General Climate Change

[sunny starry skies]

If you care to search the forum I posted an article regarding the MWP. I can't believe your seriously trying to suggest it as any credibility in the world of HONEST scientific research! As for the rest of your post, I suggest you read a little more than the AGW handbook. There is enough literature out there, if you care to take the blinkers off now and again!

Not sure what you mean about the MWP lacking credibility SC - it's perfectly real in the North Atlantic area, but just not really in a global sense. If it turns out to be real in the global sense, we should all be much more scared about how hot the world will get, as that would imply high climate sensitivity, which we are now forcing with GHGs. As for your accusation about me not reading the literature, maybe I could say the same of you? Point me to unrefuted scientific papers showing that AGW does not exist or is vastly overstated. The ones I've read tend to get little things wrong, like removing trendlines and saying there's no trend, or confusing degrees and radians. Very few "skeptical papers make in into the peer-reviewed literature, and the ones that do tend to be shown to have errors, minor or major, that contradict their findings. The ones that don't (that end up in junk journals like E&E) are even worse! Meanwhile there is a huge coherent body of empirical evidence, supported by physical theory, laboratory experiments and various kinds of modelling, showing that AGW is on perfectly solid ground.

You'd be surprised about how it's well worth looking at places like WUWT, Climate Audit or other denier blogs, but only to hone your deductive skills in determining exactly where they've gone wrong with their pseudoscience this time! A recent example on WUWT had Steve Goddard suggesting that atmospheric pressure was proportional to temperature, therefore CO2 was not a greenhouse gas. I hope that on a weather forum you would be aware that the air pressure in Antarctica and Europe is approximately the same!

sss

[Yorkshiresnows]

Y.S.

The hockey stick has not been discredited (maybe only in your mind), and has been successfully reproduced many times over. Actually, the only value in the 'hockey stick' is to place some limitations on our climate sensitivity - the physics of the atmosphere does the actual 'AGW' bit.

http://www.realclima...ck-controversy/

http://www.realclima...ick-were-wrong/

It's well-known that the Sun is the dominant driver over the millennium prior to the Industrial period - find a respectable climate scientist who thinks it isn't! It's just that since industrial times and especially in the last 50 years, GHGs have become dominant. I'm also happy to agree that it may have some particular impact on regional (North Atlantic) climate - a very recent paper whose link I can't find supports this.

BTW, Roy Spencer has been debunked more times than a chocolate teapot, so why use him as a data source?

http://tamino.wordpr...spencers-folly/

http://www.realclima...e-easy-lessons/

http://www.skeptical...c-consensus.htm

among many others. His GRL paper is old hat, and the 2010 papers show him to be wrong.

Clouds - apart from having no identifiable link with climate, the projected feedback by the IPCC of clouds is negative, not positive as you state:

http://www.realclima...007_radforc.jpg

Your graph nicely shows that solar activity and climate have gone their separate ways since 1950 or so, and that divergence is proven by the spatial pattern of warming.

The problem here is that there is no rational position to suggest that solar, clouds or a "cycle" dominates recent climate change, far less then how such factors would explain why the physics of the CO2 molecule fails to work under such an hypothesis. And even more how such a process can work, inhibit the radiative properties of CO2 (despite the fact that we observe these properties operating in the real world), and yet produce a spatial pattern of warming that is inconsistent with any process except for greenhouse gases!!

sss

Edit: Deepsnow Not heard of that argument before - I've heard the old canard about CO2 lagging temperature in the distant past - see this link:

http://www.skeptical...temperature.htm

The fallacy is to suggest that because one process drove climate in the past (orbital forcing), another one cannot drive climate now (humans emitting vast amounts of CO2). Much like saying that because ancient forest fires were caused by lightning, no modern forest fire was caused by people...

Oh Crikey,

Sorry Sunnyskies, I'm going to have to bow out of this one. Guess we will have to agree to disagree on the hockey stick graph ..... funny the IPCC have dropped it !!!

Roy Spencer's work is published and peer reviewed. But, he is not the only one to have come to the same conclusions. But, all of this is getting tiresome, If you want to believe the AGW theory then that's your absolute right and I've no problem with it.

If you have a little look around you will see a lot of support for the effect of clouds on the climate system. As stated hundreds of times previously the IPCC models rely on their SUPPOSED positive feedback (that is to amplify the warming) to get us to the amplification needed for their warming charts. Satellite data suggests they have a strong overall negative feedback (greater water low cloud density leading to reduced solar radiation absorption) ..... so something is not correct.

I've read literally hundreds of papers and books on this subject and I've come round more and more to what I have previously stated. Untill a short while ago I was firmly in the AGW camp.

The amount of CO2 we are emitting as I've shown previously really is quite small in the overall scheme of things ...... from 0.0003 to 0.0004 of a fraction of the atmoshpere from 1950's to 2010. If we can cut it, that's also fine with me as it is a greenhouse gas and I'd rather promote a greener way of life for many other reasons as well as that.

Perhaps you could explain why the IPCC forecasts range from 1.5 degree C of warming to 6 degrees C of warming by the turmn of the century and also why we are currently so far off their predicted charts ..... I say again, no overall warming since 2000 !!!?

PDO = negative // solar activity low = probable cooling for me !!

Y.S

Edited May 27, 2010 by Yorkshiresnows

[Gray-Wolf]

Welcome back S.S.S. and farewell V.P. (you WILL be missed but I can appreciate your dissatisfaction).

I've been told off for focusing here on a 'general' thread but I do feel the rapid changes in the Arctic are driving not only the speed of climate shift but also the ferocity of exchanges on here ( from one entrenched viewpoint to the other).

The undeniability of this years ice decline (in line with the predictions) and the unavailability of evidence that such a matter is a 'cyclical thing' seems to mean some folk are ever more desperate to ram their 'point' (not evidence) home.

It is costing us valued posters and will not alter the changes we witness.

It has a 'taste' of sour grapes to it all and ,to me, seems as if all of this were some school debating society (playing games) and not a real and urgent matter for us all.

Edited May 27, 2010 by Gray-Wolf

[Yorkshiresnows]

Not sure what you mean about the MWP lacking credibility SC - it's perfectly real in the North Atlantic area, but just not really in a global sense. If it turns out to be real in the global sense, we should all be much more scared about how hot the world will get, as that would imply high climate sensitivity, which we are now forcing with GHGs. As for your accusation about me not reading the literature, maybe I could say the same of you? Point me to unrefuted scientific papers showing that AGW does not exist or is vastly overstated. The ones I've read tend to get little things wrong, like removing trendlines and saying there's no trend, or confusing degrees and radians. Very few "skeptical papers make in into the peer-reviewed literature, and the ones that do tend to be shown to have errors, minor or major, that contradict their findings. The ones that don't (that end up in junk journals like E&E) are even worse! Meanwhile there is a huge coherent body of empirical evidence, supported by physical theory, laboratory experiments and various kinds of modelling, showing that AGW is on perfectly solid ground.

You'd be surprised about how it's well worth looking at places like WUWT, Climate Audit or other denier blogs, but only to hone your deductive skills in determining exactly where they've gone wrong with their pseudoscience this time! A recent example on WUWT had Steve Goddard suggesting that atmospheric pressure was proportional to temperature, therefore CO2 was not a greenhouse gas. I hope that on a weather forum you would be aware that the air pressure in Antarctica and Europe is approximately the same!

sss

I believe that The liitle ice age had a global effect. Why do you think that the Northern Ice cap expanded, the Vikings were forced to abandon their Greenland settlements and Northern Glaciers expanded into valley bottoms. Then their are the Farming records to consider. Their is a book called 'The little Ice Age' which charts agricultural changes as well as written records of the climate in an historical context from the end of the medieval warm period up until the 1850's. There are also several papers charting Pacific and Indian ocean proxy data (you'd have to google search as I cannot remember the titles) that also show reductions in temperature over this period.

Y.S

[Yorkshiresnows]

Welcome back S.S.S. and farewell V.P. (you WILL be missed but I can appreciate your dissatisfaction).

I've been told off for focusing here on a 'general' thread but I do feel the rapid changes in the Arctic are driving not only the speed of climate shift but also the ferocity of exchanges on here ( from one entrenched viewpoint to the other).

The undeniability of this years ice decline (in line with the predictions) and the unavailability of evidence that such a matter is a 'cyclical thing' seems to mean some folk are ever more desperate to ram their 'point' (not evidence) home.

It is costing us valued posters and will not alter the changes we witness.

It has a 'taste' of sour grapes to it all and ,to me, seems as if all of this were some school debating society (playing games) and not a real and urgent matter for us all.

And .... your ever increasingly upbeat and informative posts have nothing to do with it?

How's the antarctic ice holding up this year !!!

Also, its only your opinion that the Arctic situation is unprecedented. We do not have accurate records from satellites prior to the late 70's ... you seem to readily dismiss the notion that during such warm periods as the medieval warm period this could not have been the case ...... ! Puzzling.

Y.S

Edited May 27, 2010 by Yorkshiresnows

[Devonian]

Oh Crikey,

Sorry Sunnyskies, I'm going to have to bow out of this one. Guess we will have to agree to disagree on the hockey stick graph ..... funny the IPCC have dropped it !!!

Roy Spencer's work is published and peer reviewed. But, he is not the only one to have come to the same conclusions. But, all of this is getting tiresome, If you want to believe the AGW theory then that's your absolute right and I've no problem with it.

If you have a little look around you will see a lot of support for the effect of clouds on the climate system. As stated hundreds of times previously the IPCC models rely on their SUPPOSED positive feedback (that is to amplify the warming) to get us to the amplification needed for their warming charts. Satellite data suggests they have a strong overall negative feedback (greater water low cloud density leading to reduced solar radiation absorption) ..... so something is not correct.

I've read literally hundreds of papers and books on this subject and I've come round more and more to what I have previously stated. Untill a short while ago I was firmly in the AGW camp.

The amount of CO2 we are emitting as I've shown previously really is quite small in the overall scheme of things ...... from 0.0003 to 0.0004 of a fraction of the atmoshpere from 1950's to 2010. If we can cut it, that's also fine with me as it is a greenhouse gas and I'd rather promote a greener way of life for many other reasons as well as that.

Ys, I've pointed out once before that wrt CO2 it's not .0003 to .0004 but .03 to .04. If you think CO2 is that scarce I can understand you think it non existent...

Perhaps you could explain why the IPCC forecasts range from 1.5 degree C of warming to 6 degrees C of warming by the turmn of the century and also why we are currently so far off their predicted charts ..... I say again, no overall warming since 2000 !!!?

Again, this is also plain wrong - all you have to do is go to wood for trees and do your own graphs. Oh, and by the turn of the NEXT century.

PDO = negative // solar activity low = probable cooling for me !!

Y.S

The PDO is an internal climate system.

Edited May 27, 2010 by Devonian

[Yorkshiresnows]

Ys, I've pointed out once before that wrt CO2 it's not .0003 to .0004 but .03 to .04. If you think CO2 is that scarce I can understand you think it non existent...

Again, this is also plain wrong - all you have to do is go to wood for trees and do your own graphs. Oh, and by the turn of the NEXT century.

The PDO is an internal climate system.

Regarding CO2. Nope its as I've stated (fraction of the atmosphere)!!

Open your eyes .... you might see something !

Edited May 27, 2010 by Yorkshiresnows

[Devonian]

Regarding CO2. Nope its as I've stated (fraction of the atmosphere)!!

Actually you've initially said (page 25) "As a fraction of the atmosphere and looking back from 1955 to 2010 we will have increased the overall atmospheric value from around 0.0003 to around 0.0004. " that is wrong - or your English is opaque and you're trying to say somthing else i don't get. This time your words are different and I still think you're wrong but please show your working so I can understand what you mean because what you say makes no sense to me (which saves you accusing me of being you know what...).

Open your eyes .... you might see something !

Cheers, how nice of you.

Edited May 27, 2010 by Devonian

[Pennine Ten Foot Drifts]

Just for a layman's sake, is .0003 three parts per thousand ? From what I can find there are two ways of quoting it - as 390 ppm or 0.039% of the atmosphere.

Edited May 27, 2010 by Pennine Ten Foot Drifts

[Devonian]

Just for a layman's sake, is .0003 three parts per thousand ? From what I can find there are two ways of quoting it - as 390 ppm or 0.039% of the atmosphere.

That's my understanding.

[pottyprof]

That's my understanding.

Mine too....

[Yorkshiresnows]

Mine too....

Agreed.

I apologise to all.

The figure I quoted was from graph (which I cannot show you at the moment) that details the change in Co2 content over a 5 year period from a supposed human emissions of 70 million tons of CO2 per day.

As such, and quite obviously to all I was wrong on that statement.

The rest of the information I provided. I stand by.

Y.S

[osmposm]

Actually, you're all wrong in part - and you're all right in part. Everyone's so busy arguing they can't see that they agree with each other!

Um....no, Pennine, Dev, Potty - 0.0003 is three parts per ten thousand, not per thousand**. But it is the same thing as three hundred parts per million (ppm), yes. Or if you like percentages, you can also call it 0.03%....which is (I assume) what you were getting at, Dev, though I think you were pretty confused.

So YS, you were right all along in talking about 0.0003 to 0.0004 of the total atmosphere, and wrong to subsequently agree that you had been wrong before! You now tell us that although that statement was wrong, everything else was right.....hmmmm.....well, I'm not sure where that leaves us!?

Time, I think, for a laugh about this: you'd all have failed 'O' Levels Maths in my day, and here you are expecting us to believe what you say about infinitely more complex climate change calculations. I think you're both rubbish at maths, and therefore probably at physics, too, and I shall be taking your learned and passionate pronouncements with a large pinch of salt from here on in!

[**If you're still not clear: 0.3 = 3 parts per ten (or 3/10); 0.03 = 3 parts per hundred (or 3/100); 0.003 = 3 parts per thousand (or 3/1000); 0.0003 = 3 parts per ten thousand (or 3/10000). And 3 parts per 10,000 = 30 parts per 100,000 = 300 parts per 1,000,000)]

[Gray-Wolf]

How's the antarctic ice holding up this year !!!

http://www.livescience.com/environment/south-pole-warmest-year-100510.html

Indeed! the warmest year on record!!!

Seeing as it is warming faster that the Arctic (well above the Surface in the middle atmosphere it is!) you have to wonder whether the closing of the Ozone hole will bring in the warming at ground level or whether it's own 'warming' will work down to ground level before then!!!

Of course the Southern oceans have already breached the circumpolar current and are lapping around areas of the coast as the Wilkins Ice sheet found to it's cost........

[laserguy]

Indeed! the warmest year on record!!!

Oh fergawd's sake. Will 2010 be the year when more climate change claptrap is recorded than any other? You bet,until next year that is...

[Solar Cycles]

Oh fergawd's sake. Will 2010 be the year when more climate change claptrap is recorded than any other? You bet,until next year that is...

They have already written the press release for 2011 being the warmest on record!

[noggin]

They have already written the press release for 2011 being the warmest on record!

I like it! :lol:

Anyway, what I really wanted was to post this http://news.bbc.co.uk/1/hi/science_and_environment/10178124.stm .

The Royal Society is to have a review of it's stance on AGW. 'Twill be interesting to see what they come up with in July. It is interesting also, that the dear old Beeb has seen fit to report the matter.

It seems to me that there are two "things" going on generally. One is the scientific discussion that goes on in as assortment of places ranging from big places like NOAA, NASA, Hadley Centre to internet sites such as our very own NW. The other thing is how the discussions are seen and received from outside these enclaves. For instance, The Royal Society review and the Beeb's reporting of it. I certainly detect more open questioning of the whole matter and who can possibly deny that this is a very good thing?

[Yorkshiresnows]

Actually, you're all wrong in part - and you're all right in part. Everyone's so busy arguing they can't see that they agree with each other!

Um....no, Pennine, Dev, Potty - 0.0003 is three parts per ten thousand, not per thousand**. But it is the same thing as three hundred parts per million (ppm), yes. Or if you like percentages, you can also call it 0.03%....which is (I assume) what you were getting at, Dev, though I think you were pretty confused.

So YS, you were right all along in talking about 0.0003 to 0.0004 of the total atmosphere, and wrong to subsequently agree that you had been wrong before! You now tell us that although that statement was wrong, everything else was right.....hmmmm.....well, I'm not sure where that leaves us!?

Time, I think, for a laugh about this: you'd all have failed 'O' Levels Maths in my day, and here you are expecting us to believe what you say about infinitely more complex climate change calculations. I think you're both rubbish at maths, and therefore probably at physics, too, and I shall be taking your learned and passionate pronouncements with a large pinch of salt from here on in!

[**If you're still not clear: 0.3 = 3 parts per ten (or 3/10); 0.03 = 3 parts per hundred (or 3/100); 0.003 = 3 parts per thousand (or 3/1000); 0.0003 = 3 parts per ten thousand (or 3/10000). And 3 parts per 10,000 = 30 parts per 100,000 = 300 parts per 1,000,000)]

Great post,

To be honest, I have often been so busy attempting to defend this and that from multiple posts, that the whole principal message of what I hoped to start and discuss has now long been lost in the mud !!

That tied up last night (on travel) working out if I had made a boob that I tied myself up in knots.

Oh, well, the actual point was that the amount of CO2 we pump out although seems to be huge is, quite small .... from an atmospheric perspective. Also, this was also in itself just a defence on a point made by another poster away from the natural cycle versus greenhouse gas theory.

But, I only mean that I stand by the accuracy of what I have posted (i.e. I myself have not made any of it up). I am a reviewer and not a climate scientist, so I was just hoping to get a good discussion and present a summary of some of the interesting science that has / is coming out and that has supported by recent change in viewpoint.

Anyway, your post has made me laugh so I'll thank you for that.

Y.S

[Admiral_Bobski]

The problem here is that there is no rational position to suggest that solar, clouds or a "cycle" dominates recent climate change, far less then how such factors would explain why the physics of the CO2 molecule fails to work under such an hypothesis. And even more how such a process can work, inhibit the radiative properties of CO2 (despite the fact that we observe these properties operating in the real world), and yet produce a spatial pattern of warming that is inconsistent with any process except for greenhouse gases!!

sss

Edit: Deepsnow Not heard of that argument before - I've heard the old canard about CO2 lagging temperature in the distant past - see this link:

http://www.skeptical...temperature.htm

The fallacy is to suggest that because one process drove climate in the past (orbital forcing), another one cannot drive climate now (humans emitting vast amounts of CO2). Much like saying that because ancient forest fires were caused by lightning, no modern forest fire was caused by people...

I have to take issue with the comment I have highlighted above - the Leaky Integrator is a perfectly rational position, as you should be able to see. Whether it's right or not is a different matter, but it is certainly rational.

CB

[Devonian]

Actually, you're all wrong in part - and you're all right in part. Everyone's so busy arguing they can't see that they agree with each other!

Um....no, Pennine, Dev, Potty - 0.0003 is three parts per ten thousand, not per thousand**. But it is the same thing as three hundred parts per million (ppm), yes. Or if you like percentages, you can also call it 0.03%....which is (I assume) what you were getting at, Dev, though I think you were pretty confused.

So YS, you were right all along in talking about 0.0003 to 0.0004 of the total atmosphere, and wrong to subsequently agree that you had been wrong before! You now tell us that although that statement was wrong, everything else was right.....hmmmm.....well, I'm not sure where that leaves us!?

Time, I think, for a laugh about this: you'd all have failed 'O' Levels Maths in my day, and here you are expecting us to believe what you say about infinitely more complex climate change calculations. I think you're both rubbish at maths, and therefore probably at physics, too, and I shall be taking your learned and passionate pronouncements with a large pinch of salt from here on in!

[**If you're still not clear: 0.3 = 3 parts per ten (or 3/10); 0.03 = 3 parts per hundred (or 3/100); 0.003 = 3 parts per thousand (or 3/1000); 0.0003 = 3 parts per ten thousand (or 3/10000). And 3 parts per 10,000 = 30 parts per 100,000 = 300 parts per 1,000,000)]

Humm...I didn't fail O level maths :winky: (though it was a long time ago...) and, since this confusion was apparent over on Rabett Run some time ago, I'm still trying to get all the 0's in the right places...So MY apoligies for MY misunderstandings.

So, moving on to either dig myself in (or better to clarify all this) the atmospheric conc has changed from 270ppm, .027% or (and here the confusion sets in...) .00027?) to 380ppm (which is .038% 0r (ditto) .00038?)?

Btw, you're a good teacher (and yes, I get physics concepts but not so well the maths in it) but, imo, a good teacher really should not rubbish his pupils (I used to hate that, it's not helpful)

Edit: more scribblings (hopefully to help me and all of us)...

Start with 1,000,000

100,000 = 10% of that or .1

10,000 = 1% of that or .01

1,000 = .1% of that or .001

100 = .01% of that .0001

And

100/1,000,000ths also = 10/100,000th = 1/10,000th = .1/1,000th and, wait for it, .01/100th?

What does this all mean?

It means that you'd have to check about 10000 parts of the atmosphere to be sure (lets not get into probability as well!) of seeing a CO2 molecule

It means that in the atmosphere there are likely to be 3 or 4 CO2 molecules in every 10,000 and .03 to .04 CO2 molecules in every 100 you look at you look at BUT that also means that in terms of distance it's a fantastically small amount given the number of atoms per unit volume in the atmosphere?

or something...

I think...

Another edit :lol:

Imagine a football crowd of 10,000. You throw tennis balls at them but 9,997* of them completely ignore the balls - they go though the crowd. However, three people grab the tennis balls and throw them back and, since there are other crowds packed in side by side (this is the atmosphere I'm paralleling), up and down as well, the tennis balls ping about until, by chance they get through? Now, for a hundred years people have been calculting this effect and it seems just adding one 'person' has a notable effect on hoe much gets through.

*of course there is WV to think about as well

Edited May 28, 2010 by Devonian

[Gray-Wolf]

And just to keep current;

http://www.scienceda...00527141959.htm

scientists have now discovered the 'Carbon Burp' that ended the last ice age (What!!! CO2 leading temps????) and also the role of oceanic sinks dragging the carbon out of the atmosphere and locking it away to aid the formation and maitainance of the ice age.......

Fancy that a solar 'nudge' to climate being positively reinforced and made real by positive CO2 feedbacks.

Now what was that about it being ALL solar?

EDIT: and I don't know how this slipped by me;

http://www.news.ucda...l.lasso?id=9479

I seem to remember back in 91' a U.S. fuel comp. putting out a vid, that told us all more CO2 was good for 'green things' (though most of us weren't fooled) and would 'green the globe'........

It seems they couldn't have been more wrong!

(Here we go! "the greening of planet Earth"!!!)

http://www.youtube.com/watch?v=aUjnQT5fRdk

Edited May 28, 2010 by Gray-Wolf

[Yorkshiresnows]

And just to keep current;

http://www.scienceda...00527141959.htm

scientists have now discovered the 'Carbon Burp' that ended the last ice age (What!!! CO2 leading temps????) and also the role of oceanic sinks dragging the carbon out of the atmosphere and locking it away to aid the formation and maitainance of the ice age.......

Fancy that a solar 'nudge' to climate being positively reinforced and made real by positive CO2 feedbacks.

Now what was that about it being ALL solar?

I do not recall anybody saying it was ALL solar, only that there is good evidence for a link between solar activity and Northern hemisphere climate / possibly world temps. Lots of papers blah blah blah and previous charts posted that show this.

If you can accept that, then this leads you on to believe that solar activity has an impact that is not currently modelled. Yes?

Y.S

[sunny starry skies]

Great post,

To be honest, I have often been so busy attempting to defend this and that from multiple posts, that the whole principal message of what I hoped to start and discuss has now long been lost in the mud !!

That tied up last night (on travel) working out if I had made a boob that I tied myself up in knots.

Oh, well, the actual point was that the amount of CO2 we pump out although seems to be huge is, quite small .... from an atmospheric perspective. Also, this was also in itself just a defence on a point made by another poster away from the natural cycle versus greenhouse gas theory.

But, I only mean that I stand by the accuracy of what I have posted (i.e. I myself have not made any of it up). I am a reviewer and not a climate scientist, so I was just hoping to get a good discussion and present a summary of some of the interesting science that has / is coming out and that has supported by recent change in viewpoint.

Anyway, your post has made me laugh so I'll thank you for that.

Y.S

Well done Osmoposm, 0.0003 is 3 parts per 10,000, and I laughed seeing everyone agree on the wrong answer! (happens to us all...)

The "there's not much in the atmosphere" fallacy:

It's another common fallacy that many people fall into, believing that just because CO2 comprises 0.038% of our atmosphere it couldn't possibly have an effect. I think it comes down to people thinking of the greenhouse like a thick cosy blanket, which of course something so sparse couldn't be, right? But it's not to do with it being a cosy blanket, it's about optical depth, and these are two totally different things.

Consider stratospheric ozone and ultraviolet rays - the concentration of stratospheric ozone is measured in parts per billion (~200-400ppb), which on our measure is 0.0000004 as a fraction of 1, or 0.00004%. Fortunately the optical depth of this very sparse gas is sufficient to protect us from UV radiation from the Sun. Is it so crazy to think that a gas that is 3 order of magnitude more prevalent by concentration (and mixed through the troposphere too) might be effective at intercepting radiation of a particular wavelength?

http://chriscolose.w...fect-revisited/

The graphs on this page by Chris Colose are very nice at showing what happens to the longwave spectrum of emitted radiation when you add concentrations of CO2. The red curves on the graphs show the emitted spectrum as more and more CO2 is added. You see that the effect of adding just 2ppm to a CO2-free atmosphere is dramatic, and leads immediately to a 1.9C warming. The amount of intercepted radiation is shown by the dent in the red curve, reducing the total outgoing longwave radiation. The logarithmic decrease in the effect is visible as the rate at which the absorption bands saturate and broaden slows down as the concentration increases:

No CO2

2ppm CO2 - immediate effect, 1.9C warming.

50ppm CO2, beginning of saturation, but bands still able to broaden so atmosphere not completely saturated.

390ppm CO2, modern concentration. Greenhouse effect slowing down w.r.t. CO2-free atmosphere due to the logarithmic effect, but producing something like ~1C/doubling as in all above cases. Add onto that the water vapour feedback, and the impact of gases with smaller concentration (e.g. CH4 and others) and you understand not only the impact of small concentrations, but why the concentration of CO2 has a lesser effect per tonnage/concentration increase than methane - methane is increasing from much smaller concentrations/less saturation so we can effect a 'doubling' much more easily, and so it is called a 'super-grenhouse gas' even though it is no more effective than CO2 at trapping IR radiation.

All above figure created by Chris Colose from his linked page, using the MODTRAN atmospheric model. The last paragraph of his post relating to water vapour is well worth a read too. The enhanced greenhouse effect has been observed both from the ground and from satellites, with the changes occurring in the spectral signature bands of the GHGs, confirming that it is the human-produced greenhouse gases warming the Earth and not anything else.

sss

[Methuselah]

Thanks for that, SSS. :lol:

I do believe that it's only coz so many folks do not understand the concept of broadening bands that all this 'saturation of wavelengths' stuff has been able to muddy the waters...Or - to use a god-awful attempt at humour - to cloud the issue quite as much as it has...Mysterious, as-yet undiscovered feedback uncertainty, anyone???

[Yorkshiresnows]

Well done Osmoposm, 0.0003 is 3 parts per 10,000, and I laughed seeing everyone agree on the wrong answer! (happens to us all...)

The "there's not much in the atmosphere" fallacy:

It's another common fallacy that many people fall into, believing that just because CO2 comprises 0.038% of our atmosphere it couldn't possibly have an effect. I think it comes down to people thinking of the greenhouse like a thick cosy blanket, which of course something so sparse couldn't be, right? But it's not to do with it being a cosy blanket, it's about optical depth, and these are two totally different things.

Consider stratospheric ozone and ultraviolet rays - the concentration of stratospheric ozone is measured in parts per billion (~200-400ppb), which on our measure is 0.0000004 as a fraction of 1, or 0.00004%. Fortunately the optical depth of this very sparse gas is sufficient to protect us from UV radiation from the Sun. Is it so crazy to think that a gas that is 3 order of magnitude more prevalent by concentration (and mixed through the troposphere too) might be effective at intercepting radiation of a particular wavelength?

http://chriscolose.w...fect-revisited/

The graphs on this page by Chris Colose are very nice at showing what happens to the longwave spectrum of emitted radiation when you add concentrations of CO2. The red curves on the graphs show the emitted spectrum as more and more CO2 is added. You see that the effect of adding just 2ppm to a CO2-free atmosphere is dramatic, and leads immediately to a 1.9C warming. The amount of intercepted radiation is shown by the dent in the red curve, reducing the total outgoing longwave radiation. The logarithmic decrease in the effect is visible as the rate at which the absorption bands saturate and broaden slows down as the concentration increases:

No CO2

2ppm CO2 - immediate effect, 1.9C warming.

50ppm CO2, beginning of saturation, but bands still able to broaden so atmosphere not completely saturated.

390ppm CO2, modern concentration. Greenhouse effect slowing down w.r.t. CO2-free atmosphere due to the logarithmic effect, but producing something like ~1C/doubling as in all above cases. Add onto that the water vapour feedback, and the impact of gases with smaller concentration (e.g. CH4 and others) and you understand not only the impact of small concentrations, but why the concentration of CO2 has a lesser effect per tonnage/concentration increase than methane - methane is increasing from much smaller concentrations/less saturation so we can effect a 'doubling' much more easily, and so it is called a 'super-grenhouse gas' even though it is no more effective than CO2 at trapping IR radiation.

All above figure created by Chris Colose from his linked page, using the MODTRAN atmospheric model. The last paragraph of his post relating to water vapour is well worth a read too. The enhanced greenhouse effect has been observed both from the ground and from satellites, with the changes occurring in the spectral signature bands of the GHGs, confirming that it is the human-produced greenhouse gases warming the Earth and not anything else.

sss

I disagree with the above being able to conclude your final point.

The water vapour feedback effect is exactly the point. It is assumed it is a positive one (for warming), yet there is satellite evidence that is has the exact opposite effect, thereby blunting the forcing. I've shown this in previous posts (publications by Wild et al, 2004 and 2005).

Even the IPCC discussed this in one of the 2007 (4th) working group summaries:

"The changes in both satellite derived and surface measured insolation data are in line with changes in global cloudiness .... which show an increase until the late 1980's and a decrease thereafter, on the order of 5% from the late 1980s to 2002",

This corresponds to a reported 6 watts per square metre in absorbed solar irradiation by the globe.

Y.S

Coincidence that these patterns fit with changing PDO cycles .... or not.