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# Blog - doubling CO2... then what?

I've started to draft a blog article:

It's far from being ready, so I would discourage reading it yet.

Only the paragraphs "executive summary" and "linear temperature drop" are probably in a kind of finalized form.

So far the double dollar equations didn't seem to work, maybe because I use a lot of fracs etc... so I stuck to the begin-end-equation style... But I'll change this in the end.

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## Comments

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1.
edited December 2012

I reshuffled some parts.

I think I could cut the blog post into three smaller units, if necessary, so I've put some tentative breaks.

I still need to expand some sections though and fill in some missing binding text. But I'm positive this should not take too long.

Ideally, I would write out the arguments with equations in a later blog post.

Comment Source:I reshuffled some parts. I think I could cut the blog post into three smaller units, if necessary, so I've put some tentative breaks. I still need to expand some sections though and fill in some missing binding text. But I'm positive this should not take too long. Ideally, I would write out the arguments with equations in a later blog post.
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2.
edited December 2012

Let me know when I should peek!

Three shortish posts are usually better than one long one. It's good if each post has a beautiful picture in it... or at least a picture. People like pictures, especially when I advertise posts on Google+.

People also like jokes, stories, and other signs that the author is human.

Double dollar signs should work if you have well-formed TeX. At the very end, on the blog, I need to turn all



to

$latex$

Comment Source:Let me know when I should peek! Three shortish posts are usually better than one long one. It's good if each post has a beautiful picture in it... or at least a picture. People like pictures, especially when I advertise posts on Google+. People also like jokes, stories, and other signs that the author is human. Double dollar signs should work if you have well-formed TeX. At the very end, on the blog, I need to turn all  to $latex$
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3.
edited December 2012

Let me know when I should peek!

Not yet, but maybe when you're back after Christmas. I'll keep you informed!

Double dollar signs should work if you have well-formed TeX.

I'll do my best. I thought it failed to interprete \frac{}{} but perhaps it was somehting else.

People also like jokes, stories, and other signs that the author is human.

I try to be humorous (in a certain way.)

Three shortish posts are usually better than one long one.

I had moved back to the one long format, but if needed we can still split it into short posts.

If I can't find any pictures myself, I'll add some suggestions for pictures.

Comment Source:> Let me know when I should peek! Not yet, but maybe when you're back after Christmas. I'll keep you informed! > Double dollar signs should work if you have well-formed TeX. I'll do my best. I thought it failed to interprete \frac{}{} but perhaps it was somehting else. > People also like jokes, stories, and other signs that the author is human. I try to be humorous (in a certain way.) > Three shortish posts are usually better than one long one. I had moved back to the one long format, but if needed we can still split it into short posts. If I can't find any pictures myself, I'll add some suggestions for pictures.
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4.
edited December 2012

Ok, I finally split the text in three shortish posts, by creating Blog - the log forcing (part two) which will be about the temperature, pressure and density profiles in the troposphere, and Blog - the log forcing (part three), which will be about the Schwarschild equation and optical depth, and will contain the conclusion too. The third will be the longest.

The introduction, Blog - the log forcing, is ready to be looked at. Comments are welcome! The red boxes are mainly reminders for myself. If you prefer to restrain from comments before the other two parts are finished, I'll try t finalize them as soon as possible.

Comment Source:Ok, I finally split the text in three shortish posts, by creating [[Blog - the log forcing (part two)]] which will be about the temperature, pressure and density profiles in the troposphere, and [[Blog - the log forcing (part three)]], which will be about the Schwarschild equation and optical depth, and will contain the conclusion too. The third will be the longest. The introduction, [[Blog - the log forcing]], is ready to be looked at. Comments are welcome! The red boxes are mainly reminders for myself. If you prefer to restrain from comments before the other two parts are finished, I'll try t finalize them as soon as possible.
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5.

Fredrik, This is a really nice beginning for your blog series. The content is interesting and pertinent, the idea and spirit is clear, and the first section has a great poetry as well.

But I think that the third section, where you dig into the heart of the subject, needs more explaining and expansion. I got lost pretty quickly there, because I have no familiarity with these really interesting topics, and the references just went by too quickly. I would have to go study up on the Schwarzchild equation, etc., before I could follow the real thread of what you are saying.

It's pretty clear that you have all the knowledge needed to spell out the concepts you are trying to explain. Try to step outside of your expertise for a bit, and imagine what it would take to get these ideas across to e.g. someone who just got an undergrad degree in math, but had only studied high school physics. Or a top-notch software engineer.

The post is also a bit short, but that would be naturally addressed if you decompressed the explanations in the third section -- it seems like a good amount of content for a blog article.

Let's start with the first few sentences:

> The outgoing radiation is governed by Schwarzschild’s equation, which describes the vertical changes in radiation due to local emission and absorption. The absorption is proportional to the radiation, the local emission depends on the local temperature. Both are influenced by a prefactor that depends on the concentration of carbon dioxide, and on the pressure.

Here is are various thoughts that I had when trying to interpret this. My statements here could be wrong, because I am making inferences based on a low level of expertise in atmospheric physics.

• What is the underlying "setup" for the Schwarzchild equation. Radiation is flowing from the sun towards the Earth's surface, and is passing through the atmosphere. Molecules in the atmosphere are absorbing the photons. At each layer of the atmosphere, some of the photons pass through to the lower layers without interaction, some of them reflect off of the air molecules, and some get absorbed the the air molecules. At a later point in time, the energized molecules may release the energy back, through photons, generally at other frequencies. Side question: is reflection just the special case of absorption and immediate re-emission at the same frequency -- or is it a distinct phenomenon?

• Where can more about the Schwarzchild equation, a like would help.

• The outgoing radiation = the radiation produced by reflection and re-emission, right?

• The "vertical changes in radiation due to local emission and absorption". Is this different than the total radiation at each height, which would also include the energy of the photons that are passing through without modification?

• "The absorption is proportional to the radiation." Why? Is this a linearizing approximation? I could imagine a scenario where a doubling of input photons would lead to less than a doubling of the number that get absorbed, because of a saturation effect -- the absorption of a photon by a molecule removes it from the pool of available molecules that can absorb the photon at that frequency.

• "The local emission depends on the local temperature." Why? Because local emission is a "thermal phenomenon" that is largely driven by collisions between the molecules? There are also non-thermal, spontaneous emissions of a photon by a molecule, right? But maybe the thermal aspect is dominant...

• "Both are influenced by a prefactor that depends on the concentration of carbon dioxide, and on the pressure." Need help here. How is a prefactor different than a factor. Is carbon dioxide in a special role here, or is there also a prefactor that depends on e.g. on ozone concentration? If so, what is special about carbon dioxide. If it is a general phenomenon, then what is the general idea. Is it simply a matter of how "how much stuff" there is concentrated, that the photons can interact with?

What is the role of pressure per se? Pressure is density of kinetic energy. How does this impact absorption, and local emission? At a fixed temperature, pressure is proportional to density, and density will clearly have an effect on absorption and re-emission.

Now I'm not saying that a first blog article should explain all of these ideas from the ground up. But these were the questions that went through my mind, and which I would need to have some more clarity on, before I could really appreciate the flow of the logic. You definitely could gloss over these matters with some general statements -- even just at the level of detail of my questions -- but I think some statements along these lines are needed to orient the non-physicist reader.

I hope this wasn't too annoying for you hear...and I do think you have the beginnings here of a really fine blog series.

Happy Holidays

Comment Source:Fredrik, This is a really nice beginning for your blog series. The content is interesting and pertinent, the idea and spirit is clear, and the first section has a great poetry as well. But I think that the third section, where you dig into the heart of the subject, needs more explaining and expansion. I got lost pretty quickly there, because I have no familiarity with these really interesting topics, and the references just went by too quickly. I would have to go study up on the Schwarzchild equation, etc., before I could follow the real thread of what you are saying. It's pretty clear that you have all the knowledge needed to spell out the concepts you are trying to explain. Try to step outside of your expertise for a bit, and imagine what it would take to get these ideas across to e.g. someone who just got an undergrad degree in math, but had only studied high school physics. Or a top-notch software engineer. The post is also a bit short, but that would be naturally addressed if you decompressed the explanations in the third section -- it seems like a good amount of _content_ for a blog article. Let's start with the first few sentences: &gt; The outgoing radiation is governed by Schwarzschild’s equation, which describes the vertical changes in radiation due to local emission and absorption. The absorption is proportional to the radiation, the local emission depends on the local temperature. Both are influenced by a prefactor that depends on the concentration of carbon dioxide, and on the pressure. Here is are various thoughts that I had when trying to interpret this. My statements here could be wrong, because I am making inferences based on a low level of expertise in atmospheric physics. * What is the underlying &quot;setup&quot; for the Schwarzchild equation. Radiation is flowing from the sun towards the Earth's surface, and is passing through the atmosphere. Molecules in the atmosphere are absorbing the photons. At each layer of the atmosphere, some of the photons pass through to the lower layers without interaction, some of them reflect off of the air molecules, and some get absorbed the the air molecules. At a later point in time, the energized molecules may release the energy back, through photons, generally at other frequencies. Side question: is reflection just the special case of absorption and immediate re-emission at the same frequency -- or is it a distinct phenomenon? * Where can more about the Schwarzchild equation, a like would help. * The outgoing radiation = the radiation produced by reflection and re-emission, right? * The &quot;vertical changes in radiation due to local emission and absorption&quot;. Is this different than the total radiation at each height, which would also include the energy of the photons that are passing through without modification? * &quot;The absorption is proportional to the radiation.&quot; Why? Is this a linearizing approximation? I could imagine a scenario where a doubling of input photons would lead to less than a doubling of the number that get absorbed, because of a saturation effect -- the absorption of a photon by a molecule removes it from the pool of available molecules that can absorb the photon at that frequency. * &quot;The local emission depends on the local temperature.&quot; Why? Because local emission is a &quot;thermal phenomenon&quot; that is largely driven by collisions between the molecules? There are also non-thermal, spontaneous emissions of a photon by a molecule, right? But maybe the thermal aspect is dominant... * &quot;Both are influenced by a prefactor that depends on the concentration of carbon dioxide, and on the pressure.&quot; Need help here. How is a prefactor different than a factor. Is carbon dioxide in a special role here, or is there also a prefactor that depends on e.g. on ozone concentration? If so, what is special about carbon dioxide. If it is a general phenomenon, then what is the general idea. Is it simply a matter of how &quot;how much stuff&quot; there is concentrated, that the photons can interact with? What is the role of pressure per se? Pressure is density of kinetic energy. How does this impact absorption, and local emission? At a fixed temperature, pressure is proportional to density, and density will clearly have an effect on absorption and re-emission. * * * Now I'm not saying that a first blog article should explain all of these ideas from the ground up. But these were the questions that went through my mind, and which I would need to have some more clarity on, before I could really appreciate the flow of the logic. You definitely could gloss over these matters with some general statements -- even just at the level of detail of my questions -- but I think some statements along these lines are needed to orient the non-physicist reader. I hope this wasn't too annoying for you hear...and I do think you have the beginnings here of a really fine blog series. Happy Holidays
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6.

Hi David,

thanks for your comments! I think you're right that I should discuss these issues, but for me the question is where: in the summary or in the main sections? I had the idea of making an "executive summary" first, to describe the content of what's going to follow. But if it is more distractive than illuminative (because you want all these questions answered) I could perhaps leave the summary aside and start to explain the mechanisms in more detail after the introduction (without an overview first). I'm also considering extending the summary, but I'm not sure I can expand too much there, I would like to avoid repeating myself in the later parts.

But it's good that you give your expectations, so I get some feelings what the reader expects. Merry christmas too!

Comment Source:Hi David, thanks for your comments! I think you're right that I should discuss these issues, but for me the question is where: in the summary or in the main sections? I had the idea of making an "executive summary" first, to describe the content of what's going to follow. But if it is more distractive than illuminative (because you want all these questions answered) I could perhaps leave the summary aside and start to explain the mechanisms in more detail after the introduction (without an overview first). I'm also considering extending the summary, but I'm not sure I can expand too much there, I would like to avoid repeating myself in the later parts. But it's good that you give your expectations, so I get some feelings what the reader expects. Merry christmas too!
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7.

I looked at my blog post again after a break and I think David Tanzer is right that the "executive summary" is not clear.

So I see the following options:

• I expand the executive summary such that the new concepts are introduced, but I doubt I can expand it without distracting from the main points.

• I dress the executive summary with lots of hyperlinks, each of which links a new concept to the relevant section which is going to explain it in depth. This should be easy to do in an blog setting compared to e.g. a book, but I'm not sure if this is the best format for the human brain, and esthetically (I expect a lot of hyperlinks) it doesn't look nice either.

• I change the executive summary to a kind of short overview of what's going to come, without addressing the mechanisms yet. (and I extend the first blog post with part of what's going to come) In the end of the mini-series, I can reuse the executive summary, which should, by then, be clear, hopefully. The readers will have to be patient then until the end (so it's not really an executive summary anymore ;))

If someone has another suggestion, please feel free to comment. I would opt for the last option.

Comment Source:I looked at my blog post again after a break and I think David Tanzer is right that the "executive summary" is not clear. So I see the following options: - I expand the executive summary such that the new concepts are introduced, but I doubt I can expand it without distracting from the main points. - I dress the executive summary with lots of hyperlinks, each of which links a new concept to the relevant section which is going to explain it in depth. This should be easy to do in an blog setting compared to e.g. a book, but I'm not sure if this is the best format for the human brain, and esthetically (I expect a lot of hyperlinks) it doesn't look nice either. - I change the executive summary to a kind of short overview of what's going to come, without addressing the mechanisms yet. (and I extend the first blog post with part of what's going to come) In the end of the mini-series, I can reuse the executive summary, which should, by then, be clear, hopefully. The readers will have to be patient then until the end (so it's not really an executive summary anymore ;)) If someone has another suggestion, please feel free to comment. I would opt for the last option.
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8.

This is a tough writing predicament, because there is a steep hill to be climbed -- how do you "gently" introduce a reader to a whole new web of interlocking ideas.

Then links won't really cut it, because pointing elsewhere is dodging the explanation.

I would suggest a synthesis of options 1 and 3. That is an overview that also provides some insight into the mechanisms that are involved, but that stops short of a reduction to first principles. Think of an abstract for a science paper.

A pure overview can fail to truly engage the reader, because it's just promises of what's to come. A full explanation of the mechanisms would bloat the article, and, as you say, distract from the main flow of ideas.

Think of that idea of explaining the gist of the ideas to the bartender. It takes a lot of work to boil it down to this level, but it's worth the effort.

Suggestion, how about weaving some kind of "short story" answer to the questions I posed above -- to the extend they are pertinent to the ideas that you need to convey.

The tone could be something like this:

The sun is pouring energy down to the earth in a continuous flow of "photons," some of which get soaked up by air molecules that they collide with. The molecules are also colliding with each other, which sometimes causes them to emit photons in all directions. There is a complex balance of these flows, which determines the temperature at each point in space. We are going to want to know about the nature of these flows and the temperature at each height. In our next article, we will look at the Schwarzchild equation, which ... [say something substantive, yet not expansive] ...we will be seeing how this connects with Log forcing in the next post [say something substantive yet not expansive about the relationship between the Schwarzchild and the log forcing relationship] ...

Comment Source:This is a tough writing predicament, because there is a steep hill to be climbed -- how do you "gently" introduce a reader to a whole new web of interlocking ideas. Then links won't really cut it, because pointing elsewhere is dodging the explanation. I would suggest a synthesis of options 1 and 3. That is an overview that also provides _some_ insight into the mechanisms that are involved, but that stops short of a reduction to first principles. Think of an abstract for a science paper. A pure overview can fail to truly engage the reader, because it's just promises of what's to come. A full explanation of the mechanisms would bloat the article, and, as you say, distract from the main flow of ideas. Think of that idea of explaining the gist of the ideas to the bartender. It takes a lot of work to boil it down to this level, but it's worth the effort. Suggestion, how about weaving some kind of "short story" answer to the questions I posed above -- to the extend they are pertinent to the ideas that you need to convey. The tone could be something like this: The sun is pouring energy down to the earth in a continuous flow of "photons," some of which get soaked up by air molecules that they collide with. The molecules are also colliding with each other, which sometimes causes _them_ to emit photons in all directions. There is a complex balance of these flows, which determines the temperature at each point in space. We are going to want to know about the nature of these flows and the temperature at each _height_. In our next article, we will look at the Schwarzchild equation, which ... [say something substantive, yet not expansive] ...we will be seeing how this connects with Log forcing in the next post [say something substantive yet not expansive about the relationship between the Schwarzchild and the log forcing relationship] ...
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9.
edited December 2012

Yes, thank you for your suggestion.

The tone could be something like this: The sun is pouring energy down to the earth [...]

The discussion is actually about the long-wave radiation emitted by the earth (the solar radiation peaks in the visible wavelengths where carbon dioxide doesn't absorbs much) but that's something I should make clear in the blog.

Comment Source:Yes, thank you for your suggestion. > The tone could be something like this: The sun is pouring energy down to the earth [...] The discussion is actually about the long-wave radiation emitted by the earth (the solar radiation peaks in the visible wavelengths where carbon dioxide doesn't absorbs much) but that's something I should make clear in the blog.
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10.

On the summary: it seems to me that the concept of effective emission height is the central one, and this is not defined, or even emboldened. I think it needs a subsection to itself, even if you can't define it precisely yet.

Also diagrams or graphs would be good, to illustrate the overall picture, again they don't have to be precise.

Comment Source:On the summary: it seems to me that the concept of effective emission height is the central one, and this is not defined, or even emboldened. I think it needs a subsection to itself, even if you can't define it precisely yet. Also diagrams or graphs would be good, to illustrate the overall picture, again they don't have to be precise.
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11.

@Graham: good points, thanks.

Comment Source:@Graham: good points, thanks.
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12.
edited January 2013

Frederik: the first part looks good to me, modulo those comments to yourself!

At some point I would like to go through it and make lots of little changes, if that's okay with you. It'll be quicker for me to do them myself than figure out what they are and explain them to you here. Then you can undo or modify any changes you feel like. Okay?

David Tanzer asked about the Schwarzschild equation and its underlying setup. I explained that in Mathematics of the Environment (Part 3), and you should feel free to borrow any text and pictures you want from that and adapt them. This article also has information about carbon dioxide absorption bands, including graphs. Feel free to borrow those too!

To make it easier, I will copy that article onto the wiki in a minute or two.

Comment Source:Frederik: the first part looks good to me, modulo those comments to yourself! At some point I would like to go through it and make lots of little changes, if that's okay with you. It'll be quicker for me to do them myself than figure out what they are and explain them to you here. Then you can undo or modify any changes you feel like. Okay? David Tanzer asked about the Schwarzschild equation and its underlying setup. I explained that in [Mathematics of the Environment (Part 3)](http://johncarlosbaez.wordpress.com/2012/10/13/mathematics-of-the-environment-part-3/), and you should feel free to borrow any text and pictures you want from that and adapt them. This article also has information about carbon dioxide absorption bands, including graphs. Feel free to borrow those too! To make it easier, I will copy that article onto the wiki in a minute or two.
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13.

Okay, you can now get that article on the wiki here:

Feel free to cut and paste information to your heart's content!

Comment Source:Okay, you can now get that article on the wiki here: * [[Blog - mathematics of the environment (part 3)]] Feel free to cut and paste information to your heart's content!
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14.

I still need to work on the second half of the text.

and you should feel free to borrow any text and pictures you want from that and adapt them. This article also has information about carbon dioxide absorption bands, including graphs. Feel free to borrow those too!

Thanks! I may borrow some lines but I will try to be brief. I'll refer the interested reader to the original article for more depth.

At some point I would like to go through it and make lots of little changes, if that’s okay with you. It’ll be quicker for me to do them myself than figure out what they are and explain them to you here. Then you can undo or modify any changes you feel like. Okay?

Yes, I suppose that's the best way. I am certainly fine with any language corrections. And maybe the reasoning could be brushed up too. I already made a lot of little changes myself to optimize the wording.

Comment Source:I still need to work on the second half of the text. > and you should feel free to borrow any text and pictures you want from that and adapt them. This article also has information about carbon dioxide absorption bands, including graphs. Feel free to borrow those too! Thanks! I may borrow some lines but I will try to be brief. I'll refer the interested reader to the original article for more depth. > At some point I would like to go through it and make lots of little changes, if that’s okay with you. It’ll be quicker for me to do them myself than figure out what they are and explain them to you here. Then you can undo or modify any changes you feel like. Okay? Yes, I suppose that's the best way. I am certainly fine with any language corrections. And maybe the reasoning could be brushed up too. I already made a lot of little changes myself to optimize the wording.
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15.

Hi John,

If you like to edit, I've practically finished my work on the second half, the text is roughly finished. Of course I still need to gather some pictures and diagrams to illustrate the text.

I couldn't incorporate all comments of David Tanzer and Graham yet. Maybe I can give it another try later but I lacked some inspiration right now. And with a reference to your blog post it may be possible to follow it as it is. More explanations will appear in the second and third part.

(If wished, I could put all three parts together, but that would make a long post)

Comment Source:Hi John, If you like to edit, I've practically finished my work on the second half, the text is roughly finished. Of course I still need to gather some pictures and diagrams to illustrate the text. I couldn't incorporate all comments of David Tanzer and Graham yet. Maybe I can give it another try later but I lacked some inspiration right now. And with a reference to your blog post it may be possible to follow it as it is. More explanations will appear in the second and third part. (If wished, I could put all three parts together, but that would make a long post)
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16.

Okay, I probably won't edit it tonight but I'll try to do it soon.

I think more short posts is better than one long post. It's good to have some repetition, though, since you can't expect people to remember everything you said. This is actually good for you, since it allows you to say the same thing in a couple of different ways, instead of having to pick the one 'best' way (which is impossible).

Comment Source:Okay, I probably won't edit it tonight but I'll try to do it soon. I think more short posts is better than one long post. It's good to have some repetition, though, since you can't expect people to remember everything you said. This is actually good for you, since it allows you to say the same thing in a couple of different ways, instead of having to pick the one 'best' way (which is impossible).
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17.

Okay, I probably won’t edit it tonight but I’ll try to do it soon.

For me there's no hurry. I've thought it might be good for me to take another look at part one when part three will be finished.

since it allows you to say the same thing in a couple of different ways, instead of having to pick the one ’best’ way (which is impossible)

yes, that's right. Although I'm already happy when I've found one way to explain something ;-)

Comment Source:> Okay, I probably won’t edit it tonight but I’ll try to do it soon. For me there's no hurry. I've thought it might be good for me to take another look at part one when part three will be finished. > since it allows you to say the same thing in a couple of different ways, instead of having to pick the one ’best’ way (which is impossible) yes, that's right. Although I'm already happy when I've found one way to explain something ;-)
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18.

Yes, if you're not in a hurry to get published it will be best to write all three parts and let all of us look them over before publishing the first one. That way we can see the whole story, not just the first chapter.

By the way: I think this blog series deserves an attractive title, at least by the time it gets published on the blog. "The log forcing" doesn't mean much to most people - they might think someone is forcing someone to burn wood for fuel. How about something like

What doubling carbon dioxide in the atmosphere will do

That will instantly attract attention.

Comment Source:Yes, if you're not in a hurry to get published it will be best to write all three parts and let all of us look them over before publishing the first one. That way we can see the whole story, not just the first chapter. By the way: I think this blog series deserves an attractive title, at least by the time it gets published on the blog. "The log forcing" doesn't mean much to most people - they might think someone is forcing someone to burn wood for fuel. How about something like **What doubling carbon dioxide in the atmosphere will do** That will instantly attract attention.
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19.
edited January 2013

I agree that "the log forcing" is not a good title for those who haven't heard what it is. I liked it because it sounded a bit mysterious, but I think your right.

What doubling carbon dioxide in the atmosphere will do

sounds a little wider than I intended, because I'll look at the temperature response. So then I'd suggest

How do temperatures respond to doubling carbon dioxide? (And subtitle:) An explanation of the log forcing.

By the way, you once said jokes are important and your remark made me think of "If you burn a log, the temperature rises." but I'm kind of doubtful if this is actually funny.

Yes, if you’re not in a hurry to get published

But I will try to finish it in a reasonable time. I just need to collect some momentum to finish the backbone of the third part.

About figures, is it okay if I pluck them from Wikipedia (or a few from your post)? It's maybe not the most original but wouldn't know where to find them otherwise (without copyright)

Comment Source:I agree that "the log forcing" is not a good title for those who haven't heard what it is. I liked it because it sounded a bit mysterious, but I think your right. > What doubling carbon dioxide in the atmosphere will do sounds a little wider than I intended, because I'll look at the temperature response. So then I'd suggest **How do temperatures respond to doubling carbon dioxide?** (And subtitle:) An explanation of the log forcing. By the way, you once said jokes are important and your remark made me think of "If you burn a log, the temperature rises." but I'm kind of doubtful if this is actually funny. > Yes, if you’re not in a hurry to get published But I will try to finish it in a reasonable time. I just need to collect some momentum to finish the backbone of the third part. About figures, is it okay if I pluck them from Wikipedia (or a few from your post)? It's maybe not the most original but wouldn't know where to find them otherwise (without copyright)
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20.
edited January 2013

If you want to be honest, before you pluck pictures from Wikipedia you should look at their copyright information and honor that. I usually try to do this, though sometimes I get lazy.

For example, if you look below this picture about radiative forcings you'll see it has Creative Commons Attribution-Share Alike 3.0 Unported license, and the main thing that means is that you should attribute it, i.e., credit its author.

You could make a joke about 'log forcing' and carbon emissions and burning logs in your fireplace, but you have to actually create the joke from these ingredients and have it fit naturally into the text so that it suddenly shocks the reader, if you want it to actually be funny.

Comment Source:If you want to be honest, before you pluck pictures from Wikipedia you should look at their copyright information and honor that. I usually try to do this, though sometimes I get lazy. For example, if you look below [this picture about radiative forcings](http://en.wikipedia.org/wiki/File:Radiative-forcings.svg) you'll see it has Creative Commons Attribution-Share Alike 3.0 Unported license, and the main thing that means is that you should attribute it, i.e., credit its author. You could make a joke about 'log forcing' and carbon emissions and burning logs in your fireplace, but you have to actually create the joke from these ingredients and have it fit naturally into the text so that it suddenly shocks the reader, if you want it to actually be funny.
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21.

"What doubling carbon dioxide in the atmosphere will do" and "How do temperatures respond to doubling carbon dioxide?" could be misleading because the post is mainly about the no-feedback temperature response (or the Planck-only feedback). But climate system feedbacks are likely responsible for most of the real-world temperature response.

Comment Source:"What doubling carbon dioxide in the atmosphere will do" and "How do temperatures respond to doubling carbon dioxide?" could be misleading because the post is mainly about the no-feedback temperature response (or the Planck-only feedback). But climate system feedbacks are likely responsible for most of the real-world temperature response.
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22.

could be misleading

yes, that's true. I hadn't thought of that because we consider a 1D atmosphere and a pointlike earth, so no climate...

What about:

How does the world's average temperature respond to doubling carbon dioxide?

or

How does a pointlike world's temperature respond to doubling carbon dioxide?

On the other hand, the climate system feedbacks will alter the spatial distribution of the temperature response, but I would naively expect that the mean won't be disturbed that much.

Comment Source:> could be misleading yes, that's true. I hadn't thought of that because we consider a 1D atmosphere and a pointlike earth, so no climate... What about: > How does the world's average temperature respond to doubling carbon dioxide? or > How does a pointlike world's temperature respond to doubling carbon dioxide? On the other hand, the climate system feedbacks will alter the spatial distribution of the temperature response, but I would naively expect that the mean won't be disturbed that much.
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23.
edited January 2013

These are too long to be good titles. It's fine to have an overly broad title and then say you're going to focus on a particular issue.

And if you're not talking about the real world, but merely a 1d atmosphere and a pointlike world, ignoring feedbacks, you should say that - no matter what title you use! - because otherwise someone will misunderstand what you are doing. It's good to point out that

... climate system feedbacks are likely responsible for most of the real-world temperature response.

before settling down on the topic you're actually interested in.

Now I'm wanting an even shorter title, like

What does doubling carbon dioxide do?

This is so short and vague nobody could accuse you of meaning anything in particular, but it will attract more attention than a lot of other titles that have been suggested. I think "does" is better than "will" because the latter one suggests you're predicting the future of our world.

Comment Source:These are too long to be good titles. It's fine to have an overly broad title and then say you're going to focus on a particular issue. And if you're not talking about the real world, but merely a 1d atmosphere and a pointlike world, ignoring feedbacks, you should say that - _no matter what title you use!_ - because otherwise someone will misunderstand what you are doing. It's good to point out that > ... climate system feedbacks are likely responsible for most of the real-world temperature response. before settling down on the topic you're actually interested in. Now I'm wanting an even shorter title, like > What does doubling carbon dioxide do? This is so short and vague nobody could accuse you of meaning anything in particular, but it will attract more attention than a lot of other titles that have been suggested. I think "does" is better than "will" because the latter one suggests you're predicting the future of our world.
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24.

Another suggestion:

Quantifying the effects of increased carbon dioxide

Comment Source:Another suggestion: Quantifying the effects of increased carbon dioxide
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25.
edited January 2013

That's clear and short, though a bit "dry".

Comment Source:That's clear and short, though a bit "dry".
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26.

Those were my thoughts, exactly, after I posted it

Comment Source:Those were my thoughts, exactly, after I posted it
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27.

I should actually better focus on the content first, but what about:

Doubling $CO_2$... then what?

(subtitle: An explanation of the log forcing)

I like $CO_2$ because it's shorter then carbon dioxide and almost everybody knows what it means, and the few who don't, should be notified that the 2 is in subscript ;-)

you should say that - no matter what title you use!

Yes, you're right, I mention the 1D atmosphere somewhere, but I should make it more prominent. And adding Nathan's comment.

Quantifying the effects of increased carbon dioxide

Stylistically I like this (I'm not against dry titles) however quantifying is flattering here, because I would say it's halfway a qualitative approach, since I focus on the origin of the logarithm.

Comment Source:I should actually better focus on the content first, but what about: **Doubling $CO_2$... then what?** (subtitle: An explanation of the log forcing) I like $CO_2$ because it's shorter then carbon dioxide and almost everybody knows what it means, and the few who don't, should be notified that the 2 is in subscript ;-) > you should say that - no matter what title you use! Yes, you're right, I mention the 1D atmosphere somewhere, but I should make it more prominent. And adding Nathan's comment. > Quantifying the effects of increased carbon dioxide Stylistically I like this (I'm not against dry titles) however quantifying is flattering here, because I would say it's halfway a qualitative approach, since I focus on the origin of the logarithm.
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28.
edited January 2013

The mathematics of increased carbon dioxide

Comment Source:The mathematics of increased carbon dioxide
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29.
edited January 2013

I like

Doubling CO2... then what?

I'll need to see if subscripts can appear in titles in the Azimuth Blog.

Comment Source:I like **Doubling CO<sub>2</sub>... then what?** I'll need to see if subscripts can appear in titles in the Azimuth Blog.
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30.

Yes, they can. Not using HTML, but using the UNICODE subscripts. So, that's fine.

Comment Source:Yes, they can. Not using HTML, but using the [UNICODE subscripts](http://en.wikipedia.org/wiki/Unicode_subscripts_and_superscripts). So, that's fine.
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31.
edited January 2013

I've looked up some terms to see if they were mentioned in the blog history and I think I can refer to and quote from e.g. Week 301 and Week 302, for climate sensititvity and radiative forcing.

I like the idea to quote (with references) from old TWF issues, it'll improve my text. If that's fine, of course.

Meanwhile I've also noticed that Tim van Beek had the intention to explain the log forcing in his draft The color of night. Since that's still a draft, and the relationship is not yet explained at all there, I guess it's still fine that I continue my little blog series.

Comment Source:I've looked up some terms to see if they were mentioned in the blog history and I think I can refer to and quote from e.g. Week 301 and Week 302, for climate sensititvity and radiative forcing. I like the idea to quote (with references) from old TWF issues, it'll improve my text. If that's fine, of course. Meanwhile I've also noticed that [[Tim van Beek]] had the intention to explain the log forcing in his draft [[The color of night]]. Since that's still a draft, and the relationship is not yet explained at all there, I guess it's still fine that I continue my little blog series.
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32.

Frederik wrote:

If that’s fine, of course.

Yes, referring to previous Azimuth Blog articles, including TWF, is a good thing. My dream is that we'd eventually explain lots of important things on the blog. We can't make every article self-contained, but we can keep referring back to previous articles. Of course we should try to be comprehensible to new readers, too.

Since that’s still a draft, and the relationship is not yet explained at all there, I guess it’s still fine that I continue my little blog series.

Sounds okay to me. Even if Tim winds up writing his own explanation, a certain amount of redundancy is good, especially if the same subject is explained in interestingly different ways.

Comment Source:Frederik wrote: > If that’s fine, of course. Yes, referring to previous Azimuth Blog articles, including TWF, is a good thing. My dream is that we'd eventually explain lots of important things on the blog. We can't make every article self-contained, but we can keep referring back to previous articles. Of course we should try to be comprehensible to new readers, too. > Since that’s still a draft, and the relationship is not yet explained at all there, I guess it’s still fine that I continue my little blog series. Sounds okay to me. Even if Tim winds up writing his own explanation, a certain amount of redundancy is good, especially if the same subject is explained in interestingly different ways.
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33.
edited January 2013

referring to previous Azimuth Blog articles, including TWF, is a good thing

Good -- thanks! I just noticed I can even refer to your post of today, I'll have to speed up a little bit...

Comment Source:> referring to previous Azimuth Blog articles, including TWF, is a good thing Good -- thanks! I just noticed I can even refer to your post of today, I'll have to speed up a little bit...
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34.
edited January 2013

Frederik wrote:

Meanwhile I’ve also noticed that Tim van Beek had the intention to explain the log forcing in his draft The color of night. Since that’s still a draft, and the relationship is not yet explained at all there, I guess it’s still fine that I continue my little blog series.

Yes, of course. My draft happened to stay a draft partly because I realized that it is far from easy to explain the log law. But maybe I can help you out a little bit with your part, I'll start by reading your first post draft...

Update: I left some comments over on the Wiki page. It still seems to me that there is a lot of material to cover, which is a lot of work, and that the first blog post still tries to cover too much area all at once.

Comment Source:Frederik wrote: <blockquote> <p> Meanwhile I’ve also noticed that Tim van Beek had the intention to explain the log forcing in his draft The color of night. Since that’s still a draft, and the relationship is not yet explained at all there, I guess it’s still fine that I continue my little blog series. </p> </blockquote> Yes, of course. My draft happened to stay a draft partly because I realized that it is far from easy to explain the log law. But maybe I can help you out a little bit with your part, I'll start by reading your first post draft... Update: I left some comments over on the Wiki page. It still seems to me that there is a lot of material to cover, which is a lot of work, and that the first blog post still tries to cover too much area all at once.
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35.

Thank you for the feedback.

I don’t think it is a good idea to mention this

Yes, I think you're right. I wasn't too sure about it when I wrote it (never awake sleeping dogs) but I wrote that part relatively fluently and it's always hard to remove such sentences. But it should be done.

There seems to be something missing here

There is indeed some part missing. I added some lines, and then intended to add some other lines later. Basically, every time I want to insert a picture a delay appears. I just have to copy the right part from John's post.

My first impression is that you try to do too much in this chapter for one blog post.

There will be part two and three as follow-ups to explain everything in more depth. But I wanted to give a broad overview in the first post. It was shorter first, but less comprehensible, so that's why I've extended it. But if you say it's still too much material compressed... Maybe I have to drop the idea of the overview then.

Comment Source:Thank you for the feedback. > I don’t think it is a good idea to mention this Yes, I think you're right. I wasn't too sure about it when I wrote it (never awake sleeping dogs) but I wrote that part relatively fluently and it's always hard to remove such sentences. But it should be done. > There seems to be something missing here There is indeed some part missing. I added some lines, and then intended to add some other lines later. Basically, every time I want to insert a picture a delay appears. I just have to copy the right part from John's post. > My first impression is that you try to do too much in this chapter for one blog post. There will be part two and three as follow-ups to explain everything in more depth. But I wanted to give a broad overview in the first post. It was shorter first, but less comprehensible, so that's why I've extended it. But if you say it's still too much material compressed... Maybe I have to drop the idea of the overview then.
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36.
edited January 2013

There will be part two and three as follow-ups to explain everything in more depth. But I wanted to give a broad overview in the first post. It was shorter first, but less comprehensible, so that’s why I’ve extended it. But if you say it’s still too much material compressed… Maybe I have to drop the idea of the overview then.

Do you see how to explain the log forcing within the overview? I can think of a way to do an overview like

1) we'll look at an earth with an atmosphere like a 1D energy balance model,

2) make a simple assumption about the stratification of the atmosphere following thermodynamics,

3) mention the radiative properties of the components of the atmosphere and how they change between the strata.

But I think even a short explanation of 2) and 3) would already be too much for one single blog post. Or one does not try to explain the concepts, but does simply an outline, like a proof strategy, which just throws all the buzz words around that people will have to understand later.

Comment Source:<blockquote> <p> There will be part two and three as follow-ups to explain everything in more depth. But I wanted to give a broad overview in the first post. It was shorter first, but less comprehensible, so that’s why I’ve extended it. But if you say it’s still too much material compressed… Maybe I have to drop the idea of the overview then. </p> </blockquote> Do you see how to explain the log forcing within the overview? I can think of a way to do an overview like 1) we'll look at an earth with an atmosphere like a 1D energy balance model, 2) make a simple assumption about the stratification of the atmosphere following thermodynamics, 3) mention the radiative properties of the components of the atmosphere and how they change between the strata. But I think even a short explanation of 2) and 3) would already be too much for one single blog post. Or one does not try to explain the concepts, but does simply an outline, like a proof strategy, which just throws all the buzz words around that people will have to understand later.
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37.
edited January 2013

Do you see how to explain the log forcing within the overview?

Well, I thought I saw a way to present the overview, and I actually gave the overview in the first post. I gave an outline with buzzwords in my first draft, and then David Tanzer recommended I'd expand the outline because it was too short to be comprehensible. After some thoughts I think he was right that it was not clear because it was short, so I expanded it.

But if you didn't find my overview in the post in the newest draft, it's clear to me that my presentation of the overview is not clear. And if it's not clear to you I actually doubt if it will be clear to any reader.

mention the radiative properties of the components of the atmosphere and how they change between the strata

One only needs the stratosphere and the troposphere, so I wouldn't really bother to explain UV absorption by ozone etc, this has influence on the incoming radiation but not on the outgoing. I mean, in a first approximation everything on top of the stratosphere can be neglected.

The two following blog posts describe in more depth (work in progress) (2) the profiles in the atmosphere following thermodynamics (3) radiative properties of carbon dioxide, and the 1D radiation balance model

Comment Source:> Do you see how to explain the log forcing within the overview? Well, I thought I saw a way to present the overview, and I actually gave the overview in the first post. I gave an outline with buzzwords in my first draft, and then David Tanzer recommended I'd expand the outline because it was too short to be comprehensible. After some thoughts I think he was right that it was not clear because it was short, so I expanded it. But if you didn't find my overview in the post in the newest draft, it's clear to me that my presentation of the overview is not clear. And if it's not clear to you I actually doubt if it will be clear to any reader. > mention the radiative properties of the components of the atmosphere and how they change between the strata One only needs the stratosphere and the troposphere, so I wouldn't really bother to explain UV absorption by ozone etc, this has influence on the incoming radiation but not on the outgoing. I mean, in a first approximation everything on top of the stratosphere can be neglected. The two following blog posts describe in more depth (work in progress) (2) the profiles in the atmosphere following thermodynamics (3) radiative properties of carbon dioxide, and the 1D radiation balance model
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38.
edited January 2013

One possibility is to take the overview and make it very short and sketchy, like one paragraph long. This can serve as a road map for the reader. You can make it clear that you're not really explaining the ideas yet, just sketching them. If it's very short, readers won't be scared of it.

Another possibility is to have an overview after the detailed explanation, as a kind of 'summary and review'.

Actually it's often good to have both. People often give this advice for talks: "first say what you're going to say, then say it, then say what you said."

I'm busy teaching lots of courses these days, so I'm not helping as much as I should... but when you get an article that seems 'finished', let me know, and I will read it and - if it's okay with you - make lots of small stylistic changes. I enjoy polishing things that are 'finished'... in the sense that all the material is there, I can understand most of it, and my job is merely to make it clearer and more fun to read.

Comment Source:One possibility is to take the overview and make it _very_ short and sketchy, like one paragraph long. This can serve as a road map for the reader. You can make it clear that you're not really explaining the ideas yet, just sketching them. If it's _very_ short, readers won't be scared of it. Another possibility is to have an overview _after_ the detailed explanation, as a kind of 'summary and review'. Actually it's often good to have both. People often give this advice for talks: "first say what you're going to say, then say it, then say what you said." I'm busy teaching lots of courses these days, so I'm not helping as much as I should... but when you get an article that seems 'finished', let me know, and I will read it and - if it's okay with you - make lots of small stylistic changes. I enjoy polishing things that are 'finished'... in the sense that all the material is there, I can understand most of it, and my job is merely to make it clearer and more fun to read.
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39.

Actually it’s often good to have both.

I'll give it a try. I let you know as soon as something gets to the 'finished' state.

Comment Source:> Actually it’s often good to have both. I'll give it a try. I let you know as soon as something gets to the 'finished' state.
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40.
edited February 2013

Ok, there has been some delay (mea culpa) but I think I will soon be able to work on it again.

Some good news is I, rather accidentally, found a small chapter in a booklet of 1982 (!) that does not explain the logarithm (apparently the log was not an issue at that time) but discusses some other aspects of climate sensitivity which are very welcome in the first post for the reader's qualitative understanding of radiative processes. And it has pictures! (I mean scientific figures) Of course I'll duly credit it.

Comment Source:Ok, there has been some delay (mea culpa) but I think I will soon be able to work on it again. Some good news is I, rather accidentally, found a small chapter in a booklet of 1982 (!) that does not explain the logarithm (apparently the log was not an issue at that time) but discusses some other aspects of climate sensitivity which are very welcome in the first post for the reader's qualitative understanding of radiative processes. And it has pictures! (I mean scientific figures) Of course I'll duly credit it.
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41.

Great! I've been really busy teaching, so my own Azimuth work has slowed down too. But soon life will get better for me - this quarter is done on March 15th.

Comment Source:Great! I've been really busy teaching, so my own Azimuth work has slowed down too. But soon life will get better for me - this quarter is done on March 15th.
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42.
edited March 2013

In addition, I've bought Craig Bohren's book "Clouds in a glass of beer". It also has a chapter on the greenhouse effect, so I think I can perhaps get some ideas from his explanation (he has no equations) and credit his book too, of course. It's from 1987, and I would say he was rather "agnostic" at that time -- at least, with respect to the earth feedback system (he's absolutely clear about the radiative forcing effect of carbon dioxide). That is, he mentions at the end that the link between the radiative forcing and average earth temperature is not easily determined, and there could be additional feedbacks not taken into account (he mentions the possibility that more water vapor and clouds could suppress the warming, but I would say at the same time he's forgetting to add another sentence on the higher greenhouse effect of water vapor...). Anyway, it's a explanatory textbook (perhaps in the vein of Feynman's Strange theory of light and matter: for the layman, but not oversimplified!), not a review of the literature, and most importantly, science has not stood still since then, it was written 25 years ago. But the greenhouse effect (radiative forcing part) was perfectly understood then, so it contains useful information :)

Comment Source:In addition, I've bought Craig Bohren's book "Clouds in a glass of beer". It also has a chapter on the greenhouse effect, so I think I can perhaps get some ideas from his explanation (he has no equations) and credit his book too, of course. It's from 1987, and I would say he was rather "agnostic" at that time -- at least, with respect to the earth feedback system (he's absolutely clear about the radiative forcing effect of carbon dioxide). That is, he mentions at the end that the link between the radiative forcing and average earth temperature is not easily determined, and there *could* be additional feedbacks not taken into account (he mentions the possibility that more water vapor and clouds could suppress the warming, but I would say at the same time he's forgetting to add another sentence on the higher greenhouse effect of water vapor...). Anyway, it's a explanatory textbook (perhaps in the vein of Feynman's Strange theory of light and matter: for the layman, but not oversimplified!), not a review of the literature, and most importantly, science has not stood still since then, it was written 25 years ago. But the greenhouse effect (radiative forcing part) was perfectly understood then, so it contains useful information :)
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43.

Cool.

Comment Source:Cool.
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44.
edited November 2013

Just to let you know I still work on this (intermittently). But I have changed my approach: I decided I can better focus on delivering a (hopefully) clear message. Whether it's fun to read is something which can be worked on afterwards.

By the way, does anybody have an opinion about if an atmosphere of an Earth without photosynthesis would have a different temperature response to $CO_2$ concentration? I was thinking that there would be no ozone layer, hence no stratosphere with stable stratification, which does appear in the log forcing derivation. Another point would be a different equilibrium temperature but I guess (should check) that a small shift of the earth's emission spectrum does not matter too much. The first comment actually doesn't matter for the log forcing derivation I'm working on (for which the present day atmosphere is assumed) I just think it's ironic that plants have an indirect influence on my derivation even though I neglect them: I don't consider plant feedback like CO2 fertilization, but I do need plants to explain the present composition (and T-profile) of the atmosphere (I don't think there's a problem in the derivation because of the response time).

Comment Source:Just to let you know I still work on this (intermittently). But I have changed my approach: I decided I can better focus on delivering a (hopefully) clear message. Whether it's fun to read is something which can be worked on afterwards. By the way, does anybody have an opinion about if an atmosphere of an Earth without photosynthesis would have a different temperature response to $CO_2$ concentration? I was thinking that there would be no ozone layer, hence no stratosphere with stable stratification, which does appear in the log forcing derivation. Another point would be a different equilibrium temperature but I guess (should check) that a small shift of the earth's emission spectrum does not matter too much. The first comment actually doesn't matter for the log forcing derivation I'm working on (for which the present day atmosphere is assumed) I just think it's ironic that plants have an indirect influence on my derivation even though I neglect them: I don't consider plant feedback like CO2 fertilization, but I do need plants to explain the present composition (and T-profile) of the atmosphere (I don't think there's a problem in the derivation because of the response time).
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45.

Frederik wrote:

Just to let you know I still work on this (intermittently).

Great! It's just a blog article, not a Ph.D. thesis; it should not become a massive project that hangs over your head for years. I agree that you should just write something clear. Then if you want, I can make it more 'fun'.

I was thinking that there would be no ozone layer, hence no stratosphere with stable stratification, which does appear in the log forcing derivation.

That's really interesting, but you know more atmospheric physics than I do, so I can't really help. I hadn't know the ozone layer was required for a stratosphere with stable stratification!

This whole issue, of how life on Earth affects the atmosphere and thus the climate, is really interesting. If you want to include a paragraph about this in the blog article, that would be great. If it's too distracting (and makes your task harder), we can just talk about it in the comments to the blog article.

Comment Source:Frederik wrote: > Just to let you know I still work on this (intermittently). Great! It's just a blog article, not a Ph.D. thesis; it should not become a massive project that hangs over your head for years. I agree that you should just write something clear. Then if you want, I can make it more 'fun'. > I was thinking that there would be no ozone layer, hence no stratosphere with stable stratification, which does appear in the log forcing derivation. That's really interesting, but you know more atmospheric physics than I do, so I can't really help. I hadn't know the ozone layer was required for a stratosphere with stable stratification! This whole issue, of how life on Earth affects the atmosphere and thus the climate, is really interesting. If you want to include a paragraph about this in the blog article, that would be great. If it's too distracting (and makes your task harder), we can just talk about it in the comments to the blog article.
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46.
edited January 2014

Hi John,

I've cleaned up the first part of Blog - the log forcing. This first part is very basic (and repeats stuff that has been put online by you and Tim but in my wording). Slightly more advanced basics (an appreciation of optical depth and of profiles in the atmosphere) are to follow in part two, before we can discuss the logarithmic profile in part three.

If you want you can take a look at it. I hope it's not too disappointing, but anyway it would be good to hear where I'm skipping steps that make it hard to follow.

Comment Source:Hi John, I've cleaned up the first part of [[Blog - the log forcing]]. This first part is very basic (and repeats stuff that has been put online by you and Tim but in my wording). Slightly more advanced basics (an appreciation of optical depth and of profiles in the atmosphere) are to follow in part two, before we can discuss the logarithmic profile in part three. If you want you can take a look at it. I hope it's not too disappointing, but anyway it would be good to hear where I'm skipping steps that make it hard to follow.
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47.
edited January 2014

Great! Everyone: let's start reading and editing Frederik's post Blog - the log forcing!

This post will show up after Blog - Lyapunov functions for complex-balanced systems and Blog - Relative entropy in evolutionary dynamics since those are almost done and they should appear in sequence without interruption. It may show up before Blog - stochastic cross impact balance analysis, since that one should wait until Vanessa has written her companion post.

It's actually good to repeat things that have already appeared - most people don't actually follow most of the blog articles in detail, and people forget things, too.

Comment Source:Great! Everyone: **let's start reading and editing Frederik's post [[Blog - the log forcing]]!** This post will show up after [[Blog - Lyapunov functions for complex-balanced systems]] and [[Blog - Relative entropy in evolutionary dynamics]] since those are almost done and they should appear in sequence without interruption. It may show up before [[Blog - stochastic cross impact balance analysis]], since that one should wait until Vanessa has written her companion post. It's actually _good_ to repeat things that have already appeared - most people don't actually follow most of the blog articles in detail, and people forget things, too.
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48.

I find it helpful when thinking about the atmosphere to imagine it compressed to the density of water. The whole thing it is about 10m thick, oxygen is 2m, CO2 is 4mm, methane is 0.02mm. I generally expect things that are 4mm thick to be opaque, but things 0.02mm thick to let some light through. I don't know if this likely to help anyone else.

Comment Source:I find it helpful when thinking about the atmosphere to imagine it compressed to the density of water. The whole thing it is about 10m thick, oxygen is 2m, CO2 is 4mm, methane is 0.02mm. I generally expect things that are 4mm thick to be opaque, but things 0.02mm thick to let some light through. I don't know if this likely to help anyone else.
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49.

Sounds helpful to me!

Comment Source:Sounds helpful to me!
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50.
edited January 2014

Graham said:

The whole thing it is about 10m thick

I thought to add this in part two, when I discuss optical depth.

opaque

One should also keep in mind the absorptivity, oxygen may be two meters thick, but it's insensitive to infrared radiation.

John said:

This post will show up after

I would be more comfortable if all parts of the logarithmic forcing would be finished first, but if you think it's decent enough, it's perhaps better for my productivity for the following blog sections if I feel unfomfortable ;-)

Comment Source:Graham said: > The whole thing it is about 10m thick I thought to add this in part two, when I discuss optical depth. > opaque One should also keep in mind the absorptivity, oxygen may be two meters thick, but it's insensitive to infrared radiation. John said: > This post will show up after I would be more comfortable if all parts of the logarithmic forcing would be finished first, but if you think it's decent enough, it's perhaps better for my productivity for the following blog sections if I feel unfomfortable ;-)
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