2011-08-16 09:44:31Greenhouse Gas: It's not just about CO2
John Cook


Here's a first blog post by new SkSer Mythago who I've just invited to the forum:


So feedback welcome for this blog post.

2011-08-16 23:43:49
Ari Jokimäki


The article discusses "greenhouse gases" but doesn't even mention water vapor. I think different term should be used instead of greenhouse gases (anthropogenic greenhouse gases perhaps?), at least when introducing the term.

2011-08-17 01:05:36
John Garrett


I enjoyed this article, and will read it a few more times.

Question: in the 4th paragraph you mention nitrogen dioxide but the pie chart and later text mentions nitrous oxide. Did you mean nitrous oxide in the 4th paragraph?

Where you mention methane, it might be worthwhile to add that methane breaks down into CO2. Also in this same paragraph you mention methane as a cause in reaching an environmental tipping point. Could you provide a source for this? I recall a blog post by Pierre-Humbert on RealClimate arguing differently: http://www.realclimate.org/index.php/archives/2010/12/losing-time-not-buying-time/



2011-08-17 04:38:38


Hello all,

I have change some things already but your observations are valid. I will change the nitrogen Dioxide to Nitrous Oxide as that is what I meant and as for the water vapour not being mentioned I was partially relying on the pie chart from NOAA as a backdrop to the idea of promoting the issue of greenhouse gases relating directly to human activity such as air con units and fertilisers in their gardens. However it is a valid point and probably needs to be added as a kind of note to clarify that it hasn't been ignored accidentally or deliberately. Leave it with me and I will have a look.

Kev C

2011-08-17 04:49:31


Have inserted a paragraph as a Note to explain the water vapour ommission.

I also note the tipping point reference and will take a look for some supporting evidence. I do believe there was something recently mentioned on the Crisis Forum which cited a paper on the issue.

Will return to this later. Have to go to work now. Many thanks for the observations. Much appreciated.

Kev C

2011-08-17 08:39:09
Rob Painting


- "Many have a disproportionate heat trapping impact compared to their elemental consist." - Does that make sense?

- "Nitrous Oxide is common in fertilisers"- Artificial fertilisers have very high amounts of nitrogen, which soils microbes break-down forming nitrous oxide. Maybe what you mean but it doesn't read that way.

Oxfordshire eh? That's where my father's side of the family hail from.

2011-08-18 22:31:04
Sarah Green
Be careful with this paragraph: "With the more exotic gases their lifetime is extremely long because they are not produced by any natural processes. Being entirely man-made they are more likely to endure. There is no reverse mechanism in the natural world outside of the human manufacturing zone that can dismantle and reprocess a lot of these exotic gases. They simply remain intact causing major climatic issues for a very long time. Many have a disproportionate heat trapping impact compared to their elemental consist."

The fact of compounds being man-made has little to do with their longevity. Humans make short-lived gases, too (e.g. silane). CFCs (now banned) were specifically designed to be unreactive, and thus very nontoxic when inhaled, but the corollary is they last a long time in the atmosphere. Some natural compounds are extremely resistant to degradation, e.g. Lignin.

Ditto on Rob's comments. N2O is not "in" fertilizers, soil bacteria make it when presented with excess nitrogen. Part of the solution is to check when and where N should be supplied to fields to avoid applying too much. Certainly artificial N is much more likely to be vastly over applied than is compost!

You might consider putting the note on water as a footnote with a briefer mention in the text. I'd also point out that it's atmo concentration is affected by temperature (feedbacks).

This phrase is a bit awkward: "The gases they can reduce the usage of form part"

Welcome to SKS! Sarah

2011-08-19 11:02:06


I'm not that happy with "warming effect". I assume you mean radiative forcing. As it is, it seems to imply that if you removed all the CO2 from atmosphere, then the incoming radiation (without feedbacks) would only drop by 1.7.

2011-08-19 14:21:00
Glenn Tamblyn


Interesting first post Kev

Picking up on a grammar thing "my additional search for additional data" perhaps.


Why the tag Mythago? Are you a Robert Holdstock fan?

2011-09-02 03:16:38First post and a baptism of welcome critical reviews


Hello all again,

Many thanks for taking the trouble to read my article. It is obvious that I have a lot to learn about presentation but I am more than willing to do the best I can.

I take on board the obvious mistakes like N2O instead of simply Nitrogen in the fertiliser. It is causing grave concern with regards dead zones around coastlines so I will have to investigate the impact, if any, of these dead zones on the ecosystem cycles that may or may not add to the problems of climate changing emissions.

Also my grammar needs to be brushed up substantially. :) Yes its a long time since I wrote anything, (in anger as they say).

The thing about long lived gases I will remove from the article. I know what I was thinking but I clearly did not phrase it correctly so I will save that for another day and review how to get the point across in a more appropriate way.

For the record I am an environmental studies student of advancing years with a penchant for ancient trees (I am one of 136 Ancient Tree Hunt volunteer verifiers in the UK working to catalogue all the ancient trees we have left so that we may be better able to protect them and their habitats from developers and agricultural and forestry malpractices. Hence Mythago (from Mythago Wood by Robert Holdstock) which is an amazing story and one of my all time favourites. Having read the entire cycle I can safely say he ranks with Tolkien as a Fantasy writer.

Now its onwards to correct the errors and try to get it right. Please keep me posted on anything you see that is clearly incorrect. After all I would hate to be the one to draw fire towards this site for inaccurate comments. :)

Once again many thanks from Oxfordshire (I hale from Lancashire via North Yorkshire and the North East of England)


Kev C

PS I have placed 2 links to outside sources regarding Methane and tipping points which have been sent to me from the Crisis Forum which I also subscribe to (along with about 200 other sites of scientific and environmental interest etc. Your comments would be welcome as usual. Including a spell check facility. It would appear that there isn't one on the above list of tools. Have I missed the link to it?

2011-09-02 05:28:46Most changes made as suggested


I hope I have covered most things but I would appreciate the opinions of the group as to the robust nature of the article. Anything that is missed or still in need of refinement please let me know.

I would appreciate knowing the exact place where 'Warming effect' was quoted as I had difficulty in locating it. I will correct the term later when I know where it was used incorrectly.

Bit of a rush right now as off to work (night shift for the record).


Kev C

2011-09-02 14:21:19


The article refers to methane as being 25 times more potent than CO2.  This is true but the point ought to be qualified by inserting "over a 100 year timescale".

Methane has in fact a much higher GWP over its life-time in the atmosphere, 15-20 years depending on the level of OH radicals present in the atmosphere and the concentration of CH4.  Over a 10-15 year timescale, it has a a GWP of ~70-75.

The article rightly points out that the real threat to global warming is more properly attributed to CH4 than CO2, particularly CH4 released by thawing permafrost.

2011-09-02 20:04:19


But methane breaks down over time; CO2 doesn't.

2011-09-03 00:21:46
Alex C


I would recommend a much more pertinent introduction, it does not relate to the article.  I'll also be making suggestions for grammatical changes or syntactical changes, bolded text is what I think should replace what is there.  Comments RE text in brackets.

>>>...are affecting the planet's climate requires...

>>>and their energy trapping impact on the larger planetary climate. [Eh, this is a bit redundant with the previous lead-in of "affecting the planet's climate.']

>>>known and talked about greenhouse gas *(See Note at end of paragraph)...

>>>...what people don’t quite get is why it is. [Or, "what people don't quite get is, why is it?"]

>>>They simply don’t get it and if they don’t get it they won’t do anything about it either, which is bad news for everyone. [A lot of "don't get it"s, back away from that saying and mix it up a bit.  "Understand," "doesn't click with them," "comprehend," "overloads," so on.  "Get it" is rather informal too, bordering slang esp. when used so much.]

>>>*Note:[space]This is apart from...

>>>...which shows the various ratios of greenhouse...

>>>...and how they impact on the planet individually in terms of warming influence.

>>>They also include the other less-well known greenhouse gases.

>>>Proportions of greenhouse gases by Warming Influence (watts/m2). The direct warming influence of all long-lived greenhouse gases in the atmosphere today attributable to human activities. [This is unclear - I understand the message that this graph displays the component breakdown of the GHG forcing over the pre-industrial levels, but stating it as such above doesn't succinctly convey that.  Also, the second sentence is a fragment anyways, so it ought to be modified for that reason at least.]

>>>The category “other“ includes a few very long-lived...

>>>...yet it is not the most potent of the family. [You imply the pie chart shows this, but it does not.  You would need a concentration chart to compare against to determine this.]

>>>...impact of these particular gases, I discovered... [comma after "gases"]

>>>...come across before: how long we have actually known about the greenhouse effect.

>>>Thinking time is a luxury we nolonger have in terms of the impacts now occurring and the long term trends which we need to address. [I think, "Thinking-time is a luxury we no longer have, with short term impacts already occurring and long term impacts needing to be addressed." sounds better.  Otherwise, hyphen between "thinking" and "time," and a space within "nolonger."]

>>>So what about their lifecycles in the atmosphere? ["Lifetime" is the more common word, also "lifecycle" has the connotation of being for a particular molecule's run-through of the atmosphere, which is always shorter than the lifetime of a bulk parcel of GHGs.  Take CO2 for instance, which has an overall lifetime of at least several decades, but an individual molecule will stay in the atmosphere for only a few years.]

>>>...atmosphere for 50 to 500+ years.


That's all for now, I'll have a further look when I get some more time.  Good article so far.

As to the methane GWP potential, it is imperative that you clarify the 25 GWP is ONLY over a 100-year timescale.  Methane is much stronger during its actual existence in the atmosphere, but it is its decay (well, reaction) to CO2 that, when averaged out over longer and longer time scales, brings its GWP down.  Agnostic is right in that respect, though I disagree that methane is the biggest threat.  As shown by the forcing component chart, it's not - its concentration is still too low.  It is perhaps the largest natural threat, with possible methane clathrates releasing very large amounts of, well, methane, but as we have already gone over in previous articles, focusing on methane reduction may forego short term warming, but the long term warming will persist as CO2 increases.  Hence, I think, Neal's point.

AFAIK too Mythago, there is no spell-check tool.

2011-09-03 06:36:55



Very true - methane does breakdown but continuous venting of methane can cause far more warming than CO2

And then there is the question of how long methane stays in the atmosphere.  If OH radicals are insufficient to oxidise an eruption of say 30 gigatonnes CH4, it will presumably remain in the atmosphere and flex its GWP muscles.

However, eventually CH4 will be oxidised into CO2 and CO2 can remain in the atmosphere for over 1,000 years, possibly longer, until absorbed by oceans, vegetation or silicate rock