discipline at this point – we’re still in the frontiers of science. But some of the components are there, or at least close.

First is the CO2 radiative forcing effect. There are a large variety of ways to parametrize the atmospheric layers, even with our apparently pretty good knowledge of the radiative physics. Chapter 10 of IPCC AR4 WG1 goes into the projection issues in some detail, with section 10.2 in particular looking at radiative forcings. Table 10.2 shows the forcings for doubled CO2 from a variety of different models: there is some residual uncertainty but the average is 3.80 W/m^2 forcing, with standard deviation 0.33 W/m^2.

Now a nearly 10% standard deviation in a key number is pretty good for science, but it’s pretty abysmal for engineering – perhaps the first clue that we’re not talking about engineering here!

Second is the temperature response to forcing. Assuming the forcing is small, the response should be linear in the perturbation; the question is what is the ratio. James Annan gives the mean Stefan-Boltzmann response, which would be fine if the Earth were uniformly at the effective temperature and the total greenhouse effect was small. But it’s not (though not bad as a very rough approximation – Annan perhaps thought an engineering account would be happy with 50% error-bars…). You have to take into account the range of present temperatures and atmospheric layers to get an accurate response temperature; this is roughly Moeller’s calculation of 1966 referenced at Spencer Weart’s site:

Möller, Fritz (1963). “On the Influence of Changes in the CO2 Concentration in Air on the Radiation Balance of the Earth’s Surface and on the Climate.” J. Geophysical Research 68: 3877-86. http://www.aip.org/history/climate/Radmath.htm

Moeller’s number for the bare response to doubling CO2 was 1.5 K. This is under the assumption of no water-vapor response (no increased evaporation and latent-heat effect either). The error-bars on that should be at least the 10% standard deviation in the pure radiative number (so 1.35 K wouldn’t be unlikely).

Adding in the water-vapor response is where you actually have to go to the detailed climate models. Contrary to Steve M’s claim above, the climate models these days don’t “assume constant relative humidity”, they calculate physical processes at sea surface/air boundaries and look at the resulting water vapor, temperature, and other numbers for the different atmospheric layers in the grids.

But of course that’s getting into the modeling business – if you don’t believe any of them, there’s not much point discussing further, because the only other way to get to the bottom of the water vapor response is to run the doubling experiment and see what happens…

[neverendingaudit]

I hope I’m not the only one who appreciates your juxtaposition of a note asking where you attacked someone, with a note in which you make broadscale condemnation of people.

Robert Grumbine, not being the only one who appreciates the Auditor's irony, in a comment thread where he could not get an idea of what an engineer-level report would look like.

[neverendingaudit]

It’s not easy to provide specifications, or I would have done so long ago.

The Auditor finally fesses up, while refusing to admit that his "constructive suggestion" might not be that constructive when we see how post hoc it is.

[neverendingaudit]

By Lindzenians, for Lindzenians.

A suggested tagline to coax Rud Istvan to cough up 20 millions for en engineer-level derivation of that doubling of CO2 thing.

[neverendingaudit]

I believe he is being somewhat unrealistic in how much to expect in the way of blogosphere explanations of doubled CO2 climate sensitivity and related issues.

Fred Moolten, just a bit before being misread by Auditor and correctly concluding that the Auditor expects too much and that "what we already have shouldn’t be belittled – it’s highly useful information that has been gathered at the expense of considerable skill, dedication, and effort".

[neverendingaudit]

Earth as a Space Station

[Wherein we situate the Auditor's sealioning.]

On Dec 24, 2009 at 10:44, George Steiner confides that he's a cynical engineering type, wishing results and disregarding INTEGRITY(tm):

With his most solemn Voice of God, the Auditor answers:

I’ve asked proponents for a few years now to provide an engineering quality derivation showing how doubled CO2 leads to a big problem. Thus far, I haven’t been able to get anyone to give me such a reference. Gerry North, a prominent climate scientist, has made fun of me for asking such a question, but maybe you’d have better luck with him than me. Unlike many readers, I do not presume that such a derivation is impossible or even that it doesn’t exist. If you can locate one, please bring it to my attention.

Presuming that something:

exists,

is necessary, and

has not been located after many years of search

looks a lot like looking for the Round Tuit.

I have yet to locate an engineering level report showing that the "correctness" of the "CO2 global warming hypothesis" might not depend on an engineering study for a chemical plant or semiconductor plant or space station.

Earth might be a special space station.

[neverendingaudit]

I’m mulling over the following thought: if the science is settled, then determining whether the impact of doubled CO2 is 0.5 deg C or 2.5 deg C or 10 deg C is an engineering problem. Arm-waving expositions – the higher, the colder – don’t answer this.

The Auditor, with two tricks in one.

[neverendingaudit]

Whining That It Does Not Exist Does Not Fix It

[A comment by Michael Tobis]

An engineering report is not issued to everyone on earth. It is issued to a specific audience with specific interests and specific sophistication on specific topics. The closest thing possible, in short, may well be something the IPCC WG I report and the literature to which it refers.

The alternative is to address the document to people with a particular level of sophistication, for instance, people who are ready to take their prelims in a serious meteorology/oceanography program. Such a document might well be very different in character from WG I, but it would follow on at least three or four semesters of slogging through textbooks.

Is an engineering report of the sort McIntyre envisions accessible to a general population, say understandable at the level of a high school education and yet compelling at a PhD level? Harder still, to such a population which includes many people inclined to disbelieve every word? It is hard for me to believe that such a document exists in any field. If it does, I would be eager to see it.

That all said, I appreciate the frustration that many are expressing, having come into the field from an undergrad engineering degree. The pedagogy in engineering is much clearer, and the problems are much cleaner, than in the climate sciences. It’s not surprising: a smaller student population gets a weaker pedagogical tradition.

But what people on the outside see as secrecy or caginess turns out up close to be just lack of resources to develop a clear pedagogy for anyone except the fields own graduate students. We definitely should try to fix this. But it isn’t easy. People with an amateur interest could roll up their sleeves, learn what they want to know, and contribute to the literature, rather than expecting it to already exist. Alternatively, they could push for new funding to pay professionals to work on it. Whining that it doesn’t exist won’t fix it.