Relationship between CO2 and Global Warming

Click For Summary
The discussion centers on the debate over whether CO2 is the primary driver of recent global warming, with various alternative hypotheses proposed, including oceanic and atmospheric oscillations, solar activity, and changes in land and ocean albedo. Participants argue that while these factors may play a role, they struggle to account for observed warming trends, particularly in relation to stratospheric cooling and polar amplification. The consensus leans towards CO2 as a significant factor, amplified by water vapor feedback, despite acknowledging uncertainties in climate models. Some participants highlight the influence of aerosols and human-generated heat on climate dynamics. The conversation reflects ongoing complexities in understanding the multifaceted relationship between CO2 and global warming.

Relationship of CO2 with global temperature

  • is the primary driver

    Votes: 0 0.0%
  • is an important factor

    Votes: 9 52.9%
  • There is only a weak correlation, if at all

    Votes: 6 35.3%
  • Global temperature is the driver of CO2

    Votes: 2 11.8%

  • Total voters
    17
  • #31
I stand by what I state.

Your graph http://home.wanadoo.nl/bijkerk/El-chichon-Pinatobo.JPG . And the Hadley Centre Graphs I refer to http://www.metoffice.gov.uk/research/hadleycentre/CR_data/Monthly/upper_air_temps.gif both show that what I state in my post above, that both El Chichon and Pinatubo produced a clear stratospheric warming. Furthermore the Hadley Centre graph shows that in the recorded period roughly 1960 to present, there are three incidents of vulcanism that produced a strato injection leading to strato warming. This is the marker that shows they are associated with volcanic aerosol injection (or is this 3 more coincidences to add to the list of global changes I referred to earlier in this thread?). The tropo cooling periods you state in 1984 and 1989 do not have a strato warming, therefore they were not due to stratospheric injection of volcanic plumes. So my point stands, citing them does not in any way undermine the conclusions of Soden et al.

Re your introduction of the MSU records. I quote from the IPCC Third Assesment Report, Chapter 2; (co authored by a Mr Christy if I recall correctly - see TAR appendix) http://www.grida.no/climate/ipcc_tar/wg1/059.htm

“The three temperature products that are commonly available from MSU are: the low to mid-troposphere (MSU 2LT, surface to about 8 km), mid-troposphere (MSU 2, surface to about 18 km, hence including some stratospheric emissions) and the lower stratosphere (MSU 4, 15 to 23 km, hence including some tropical tropospheric emissions) (Christy et al., 2000).”

So you are attempting to draw simple conclusions from a data set that requires complex analysis to avoid contamination. MSU-2 is contaminated by the stratosphere, as stated above. So without the analytical techniques needed to remove that contamination your conclusion is specious. I wouldn't even trust MSU-4 supporting my contention re strato warming without such adjustment to remove the effect of the tropical troposphere - despite it supporting my contention, as I say drawing conclusions from direct data is risky, best to rely on professionally derived data. PS if you have carried out the adjustments I refer to above can you advise me what procedure you used? TIA.

Yet again I assert: Soden et al's paper supports the model’s ability to model water vapour reaction to a change in forcing.
 
Last edited by a moderator:
Earth sciences news on Phys.org
  • #32
I stand by what I state.

Hmm. Luckily enough that’s not a scientific dogma, otherwise the Earth would still be flat.

there are three incidents of vulcanism that produced a strato injection leading to strato warming.

Exactly and since there are no other clear spikes in the known statistics, the causality seems pretty strong. No doubt about it.

The tropo cooling periods you state in 1984 and 1989 do not have a strato warming, therefore they were not due to stratospheric injection of volcanic plumes. So my point stands, citing them does not in any way undermine the conclusions of Soden et al.

Here is where the troubles start. There are several sudden lower troposphere cooling events not associated with major volcano aerosol injections. There are two counts of distinct volcanic aerosol injections not associated with cooling. This lack of reproducibility simply falsifies any distinct correlation between aerosol injection, stratospheric warming versus troposphere cooling.

Check http://home.wanadoo.nl/bijkerk/reproduceability.jpg , three thumbs ups for three volcanic events for the lower stratosphere (lower graph), no thumbs down. Rather convincing. For the lower troposphere there is only one thumbs up for the Pinatubo, one count of undetermined for Agung to say the best and fat thumbs down for El Chichon as well for all the other unrelated clear cooling events. No wonder that IPCC makes no suggestion of a correlation.

MSU-2 is contaminated by the stratosphere, as stated above. So without the analytical techniques needed to remove that contamination your conclusion is specious.
The contamination is only a minor fraction, hardly enough to change anything in the trends. I would concur that this contamination introduces some larger error bars in the spikes but it would not remove the spikes and shape them into nicely reproducing aerosol effects.

Yet again I assert: Soden et al's paper supports the model’s ability to model water vapour reaction to a change in forcing.

No doubt the paper does, nicely omitting adverse evidence, however the reality does not. The question seems to be if the models are right and reality is wrong?
 
Last edited by a moderator:
  • #33
“There are several sudden lower troposphere cooling events not associated with major volcano aerosol injections.” Yes, and so what? There are also warming events, but the key here is the strato warming spikes which do pick out certain tropo cooling events as assoc with volcanic aerosol injections into the strato. http://www.metoffice.gov.uk/research/hadleycentre/CR_data/Monthly/upper_air_temps.gif The importance of this strato warming is that it allows us to see a pattern associated with such eruptions as discussed here http://www.cru.uea.ac.uk/cru/info/volcano/. And I quote from the closing para of that paper:

“Impact apart, the importance of volcanic events is that forecasts can be tested relatively quickly over the subsequent few years. Other natural (e.g. solar output changes) and anthropogenic (increases in greenhouse gases and sulphate aerosols) operate on decadal-to-century timescales and any changes over short timescales are very difficult to distinguish from the natural variability of the climate system. Volcanic-induced forcing is sufficiently large to be clearly seen and provides a good test of climate model performance.”

So Soden et al can pick out the event they use as probably being caused by Pinatubo and not being one of the other non-volcanic cooling events that you seem to be obsessed with.

You say, “But the lower trophosphere MSU-2 is following it's own logic, warming after one event and cooling after another. Yet, you happily persist in a 100% relationship of Volcanoes and the lower troposphere.”

Perhaps it would help you to understand if I were to explain that vulcanism is not the only effect that can cause changes in Global Average Temperature. Not every cooling is due to vulcanism and sometimes the signature of vulcanism is lost because of other factors in the climatic system. Again it is you, having grabbed the wrong end of the stick, who are obsessed with every wiggle in the tropo temp record. I am only concerned with Pinatubo and it’s utility in the examination by Soden et al. In that respect you have failed to invalidate it.

As is seen in the El-Chichon eruption where, as I point out above, the cooling period was already underway thus undermining it’s utility as a scenario for this study.

According to the graph I have always been relying on, http://www.metoffice.gov.uk/research/hadleycentre/CR_data/Monthly/upper_air_temps.gif , there is a CLEAR drop associated with Agung. But as it’s before 1979 when the MSU record began (again see the earliest period that the graph I link to). So being before the MSU record it’s not as good a study as Mt Pinatubo, because the observational evidence against which to test the model performance is not as comprehensive.

Why on Earth would the IPCC make any suggestion of a correlation in this case? IPCC may well address Soden et al in the Fourth Assessment report, but this issue is not relevant to the SAR or TAR.

Soden et al's paper supports the model’s ability to model water vapour reaction to a change in forcing.
 
Last edited by a moderator:
  • #34
“There are several sudden lower troposphere cooling events not associated with major volcano aerosol injections.” Yes, and so what?

So what??
Not every cooling is due to vulcanism and sometimes the signature of vulcanism is lost because of other factors in the climatic system

You answer the question yourself. Due to the other factors in the climatic system the signature of volcanism is lost. This also goes for the pinatubo event. You cannot switch off those other factors at your own convenience. Yet that is what you do:
I am only concerned with Pinatubo

Would the term obsessed be applicable here too? I'm obsessed only to let the scientific method prevail instead of your data mining: "The data of Pinatubo is convenient so let's use that and skip the rest".

According to the graph I have always been relying on, http://www.metoffice.gov.uk/researc...r_air_temps.gif , there is a CLEAR drop associated with Agung.

You are looking at identical http://home.wanadoo.nl/bijkerk/reproduceability.jpg A copy paste job, with only some excess data removed.

Immediately after Agung the UKMO 2LT rose slighly for well over year before the dip started. There are many more dips like that. Why would Agung have caused it after such a delay? Nevertheless I gave it an undetermined. thumbs horizontal.

As is seen in the El-Chichon eruption where, as I point out above, the cooling period was already underway thus undermining it’s utility as a scenario for this study

Look again, why is El Chichon appartly causing a rise with the cooling already on its way? Isn't that exactly the opposite effect of the expected reaction?

Now with two cases of non compliance with the models, why are we so sure that Pinatubo is spot on all of a sudden with no influence of other factors in the climatic system, other than that we want it to be spot on?
 
Last edited by a moderator:
  • #35
You state ”Now with two cases of non compliance with the models, why are we so sure that Pinatubo is spot on all of a sudden with no influence of other factors in the climatic system, other than that we want it to be spot on?”

Firstly, you have clearly not demonstrated “non compliance with the models” What models are you referring to? The study we are discussing only addresses Pinatubo, it is not concerned with the cases you are raising. Soden's models do not model vulcanism - they account for it's effects using forcings calculated from observation.

Secondly nothing in a system as complex as the climate can be 'spot on'. But for the reasons I have already repeatedly stated Pinatubo gives a good clean response. AND the models reproduce it well. Indeed it is not only in the case of Soden et al that Pinatubo shows a good response. Figure 4 of the IPCC SPM is one other example (don't ask for more I haven't got time to waste on that).

Thirdly your attempt at (what I see as) obfuscation has demonstrably failed. It is simply not reasonable for you to expect me to account for every possible climatic influence on Agung and El Chichon. I have provided you with a link to a paper written by the CRU http://www.cru.uea.ac.uk/cru/info/volcano/. Do you disagree with their final statement? If you do then research it and publish.


I have indulged you for long enough Andre. Now I have a question for you:

Given that other factors may be involved and that you are seeking to cast doubt on their work: How is it that the models used in Soden et al reproduce, to a good degree, the short wave and long wave radiation anomalies (fig 1). The temperature, total column water vapour, and upper tropo water vapour (fig2). And the 6.7um brightness (fig 3)?


I've spent enough time on this issue. Have you any substantive points to make on the issue at hand? That being that Soden et al demonstrates the ability of their GCMs to accurately model the response of atmospheric water vapour to a change in forcing.
 
  • #36
Firstly, you have clearly not demonstrated “non compliance with the models”

That sounds like a conclusion but I seem to miss the elaborated reasoning to underscore it; the lack thereof reduces that statement to have the same merit as “Firstly, you have clearly not demonstrated that 1+1=2”

The study we are discussing only addresses Pinatubo, it is not concerned with the cases you are raising.

Exactly! And that’s the reason why it is fundamentally flawed (to use a popular partisan term in the global warming circles), Why? The selective use of data and implicitly discarding the data that falsify it.

Soden's models do not model vulcanism - they account for it's effects using forcings calculated from observation.

Straw man, we are talking about that all the time. Why do those models not account for Agung and La Chichon. Two against one is not an impressive score.

Secondly nothing in a system as complex as the climate can be 'spot on'. But for the reasons I have already repeatedly stated Pinatubo gives a good clean response.

And repeatedly excluding other factors that influence the troposphere temperature. Repeating things does not make them right. You cannot exclude that the post Pinatubo dip would also have occurred without the eruption.

AND the models reproduce it well.

Circular reasoning / aka begging the question. The clean dry effect of aerosols was supposed to be to small to account for all the cooling so, if the remainder is assumed to be water vapour feedback, then the models reproduce it well based on the same assumption that was to be proved. Circular reasoning.

Now what if the cooling was natural whilst in reality -equal to Agung and La Chchon- the real effect of Pinotuba was not only radiative warming of the Stratosphere but also radiative warming of the Troposphere that happened to be superseded by a large natural cooling?

Thirdly your attempt at (what I see as) obfuscation has demonstrably failed.
There you are again: Thirdly your attempt at (what I see as) 2+2=4 has demonstrably failed.

It is simply not reasonable for you to expect me to account for every possible climatic influence on Agung and El Chichon.

Why not? Why give Pinatubo a privileged accounting?

If you do then research it and publish.

Fallacy of the restricted choice. In reality I have a lot more choices, none of which, by the way would have any influence on the failure of the troposphere to react consistently with the same trend on Volcanic induced aerosol forcing like the Stratosphere does.

Anyway, Viner Jones address only Pinatubo, meaning that the paper does not exceed the scientific level of Soden. Restricted data, restricted scope.

I have indulged you for long enough

Absolutely, quite happy to take the candy and expose the fallacies. Appreciate it.

How is it that the models used in Soden et al reproduce, to a good degree, the short wave and long wave radiation anomalies (fig 1)

As I said, begging the question. To put it bluntly: the models are developed empirically to fit reality. They fit reality hence they are right. That is, until reality decides to come up with yet another big unknown.

But now another question. Where do models belong in the scientific method?

I've spent enough time on this issue.

Hmm not enough time to go over whatever I produce and yet spend enough time? But why is it of importance to tell it here? To use it as a emotional appeal fallacy? (The master has no time for the obnoxious pupil and implying that the master is right and the pupil is wrong) I have not forgotten about your opening statement about James Lovelock and my assumed lack of knowledge.

I’d love to have you around some more and give me a chance to expose some more of those abundant fallacies that the global warming hype needs, missing real evidence of the assumed GHG-water vapour effect..

Have you any substantive points to make on the issue at hand? That being that Soden et al demonstrates the ability of their GCMs to accurately model the response of atmospheric water vapour to a change in forcing.

Now if those models are so accurate, why not a reality check and do the same exercise for Agung and La Chichon? Isn’t that how the scientific method works?
 
Last edited:
  • #37
I wonder over and over again why good news in climate studies never hits major news channels. With this kind of research you'd expect: "Detailed Research Ends Global Warming Myth, World Leaders Consider Abandoning Kyoto":

http://www.nasa.gov/vision/earth/lookingatearth/warmer_humidity.html

...like carbon dioxide, the Earth warms, more water evaporates from the ocean, and the amount of water vapor in the atmosphere increases. Since water vapor is also a greenhouse gas, this leads to a further increase in the surface temperature. This effect is known as "positive water vapor feedback." Its existence and size have been contentiously argued for several years.
...

They found the increases in water vapor were not as high as many climate-forecasting computer models have assumed. "Our study confirms the existence of a positive water vapor feedback in the atmosphere, but it may be weaker than we expected"

Obviously, the same saturation effect that causes the greenhouse effect to be rather stable with various concentations, the same is true for water vapor. Larger changes in humidity seem to have not much impact on it's greenhouse effect. The first ppms are doing the trick. Water vapor feedback is a very small change (greenhouse gas) of a very small change (temperature) of a very small change (humidity) of a very small change (temperature).
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 28 ·
Replies
28
Views
4K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 22 ·
Replies
22
Views
5K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 2 ·
Replies
2
Views
7K
  • · Replies 7 ·
Replies
7
Views
6K
  • · Replies 1 ·
Replies
1
Views
3K
Replies
2
Views
2K