Greenhouse Thought Experiment

Greenhouse Thought Experiment. A Guest Post from Jeff Condon. Denialists go to great lengths to misrepresent the “greenhouse” effect and direct our attention to partisan television commercials telling us that CO2 is “essential for life”. Mr. Dunning–Kruger Derek Alker, inspired by Tim Ball et. al.’s comic novel Slaying the Sky Dragon – Death of the Greenhouse Gas Theory, sent Jeff an Excel spreadsheet and a really ugly PDF that “ends the AGW scam” (again).

Apparently Derek received a geometric flash of insight into Earth’s shape. Them dumb physicists are ignoring the “back” half! Only they’re not of course…Science of Doom tries to turn the conversation back to reality on Jeff’s “No Consensus” website (sorry, I can’t write that without quotes around it).

But for us, this is Jeff’s launching point for a thought experiment about “the greenhouse”. He considers two Earths (specifically, a happy 1℃ warmer Republican Earth and a miserable colder Democratic Earth). Which will appear “warmer” to an external observer? After-all, a real greenhouse will appear warmer to an external observer. As any Physics 100 student will tell you, the answer is that the two Earths must exactly balance the radiative energy. In = out.

The interesting question is how could one Earth be 1℃ warmer than the other. Who wants to guess?

6 thoughts on “Greenhouse Thought Experiment

  1. Ooh! Ooh! I know! Because it watches Fox News. Everyone knows their presenters are hotter

    [Hotter under the collar! – Ben]

  2. I’m in the middle of that Jeff ID thread and I gotta say it is pure awesomeness on steroids. I have nothing but admiration for the sterling job SoD does in trying to engage with someone (Derek) who is clearly a physics crank. One of the highlights is when he says he disagrees with the “greenhouse theory” because he doesn’t find any evidence for it in the things he “sees” and “feels” in the physical world. Take a thermal imaging picture of an actual greenhouse and you’ll see it radiates out energy. So it’s not a black body. There is no global warming. The final nail in the coffin! Never mind that the term “greenhouse effect” is just a rough analogy for what actually goes on up there. Derek’s not having a bar of it!

    But it gets better. SoD points out that judging science by whether it matches what we “feel” and “experience” is a terrible rule. (I didn’t say “feel” and “experience”, Derek fires back. I said “see” and “feel”. Gotcha!) What about day and night, asks SoD. The fact of day and night doesn’t lead to our understanding that Earth rotates. Rubbish! cries Derek. Of course it rotates, that’s why we have day and night. Carrick jumps in: actually, until Galileo came along, we all thought the Earth was stationary.

    What amuses me the most about the thread is Derek’s supreme confidence that he is right and an entire of field of science is wrong and Must Be Overturned At Once. It’s like laughing at Bozo the Clown.

  3. I must say that Judy Curry’s blog is giving WTFWT a run for its money in the utter inanity of the comments.


    Post 22 should help you a bit..

    dividing P by 4 means either,

    1) The modeled surface has been moved four times the distance away from the single source of P.
    2) The modeled “sphere” must be completely revolving once per time unit.

    As far as I’m aware the earth is not
    i) a “flat” (saucer shaped and in constant flux back and forth to maintain a constant input of W/m2 per second) disc 374 million miles from the sun,
    nor does earth,
    ii) fully revolve once per second.

    [Sorry, I’m going to stick with the trained physicists. Your point 1) seems ill-founded by the way. High-school physics suggests that, according to the inverse-square law increasing distance four times will actually decrease received radiation by a factor of 16. – Ben]

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