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# Methane

I rather accidentally started a page on methane. This page too needs to be improved a lot... There's a link to the nonexistent page global warming potential.

Btw, would there be a way to automatically look up a keyword of a new page in other pages and surround it with double square brackets?

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1.

Btw, would there be a way to automatically look up a keyword of a new page in other pages and surround it with double square brackets?

The best way to get an answer is to start a new thread in the category "Technical", then our task force leader Andrew Stacey will take a look :-)

Comment Source:<blockquote> <p> Btw, would there be a way to automatically look up a keyword of a new page in other pages and surround it with double square brackets? </p> </blockquote> The best way to get an answer is to start a new thread in the category "Technical", then our task force leader [[Andrew Stacey]] will take a look :-)
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edited November 2010

Canonicalised page name and did some minor edits. (Incidentally, I assume using TeX notation for chemical compounds is OK: we don't want to be using some chemical markup language?)

Comment Source:Canonicalised page name and did some minor edits. (Incidentally, I assume using TeX notation for chemical compounds is OK: we don't want to be using some chemical markup language?)
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edited November 2010

The first paragraph is a verbatim lift from Wikipedia without modification. As a policy we must attribute all quotes, images etc. Limited attributed quotation for scholarship may be a defense, but don't count on it.

I raised chemical markup in some thread: it's possible on a Wordpress blog, probably not on instiki. LaTeX (itex2MML in this case) should be adequate though some of the spacing will not be optimum.

Comment Source:The first paragraph is a verbatim lift from Wikipedia without modification. As a policy we _must_ attribute all quotes, images etc. Limited attributed quotation for scholarship may be a defense, but don't count on it. I raised chemical markup in some thread: it's possible on a Wordpress blog, probably not on instiki. LaTeX (itex2MML in this case) should be adequate though some of the spacing will not be optimum.
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edited November 2010

Frederik:

1) You forgot to click "Markdown+Itex" when you first posted your comment above, so the links didn't work. Make sure to do that; if you allow your browser to remember this setting, you should only need to do it once. By previewing your comment you can see if it worked.

I believe you can also edit your comments after you've written then, and click Markdown+Itex then. Since I have superpowers, I am able to edit everyone's comments - so I fixed yours.

2) if you're going to quote the Wikipedia, that's okay if and only if you say you're quoting Wikipedia, and include a reference like this at the end of the page.

## References ##

* [Methane](http://en.wikipedia.org/wiki/Methane), Wikipedia.


3) But, it's always better to write your own stuff than simply copy the Wikipedia. The Wikipedia already exists, after all. And the focus of Azimuth is on saving the planet, while the Wikipedia is a general-purpose encyclopedia. So we should talk about things in a different way, which keeps that goal in mind.

Comment Source:Frederik: 1) You forgot to click "Markdown+Itex" when you first posted your comment above, so the links didn't work. Make sure to do that; if you allow your browser to remember this setting, you should only need to do it once. By previewing your comment you can see if it worked. I believe you can also edit your comments after you've written then, and click Markdown+Itex then. Since I have superpowers, I am able to edit everyone's comments - so I fixed yours. 2) if you're going to quote the Wikipedia, that's okay if and **only if** you _say_ you're quoting Wikipedia, and include a reference like this at the end of the page. ~~~ ## References ## This page is based on: * [Methane](http://en.wikipedia.org/wiki/Methane), Wikipedia. ~~~ 3) **But**, it's always better to write your own stuff than simply copy the Wikipedia. The Wikipedia already exists, after all. And the focus of Azimuth is on _saving the planet_, while the Wikipedia is a general-purpose encyclopedia. So we should talk about things in a different way, which keeps that goal in mind.
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5.

Walter wrote:

I raised chemical markup in some thread: it's possible on a Wordpress blog, probably not on instiki. LaTeX (itex2MML in this case) should be adequate though some of the spacing will not be optimum.

I've been using a mix of HTML and LaTeX to make the spacing nice, e.g. in Enhanced weathering I wrote:

To understand the chemistry involved, for simplicity let us consider the extreme form of olivine with all magnesium and no iron, known as **fosterite**.  Fosterite reacts with carbon dioxide as follows:

CO<sub>2</sub> + $\frac{1}{2}$ Mg<sub>2</sub>SiO<sub>4</sub> $\to$ MgCO<sub>3</sub> + $\frac{1}{2}$ SiO<sub>2</sub> + 90 kilojoules/mole

or in words:

carbon dioxide + fosterite $\to$ dolomite + silica

A related reaction is:

Mg<sub>2</sub>SiO<sub>4</sub> + 4 CO<sub>2</sub> + 4 H<sub>2</sub>O $\to$ 2 Mg<sup>2+</sup> + 4 HCO<sub>3</sub><sup>-</sup> + H<sub>4</sub>SiO<sub>4</sub>


which gives

To understand the chemistry involved, for simplicity let us consider the extreme form of olivine with all magnesium and no iron, known as fosterite. Fosterite reacts with carbon dioxide as follows:

CO2 + $\frac{1}{2}$ Mg2SiO4 $\to$ MgCO3 + $\frac{1}{2}$ SiO2 + 90 kilojoules/mole

or in words:

carbon dioxide + fosterite $\to$ dolomite + silica

A related reaction is:

Mg2SiO4 + 4 CO2 + 4 H2O $\to$ 2 Mg2+ + 4 HCO3- + H4SiO4

By the way, I raised two chemistry questions on this page, which I really hoped Walter could answer:

Question: what is the relation between the two reactions shown here? Are they alternatives, different ways of viewing what actually happens, or what? It needs clarifying.

Also: the first reaction produces '90 kilojoules per mole' according to Philip Goldberg et al. Is that moles of CO2, as opposed to Mg2SiO4? Is that what the $1/2$ is for? I.e. if we double the quantities on both sides of this reaction, we get 180 kilojoules per mole of Mg2SiO4?

Comment Source:Walter wrote: >I raised chemical markup in some thread: it's possible on a Wordpress blog, probably not on instiki. LaTeX (itex2MML in this case) should be adequate though some of the spacing will not be optimum. I've been using a mix of HTML and LaTeX to make the spacing nice, e.g. in [[Enhanced weathering]] I wrote: ~~~ To understand the chemistry involved, for simplicity let us consider the extreme form of olivine with all magnesium and no iron, known as **fosterite**. Fosterite reacts with carbon dioxide as follows: CO<sub>2</sub> + $\frac{1}{2}$ Mg<sub>2</sub>SiO<sub>4</sub> $\to$ MgCO<sub>3</sub> + $\frac{1}{2}$ SiO<sub>2</sub> + 90 kilojoules/mole or in words: carbon dioxide + fosterite $\to$ dolomite + silica A related reaction is: Mg<sub>2</sub>SiO<sub>4</sub> + 4 CO<sub>2</sub> + 4 H<sub>2</sub>O $\to$ 2 Mg<sup>2+</sup> + 4 HCO<sub>3</sub><sup>-</sup> + H<sub>4</sub>SiO<sub>4</sub> ~~~ which gives > To understand the chemistry involved, for simplicity let us consider the extreme form of olivine with all magnesium and no iron, known as **fosterite**. Fosterite reacts with carbon dioxide as follows: > CO<sub>2</sub> + $\frac{1}{2}$ Mg<sub>2</sub>SiO<sub>4</sub> $\to$ MgCO<sub>3</sub> + $\frac{1}{2}$ SiO<sub>2</sub> + 90 kilojoules/mole > or in words: > carbon dioxide + fosterite $\to$ dolomite + silica > A related reaction is: > Mg<sub>2</sub>SiO<sub>4</sub> + 4 CO<sub>2</sub> + 4 H<sub>2</sub>O $\to$ 2 Mg<sup>2+</sup> + 4 HCO<sub>3</sub><sup>-</sup> + H<sub>4</sub>SiO<sub>4</sub> By the way, I raised two chemistry questions on this page, which I really hoped Walter could answer: > Question: what is the relation between the two reactions shown here? Are they alternatives, different ways of viewing what actually happens, or what? It needs clarifying. > Also: the first reaction produces '90 kilojoules per mole' according to Philip Goldberg _et al_. Is that moles of CO<sub>2</sub>, as opposed to Mg<sub>2</sub>SiO<sub>4</sub>? Is that what the $1/2$ is for? I.e. if we double the quantities on both sides of this reaction, we get 180 kilojoules per mole of Mg<sub>2</sub>SiO<sub>4</sub>?
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edited November 2010

The only reason for asking about chemical markup is that, as ever, I'm interested in what may happen once pattern mining algorithms that don't quite understand things (ie, isn't artificial intelligence) gets to crunch on large portions of the web. (Of course, they'll also have to recognise the real words behind my typos. In my defence, I haven't come across a web browser where the text area widget isn't incredibly slow, so that it's always at least a sentence in actually putting letters onto the display behind my typing. So I'm often typing blind.) I can't tell the difference between the various ways of rendering chemicals unless I look really hard (and bear in mind conventions about usage of italics vs non-italics).

Comment Source:The only reason for asking about chemical markup is that, as ever, I'm interested in what may happen once pattern mining algorithms that don't quite understand things (ie, isn't artificial intelligence) gets to crunch on large portions of the web. (Of course, they'll also have to recognise the real words behind my typos. In my defence, I haven't come across a web browser where the text area widget **isn't incredibly slow**, so that it's always at least a sentence in actually putting letters onto the display behind my typing. So I'm often typing blind.) I can't tell the difference between the various ways of rendering chemicals unless I look really hard (and bear in mind conventions about usage of italics vs non-italics).
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7.

Hi John, I just specified that I took Methane from Wikipedia. Of course you are right about writing the material myself, but I'm not a chemist, and I had no idea how to write it better or more appropriate for Azimuth's purposes than Wikipedia did. Yesterday I wanted to pat myself on the back and quickly create an article, hoping a real chemist would come along and brush it up. But I'll keep your comments in mind for my next contribution.

Comment Source:Hi John, I just specified that I took [[Methane]] from Wikipedia. Of course you are right about writing the material myself, but I'm not a chemist, and I had no idea how to write it better or more appropriate for Azimuth's purposes than Wikipedia did. Yesterday I wanted to pat myself on the back and quickly create an article, hoping a real chemist would come along and brush it up. But I'll keep your comments in mind for my next contribution.
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edited November 2010

John Baez wrote here:

"Question: what is the relation between the two reactions shown here? Are they alternatives, different ways of viewing what actually happens, or what? It needs clarifying.

Also: the first reaction produces '90 kilojoules per mole' according to Philip Goldberg et al. Is that moles of CO2, as opposed to Mg2SiO4? "

It's per mole of CO2. Using standard enthalpy data in kJ/mol from NIST Standard Reference Data, my notes say this:

    -2176.94        -787.02         -2223.38        -910.8568
Mg2SiO4     +   2 CO2   --->    2 MgCO3     +   SiO2


i.e. delta 'H' is -170.28 kJ/mol, -85.14 kJ per mole CO2.

The article said "fosterite"; it's forsterite. I fixed that.

The relation between the above reaction and the one involving ions is that when the solid magnesium carbonate product above -- also known as magnesite -- dissolves in water, more atmospheric CO2 can be taken down,

2 MgCO3 + 2 CO2 + 2 H2O ---> 2 Mg++(aq) + 4 HCO3-(aq)

and summing the two processes, we get

Mg2SiO4 + 4 CO2 + 2 H2O ---> 2 Mg++(aq) + 4 HCO3-(aq) + SiO2

and then if we suppose the silica gets hydrated with two more waters, that will give the second reaction above asked about,

Mg2SiO4 + 4 CO2 + 4 H2O ---> 2 Mg++(aq) + 4 HCO3-(aq) + H4SiO4,

not that it matters what the silica does.

Comment Source:John Baez wrote [here](http://www.math.ntnu.no/~stacey/Mathforge/Azimuth/comments.php?DiscussionID=203&Focus=963#Comment_963): > "Question: what is the relation between the two reactions shown here? Are they alternatives, different ways of viewing what actually happens, or what? It needs clarifying. > Also: the first reaction produces '90 kilojoules per mole' according to Philip Goldberg et al. Is that moles of CO2, as opposed to Mg2SiO4? " It's per mole of CO2. Using standard enthalpy data in kJ/mol from [NIST Standard Reference Data](http://webbook.nist.gov/chemistry/form-ser.html), my notes say this: -2176.94 -787.02 -2223.38 -910.8568 Mg2SiO4 + 2 CO2 ---> 2 MgCO3 + SiO2 i.e. delta 'H' is -170.28 kJ/mol, -85.14 kJ per mole CO2. The article said "fosterite"; it's forsterite. I fixed that. The relation between the above reaction and the one involving ions is that when the solid magnesium carbonate product above -- also known as magnesite -- dissolves in water, more atmospheric CO2 can be taken down, 2 MgCO3 + 2 CO2 + 2 H2O ---> 2 Mg++(aq) + 4 HCO3-(aq) and summing the two processes, we get Mg2SiO4 + 4 CO2 + 2 H2O ---> 2 Mg++(aq) + 4 HCO3-(aq) + SiO2 and then if we suppose the silica gets hydrated with two more waters, that will give the second reaction above asked about, Mg2SiO4 + 4 CO2 + 4 H2O ---> 2 Mg++(aq) + 4 HCO3-(aq) + H4SiO4, not that it matters what the silica does.
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9.

Thanks a million, G. R. L.! I used your information to improve the Enhanced weathering page.

So dolomite and magnesite are both MgCO3?

I also took the liberty of spiffing up your comment above - I believe you can click "edit" to see how I did it. The key trick was clicking "Markdown+Itex".

I would like to create a tiny page G.R.L. Cowan linking to what I presume is your homepage, since I mentioned your name on Enhanced weathering... but now I can't get through to the Azimuth Project.

Of course, if you don't want to be cited, just delete mentions of your name.

Comment Source:Thanks a million, G. R. L.! I used your information to improve the [[Enhanced weathering]] page. So dolomite and magnesite are both MgCO<sub>3</sub>? I also took the liberty of spiffing up your comment above - I believe you can click "edit" to see how I did it. The key trick was clicking "Markdown+Itex". I would like to create a tiny page [[G.R.L. Cowan]] linking to what I presume is your [homepage](http://www.eagle.ca/~gcowan/), since I mentioned your name on [[Enhanced weathering]]... but now I can't get through to the Azimuth Project. Of course, if you don't want to be cited, just delete mentions of your name.
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10.
Dolomite, I seem to recall, is MgCO3·CaCO3.
Comment Source:Dolomite, I seem to recall, is MgCO3·CaCO3.
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11.
A tiny page on me is fine.
Comment Source:A tiny page on me is fine.
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12.

I haven't added that page itself yet, it doesn't have many references, and it more or less claims that burning coal is less bad than burning natural gas. Has anybody heard of this claim?

Nevertheless, there are some interesting remarks on that page, so if I find a way to refer to it carefully, I'll do that.

Comment Source:I've added the Tetlow-Smith reference about Methane from [this page about natural gas](http://www.cypenv.org/world/Files/methane.htm) which someone called Darin added to the blog. I haven't added that page itself yet, it doesn't have many references, and it more or less claims that burning coal is less bad than burning natural gas. Has anybody heard of this claim? Nevertheless, there are some interesting remarks on that page, so if I find a way to refer to it carefully, I'll do that.
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edited January 2011

I don't know about any of those claims, but the mention of radon as source of pollution sets off my spider-sense, since at least in the UK if you're in a house in the "wrong" area the ground emits radon with the only medical advice being to ensure the house is frequently aired out.

Amusingly, that page wants to claim that methane typically has a greater global warming potential than commonly claimed, whilst I spent an hour or so trying to look up any direct evidence that methane is a GHG after coming across a dinner-party politician's claims that methane isn't a greenhouse gas. The most I came to was passing mention to SAR monitoring that correlated methane with temperature rises but without references. If anyone knows of anything it'd be good to put that on the page.

Comment Source:I don't know about any of those claims, but the mention of radon as source of pollution sets off my spider-sense, since at least in the UK if you're in a house in the "wrong" area the ground emits radon with the only medical advice being to ensure the house is frequently aired out. Amusingly, that page wants to claim that methane typically has a greater global warming potential than commonly claimed, whilst I spent an hour or so trying to look up any direct evidence that methane is a GHG after coming across a dinner-party politician's claims that methane isn't a greenhouse gas. The most I came to was passing mention to SAR monitoring that correlated methane with temperature rises but without references. If anyone knows of anything it'd be good to put that on the page.
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edited January 2011

Hi David,

thanks for commenting — besides the interesting remarks there are some suspicious too

I was somewhat enthusiastic because there weren't many comments on Stabilization Wedges 4 yet (and none on the wedges itself!) and this was at least something new

unfortunately, I don't understand your last paragraph very well, methane is a greenhouse gas after all (I think you agree here? so I don't understand the joke very well)

Last month I made the stub Global warming potential where I put the IPCC estimates, among which methane.

If anyone knows of anything it'd be good to put that on the page.

Maybe we should stick to IPCC knowledge like:

The CH4 abundance in 2005 of about 1774 ppb is more than double its pre-industrial value. Atmospheric CH4 concentrations varied slowly between 580 and 730 ppb over the last 10,000 years, but increased by about 1000 ppb in the last two centuries, representing the fastest changes in this gas over at least the last 80,000 years. In the late 1970s and early 1980s, CH4 growth rates displayed maxima above 1% yr–1, but since the early 1990s have decreased signifi cantly and were close to zero for the six-year period from 1999 to 2005. Increases in CH4 abundance occur when emissions exceed removals. The recent decline in growth rates implies that emissions now approximately match removals, which are due primarily to oxidation by the hydroxyl radical (OH).

Comment Source:Hi David, thanks for commenting &mdash; besides the interesting remarks there are some suspicious too I was somewhat enthusiastic because there weren't many comments on Stabilization Wedges 4 yet (and none on the wedges itself!) and this was at least something new unfortunately, I don't understand your last paragraph very well, methane is a greenhouse gas after all (I think you agree here? so I don't understand the joke very well) Last month I made the stub [[Global warming potential]] where I put the IPCC estimates, among which methane. > If anyone knows of anything it'd be good to put that on the page. Maybe we should stick to IPCC knowledge like: > The CH4 abundance in 2005 of about 1774 ppb is more than double its pre-industrial value. Atmospheric CH4 concentrations varied slowly between 580 and 730 ppb over the last 10,000 years, but increased by about 1000 ppb in the last two centuries, representing the fastest changes in this gas over at least the last 80,000 years. In the late 1970s and early 1980s, CH4 growth rates displayed maxima above 1% yr–1, but since the early 1990s have decreased signifi cantly and were close to zero for the six-year period from 1999 to 2005. Increases in CH4 abundance occur when emissions exceed removals. The recent decline in growth rates implies that emissions now approximately match removals, which are due primarily to oxidation by the hydroxyl radical (OH).
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edited January 2011

Certainly it's interesting stuff, as you say I was just commenting on one particular thing that struck me.

The last paragraph was just me being amused by the fact that one "critic" is arguing for an increase in methane's GW potential whilst another "critic" was claiming methane's GW potential is vastly overstated. Pages by scientists who I trust to understand these things say that methane is a very potent greenhouse gas, so I accept that. I was just noting that I couldn't immediately find any pages that either explain theoretically why that's the case or describe experiments that show empirically methane is a potent greenhouse gas. If anyone (including me) ever comes across any such details it would be useful to add a brief reference.

Comment Source:Certainly it's interesting stuff, as you say I was just commenting on one particular thing that struck me. The last paragraph was just me being amused by the fact that one "critic" is arguing for an increase in methane's GW potential whilst another "critic" was claiming methane's GW potential is vastly overstated. Pages by scientists who I trust to understand these things say that methane is a very potent greenhouse gas, so I accept that. I was just noting that I couldn't immediately find any pages that either explain theoretically why that's the case or describe experiments that show empirically methane is a potent greenhouse gas. If anyone (including me) ever comes across any such details it would be useful to add a brief reference.
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16.

in AR4-WGI (Ch2,pg140)

Methane has the second-largest RF of the LLGHGs after CO2 (Ramaswamy et al., 2001).

they refer to chapter 6 of the 2001 report and here they seem to cite IPCC1990 but also other studies.

If anyone (including me) ever comes across any such details it would be useful to add a brief reference.

Sure!

Comment Source:It's not GWP, but if you're happy with radiative forcing (btw we don't seem to have a page about this subject): in AR4-WGI (Ch2,pg140) > Methane has the second-largest RF of the LLGHGs after CO2 (Ramaswamy et al., 2001). they refer to [chapter 6 of the 2001 report](http://www.grida.no/climate/ipcc_tar/wg1/pdf/TAR-06.pdf) and here they seem to cite IPCC1990 but also other studies. > If anyone (including me) ever comes across any such details it would be useful to add a brief reference. Sure!
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edited January 2011

Yes, we need good information on "Radiative forcing" and a good comparison of the various greenhouse gases. A lot of information on this is available from the IPCC reports.

category:carbon

to the page Methane - not sure that's best, but it's better than no category at all!

I also made some other tiny changes.

Comment Source:Yes, we need good information on "Radiative forcing" and a good comparison of the various greenhouse gases. A lot of information on this is available from the IPCC reports. I added category:carbon to the page [[Methane]] - not sure that's best, but it's better than no category at all! I also made some other tiny changes.
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edited July 2011

Hi David,

what do you think of:

Haven't read much more than the abstract yet, but it appears good. I'll add it to the wiki.

Comment Source:Hi David, what do you think of: * M J Elrod, [Greenhouse Warming Potentials from the Infrared Spectroscopy of Atmospheric Gases](http://alpha.chem.umb.edu/chemistry/ch361/spring2006/greenhouse%20warming%20potential.pdf) Journal of Chemical Education **76** (1999) 1705 Haven't read much more than the abstract yet, but it appears good. I'll add it to the wiki.
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19.

The effect of rising CO2 on plant life is a controversial and important topic. A new meta-analysis in Nature claims that more CO2 boosts soil emissions of nitrous oxide in all ecosystems, and more methane in in rice paddies and wetlands. This would be bad, since these are potent greenhouse gases, far more so than CO2. Claimed explanation: higher CO2 concentrations reduce plant water use, making soils wetter, in turn reducing the availability of oxygen in soil, favoring microorganisms that make methane and N2O. Also: increasing CO2 makes plants grow faster, which supplies these microorganisms with extra energy.

I've added this information to Methane.

Comment Source:* Mark Dunphy, [Climate Change Argument Brought Back Down To Earth](http://www.irishweatheronline.com/news/climate-news/climate-change-argument-brought-back-down-to-earth/26570.html), 14 July 2011. The effect of rising CO<sub>2</sub> on plant life is a controversial and important topic. A new meta-analysis in _Nature_ claims that more CO<sub>2</sub> boosts soil emissions of nitrous oxide in all ecosystems, and more methane in in rice paddies and wetlands. This would be bad, since these are potent greenhouse gases, far more so than CO<sub>2</sub>. Claimed explanation: higher CO<sub>2</sub> concentrations reduce plant water use, making soils wetter, in turn reducing the availability of oxygen in soil, favoring microorganisms that make methane and N<sub>2</sub>O. Also: increasing CO<sub>2</sub> makes plants grow faster, which supplies these microorganisms with extra energy. I've added this information to [[Methane]].
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20.

I've added this to Methane and Tipping point:

Comment Source:I've added this to [[Methane]] and [[Tipping point]]: * Ivan Sudakov and Sergey Vakulenko, [Study of the climate system bifurcations: permafrost methane emission case](http://www.ima.org.uk/_db/_documents/Sudakov.pdf).
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21.

This seems to be a talk and thus its hard to understand, but some more references are listed. The authors seem to use a specific model for the release of methane and as how I understood the words

"An explicit relation for critical methane emission level is obtained; Hypothesis of “methane hydrate gun” is confirmed; the calculations support the

Clathrate gun hypothesis

11 Benjamin J. Phrampus, Recent changes to the Gulf Stream causing widespread gas hydrate destabilization, Nature490,527–530(25 October 2012)doi:10.1038/nature11528,

Comment Source:This seems to be a talk and thus its hard to understand, but some more references are listed. The authors seem to use a specific model for the release of methane and as how I understood the words >"An explicit relation for critical methane emission level is obtained; Hypothesis of “methane hydrate gun” is confirmed; the calculations support the <a href="http://en.wikipedia.org/wiki/Clathrate_gun_hypothesis">Clathrate gun hypothesis</a> By the way on that Wikipedia page there was a link to a Nature article: 11 Benjamin J. Phrampus, Recent changes to the Gulf Stream causing widespread gas hydrate destabilization, Nature490,527–530(25 October 2012)doi:10.1038/nature11528,
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22.

(The word "chemistry" rang a bell, reminding me of 2-3 discussions I had with chemistry wonks. They couldn't believe that the liftetime in the atmosphere is only 10years.)

I'm meanwhile no longer scared of methane, only worried. (Cf. end of http://www.newscientist.com/article/dn23205-major-methane-release-is-almost-inevitable.html ) The greatest danger of thawing permafrost seems to be disruption of gas pipelines, which would have major implications for European heating fuel supply and cost.

Comment Source:Added a section "Lifetime of methane in the atmosphere". (The word "chemistry" rang a bell, reminding me of 2-3 discussions I had with chemistry wonks. They couldn't believe that the liftetime in the atmosphere is only 10years.) I'm meanwhile no longer scared of methane, only worried. (Cf. end of [http://www.newscientist.com/article/dn23205-major-methane-release-is-almost-inevitable.html](http://www.newscientist.com/article/dn23205-major-methane-release-is-almost-inevitable.html) ) The greatest danger of thawing permafrost seems to be disruption of gas pipelines, which would have major implications for European heating fuel supply and cost.
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edited March 2013

and I saw that you had found a direct link to that Boucher et al article, great!

which is cited in Wikipedia as a reference for that 10 year lifetime before -as I learned now -decaying mainly into co2. (I cite "This gives a lower bound of 0.51... and an upper bound of 1.0 for the fraction of methane that is converted to carbon dioxide. page 3 of Boucher paper)

I still haven't understood these co2 vs temperature curves there (see ongoing discussion here here in the forum. But if co2 concentrations should really lag behind temperature fluctuations then this could be due to the fact that methane plays a major role in this process. Do you have any idea where one could get methane in the atmossphere measurements, like they exists for co2?

Comment Source:>added a section “Lifetime of methane in the atmosphere”. and I saw that you had found a direct link to that Boucher et al article, great! which is cited in Wikipedia as a reference for that 10 year lifetime before -as I learned now -decaying mainly into co2. (I cite "This gives a lower bound of 0.51... and an upper bound of 1.0 for the fraction of methane that is converted to carbon dioxide. page 3 of Boucher paper) I had also added that reference to the page: <a href="http://www.azimuthproject.org/azimuth/show/Does+global+warming+lag+or+lead+a+rise+in+greenhouse+gas+concentration%3F">Does global warming lag or lead a rise in greenhouse gas concentrations</a> but I hadnt found a direct access to it. I still haven't understood these co2 vs temperature curves there (see ongoing discussion here <a href="http://forum.azimuthproject.org/discussion/1178/temperature-vs-ghg-concentrations/#Item_24">here in the forum.</a> But if co2 concentrations should really lag behind temperature fluctuations then this could be due to the fact that methane plays a major role in this process. Do you have any idea where one could get methane in the atmossphere measurements, like they exists for co2? for methane and soil see also: <a href="http://www.randform.org/blog/?p=4146">http://www.randform.org/blog/?p=4146</a>
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24.

As explained on RealClimate, the reason short-term fluctuation in CO2 lag short-term fluctuations in temperature seems to be that these fluctuations are both caused by something else: the El Niño cycle or ENSO. During an El Niño, portions of the Pacific get hot. This increases global average temperature and then the hot ocean releases carbon dioxide. One reason this is believable is that you can see how the fluctuations are correlated to the ENSO.

These short-term changes can be, and probably are, quite different than the gradual increase in CO2 and thus temperature that characterizes global warming.

I don't think methane has anything to do with this. But you can try to analyze the data and see.

Comment Source:[As explained on RealClimate](http://www.realclimate.org/index.php/archives/2012/09/el-ninos-effect-onco2-causes-confusion/), the reason short-term fluctuation in CO2 lag short-term fluctuations in temperature seems to be that these fluctuations are both caused by something else: the El Ni&ntilde;o cycle or [[ENSO]]. During an El Ni&ntilde;o, portions of the Pacific get hot. This increases global average temperature and then the hot ocean releases carbon dioxide. One reason this is believable is that you can see how the fluctuations are correlated to the ENSO. These short-term changes can be, and probably are, quite different than the gradual increase in CO2 and thus temperature that characterizes global warming. I don't think methane has anything to do with this. But you can try to analyze the data and see.
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25.

and moved all the contents of the page Methane Cycle to this page.

Comment Source:I have added more information to * [[Methane]] and moved all the contents of the page Methane Cycle to this page.
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edited October 2013

don’t think methane has anything to do with this. But you can try to analyze the data and see.

If you look on the corresponding Azimuth page and the links then it looks to me very much that actually methane may be a bigger driving force for temperature increase than CO2 as a Greenhouse gas.

On the Methane page the link to the article by Mark Dunphy is broken now. There exists still a URL to an abstract to that article at http://aswm.org/news/climate-change-news/1386-climate-change-argument-brought-back-down-to-earth but I am not sure wether this should be referenced. ???? should it????I guess the Nature article costs, thats why it hasnt been linked.

I currently try to find out how much of extra methane concentrations could be due to an increased rice production, see e.g.: http://www.sptimes.com/2007/05/02/Worldandnation/Scientists_blame_glob.shtml

In particular certain farming methods seem to prevent an increased methane output, at least thats what the title of an article "Shifts in rice farming practices in China reduce greenhouse gas methane" suggests but which isn't anymore available at: http://www.gsfc.nasa.gov/topstory/2002/1204paddies.html

Or is Nasa closed because of the US government shutdown?

Cheaper farming like with the help of solar pumps may increase wetlands area. (http://www.iwmi.cgiar.org/iwmi-tata/PDFs/2012_Highlight-35.pdf)

Comment Source:> don’t think methane has anything to do with this. But you can try to analyze the data and see. If you look on the <a href="http://www.azimuthproject.org/azimuth/show/Does+global+warming+lag+or+lead+a+rise+in+greenhouse+gas+concentration%3F">corresponding Azimuth page</a> and the links then it looks to me very much that actually methane may be a bigger driving force for temperature increase than CO2 as a Greenhouse gas. On the Methane page the link to the article by Mark Dunphy is broken now. There exists still a URL to an abstract to that article at <a href="http://aswm.org/news/climate-change-news/1386-climate-change-argument-brought-back-down-to-earth"> http://aswm.org/news/climate-change-news/1386-climate-change-argument-brought-back-down-to-earth</a> but I am not sure wether this should be referenced. ???? should it????I guess the Nature article costs, thats why it hasnt been linked. I currently try to find out how much of extra methane concentrations could be due to an increased rice production, see e.g.: <a href="http://www.sptimes.com/2007/05/02/Worldandnation/Scientists_blame_glob.shtml">http://www.sptimes.com/2007/05/02/Worldandnation/Scientists_blame_glob.shtml</a> In particular certain farming methods seem to prevent an increased methane output, at least thats what the title of an article "Shifts in rice farming practices in China reduce greenhouse gas methane" suggests but which isn't anymore available at: http://www.gsfc.nasa.gov/topstory/2002/1204paddies.html Or is Nasa closed because of the US government shutdown? Cheaper farming like with the help of solar pumps may increase wetlands area. (<a href="http://www.iwmi.cgiar.org/iwmi-tata/PDFs/2012_Highlight-35.pdf">http://www.iwmi.cgiar.org/iwmi-tata/PDFs/2012_Highlight-35.pdf</a>)
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In this context it is to note that groundwater levels in India aren't public. That is in Groundwater - Understanding the basics - A comprehensive FAQ manual by Dr Mihir Kumar Maitra it is written that:

Both the Central and State Ground Water Board keep track of groundwater situation in the country through regular monitoring of water level using a network of observation wells (hydrographs). For some reason, these water level data are not placed in public domain.

Comment Source:In this context it is to note that groundwater levels in India aren't public. That is in <a href="http://www.indiawaterportal.org/articles/groundwater-understanding-basics-comprehensive-faq-manual-dr-mihir-kumar-maitra">Groundwater - Understanding the basics - A comprehensive FAQ manual by Dr Mihir Kumar Maitra</a> it is written that: >Both the Central and State Ground Water Board keep track of groundwater situation in the country through regular monitoring of water level using a network of observation wells (hydrographs). For some reason, these water level data are not placed in public domain.
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In this context it would be interesting to see area comparisions of desertification vs production of wetlands like via permafrost melting. Is there data for say the last 30 ys. ??

Comment Source:In this context it would be interesting to see area comparisions of desertification vs production of wetlands like via permafrost melting. Is there data for say the last 30 ys. ??
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29.
edited October 2013

that actually methane may be a bigger driving force for temperature increase than CO2 as a Greenhouse gas.

i am aware that methane hadn't been looked so much at because amongst others of it's way smaller density in air in comparision to CO2 (factor 200 if wikipedia is right). However may be there is some factor or mechanism which had been overlooked so far and what exactly does it mean that as a Greenhouse gas methane is worse than CO2?

Comment Source:>that actually methane may be a bigger driving force for temperature increase than CO2 as a Greenhouse gas. i am aware that methane hadn't been looked so much at because amongst others of it's way smaller density in <a href="http://en.wikipedia.org/wiki/File:Atmosphere_gas_proportions.svg">air</a> in comparision to CO2 (factor 200 if wikipedia is right). However may be there is some factor or mechanism which had been overlooked so far and what exactly does it mean that as a Greenhouse gas methane is worse than CO2?
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30.

wikipedia says the impact factor of methane vs co2 is about 25 citing this paper behind a paywall: http://www.sciencemag.org/content/326/5953/716.abstract

Comment Source:wikipedia says the impact factor of methane vs co2 is about 25 citing this paper behind a paywall: http://www.sciencemag.org/content/326/5953/716.abstract
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31.

I should may be add that the paywall is rather a payfence, i.e. it is "considerably small" that is it says it is "free with registration" but it is not enough if you log in with your email and even name, but you have to consent to receive an unforseeable amount of newsletters, you have to fill in a form with all sorts of extra information and you have to consent to a privacy law text who's study would probably take a couple of hours.

Comment Source:I should may be add that the paywall is rather a payfence, i.e. it is "considerably small" that is it says it is "free with registration" but it is not enough if you log in with your email and even name, but you have to consent to receive an unforseeable amount of newsletters, you have to fill in a form with all sorts of extra information and you have to consent to a privacy law text who's study would probably take a couple of hours.
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32.

Why don't you take a look at the IPCC WG1 report? It's not paywalled.

There's the concept of Global warming potential: on it's own methane a stronger greenhouse gas (simplistically, it has four bonds and CO2 has only two double bonds, but of course also the location of the vibration modes in the spectrum plays a role, it's more important to have absorption bands around the peak of the earth's emission spectrum) but its lifetime in the atmosphere is less than that of carbon dioxide. Sorry for the vague words (such as 'lifetime') there should be more precise technical terms.

Comment Source:Why don't you take a look at the IPCC WG1 report? It's not paywalled. There's the concept of [[Global warming potential]]: on it's own methane a stronger greenhouse gas (simplistically, it has four bonds and CO2 has only two double bonds, but of course also the location of the vibration modes in the spectrum plays a role, it's more important to have absorption bands around the peak of the earth's emission spectrum) but its lifetime in the atmosphere is less than that of carbon dioxide. Sorry for the vague words (such as 'lifetime') there should be more precise technical terms.
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There’s the concept of Global warming potential

The global warming potential seems to be on a shut down server in Texas at least the Azimuth project isn't reachable anymore.

Thanks for the tip to look into the WG1 report, but there is also something strange with the server that is I get this message:

Dieser Verbindung wird nicht vertraut

Sie haben Firefox angewiesen, eine gesicherte Verbindung zu www.ipcc-wg1.unibe.ch aufzubauen, es kann aber nicht überprüft werden, ob die Verbindung sicher ist.

Wenn Sie normalerweise eine gesicherte Verbindung aufbauen, weist sich die Website mit einer vertrauenswürdigen Identifikation aus, um zu garantieren, dass Sie die richtige Website besuchen. Die Identifikation dieser Website dagegen kann nicht bestätigt werden. Was sollte ich tun?

Falls Sie für gewöhnlich keine Probleme mit dieser Website haben, könnte dieser Fehler bedeuten, dass jemand die Website fälscht. Sie sollten in dem Fall nicht fortfahren.

Comment Source:>There’s the concept of <a href="http://www.azimuthproject.org/azimuth/show/Global%20warming%20potential">Global warming potential</a> The <a href="http://www.azimuthproject.org/azimuth/show/Global%20warming%20potential">global warming potential </a> seems to be on a shut down server in Texas at least the Azimuth project isn't reachable anymore. Thanks for the tip to look into the WG1 report, but there is also something strange with the server that is I get this message: Dieser Verbindung wird nicht vertraut Sie haben Firefox angewiesen, eine gesicherte Verbindung zu www.ipcc-wg1.unibe.ch aufzubauen, es kann aber nicht überprüft werden, ob die Verbindung sicher ist. Wenn Sie normalerweise eine gesicherte Verbindung aufbauen, weist sich die Website mit einer vertrauenswürdigen Identifikation aus, um zu garantieren, dass Sie die richtige Website besuchen. Die Identifikation dieser Website dagegen kann nicht bestätigt werden. Was sollte ich tun? Falls Sie für gewöhnlich keine Probleme mit dieser Website haben, könnte dieser Fehler bedeuten, dass jemand die Website fälscht. Sie sollten in dem Fall nicht fortfahren.
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I can access the Azimuth project and I don't have problems with the server from University of Bern for the IPCC report. But if you have problems with the latter (by the way, thanks for assuming I understand German :) ) why don't you just give them a security exception. If you wouldn't trust them even for a security exception, why would you trust them enough to want to read their report?

Can you try this link directly to the final draft? I don't know which chapter you need here, in AR4 it would have been chapter two but I haven't looked at AR5 yet.

Comment Source:I can access the Azimuth project and I don't have problems with the server from University of Bern for the IPCC report. But if you have problems with the latter (by the way, thanks for assuming I understand German :) ) why don't you just give them a security exception. If you wouldn't trust them even for a security exception, why would you trust them enough to want to read their report? Can you try this link directly to the [final draft](http://www.climatechange2013.org/report/review-drafts/)? I don't know which chapter you need here, in AR4 it would have been chapter two but I haven't looked at AR5 yet.
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I didn't assume that you speak german, but you had written that you grew up in Nordrheinwestfalia: http://www.azimuthproject.org/azimuth/show/Frederik+De+Roo....(the Azimuth project website is currently again visible, Texas seems still to be alife)

Falls Sie für gewöhnlich keine Probleme mit dieser Website haben, könnte dieser Fehler bedeuten, dass jemand die Website fälscht. Sie sollten in dem Fall nicht fortfahren.

this says that somebody could have forged the webpage and since the URLs of the other working groups were different I preferred no to use the link, so thanks for the link to the final draft, I downloaded:

Chapter 8: Anthropogenic and Natural Radiative Forc ing - Final Draft Underlying Scientific- Technical Assessment (Submitted by the Co-Chairs of Working Group I) Confidential – This document is being made available in preparation of WGI-12 only and should not be cited, quoted, or distributed

so the front page says this draft is confidental, moreover the document is missing figures (like 8.1) are you sure that this is the final draft? without the figures I find it not so easy to understand.

Since the Azimuth project site was accessible again I looked at the global warming potential page and found amongst others in the there linked WG1 report on page 15 (by the way from when is this report?):

The RF due to changes in CH4 mixing ratio is calculated with the simplified yet still valid expression for CH4 given in Ramaswamy et al. (2001). which sounds like a cambridge university press book (i.e. for me inaccessible):

Ramaswamy, V., et al., 2001: Radiative forcing of climate change. In: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change[Houghton, J.T., et al. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 349– 416

the report says also that since 1985 there are now also measurements not only from NOAA but also from AGAGE. What is AGAGE? I couldnt find anything on that in the references. Do you know what this is?

you wrote:

on it’s own methane a stronger greenhouse gas (simplistically, it has four bonds and CO2 has only two double bonds, but of course also the location of the vibration modes in the spectrum plays a role, it’s more important to have absorption bands around the peak of the earth’s emission spectrum) but its lifetime in the atmosphere is less than that of carbon dioxide. Sorry for the vague words (such as ’lifetime’) there should be more precise technical terms.

Yes sounds plausible and eventually there is a different absorption if diluted in water (like in cloud droplets) or whatever other configurations there may exist apart from being in this tetrahedral molecule gas configuration, the student experiment (linked from the Azimuth project page) doesn't mention this option, if I haven't overread something, but I guess this is all discussed in the article by Ramaswamy et al.

Comment Source:I didn't assume that you speak german, but you had written that you grew up in Nordrheinwestfalia: http://www.azimuthproject.org/azimuth/show/Frederik+De+Roo....(the Azimuth project website is currently again visible, Texas seems still to be alife) >Falls Sie für gewöhnlich keine Probleme mit dieser Website haben, könnte dieser Fehler bedeuten, dass jemand die Website fälscht. Sie sollten in dem Fall nicht fortfahren. this says that somebody could have forged the webpage and since the URLs of the other working groups were different I preferred no to use the link, so thanks for the link to the final draft, I downloaded: >Chapter 8: Anthropogenic and Natural Radiative Forc ing - Final Draft Underlying Scientific- Technical Assessment (Submitted by the Co-Chairs of Working Group I) Confidential – This document is being made available in preparation of WGI-12 only and should not be cited, quoted, or distributed so the front page says this draft is confidental, moreover the document is missing figures (like 8.1) are you sure that this is the final draft? without the figures I find it not so easy to understand. Since the Azimuth project site was accessible again I looked at the global warming potential page and found amongst others in the there linked WG1 report on page 15 (by the way from when is this report?): >The RF due to changes in CH4 mixing ratio is calculated with the simplified yet still valid expression for CH4 given in Ramaswamy et al. (2001). which sounds like a cambridge university press book (i.e. for me inaccessible): >Ramaswamy, V., et al., 2001: Radiative forcing of climate change. In: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change[Houghton, J.T., et al. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 349– 416 the report says also that since 1985 there are now also measurements not only from NOAA but also from AGAGE. What is AGAGE? I couldnt find anything on that in the references. Do you know what this is? you wrote: >on it’s own methane a stronger greenhouse gas (simplistically, it has four bonds and CO2 has only two double bonds, but of course also the location of the vibration modes in the spectrum plays a role, it’s more important to have absorption bands around the peak of the earth’s emission spectrum) but its lifetime in the atmosphere is less than that of carbon dioxide. Sorry for the vague words (such as ’lifetime’) there should be more precise technical terms. Yes sounds plausible and eventually there is a different absorption if diluted in water (like in cloud droplets) or whatever other configurations there may exist apart from being in this tetrahedral molecule gas configuration, <a href="http://alpha.chem.umb.edu/chemistry/ch361/spring2006/greenhouse%20warming%20potential.pdf">the student experiment</a> (linked from the Azimuth project page) doesn't mention this option, if I haven't overread something, but I guess this is all discussed in the article by Ramaswamy et al.
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by the way I found the raise of NO_2 (probably mostly due to things like car exhaust of NO etc.) somewhat disturbing. It seems quite a bad GHG apart from that it seems to bind oxygen (see equilibrium with dinitrogen tetroxide) . According to Wikipedia its concentration in air is about 5 times more than methane so it seems CO2 is roughly only anymore 200/5 = 40 times more than NO_2 in air.

Comment Source:by the way I found the raise of <a href="http://en.wikipedia.org/wiki/Nitrogen_dioxide">NO_2</a> (probably mostly due to things like car exhaust of NO etc.) somewhat disturbing. It seems quite a bad GHG apart from that it seems to bind oxygen (see equilibrium with <a href="dinitrogen tetroxide">dinitrogen tetroxide</a>) . <a href="http://de.wikipedia.org/wiki/Luft">According to Wikipedia</a> its concentration in air is about 5 times more than methane so it seems CO2 is roughly only anymore 200/5 = 40 times more than NO_2 in air.
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Oh, I forgot about my own Azimuth page, did you really remember that or did you look it up afterwards? At that time I didn't speak German however.

• Concerning trace gases: it really matters whether you consider the concentration near the surface or in the stratosphere (where it has a stronger influence on the radiation balance).

• Here's a link to the third report with the Ramaswamy et al article. It's not behind a paywall, and it didn't take much googling, so I think you could have found this too. You will want the pdf of the sixth chapter.

• The webpage of the fifth report says it's the final draft (yet still a draft) so I assume that it is what they say. It's not the final report, I guess that will come out later (but the summary for policymakers just came out)

Before publication the Final Draft will undergo copyediting as well as any error correction as necessary, consistent with the IPCC Protocol for Addressing Possible Errors. Publication of the Report is foreseen in January 2014.

Comment Source:Oh, I forgot about my own Azimuth page, did you really remember that or did you look it up afterwards? At that time I didn't speak German however. * Concerning trace gases: it really matters whether you consider the concentration near the surface or in the stratosphere (where it has a stronger influence on the radiation balance). * **Here's a link to the [third report](http://www.ipcc.ch/ipccreports/tar/) with the Ramaswamy et al article. It's not behind a paywall**, and it didn't take much googling, so I think you could have found this too. You will want the pdf of the sixth chapter. * The webpage of the fifth report says it's the final draft (yet still a draft) so I assume that it is what they say. It's not the final report, I guess that will come out later (but the summary for policymakers just came out) > Before publication the Final Draft will undergo copyediting as well as any error correction as necessary, consistent with the IPCC Protocol for Addressing Possible Errors. Publication of the Report is foreseen in January 2014.
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edited October 2013

Oh, I forgot about my own Azimuth page, did you really remember that or did you look it up afterwards? At that time I didn’t speak German however.

No I had read your Azimuth page quite some time ago and remembered. How come that you grew up in Germany but didnt learn to speak German?

Here’s a link to the third report with the Ramaswamy et al article. It’s not behind a paywall, and it didn’t take much googling, so I think you could have found this too. You will want the pdf of the sixth chapter.

Sorry I had misinterpreted " Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change", as some extra contribution to the IPCC report and not as being a part of a report itself. (By the way I meanwhile have also realized that I had overread on the Azimuth page that the above reference is given in an IPCC report from 2007. Strangely though that that doesn't seem to be mentioned in the document itself (But may be had overlooked that too)). Reading Cambridge University Press in the reference and knowing about their prices I found it not worth the effort to google for it. (Apart from that I had to run because amongst others I had promised to help someone out in the kitchen) So thanks for googling this. The actual link to chapter 6 is actually here. The indirect radiative forcings are described in section 6. From the intro to this chapter:

"As previously indicated (IPCC, 1992, 1994; SAR), the tropospheric chemical processes determining the indirect greenhouse effects are highly complex and not fully understood. The uncertainties connected with estimates of the indirect effects are larger than the uncertainties of those connected to estimates of the direct effects. Because of the central role that O3 and OH play in tropospheric chemistry, the chemistry of CH4, CO, NMHC, and NOx is strongly intertwined, making the interpretation of the effects associated with emission changes rather complex. "

And briefly reading through it, it is not clear to me where and how the factor 25 was derived. By the way I meanwhile googled and found that AGAGE is probably this AGAGE but what is SAR??? (I originally had included the google-search result but since the Forum software doesn't swallow googlesearchURLs you might try googling SAR yourself.....whereas it is to say that of course your google result will in general differ from my google results.....)

Comment Source:>Oh, I forgot about my own Azimuth page, did you really remember that or did you look it up afterwards? At that time I didn’t speak German however. No I had read your Azimuth page quite some time ago and remembered. How come that you grew up in Germany but didnt learn to speak German? >Here’s a link to the third report with the Ramaswamy et al article. It’s not behind a paywall, and it didn’t take much googling, so I think you could have found this too. You will want the pdf of the sixth chapter. Sorry I had misinterpreted " Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change", as some extra contribution to the IPCC report and not as being a part of a report itself. (By the way I meanwhile have also realized that I had overread on the Azimuth page that the above reference is given in an IPCC report from 2007. Strangely though that that doesn't seem to be mentioned in the document itself (But may be had overlooked that too)). Reading Cambridge University Press in the reference and knowing about their prices I found it not worth the effort to google for it. (Apart from that I had to run because amongst others I had promised to help someone out in the kitchen) So thanks for googling this. The actual link to chapter 6 is actually <a href="http://www.ipcc.ch/ipccreports/tar/wg1/pdf/TAR-06.PDF">here.</a> The indirect radiative forcings are described in section 6. From the intro to this chapter: >"As previously indicated (IPCC, 1992, 1994; SAR), the tropospheric chemical processes determining the indirect greenhouse effects are highly complex and not fully understood. The uncertainties connected with estimates of the indirect effects are larger than the uncertainties of those connected to estimates of the direct effects. Because of the central role that O3 and OH play in tropospheric chemistry, the chemistry of CH4, CO, NMHC, and NOx is strongly intertwined, making the interpretation of the effects associated with emission changes rather complex. " And briefly reading through it, it is not clear to me where and how the factor 25 was derived. By the way I meanwhile googled and found that AGAGE is probably this <a href="http://agage.eas.gatech.edu/">AGAGE</a> but what is SAR??? (I originally had included the google-search result but since the Forum software doesn't swallow googlesearchURLs you might try googling SAR yourself.....whereas it is to say that of course your google result will in general differ from my google results.....)
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39.

SAR is the IPCC Second Assessment Report from 1995.

Comment Source:SAR is the IPCC Second Assessment Report from 1995.
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40.

SAR is the IPCC Second Assessment Report from 1995.

Thanks, Nathan. Sorry, but these kind of abbreviations are not really furthering readability in a couple of hundred pages document.

I meanwhile edited the global warming potential (GWP) page a bit. Frederick what is this log-forcing article about, how is it related to the radiative forcing?

It seems concerning the radiative forcings and GWPs there seem to be quite some differences in the new report vs. the older reports. I haven't sofar understood what is meant by the different life times (or pertubation life times?) like of CH4 as given in table 8.7 on p. 58. It is not allowed to cite from the new report, but it looks as that if one assumes a considerably higher life time than the usual 10 ys. lifetime of methane (before decaying into CO2. I.e. in particular I assume now that they mean the lifetime of CH4 in the stratosphere) then the GWP of methane seems to be WAY LARGER than the factor 25. :O But may be pertubative life time means here something completely different.

Comment Source:>SAR is the IPCC Second Assessment Report from 1995. Thanks, Nathan. Sorry, but these kind of abbreviations are not really furthering readability in a couple of hundred pages document. I meanwhile edited the global warming potential (GWP) page a bit. Frederick what is this log-forcing article about, how is it related to the radiative forcing? It seems concerning the radiative forcings and GWPs there seem to be quite some differences in the <a href="http://www.climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter08.pdf">new report</a> vs. the <a href="http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf">older reports.</a> I haven't sofar understood what is meant by the different life times (or pertubation life times?) like of CH4 as given in table 8.7 on p. 58. It is not allowed to cite from the new report, but it looks as that if one assumes a considerably higher life time than the usual 10 ys. lifetime of methane (before decaying into CO2. I.e. in particular I assume now that they mean the lifetime of CH4 in the stratosphere) then the GWP of methane seems to be WAY LARGER than the factor 25. :O But may be pertubative life time means here something completely different.
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edited October 2013

The methane levels were approximately contant between the ys 1999 and 2009/2010 after then they were rising again. Also observable in our visualization(I know I should write the actual ys underneath and not counting ys start at march 1958 so 1958+41=1999). If this is correct that the diff12s of the annual averages of temperature lag behind by approx one year as it handwavely looks in the visualization (i.e. the temperature values lag behind a little more than that, i.e. rather 2-3 ys) then if CH4 concentration should be a direct cause for temperature values then temperature values should increase again soon.

Comment Source:The methane levels were approximately contant between the ys 1999 and 2009/2010 after then they <a href="http://en.wikipedia.org/wiki/File:Mlo_ch4_ts_obs_03437.png">were rising again. </a> Also observable in <a href="http://www.daytar.de/art/co2ch4TempViz/index.html">our visualization</a>(I know I should write the actual ys underneath and not counting ys start at march 1958 so 1958+41=1999). If this is correct that the diff12s of the annual averages of temperature lag behind by approx one year as it handwavely looks in the visualization (i.e. the temperature values lag behind a little more than that, i.e. rather 2-3 ys) then if CH4 concentration should be a direct cause for temperature values then temperature values should increase again soon.
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edited December 2013

I wrote:

If this is correct that the diff12s of the annual averages of temperature lag behind by approx one year as it handwavely looks in the visualization

Actually it turned out this was not correct that is I found today a mistake in the drawing offsets, which makes the lag between methane and temperature smaller. However it still looks as if there would be a lag. The methane values have been updated today with the newest measurements.

So I still think this should be looked at. And there should definitely more people checking these diagrams! I wouldn't wonder if there are still mistakes to be found.

The whole issue may also be interesting in the context of the search for explanations why Carbon dioxide forcing alone is insufficient to explain Palaeocene–Eocene Thermal Maximum warming.

Comment Source:I wrote: >If this is correct that the diff12s of the annual averages of temperature lag behind by approx one year as it handwavely looks in the visualization Actually it turned out this was not correct that is I found today a <a href="http://www.azimuthproject.org/azimuth/show/Does+global+warming+lag+or+lead+a+rise+in+greenhouse+gas+concentration?">mistake in the drawing offsets</a>, which makes the lag between methane and temperature smaller. However it still looks as if there would be a lag. The methane values have been updated today with the newest measurements. So I still think this should be looked at. And there should definitely more people checking these diagrams! I wouldn't wonder if there are still mistakes to be found. The whole issue may also be interesting in the context of the search for explanations why <a href="http://www.nature.com/ngeo/journal/v2/n8/abs/ngeo578.html;">Carbon dioxide forcing alone is insufficient to explain Palaeocene–Eocene Thermal Maximum warming.</a>
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Last I looked into it, the Zeebe paper on the PETM wasn't conclusive because it made strong assumptions about the initial concentration of atmospheric CO2 in the late Paleocene. This was not well constrained, and depending on what you assume about it, you get different levels of CO2-doubling during the PETM and therefore different implied climate sensitivities. But I'm a few years out of date in this area.

Comment Source:Last I looked into it, the Zeebe paper on the PETM wasn't conclusive because it made strong assumptions about the initial concentration of atmospheric CO2 in the late Paleocene. This was not well constrained, and depending on what you assume about it, you get different levels of CO2-doubling during the PETM and therefore different implied climate sensitivities. But I'm a few years out of date in this area.
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44.

They write:

At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1, this rise in CO2 can explain only between 1 and 3.5 °C of the warming inferred from proxy records. We conclude that in addition to direct CO2 forcing, other processes and/or feedbacks that are hitherto unknown must have caused a substantial portion of the warming during the Palaeocene–Eocene Thermal Maximum. Once these processes have been identified, their potential effect on future climate change needs to be taken into account.

Thanks Nathan. So are the strong assumptions about the initial concentration of atmospheric CO2 in the late Paleocene, which you mentioned, part of their "climate sensitivity" assumption?

The article is behind a paywall, so I had only looked at the abstract.

Comment Source:They write: >At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1, this rise in CO2 can explain only between 1 and 3.5 °C of the warming inferred from proxy records. We conclude that in addition to direct CO2 forcing, other processes and/or feedbacks that are hitherto unknown must have caused a substantial portion of the warming during the Palaeocene–Eocene Thermal Maximum. Once these processes have been identified, their potential effect on future climate change needs to be taken into account. Thanks Nathan. So are the strong assumptions about the initial concentration of atmospheric CO2 in the late Paleocene, which you mentioned, part of their "climate sensitivity" assumption? The article is behind a paywall, so I had only looked at the abstract.
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45.

They use the PETM temperature change and CO2 change to infer that the PETM climate sensitivity to CO2 was high (or else there is an unexplained source of radiative forcing). But implicit in that calculation is the conversion of CO2 change to CO2 radiative forcing, which depends on their assumptions about the initial CO2.

Comment Source:They use the PETM temperature change and CO2 change to infer that the PETM climate sensitivity to CO2 was high (or else there is an unexplained source of radiative forcing). But implicit in that calculation is the conversion of CO2 change to CO2 radiative forcing, which depends on their assumptions about the initial CO2.
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46.
edited December 2013

At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1, this rise in CO2 can explain only between 1 and 3.5 °C of the warming inferred from proxy records.

I understand this "At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1" that the linear factor in the definition of climate sensitivity vs radiative forcing seems to be accepted. So the climate sensitivity basically depends in this case only more on the radiative forcing. So do you mean that their initially assumed CO2 concentration C_0 was probably to small (that is that log(C/C_0) increased "too slowly")?

Comment Source:>At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1, this rise in CO2 can explain only between 1 and 3.5 °C of the warming inferred from proxy records. I understand this "At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration1" that the linear factor in the definition of climate sensitivity vs radiative forcing seems to be accepted. So the climate sensitivity basically depends in this case only more on the radiative forcing. So do you mean that their initially assumed CO2 concentration <a href="http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/222.htm">C_0</a> was probably to small (that is that log(C/C_0) increased "too slowly")?
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47.
edited December 2013

By the way it seems nobody is interested in this comparision of methane lag as mentioned here. That is I asked Ed Dlugokencky wether he knows about research in that context and he replied that he hasn't seen anything on that. If you or anybody reading this here should know about similar comparision it would be nice to let me know.

Furthermore especially by looking at the radiative forcing formulas I think one should include N_2O data into the diagram. Do you know which dataset would be appropriate for that?

Apart from this we had above the discussion about the role of wetlands in methane emissions. Ed Dlugokencky also suggested that thus precipitation has an effect on methane emissions. Could you recommend a dataset for global precipitation data (similar to that for the temperature)?

Comment Source:By the way it seems nobody is interested in this comparision of methane lag as mentioned <a href="http://forum.azimuthproject.org/discussion/203/methane/?Focus=9620#Comment_9620">here</a>. That is I asked Ed Dlugokencky wether he knows about research in that context and he replied that he hasn't seen anything on that. If you or anybody reading this here should know about similar comparision it would be nice to let me know. Furthermore especially by looking at the radiative forcing formulas I think one should include N_2O data into the diagram. Do you know which dataset would be appropriate for that? Apart from this we had <a href="http://forum.azimuthproject.org/discussion/203/methane/?Focus=9603#Comment_9603">above the discussion about the role of wetlands in methane emissions</a>. Ed Dlugokencky also suggested that thus precipitation has an effect on methane emissions. Could you recommend a dataset for global precipitation data (similar to that for the temperature)?
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48.

I wouldn't say "probably" too small, but what I recall is that there are proxy studies that give a larger late-Eocene CO2 concentration, and some argument about which are preferred.

Comment Source:I wouldn't say "probably" too small, but what I recall is that there are proxy studies that give a larger late-Eocene CO2 concentration, and some argument about which are preferred.
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49.
edited April 2014

I wrote

by the way I found the raise of NO_2 (probably mostly due to things like car exhaust of NO etc.) somewhat disturbing. It seems quite a bad GHG apart from that it seems to bind oxygen (see equilibrium with dinitrogen tetroxide) . According to Wikipedia its concentration in air is about 5 times more than methane so it seems CO2 is roughly only anymore 200/5 = 40 times more than NO_2 in air

I do not remember why I was thinking about NO_2 being a bad GHG since in 2.10.3.4 it is written that:

Due to the lack of agreement even on the sign of the global mean GWP for NOx among the different studies and the omission of the nitrate aerosol effect, a central estimate for the 100-year GWP for NOx is not presented.

I might have thought that because of its high concentration it could be bad if there was only a slight positive effect or I might have confused it with nitrous oxide. Anyway is there a recomendable time series for nitrous oxide? If I click on the download data button at NOAA I get nothing.

Comment Source:I wrote >by the way I found the raise of NO_2 (probably mostly due to things like car exhaust of NO etc.) somewhat disturbing. It seems quite a bad GHG apart from that it seems to bind oxygen (see equilibrium with dinitrogen tetroxide) . According to Wikipedia its concentration in air is about 5 times more than methane so it seems CO2 is roughly only anymore 200/5 = 40 times more than NO_2 in air I do not remember why I was thinking about NO_2 being a bad GHG since in <a href="http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf">2.10.3.4 </a> it is written that: >Due to the lack of agreement even on the sign of the global mean GWP for NOx among the different studies and the omission of the nitrate aerosol effect, a central estimate for the 100-year GWP for NOx is not presented. I might have thought that because of its high concentration it could be bad if there was only a slight positive effect or I might have confused it with nitrous oxide. Anyway is there a recomendable time series for nitrous oxide? If I click on the <a href="http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=BRW">download data button at NOAA</a> I get nothing.
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50.

If I click on the download data button at NOAA I get nothing.

may be this is due to a major restructuring which is taking place at NOAA. that is the CO2 data which I used in the visualization moved from ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt to ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_mm_mlo.txt

products?

does this mean that NOAA intends to sell their products?

Comment Source:>If I click on the download data button at NOAA I get nothing. may be this is due to a major restructuring which is taking place at NOAA. that is the CO2 data which I used in the <a href="http://www.daytar.de/art/co2ch4TempViz/index.html">visualization</a> moved from <a href="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt">ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt</a> to <a href="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt">ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_mm_mlo.txt</a> products? does this mean that NOAA intends to sell their products?