Tuesday, April 03, 2007

The Pig Teaches

Turning the old saw on its head about not trying to teach a pig how to dance (it frustrates you and annoys the pig), the Capitalist Imperial Pig has a very nice post on the origin of the Greenhouse Effect. The teacher in me hates to give an A+, so Prof. Rabett will point out that it might have been a bit clearer if he had killed the stratospheric ozone (that's the peak at ~1100 cm^-1) by setting the scale factor to zero, and zeroed out the trop ozone and the methane. But Eli niggles. RTFP.

There are a couple of extensions to the argument Eli wants to try.....


Anonymous said...

Ahem, a post from Prometheus:

The Honest Broker Available in UK and EU This Week!

For our readers across the pond, you'll get it first (available here and here). We look forward to comments and criticisms!
Posted on April 3, 2007 07:37 AM


Sure. We have a comment. Um, Roger....you're a republican tool.

Anonymous said...

While that is a very nice graphical explanation, it's debatable whether one can really call it "simple."

It certainly would not be a good one "for a child" (except maybe Einstein as a child!)

Most people react the same way to graphs that they do to equations, which is to say they tune out completely.

And with regard to blackbody radiation curves, etc, etc?

I'd say that explanation is good for a college freshmen chemistry or physics student -- and perhaps a few advanced high school chem/physics students.

Anonymous said...

The question that prompted CIP's post

"I'm sorry I still don't really understand how exactly the greenhouse effect on Venus or even Mars can be applied to Earth."

That's not as simple a question as it sounds.
Scientists are still debating precisely why the surface temperature is so different on Earth and Venus.

By the way, Maura Rabbette is one of the NASA scientists who has studied the so-called "Runaway Greenhouse effect".

Any relation?

Anonymous said...

This is one of the better explanations I have seen for the greenhouse effect and observed temp (or close to it, any way) of the surface of the earth.

It involves use of an equation (Stefan Boltzmann) to get the actual temperature, but chances are that most people who can read a graph (eg blackbody spectrum) can probably also plug into an equation.

And to get a basic idea of what is going on with the energy flows, the graphics in the document are very good (no equation required), at any rate.

Anonymous said...


here's above link again

CapitalistImperialistPig said...

Good points Prof R. I didn't do anything about ozone because I didn't think to and don't understand what is meant by ozone scale factor. The picture is certainly cleaner without the ozone, and the energy balance question becomes more complicated with the stratosphere taken into account.

I fear the anonymous commentators are probably right about the flaws of the explanation, but it did help explain it to me!

Anonymous said...

Totally sideways: on the NOAA aggi page (here: http://www.esrl.noaa.gov/gmd/aggi/ ), can be found the expressions recommended by the TAR for calculating radiative forcings of GHGs. Do you know whence came these expressions, e.g, how the formulae were arrived at?
Secondly, my acquaintance Peter H. was curoius as to why you have a link to his weather website, and wondered whether he knows you? If you want to preserve your anonymity, please use email.
Finally: that's a neat explanation, thanks to the Pig.

EliRabett said...

Peter, who I know looks here occasionally, was an early adapter of Rabett Run on his blogroll, and I try to reciprocate. Eli was taken with his description of Rabett Run: Where I read what I think.

Also in the mid-80s I spent a sabbatical in England and we wandered into Devon and Cornwall and onto the moor quite a bit. Ms Rabett and Eli have fond memories and his photos sucked me in.

Anonymous said...

Rabett Run:
Where "If we knew the answer, it wouldn't be a problem."

Anonymous said...


Eli, thanks for your excellent comment to my latest post. It got routed to the "spam list" but that's ok. The problem is, when I went to recover it, I accidentally hit the "delete" button and it disappeared. Totally unintentional.

So, if you'd be kind enough to repost it, I'll be very careful not to make the same mistake again.

EliRabett said...


Have to wait till tomorrow. Usually when Eli promises not to make the same mistake again, he makes a different one.

Anonymous said...

Better watch out if Romney gets elected, Eli. It could be the end of the bunny trail for you.

"I've always been a rodent and rabbit hunter. Small varmints, if you will. I began when I was 15 or so and I have hunted those kinds of varmints since then. More than two times."

Yes indeed. Varmints.

"Hey, Jed, I'm a gonna go hunt varmints down by the cement pond."

"Weeee doggy, Jethro. I'll have Granny stoke the kettle."

Where do they find these people? Texas? Utah?

Anonymous said...

"I've been a Republican all my life. Small "d" Democrats, if you will. I began (voting Republican) when I was 18 or so and I have voted for those kinds of varmints since then. More than two times." -- Mitt Romney