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I'd like to avoid using the term "consensus" in contexts that imply that all scientists agree or that "the science is settled" - as this is the position advocated by Kyoto Protocol supporters in the global warming controversy, a proposition which I believe Wikipedia should not take a stand on.

So I propose using phrases like " IPCC assessment of the latest scientific research". This wording is, I believe, neutral. It does not say that there is (or is not) a consensus. It doesn't even say whether the IPCC's assessment is correct. The reader can visit the IPCC article to determine in his own mind whether he should accept their report as authoritative. Just about everyone does, I guess. But I want that to be something we leave up to the reader, instead of telling them that they must believe what that intergovermental panel says. -- Uncle Ed 13:03, 18 February 2007 (UTC)

This has been brought up before. The problem is that the consensus goes much beyond the IPCC, with essentially all major scientific organizations (e.g. the G8 Science Academies, the AGU, the AAAS, the AMetS...) having issued explicit statements supporting it. Consensus does not imply unanimity. -- Stephan Schulz 13:08, 18 February 2007 (UTC)

Indeed. People are free to disagree, or to otherwise conclude that the consensus view is in error, but it would be heavily POV to try to conceal that there is such a consensus. There is a majority view, and then there are some significant minority views, and the article should reflect that. Mishlai 17:02, 18 February 2007 (UTC)

This is a very useful clarification! I'm getting from this discussion, the idea that "consensus" can mean anything between "majority" and "unanimity". Perhaps I had misconstrued the term in the past, thinking it implied a commitment by the minority to support the majority (as in consensus decision-making). Come to think about it, this "objection to the word consensus" might be a partisan view of the anti-AGW side.

In that case, it might be better discussed at talk:Global warming controversy, as in "proportion of scientists agreeing with AGW". -- Uncle Ed 11:22, 19 February 2007 (UTC)

Or we could use the normal term for it, which is scientific consensus. Mishlai 17:44, 19 February 2007 (UTC)

Search for "recent", "recently" in Wikipedia the recent encyclopedia lead to this page amongst others.

Shall the recent climate change still be "recent" when it gets its climax and Wikipedia begins to melt too ?

I agree that the most common term used in the recent world is similar to the title of this article. But it shall have to change one day. -- DLL ^{.. T} 21:07, 2 March 2007 (UTC)

I am afraid "recent" will continue to describe the time period since the Little Ice Age until the next one. —The preceding unsigned comment was added by RonCram ( talk • contribs) 21:10, 2 March 2007 (UTC).

Have there been any responses to the claims made by the contributers to 'The Great Global Warming Swindle' on Channel 4, UK, on the 9th of March 2007? Such as that temperature change has always led carbon change by a gap of 800 years? This would make it impossible for Carbon to be causing temperature changes. Another point made was that CO2 makes up 0.54% of the atmosphere and that human CO2 emissions are 6 gigatons per annum of that, whilst animals and plants create 130 gigatons and still more is produced by either volcanoes or the ocean than human activity. I really think that a lot of people will turn to Wikipedia for answers to these sorts of questions, but it was difficult to see them clearly laid out in this article.-- 82.43.176.137 16:24, 9 March 2007 (UTC)

The problem is that nothing in that article makes any sense. Wiki climate articles don't spend much time on non-science. The T-CO2 lag is covered at http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/ if you want William M. Connolley 17:11, 9 March 2007 (UTC)

ty, I had a lot of strong reactions from people both where I agreed or disagreed with GW, so any help is much appreciated.-- 82.43.176.137 18:37, 9 March 2007 (UTC)

There is now a section on the 800 year ice core lag thing (which I did think was one of the programme's stronger arguments). The argument about CO2 only being 0.54% of the atmosphere was just meaningless. Who cares? Plutonium makes up a very small part of the mass of the Earth, but that doesn't mean we want any more of it, as it is lethal at the level of microgrammes. The absolute amount of CO2 is completely irrelevant, what matters is the effect that _increasing_ the level of CO2 has. To be honest it reduced my respect for the programme that it used arguments such as these (which are obviously fallacious). Subsequent research into the producer of the programme, and Wunsch's very public complaint about how they used his interview, have reinforced this. -- Merlinme 10:49, 14 March 2007 (UTC)

I agree that there was a lot of information presented in the Channel 4 programme that is not mainstream knowledge and should have representation in wikipedia articles so as to present a balanced view. I couldn't find information anywhere in wikipedia on the % of CO2 attributable to human activities (directly or indirectly) so that kind of thing should be added somewhere.... Think Merlinme has made a good start by putting in the section on ice core stuff. Will henderson 14:47, 15 March 2007 (UTC)

Hey, that was my section, though rewrote it :-). As to CO2: the answer is about 200%; in that only 1/2 the human-emitted CO2 stays in the atmosphere. Its Carbon_dioxide#Atmospheric_concentration there William M. Connolley 15:08, 15 March 2007 (UTC)

I dont see where B+G say "Bratcher and Giese claim the Earth was in a cooling trend from 1942 to 1975 and then saw warmer temperatures from 1976 through 2002." I don't think there is such a trend. B+G say "A similar situation existed in the early 1940’s when SST records show an equatorial Pacific cooling with the period from 1942–1976 generally cooler than the period following the 1976 climate shift [Zhang et al., 1997]." If you want them to say 42-76 (why do you say 75?) was cooler than 76 on then I'm happy with that, obviously. But if you want them to say a *global* cooling trend from 42-75/6 please quote them here William M. Connolley 22:44, 9 March 2007 (UTC)

William, throughout the article (starting in paragraph 1) B&G talk about the warming trend that began in 1976. They also predict a return to pre-1976 conditions which they describe as "cooler." I understand pre-1976 as 1975. If you think the statement should read "from 1942 to 1976," I'm okay with that. Regarding the issue of whether this is global, that is the topic of the article. Here is one example: "Given the considerable effect that tropical Pacific SST has on global atmospheric circulation, a climate shift to pre-1976 conditions could lessen the warming trend that has existed since 1976." They also write: "However the results do indicate that the human forced portion of global warming may be less than previously described." Also, "The purpose of this paper is to bring attention to the similar, but opposite in sign, pattern as that seen prior to the 1976 climate shift and emphasize the importance of understanding the separation between natural variability and anthropogenic forcing in the climate system." The "similar, but opposite in sign" climate shift could only refer to cooling. Notice the trend from 1940s to 1970s in this temperature chart that GISS published in 1999. [4] There really is not much point in trying to argue against a cooling trend if that is your goal. RonCram 23:21, 9 March 2007 (UTC)

On the contrary, I do indeed argue against 1942-1975/6 being a cooling trend. I would see it as a small peak around 194x, followed by a plateau. However the results do indicate that the human forced portion of global warming may be less than previously described - this is fair enough, and supports your (other) point. But the "pattern" stuff: no. They don't say cooling trend; and you're having to torture their words to get it out. Try replacing it with something they did actually say William M. Connolley 23:40, 9 March 2007 (UTC)

William, I am not torturing their words. They discussed the warming trend that started in 1976. They indicate a similar climate shift is happening in 2002 but with the opposite sign. That can only mean the beginning of a cooling trend. Your argument for a plateau is not in accord with the B&G. Neither is it in accord with the temperature record in which the 1930s were as warm or warmer than the 1990s (if you consider the temperature record prior to the unwarranted adjustments that were made in 2001 in time for the TAR). Did you even look at the temperature chart I linked to? If you insist on using the unreliable temperature records that are currently in vogue, the trend is still visible. This website will provide you with annual U.S. temperatures for the years being discussed. [5] RonCram 00:33, 10 March 2007 (UTC)

Why did you link to the *US* dta rather than the global? But the point is not to argue about the interpretation of 1940-70 here: clearly we disagree. The point is, what do B+G say, since we're reporting on them. And the answer is, they say nothing of a cooling trend from 42-75/6. Don't put words in their mouths William M. Connolley 08:44, 10 March 2007 (UTC)

This heading (and hence possibly this section) is clearly POV. I have marked it as such. Ben Finn 23:44, 12 March 2007 (UTC)

Errrmmm... so what do you suggest? William M. Connolley 09:48, 13 March 2007 (UTC)

I've renamed the section "Arguments which dispute attribution to CO2", and discussed the argument in more detail. I think it's worth exploring at length, because I can understand why it can be a persuasive argument, and we need to understand it if we are to understand why it is fallacious. Given that I now think the argument is reasonably presented, I've also removed the POV tag. Merlinme 10:03, 14 March 2007 (UTC)

This section is completely POV. It makes a bunch of unsubstantiated "rebuttals" with the only source being (IMHO very bias) realclimate.org, which in turn links to a single source. This section needs to be vastly improved and IMHO I think a separate article should be created that discusses the lag. In the following I'll provide a list of what I think is wrong with this section:

The main error with this argument is that it ignores whether increased CO2 levels should cause increased global temperatures, and in fact, no-one seriously disputes this (although they may dispute the level of climate sensitivity to CO2). Although other factors must have been at work in starting the period of global warming identified in these ice cores, therefore, the CO2 would have increased its effects.

• I'm not so sure about this claim that no-one seriously disputes more CO2 in the atmosphere leads to an increase in global temperature. Where is the evidence to back this up (that no-one seriously believes this)? And I don't think that it is being ignored, I believe that what is being said is that we aren't even sure how an increase in CO2 affects temperature.

Pretty well everyone agrees CO2=warming (including Lindzen, Michaels, etc); the only dispute is how much (as it says) William M. Connolley 22:32, 18 March 2007 (UTC)

From studying all the available data (not just ice cores), the probable sequence of events at a termination goes something like this. Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO2 to start rising, about 800 years later. Then CO2 further warms the whole planet, because of its heat-trapping properties. This leads to even further CO2 release. So CO2 during ice ages should be thought of as a "feedback" [23]. (emphasis mine)

• Before quoting realclimate.org, the argument was made that Although other factors must have been at work in starting the period of global warming identified in these ice cores, therefore, the CO2 would have increased its effects. However, even the realclimate.org article says that this is only probable.

Probable only refers to the starting bit. The CO2 feedback is... basic physics William M. Connolley 22:32, 18 March 2007 (UTC)

• I would like to further dispute this argument since taking a look at this graph one can see that in fact temperature starts to drop before CO2 starts dropping. How can you attribute temperature rise to "feedback" when temperature starts falling before CO2 does?

Its not terribly clear to me from that graph; but even granting you the assertion, its the same thing in reverse: falling T lowers CO2 then we're into the same feedback cycle as before. Whats new? William M. Connolley 22:32, 18 March 2007 (UTC)

The other error with this argument is that it ignores what is widely believed to be the cause of recently observed warming (that is, warming since about 1960), which is increased CO2 levels. Models which give a significant amount of weight to increased CO2 levels when attempting to explain recent temperature rises match the observed data far better than those which do not. It is from this (and other observations) that the IPCC concluded that humans (because of CO2 emissions) were 90% likely to be the cause of the recently observed warming. (emphasis mine)

• My question is, how can we conclude that it is in fact CO2 that is causing the latest increase in temperature if what we know about the past doesn't agree with this assessment?

Nothing we know about the past disagrees with this assessemnt William M. Connolley 22:32, 18 March 2007 (UTC)

• Hmm the models give a significant amount of weight to the CO2 increase? Why? Shouldn't they be considering every other source? It says that models that did were able to predict better, where is the source for this claim? What else did the models consider? More information is needed for such a claim.

Models have all the known sources put into them. People don't just say "we'll assume CO2 causes X warming and put that into the models..." the models contains the best physics they can, for CO2; and for solar William M. Connolley 22:32, 18 March 2007 (UTC)

To put it another way, while there must have been another cause than CO2 for the initial global warming at the times in history indicated in the ice core record, it does not follow from this that there is such a cause now. In fact there is strong evidence that CO2 is the cause now.

• Huh? How did this get concluded? There was a probable sequence of events and now you get such a strong conclusion? Huh?

What its trying to say is that the entire argument is a non-sequitor William M. Connolley 22:32, 18 March 2007 (UTC)

Anyways, here is more information. Codingmonkey 23:21, 16 March 2007 (UTC)

Very nice, I'm sure. In return, you may have [6] William M. Connolley 22:32, 18 March 2007 (UTC) http://www.copernicus.org/EGU/cp/cpd/3/435/cpd-3-435.pdf

Having read through the (current) final section of this article something struck me about the line:

"Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO2 to start rising, about 800 years later. Then CO2 further warms the whole planet, because of its heat-trapping properties."

If the initial 'unknown' process started the periods of global warming how do we know that it didnt cause all the warming and the CO2 had no real effect ? If the source is unknown then it could be a short or long term driver of climate and could be relatively strong or weak compared to other factors since it is 'unknown' and its characteristics are not understood. Just a thought.... 194.6.79.200 21:33, 18 March 2007 (UTC)

For one, because the events are (as far as is known) triggered by orbital variations which provide too small a forcing. For two, because in the process CO2 is released, which causes yet more radiative forcing. Unless you have some magic reason for believing that CO2 to have no radiative effect, its natural to suppose it does have one. William M. Connolley 22:16, 18 March 2007 (UTC)

And what was the magic reason that stopped the CO2 radiative effect? It is natural to suppose that something has stopped it. Ccwelt 21:09, 21 March 2007 (UTC)

No, its more likely that there is some reservoir that gets exhausted. However, no-one really knows why CO2 peaks out at 280 in interglacials - a Nobel prize awaits you! William M. Connolley 21:34, 21 March 2007 (UTC)

So let me get this straight, you don't know what caused the temperature to rise in the first place, you think/believe (=don't know) that the CO2 reservoir got exhausted which lead to stopping the temperature increase. But once the CO2 peaked out, something had to have a cooling effect? And I guess you don't know what the cooling effect was.

For me the more rational explanation would be that CO2 is driven by temperature and that something else is driving temperature. This [ [7]] simply seems much more plausible than something that nobody understands and that could earn me a Noble prize if I understand it - because I would be the first person to understand it. Ccwelt 12:02, 22 March 2007 (UTC)

You can think what you like. The current CO2 is definitely *not* driven by temperature - we know its human caused. Try to keep the ice age and now situations separate, because they are, as far as anyone can tell.

How nice of you to allow me to think what I like. I do not dispute that the level of CO2 is rising, but the fact I hear all the time is that in historic scale, CO2 drives temperature. Can I take it from your annoyed factless answer that indeed CO2 has not been driving temperatures in historic times? A simple "Yes" would be enough. Of course, you can say "No" if you like (you have the same liberty as I to think what you like), but I would like to hear some facts, please. Ccwelt 20:04, 28 March 2007 (UTC)

I cut out:

It is argued that another influence are the changes in the solar wind and the Sun's magnetic flux. These changes are causing an increased solar wind and stronger magnetic field, which lead to an decrease of the cosmic rays striking the Earth's atmosphere. As cosmic rays affect formation of clouds and clouds are responsible for a considerable amount of the Earth's albedo, the solar wind could have a major influence on Earth's climate. See: Solar variation

Firstly because its badly broken - it doesn't distinguish any kind of time scales; it asserts that CR *do* affect clouds when this is only speculation at the moment; etc. But more than that... this is already done higher up the page, considerably better. This is an unfortunate consequence of the name-change of this section :-( William M. Connolley 12:28, 22 March 2007 (UTC)

I thought we were a bit hasty to delete in full the following which had been added in the "Arguments which dispute" section:

"Climate change elsewhere in the solar system In recent years warming has been observed on Mars [8], Jupiter [9], Pluto [10], and Neptune's largest moon Triton [11]. This points to a solar explanation for the recent warming on Earth."

It is an argument which disputes, so surely it would be better to discuss in full, rebutting where reasonable? In fact most of the articles linked to gave strong arguments why this wasn't thought to indicate a single solar irradiance cause (as opposed to e.g. changes in orbits, local climate changes, etc.)

The one I would take out would be Jupiter, where it was far from clear to me from the article linked to whether we were talking about global warming, or local warming caused by changes in Jupiter's atmosphere. -- Merlinme 13:17, 19 March 2007 (UTC)

Maybe. It was more or less reflexive on my behalf, as I've seen this 15 times and over refuted crapmisinformation introduced over and over again in the various articles. -- Stephan Schulz 13:33, 19 March 2007 (UTC)

This can go in, as long as its clear that the evidence is against this having anything to do with Earth GW. As the plotu folk say: Jay Pasachoff, an astronomy professor at Williams College, said that Pluto's global warming was "likely not connected with that of the Earth. The major way they could be connected is if the warming was caused by a large increase in sunlight. But the solar constant--the amount of sunlight received each second--is carefully monitored by spacecraft, and we know the sun's output is much too steady to be changing the temperature of Pluto.". Ditto Neptune. In fact, when you look around there is *no* evidence for solar-caused warming on any planet William M. Connolley 13:36, 19 March 2007 (UTC)

Also, of course, the evidence for "global" warming is very scant in most of these cases. -- Stephan Schulz 14:10, 19 March 2007 (UTC)

New version seems fair enough. Note, BTW, that as far as I know there are no actual temperature measurements involved (there are ?some? on Mars but even there the ice caps seem to be the main evidence). Pluto for example is done by some ?reliable? measures of the atmospheric density William M. Connolley 14:26, 19 March 2007 (UTC)

I don't know about any direct measurements, even on Mars. Pluto's "global temperature" is derived from three occultation events in 1988, 2002 and 2006. There should probably also be a note that we know about the existance of Triton for about one (1) Neptunian year, and about the existance of Pluto for about 1/3rd Plutonian year. -- Stephan Schulz 15:06, 19 March 2007 (UTC)

All the planets seem to be getting warmer - there seems to be a reason given why each one is not due to more heat from the sun ( isn't it strange that they are all getting hotter at the samr time - well coordinated dust storms, and human activity and just the right tilt, the planets must all have a good communications director). Are there any planet/s that are getting cooler? 159.105.80.141 19:09, 8 May 2007 (UTC)

One might assume that all the planet should be warming if solar output was increasing (or cooling less than what would be expected given natural variations), but I don't think this is being observed. So far, the only warming I've seen argued to be connected with Earth's is Neptune's. ~ UBeR 19:51, 8 May 2007 (UTC)

On the whole I like the changes, although they perhaps make it a little heavy-going for your average lay person. However, I'm not sure about the "death spiral" bit. I thought there were processes which are believed to have eventually reduced CO2 levels because of changed atmospheric properties, e.g. rock weathering. Do the changes really help explain the ice core argument? -- Merlinme 16:43, 20 March 2007 (UTC)

Death spiral is no good. And of course the feedback does work in reverse, or at least its no great surprise if it does William M. Connolley 16:57, 20 March 2007 (UTC)

It is weak page.

If you want to attribute something you should also put out the numbers as to the percentage of the change that is attributed to that cause.

Doesn't the graph give the necessary information? Apart from anything else, I imagine it depends which model you use. Given that this is one of the most heavily disputed areas, I'm not entirely sure what numbers you are looking for. It seems pointless to me, to be very precise about things which have a large level of uncertainty. -- Merlinme 17:52, 21 March 2007 (UTC)

There is an awful lot of technical details in the TAR if you feel like reading it William M. Connolley 19:57, 21 March 2007 (UTC)

Dwc144 added [12]. I regard this as dubious:

This account of a self-reinforcing dynamic primarily involving temperature and CO₂ concentrations does carry with it an increased burden of explaining the abrupt cessation of global warming during all prior prehistoric episodes.

Why? No other explanation is asked to explain itself. The T-causes-CO2 doesn't explain the changes at all - not why they start, how big they are or why they stop.

This is not the place for a detailed explanation of glacial-interglacial CO2 changes: that would belong on ice age I guess William M. Connolley 20:24, 22 March 2007 (UTC)

DWC144's reply: cf. Paillard, 2001, "Glacial Cycles", Reviews of Geophysics, 39, 3 / August 2001: "The classical Milankovitch theory needs to be revised to account both for the traditional peculiarities of the records, like the 100-kyr cyclicity and the stage 11 problem, and for the recent observational evidence of abrupt climatic changes, in association with the main terminations." (Emphasis added) Paillard uses the term "abrupt" or derivatives more than 25 times in this piece, and for good reason. The Vostok data shows transient peaks, which still need to be explained, particularly the implied sudden reversals off the tops, if the data is as straightforward as it seems. Intuitively, conjoint, positive feedback dynamics (e.g. T-->CO2-->T-->CO2-->T etc. posited as the comeback in this section) add to the momentum of systems. It is not that this makes it impossible to explain the previous reversals off the tops, but let us agree that the mutual positive feedback thesis does make proving up an explanation (Heinrich events??) more urgent, and perhaps more complex. In the interim, this combination does properly add slightly to the case for doubt. (That is, along the lines of pondering what would be the slope of those curves during the next millenium even in the hypothetical absence of anthropogenic global warming--which of course is to be taken for granted. Can we really rule out a relatively steep slope--one way or the other--in that hypothetical absence, given the demonstrated potential for nonlinear dynamics in the system? Even in the top horizontal band on the chart, where we currently find our planet?) I'd have rather given a brief nod to this question, and I also see no problem with identifying the boundaries of current knowledge in the Wikipedia. In response to your other comment, the section appears already to be addressing "glacial-interglacial" CO2 changes; perhaps it is bound to, because of the prominence given to the ice-core data by Gore's film, and the potential relevance of the longer term context for appraising modern developments. The record of edits shows that I tried several times to inject an element of the forgoing in the piece--I would have been happy with even a sentence--but I will concede now that my colleagues here are unprepared to build on this. I'll leave it to you to determine the rightful bounds of proper discussion in the article, but I would appreciate it if you could at least leave these comments here, on the discussion page.

—The preceding unsigned comment was added by 74.99.153.7 ( talk • contribs) 02:39, 28 March 2007.

Of course we'll leave your comments on the talk page. As both WMC and I have said in our comments and on this talk page, it's not the information you're adding per se we're objecting to, it's where you're adding it. I simply don't see why the "abrupt changes" are relevant to an argument about temperature leading CO₂. WMC suggested that you add the information e.g. in the article on ice ages. You may be able to find a better place for it. If you can find a source which uses it as an argument against anthropocentric global warming caused by CO₂, perhaps it could even be given its own section. But I don't see it as relevant to the "Warming sometimes leads CO2 increases" section. -- Merlinme 09:08, 28 March 2007 (UTC)

The relevance is to the response given in the section (positive feedback), and specifically a clear complication the thesis entails. If not for the temperature-leading observations and abruptness in the ice core data, and the recourse to a positive feedback explanation, we'd have a much simpler presumed dynamic through geological history (e.g. orbital forcing --> T and/or CO2 -->T), which would present much less background noise to disentangle from modern anthropogenic contributions. Now we have an inherently unbounded feedback loop, offered in the section, combined with data showing abrupt reversals at the tops of peaks that have generally been transient in the past. Not only that, but we are currently situated in line with the peak temperatures on the chart. From a modelling perspective, even conceptually, this is not a happy situation. Parsimony is a core value of scientific endeavor; see Occam's razor. And I would add that when the data take us far beyond parisimony we need to provide a little alert to the effect that "we now departing from the world of parsimonious explanation; we've gotta do this, but we gotta acknowledge now that this makes our answers more tentative." Positive feedback may not be wrong, and it is probably the most reasonable account, but it is not parsimonious in the broader context of this data. Let's be honest. Even Gore was willing to say that the ice core data is "complex." The difference between a scientist and a hack is in the willingness to be open about the difficulties presented by his/her own explanations. Do we aspire to be scientists or hacks here? —The preceding unsigned comment was added by Dwc144 ( talk • contribs) 14:09, 28 March 2007 (UTC).

Well no. For a start, we have the obs record, which clearly isn't compatible with a orbital linear forcing assumption. And then we have the fact that the orbital forcing is too small. Please don't confuse things with D-O events. This section is about why the CO2/T lags leads shown in the ice cores don't impact modern attribution studies, from a scientific point of view - please try and hang on to that (or, alternatively, please try to find a single paper asserting it) William M. Connolley 14:17, 28 March 2007 (UTC)

Thanks for your comments. If you don't like the Paillard, I'll find another paper when I have a chance (not this week). A reasonable suggestion. Note that I did not suggest orbital forcing alone, above. And incidentally, I'd prefer to rephrase one of your comments and suggest instead that "This section is about evaluating the extent to which the ice core data, particularly the CO2/T lags/leads in conjunction with the transients and abrupt terminations of that data, complicate or do not complicate modern attribution studies, from a scientific point of view." However, on the Wikipedia it seems that the one with the less expansive concept has a natural advantage, for it is easier and more defensible to hit the delete key than to add. Dwc144 15:03, 28 March 2007 (UTC)

I'm really sorry, but I find your writing style very unclear sometimes. As far as I can understand it, you seem to be saying that abrupt reversals in temperature when CO₂ levels were very high, argue against the normal understanding that CO₂ causes warming. Please correct me if I'm wrong. If this is a true observation (and I have no idea, not being a climate scientist myself), then it is interesting, and certainly I think it is fair to say that there are questions which need answering about why greenhouse warming in the past was eventually reversed. As I understand it the normal explanation is that when CO₂ levels get very high, ocean acidity increases and calcium carbonate gets dissolved, increasing the ocean's capacity to absorb CO₂. In the long term, chemical weathering of silicate rocks then permanently removes CO₂ from the atmosphere. This was the best link I could find on it, about the Paleocene-Eocene Thermal Maximum (PETM): [13]

Anyway, there may well be a place for a discussion of all this on Wikipedia, and a place for your arguments (assuming they are sourced and not Original Research). However, the argument being described in this section is specifically about CO₂ leading temperature change in the ice core record; it says absolutely nothing about abrupt changes in the ice core dataset. If you want to talk about that argument (or whatever your argument is, apologies if I've misunderstood), you are in the wrong section; you can't simply rewrite a completely different argument so it allows you to make your point. Either find a more appropriate section for it, or create a new section (assuming you can find a source). -- Merlinme 17:30, 28 March 2007 (UTC)

Let me try to be even clearer, and I do appreciate your bearing with me. Here is a collection of a few key points, including current ones from the ice core bit, that could be registered in a section on this page. (a) The ice core data does not present a reason to discount the impact of anthropogenic CO2 on the climate, but simply a reason to believe that T and CO2 often work in tandem; (b) The abrupt reversals in that data during the past 500 k years suggest that knock-on effects or events (e.g. loss of ice cover, disruptions to ocean currents??) are likely also at work at least from time to time; (c) Given that the planet is currently in a temperature range in which such reversals have previously occurred, it is conceivable that it is currently subject to the effects of such intermittent feedbacks; (d) These feedbacks, and the rudimentary state of our knowledge about them, increase the level of difficulty involved in global climate modelling; (e) Most critically, these complications limit the ‘’precision’’ with which causation can be attributed within those models. For example, while we can likely state “mostly anthropogenic causes” with confidence, we likely cannot yet state 51% or 74% or 84.5%. (f) More research is required to understand better the feedback effects (not before acting, but just because). This line of thought is not original, but it can be referenced to very mainstream sources (e.g. the IPCC, in large part, I'm thinking). It is also squarely about the question of the page, attributing modern climate change. What’s the motivation? I think it is useful to highlight the longer term potential for disastrous, naturally caused/aggravated climatic change, because the question of how to mitigate those risks is even broader than the question of how to minimize the human footprint on the climate. (Notwithstanding that, we clearly start by simply minimizing that footprint now.)

-- Dwc144 20:02, 28 March 2007 (UTC)

Well no: Given that the planet is currently in a CO2 and temperature range in which such reversals have previously occurred is wrong: the planet hasn't been in this CO2 range for 10's of millions of years, and we have no good T or CO2 records back that far. If you want to rephrase that bit, we can go on to the rest... William M. Connolley 23:13, 28 March 2007 (UTC)

Okay... I was looking at this graph: [14], the actual ice-core data under discussion. But I take your point that this excludes the directly measured, recent data (the bit that Gore used the Sky-Jack for in his film). Anyway, that point is moot for my argument; correction made.

-- Dwc144 01:02, 29 March 2007 (UTC)

Image:Carbon Dioxide 400kyr.png is the one you want, as you've realised. Now I don't know what you mean by "abrupt reversals". Within the ice core context that usually means D-O events but you're not seeing them in that record, you're seeing events that look abrupt but only because of the timescale that they are being plotted on. But point (e) is simply wrong: the ice age stuff has no impact on attribution of present day warming (or being tediously precise has next to no impact) William M. Connolley 07:53, 29 March 2007 (UTC)

Fair warning about the scale, so help me understand this. Let's take the transient peak during the interglacial at 240k years as a numerical example. I don't have the raw data, so this will be a crude, back of the envelope. Let's say that the slope (dT/dt) during the preceding warming period was 8 degrees C / 4000 years, or 0.2 degrees C/100 years. Then, let's take the first part of the cooling, during which dT/dt is, say, -2 degrees C / 1000 years, hence -0.2 degrees C / 100 years. Furthermore, let's say that the change from the warming to the cooling mode occurred during 500 years. That implies an average rate of change in dT/dt of -0.4 degrees C per 500 years, and perhaps a peak rate of twice that at a century resolution. With even higher resolution data (e.g. decadal), though this will remain total speculation, one might expect to find multiple-higher rates of change, assuming that shorter term transient feedbacks are superimposed on this "background" signal. I don't know what you get to, but is the established view that first and second degree noise of this order of magnitude is still insignificant compared to the rates of climate change ("signal strength") being seen in modern GW? Also, don't we need to invoke factors other than solar insolation to understand these abrupt changes, particularly since we're working against the T-CO2 feedback loop? The insolation chart looks distinctly smoother assuming no artifacts from estimation. Hasn't the scientific interest in esoteric missing pieces (e.g. ocean current disruptions, ice cover, low level clouds, divine intervention--just kidding) been catalyzed somewhat by this general line of thinking out of paleoclimatology? Also, have observations such as these been sufficient in your view to induce some degree of caution in modern climate modellers as to the precision of their models?

-- Dwc144 14:29, 29 March 2007 (UTC)

0.2/100y is considerably smaller than the current warming, by a factor of 3 at least. Yes, we do need to invoke other factors than solar - as you say, the solar is smooth. And (less obviously) the 100kyr cycle is very weak - so you need to invoke non-linear feedbacks in the ice sheets, etc etc, to understand a 100kyr cycle. I'm not saying that studying this is irrelevant - just that if you look at attribution of recent climate change you'll see its not very relevant. But it would be a good idea to read that (and the TAR) to see what *is* relevant William M. Connolley 14:39, 29 March 2007 (UTC)

After all that hot air on my part, you're seriously positing 0.2/100y (or, say, 0.1/50y) as a representative *very high* rate of change during, say, 50 year periods during previous interglacials? Wouldn't you expect there to be a hefty right tail (in the distribution of 50 years temperature changes) given the nonlinearities (perhaps acting at different timescales) you say are likely in there? And why do you suggest that the "ice age stuff" of prior peak interglacials, which scientists are still trying to conceive of and define, is necessarily a completely different bag of tricks to what's been going on during the past 500 years? (If because the GCMers get a great fit with just CO2 a little insolation, and a couple of readily available other series thrown in to be nice, isn't there a little wedge of concern about the extremely high degree of colinearity between CO2 and temperature in the broader 500 k year picture?) To be clear, my point is not to dispute AGW; it is rather to raise the question about the degree of precision that can be claimed for the models. And I won't reiterate the reasons, stated above, why I believe this matter of precision could usefully be reflected on the page. In any case, I'll let you have the last word on this and will take it upon myself to do some more (secondary!) research in my spare time, as you suggest.

-- Dwc144 15:28, 29 March 2007 (UTC)

Don't let me give you the impression that I fully understand all this. I don't. No-one does. But if you're interested in the GCMs, this isn't the place to start. They don't run over these timescales anyway William M. Connolley 15:40, 29 March 2007 (UTC)

This entire section seems to be someones opinion and synthesis (ie. does the BAS hold this view? its the only source..). My questions here are:

• is there really such a dispute?
• who is disputing it?
• Is the dispute scientifical?
• why isn't there a large section in Global warming controversy about it if its a big controversy? (where it belongs if its real?)
• The size of this section (compared to the rest) seems to indicate that this is an important controversy or is it WP:Undue_weight?

-- Kim D. Petersen 07:52, 28 March 2007 (UTC)

Errrm, so why the factual-accuracy tag? But to answer your Qs: this isn't a scientific dispute, its a septic talking point (see TGGWS). Its here because its an issue with attribution. This section was smaller; its grown perhaps too much William M. Connolley 08:31, 28 March 2007 (UTC)

The tag should probably be something else (i appologize) - i selected it because the POV flag defined the whole article (which i didn't intend). Change it to something more appropriate. The section does seem to indicate a dispute (by being in a section called "Arguments which dispute attribution to CO2" - since it doesn't and isn't scientific - shouldn't the section either be labelled something else ("common misunderstandigs"? *grin*) - i think i understand the purpose as being some kind of FAQ then? -- Kim D. Petersen 08:46, 28 March 2007 (UTC)

Sorry my english deteriorates when i'm tired -- Kim D. Petersen 08:48, 28 March 2007 (UTC)

Try looking back at the original [15]. But - why this fad for tagging stuff nowadays? Whatever happened to just talking about things first? I prefer myths William M. Connolley 08:54, 28 March 2007 (UTC)

This section was created to handle the following: people look to Wikipedia for information about Global Warming; in particular they look to Wikipedia to understand arguments used for and against Global Warming; there are arguments used against Global Warming which are not particularly scientific, but they do exist and should be discussed; where they should they be discussed in Wikipedia? The original title of the section was something like "Myths of global warming", but this was felt to be rather a long way from NPOV, so it was given the title it currently has. If you have a good suggestion for how this should be handled differently, we will of course consider it, but I have to agree with WMC: this should be discussed on the talk page first. I'll remove the tag now. -- Merlinme 09:01, 28 March 2007 (UTC)

Merlinme, i was tired and probably overreacted. Sorry. Myth is better than the current title (how about "common misconceptions"? -- Kim D. Petersen 09:52, 28 March 2007 (UTC)

Sorry about tagging it (i agree with your sentiment). I'm probably a bit to tired to edit anything today. -- Kim D. Petersen 09:52, 28 March 2007 (UTC)

Don't worry, its no problem William M. Connolley 10:09, 28 March 2007 (UTC)

Lets discuss the logic here. "By amplifying each other’s response, this “positive feedback” can turn a small initial perturbation into a large climate change. There is therefore no surprise that the temperature and CO2 rose in parallel, with the temperature initially in advance". Initial rise is one thing but the subsequent falls and rises also had the co2 lag. If the feedback had been of greater importance than the main driver then it would have begun to dominate which doesn't happen. Also since this is a time slice there is no initial rise. The fact is that very little can be concluded from the graph except that there is a correlation and that co2 lags temperature. Anything else is useless speculation. The whole argument is illogical and erroneous. I'd remove it but it would just be put back again. jg17 JG17 10:02, 4 May 2007 (UTC)

Initial rise is one thing but the subsequent falls and rises also had the co2 lag - are you sure about this? As I understand it the lag is only really well established for deglaciation, and 800+/-600 is not too precise even there. very little can be concluded from the graph except that there is a correlation and that co2 lags temperature - two things. Firstly, as pointed out, people are attempting to conclude from the graph that CO2 can't be causing T rise. I'm glad to see you denying thats possible, but not everyone has realised it. Secondly, various scientists who have studied it *ahve* concluded various things from the graph: why should we prefer your interpretation to theirs? William M. Connolley 10:13, 4 May 2007 (UTC)

William: You assume "people are attempting to conclude from the graph that CO2 can't be causing T rise". I don't see that at all. To me it seems sceptics use the time lag as a rebuttal of the idea that CO2 caused temperature swings in the past when the reverse corrollory is equally plausible and indeed more likely. No one can seriously claim though that the past CO2-T relationship proves anything about current climate either pro or against AGW. Any attempt to do so by postulating that the CO2-T feedback is shown to be a driver in the past is surely accepting second or even third best interpretation of the graph and that the most logical conclusion if there is a CO2 lag - which everyone seems now to accept - is that the original driver of temperature in the past is more important than any CO2 feedback. I don't ask you to accept my point of view but I ask you to think about it yourself and conclude whether it is worthy of inclusion in Wikipedia or is it just more uncorroborated noise in the debate? Do you not feel that inclusion of this poorly thought-out theory makes even non-scientists strongly wonder about the thinking ability of the people who assert it and hence weakens their case? JG17 09:35, 5 May 2007 (UTC)

Sadly you are wrong: there really are people stupid enough to make this claim (see TGGWS) and people stupid enough to believe it. I could find you various comments from such people if required William M. Connolley 21:02, 5 May 2007 (UTC)

Are you saying that the flawed logic of the feedback argument is acceptable just to counter the flawed logic of the sceptics? Where does the truth stand in all of this? Too inconvenient? Maybe you should ask your colleagues how they explain the cooling periods with this feedback theory before it comes to court or before someone embarrasses them on CNN or Newsnight. Maybe the CO2 is sucked into a black hole at the end of the heating period thereby allowing the climate to start from scratch? JG17 09:57, 7 May 2007 (UTC)

The feedback argument isn't flawed. The argument isn't that it initiates change, only amplifies it. Hence it can explain cooling or warming, as long as they are triggered by something else William M. Connolley 10:12, 7 May 2007 (UTC)

It is flawed since if it worked there would be instances in the record where CO2 initiated warming. I mean one supposes that this feedback doctrine is at least possible. But you have no evidence for it so its misleading to be telling people that its a real effect.

In that case "positive feedbacks from CO2 concentrations amplify warming initially caused by other factors" should have "or cooling" inserted after "warming" and "temperature and CO2 rose in parallel" should be "rose and fell in parallel." In that case the idea of removing CO2 from the air as mooted on the IPCC website and encouraged by the Gore/Branson prize should be discouraged forthwith because the climate is clearly such a delicate system that if we remove too much CO2 we'll initiate a catastrophic ice age. But then you don't really believe that do you? Oh what a tangled web we weave.... JG17 16:07, 7 May 2007 (UTC)

Since the text mostly focusses on the lag where its best understood, ie deglaciations, ie T rise, the current text is probably OK. We'd need to remove an awful lot of CO2 from the air to get towards glacial type levels... certainly below 300 ppmv, and we're at 380+ and climbing William M. Connolley 20:29, 7 May 2007 (UTC)

Ah what the heck - throw it into the article. 90% certainty, given all the approximations etc in the theory, probably means more like maybe not for sure. When the Vikings were farming in Greenland did the CO2 precede or follow the icecap? 159.105.80.141 19:13, 8 May 2007 (UTC)

Talk:Global_warming/FAQ#It_was_obviously_much_warmer_when_the_Norse_settled_Greenland-- Stephan Schulz 19:29, 8 May 2007 (UTC)

Point to consider?

People often say that climate change is natural and use that as a counter argument to attempts at mitigation. However, I don't believe that argument in itself is a valid counter argument to undertaking mitigation. Even if climate change is mostly natural, it is still a situation that our civilisation needs to contend with. Of course one of the ways to deal with it is to reduce greenhouse gas emissions (the science behind that is not disputed at all as far as I'm aware - correct me if you have better information though). Simply saying that climate change is natural (even though it is not believed to be so) is not a counter argument against reducing greenhouse gas emission. I would almost go so far as to say that using the 'climate change is natural' argument is irrelevant to the entire debate.

I am sort of new to this so sorry if the format or section placing of this point is wrong. I wonder whether there is a case for putting a section like this into this article (or a more appropriate one? Open to suggestions). Anyway what do people think?... Gaz —The preceding unsigned comment was added by 129.242.31.43 ( talk • contribs) 12:40, 14 May 2007.

The argument is as follows: If climate change is natural, then it is not caused by (anthropogenic) CO2 emissions and hence we do not need to reduce them. Mitigation using other means than reducing human interference with the climate system is a much less understood and potentially much more controversial topic. -- Stephan Schulz 13:02, 14 May 2007 (UTC)

The reference says:

"A climate model can be used to simulate the temperature changes that occur both from natural and anthropogenic causes. The simulations represented by the band in (a) were done with only natural forcings: solar variation and volcanic activity. Those encompassed by the band in (b) were done with anthropogenic forcings: greenhouse gases and an estimate of sulphate aerosols, and those encompassed by the band in (c) were done with both natural and anthropogenic forcings included. From (b), it can be seen that inclusion of anthropogenic forcings provides a plausible explanation for a substantial part of the observed temperature changes over the past century, but the best match with observations is obtained in (c) when both natural and anthropogenic factors are included. These results show that the forcings included are sufficient to explain the observed changes, but do not exclude the possibility that other forcings may also have contributed."

The article says:

"Climate models forced by natural factors and increased greenhouse gases and aerosols reproduce the observed global temperature changes; those forced by natural factors alone do not."

I changed this to "...reproduce the observed global temperature changes better than those forced by natural factors alone."

I thought this was a better summary of the reference, however WMC has reverted it. WMC knows the science much better than I do, and rereading the reference, the inference is that graph a) (with no GHG forcing) doesn't explain the observed changes. However, I still think Wikipedia's claim is too strong: to me, "reproduce the observed global temperature changes" suggests that there's a near perfect match, and that's surely not the case. How about: ""Climate models forced by natural factors and increased greenhouse gases and aerosols produce the best match to the observed global temperature changes; those forced by natural factors alone do not produce a good match."? -- Merlinme 12:50, 7 June 2007 (UTC)

Sorry, I could have been a bit more polite here. Your last version is OK-ish; the briefer version you put in, to my mind, didn't downplay the nat-only match enough. How about "The observed patterns of warming, including greater warming over land than over the ocean, and their changes over time, are only simulated by models that include anthropogenic forcing" from the AR4 SPM? William M. Connolley 13:39, 7 June 2007 (UTC)

Sounds good to me. Presumably you'll need to change the reference as well. -- Merlinme 13:45, 7 June 2007 (UTC)

Although others may disagree, I feel that in a section where problems with the CO2 theory are being listed, this choice of wording seems awfully biased, eg. by someone who is convinced by the CO2 theory and wants to hide the problems, or even "slip them under the rug", wanting those reading to ignore this section. I suggest that it is changed from "that complicates" to "that may contradict to", not any further though (eg. not to "disproves", for that is simply bias in the wrong direction). I know it may seem a subtle change, but to me "complicates isn't very neutral". TJ 16:28UTC 07/06/07

• note, I in fact agree with the CO2 theory, but feel that there should always be some form of proper Critisism page, not trying to convince people otherwise.

• I agree, I don't like "that complicates". It implies that the theory is still 100% true, just more complicated. I'm not sure what it should be changed to. "may contradict" or "may challenge"? -- Bill.matthews 16:05, 7 June 2007 (UTC)

There have been various attempts to get a better wording for this. I'm not convinced by "that may contradict", as this implies they have significant weight, when very few (no?) scientists give them any weight at all. Previous efforts include "Myths of climate change attribution" and "Attempts to disagree with CO2 attribution" (or words to that effect). I think the current wording gets the balance reasonably well. -- Merlinme 16:13, 7 June 2007 (UTC)

(ec) People often fall into the trap of thinking the issue is either-or. But it isn't. Nobody who knows anything about the science doubts that there are roles for both CO2 and natural variations. Results that show natural variations play a larger role than presently thought (even by a factor of 2 or 3) would not "contradict" the role of CO2. "Complicate" may not be be the best word, but it's more accurate than "contradict" or "challenge." Raymond Arritt 16:18, 7 June 2007 (UTC)

How about "Frequently asked questions" - thats really what this section is William M. Connolley 16:15, 7 June 2007 (UTC)

Yes, possibly something along the lines of Talk:Global warming/FAQ might work better. Then the countertheories could be phrased as questions and answered in a less tortuous way. -- Merlinme 16:58, 7 June 2007 (UTC)

This sentence: "However, a strictly "one-way" view of the relationship between CO2 and temperature contradicts basic results in physics, specifically the fact that the absorption and emission of infrared radiation by CO2 increases as its atmospheric concentration increases." is horrendously POV, OR, and absolutely cannot remain in the article without a source. It doesn't require a source for the greenhouse effect, but rather a source that a one-way view of CO2 causality "violates basic physics." Taking a position that some reputable scientists hold and saying it contradicts basic physics without a source is exactly the kind of statement Wikipedia can't make. Oren0 07:50, 11 June 2007 (UTC)

There are no reputable scientists who argue that increasing CO2 has no effect (name one) William M. Connolley 08:44, 11 June 2007 (UTC)

From what I recall from TGGWS, though I don't remember who said it (I could look it up later), the argument goes that CO2 only follows temperature on a global scale, and that the GHE is more of a local phenomenon. If nobody is making this one-way argument, why is this straw man here? Oren0 16:38, 11 June 2007 (UTC)

Any way to verify this? Saying that the greenhouse effect is a local phenomenon is just as nonsensical as saying the effect is one-way; it would be helpful to know which flavor of nonsense was being served. The "one-way" argument is, sadly, quite common in the popular press and has been mentioned by one or two self-styled experts, so it deserves to be mentioned here. Raymond Arritt 17:07, 11 June 2007 (UTC)

I'm pretty sure that TGGWS narrator said that CO2 strictly follows T, not the other way round. Its a stupid thing to say, and no sensible scientist would say it, of course. Oh, and since you've just asserted that reputable scientists say it, its hardly a strawman William M. Connolley 19:23, 11 June 2007 (UTC)

You're having it both ways. You're saying that no reasonable scientist holds this position, therefore it can be refuted without a source. But it isn't a strawman because some scientists do hold this view. Don't you see the contradiction? Either some reasonable scientist holds this view, in which case a source is needed to refute it, or no reasonable scientist holds this view, in which case it shouldn't be on the page. I honestly don't know what the answer is, but I've read it enough places to be inclined towards the former. Oren0 01:50, 12 June 2007 (UTC)

The answer is "some unreasonable scientists hold this view." The fact that it's unquestionably contradictory to basic physics doesn't prevent someone from holding the view. One truth of this world is that there is no shortage of people willing to make pronouncements on topics of which they know nothing. Raymond Arritt 02:28, 12 June 2007 (UTC)

You may call them unreasonable, but that does not make it so. If this view is really so unquestionable, then find a source and this debate is over. 02:57, 12 June 2007 (UTC)

"And how much is absorbed by carbon dioxide? Eight hundredths of one percent. One one-thousandth as important as water vapor. You can go outside and spit and have the same effect as doubling carbon dioxide." - Reid Bryson. You did ask for a reputable scientist. Clearly the question is not whether it has an effect but by how much it has an effect; the effect of a spit isn't much is it? JG17 15:04, 12 June 2007 (UTC)

Not really- I googled that quote, and at [16] (which is, in any case, not a particularly reliable source, being a blog), the article goes on to say: "Bryson says the data fed into the computers overemphasizes carbon dioxide and accounts poorly for the effects of clouds—water vapor." That's overemphasizes carbon dioxide. Which is not the same as "carbon dioxide has no effect". -- Merlinme 15:41, 12 June 2007 (UTC)

Also, see: Greenhouse_gas#The_role_of_water_vapor -- Merlinme 15:45, 12 June 2007 (UTC)

Bryson is emeritus William M. Connolley 16:14, 12 June 2007 (UTC)

Ok, I found the original article/ interview at: [17] Bryson is fairly clear that he really does think CO2 has very little effect (although that is still not the same as no effect, and he does not deny that temperature is going up, and in fact he is proud of the fact that he was one of the first people to suggest that human activity could affect climate). However, although I'm sure he is a distinguished man, WMC's point is that Bryson is emeritus, i.e. retired. That doesn't necessarily stop you being a scientist, but it does tend to mean that your research may not be up to date. If this were published in a peer reviewed journal it wouldn't be an issue, because we would know that his work had been considered critically by other scientists. But while "Wisconsin Energy Cooperative News" seems a perfectly respectable publication, it's focus is "rural, non-rural, and statewide issues that affect electric cooperatives". A peer reviewed scientific journal it is not. People say a lot of things when they're waxing lyrical in response to interviewing, that they wouldn't say in a scientific article (or at least, they would have to justify if they said it in a scientific article). I'm not sure one newspaper interview with an 86 year old scientist (who does not even specifically deny that CO2 has an effect) justifies altering the current Wikipedia article, therefore. -- Merlinme 16:38, 12 June 2007 (UTC)

None of that stops this being a strawman argument. No-one argues the possible amplification effect so no-one argues against basic physics, but the extent of amplification cannot be determined at all from the ice-core records. Bryson says the effect of CO2 is negligible and he is by no means alone. Ian Clarke among many others say that the lag means that clearly CO2 did not drive climate in the past. Do you realise that this "feedback theory" is not published or peer-reviewed either? It seems to have first appeared on the realclimate.org blog and it is only endorsed on other blogs or webpages. How many people really believe this nonsense is quite unknown. I don't think many would actually like to debate it because it's a stone cold loser of a motion. Look at the graphs. What do you see? Do you just see what you want to see? This is a hobbyhorse the Wikipedia authors should not have got on. ( JG17 17:49, 12 June 2007 (UTC))

JG, lets get this straight right now: Clarke is correct - everyone agrees about that one (and also that its misleading). Climate in the past was not driven by CO2. Where you get things wrong is by assuming that because this is correct, the opposite cannot be true. Its a chicken/egg thing, Temperature can drive CO2 and CO2 can drive temperature. CO2 can both be a feedback and a forcing. -- Kim D. Petersen 17:59, 12 June 2007 (UTC)

Well I'm glad everyone agrees about Clarke being correct because Clarke doesn't believe in this new interpretation of the time-lag so who is misleading who? The Swindle documentary was just negating Al Gore's misleading presentation and they used Clarke (amongst others) to denounce Gore. Yes CO2 can be a feedback and a forcing but the extent of the feedback may be negligible (as Bryson argues). The extent most certainly cannot be determined from the ice-core studies: The most obvious interpretation of which is that the initial driver remains the main driver otherwise the onset of the cooling periods cannot be explained. Any other theory is guesswork.( JG17 11:07, 13 June 2007 (UTC))

Ah, so many errors, so little patience to respond. For a start, the derided "feedback theory" has indeed been published in numerous peer-reviewed publications -- as you could easily have found had you bothered to take two seconds with Google Scholar. The whole one-way argument is silly and based on fundamentally flawed logic (as Kim implies). Does heat cause fire, or does fire cause heat? Raymond Arritt 18:19, 12 June 2007 (UTC)

You are confusing the original feedback theory with this new "feedback theory" which was composed specifically to explain the CO2 time lag in the ice-core graphs (ie. reread the article please) and proposes that the CO2 feedback thence became the main heating component of climate change in the past. Anyway the one-way argument is not the issue -- as you could easily have found had you bothered to take two seconds to read my actual words. The issue is that one-way has never been argued, not even in the Swindle documentary. What has been argued is just that the data demonstrates the feedback effect to be negligible. Even the phrase "it seems to be almost completely one-way" wouldn't violate basic physics so the sentence in it's current form is clearly a strawman. If you don't want to respond then please don't. Your snark is not welcome.( JG17 11:07, 13 June 2007 (UTC))

From a transcript to The Great Global Warming Swindle: "[Professor Frederick Singer]: So obviously Carbon Dioxide is not the cause of that warming. In fact we can say that the warming produced the increase in Carbon Dioxide. [Professor Ian Clark ] CO2 clearly cannot be causing temperature changes. It's a product of temperature - it's following temperature changes." They seem to be pretty strong claims to me that warming produces more CO2, and that CO2 cannot be causing temperature changes. I don't really understand why you're getting so worked up about this, to be honest. TGGWS used the ice cores lag as an argument that CO2 does not cause warming, it follows it. This is misleading, because although there must have been some non CO2 related initial cause at the points shown in the ice core record, it ignores the expected effect on global temperature after the CO2 has been released. If you believe that CO2 has a negligible effect, then the onus is surely on you to find an alternative scientific mechanism for the recently observed warming. While it would be foolish to believe that we have perfect understanding of the atmosphere, the fact is that theories which give a significant weight to CO2 have a much better explanatory power than those which don't. As far as I can tell, very few scientists have time for the alternative "cosmic rays" theory suggested by TGGWS. See, for example, Alan Thorpe in the New Scientist: "that the presence or absence of cosmic rays in Earth's atmosphere is a better explanation for temperature variation than the concentration of CO2 and other gases. This is not a new assertion and it is patently wrong: there is no credible evidence that cosmic rays play a significant role." Until someone comes up with a better theory, I will tend to believe the theory that CO2 is a significant contributor, because I trust the large body of scientists who agree with it. -- Merlinme 12:27, 13 June 2007 (UTC)

You are wandering off from the point. I said that no-one rejects the idea of positive feedback, including Bryson, Singer, Lindzen, Clarke, etc: They only query the extent of the effect. To test theories you must use real world data. The ice-core data timelag in the heating half-cycle does not disprove the theory but the completely in-step onset of the cooling cycles conclusively shows that any feedback effect was negligible in the past. Without nitpicking the transcript you must surely realise that is what was meant. Check these scientists various writings' to confirm it if you like. Hence no-one in the world is arguing against basic physics so the text in this article is deliberately wrong ie. a strawman. If I appear worked up it is because I see this particular issue as a litmus test for the credibility of global warming science: That is do you allow dogma or data to guide you? I am not against reducing our CO2 output but I do like the truth. Perhaps I have seen the "large majority of scientists" be wrong more often than you - and wrong on so many issues and in so many areas I'd be hard put to list them all. Scientists are very, very often wrong and they are usually wrong en masse and usually when they trust theory over real data. I repeat what do you see in the ice core data? Does the argument posed in this article make any sense to you? ( JG17 14:36, 13 June 2007 (UTC))

"the completely in-step onset of the cooling cycles conclusively shows that any feedback effect was negligible in the past" -- oh dear, back to the chicken-and-egg argument again. Raymond Arritt 14:54, 13 June 2007 (UTC)

A poor analogy disproves nothing. But even if you believe in this flawed feedback-becomes-driver theory, do you suppose that the GCM's have a 1000 year time-lag in the feedback, or even 100 years? ( JG17 14:35, 15 June 2007 (UTC))

"If you believe that CO2 has a negligible effect, then the onus is surely on you to find an alternative scientific mechanism for the recently observed warming." I don't know who "you" is supposed to be in this sentence, but it's clearly an argument from ignorance. Lots of scientists fall into this camp and I think it's a perfectly reasonable position to hold. "We don't know" is not at all a sign of failure in science, and it is a position scientists have held and continue to hold on many issues. The assumption that CO2 must be causing global warming because we haven't found something else to explain it is a fallacy. That being said, do we have a source that anyone is indicating that CO2 has zero effect on temperature, as the article states? Oren0 17:23, 13 June 2007 (UTC)

I'm sorry, but your statement "the assumption that CO2 must be causing global warming because we haven't found something else to explain it" displays an unsettling lack of familiarity with the scientific literature on the topic. It's not an assumption; rather, it's the most parsimonious explanation for a broad range of theoretical and observational evidence. The onus really is on the skeptics in this case -- the supposed alternate explanations often involve a great deal of speculation (e.g., a mysterious amplification mechanism for tiny solar variations) and in general have no coherent theme ("it's cosmic rays...no, it's ocean circulation....no, it's natural variability...oh please dear Lord, let it be anything but CO2"). Raymond Arritt 18:38, 13 June 2007 (UTC)

Like many people in this debate you assume that disagreement with the conclusions of the scientific literature means unfamiliarity with it. That is just conceit. Most, if not all, of the so-called "evidence" consists of nothing more than someone's biased opinion based on ambiguous, incomplete data, poor statistics or guesswork-inspired modeling. The only real evidence is the retreat of the arctic and glaciers. But several specialists in those fields argue that these are a natural recovery from the little ice age. Who are we to argue?( JG17 14:35, 15 June 2007 (UTC))

I'm not nitpicking the transcript; those two quotes follow each other directly, and surely the implication is clear. Durkin probably did selectively edit the participants (he has a history of doing so), but his intention is clearly to imply that CO2 is a consequence, not a cause of global warming. Anyway, I agree that scientists are often wrong; in fact I'd say they're almost invariably wrong, because any scientific theory is only 'right' until contradictory data and a better theory come along. By all means look at the data and the theories critically, however you can't go from this to saying that the theory supported by the majority of scientists is usually rubbish. The theory supported by the majority of scientists should hopefully be the best fit for the data currently available. You've latched onto the ice core data, which I will confess that I initially found very convincing. Has correlation been confused with causation? If the only counter argument was that this was all a feedback loop, I would personally find it rather unconvincing; it seems a little neat, to explain away the lag by saying that A caused B but then B causes A to some extent, honest. However, this is not the only counter argument. We know that a) CO2 should increase global temperature and b) that giving significant weight to CO2 provides a better match for 20th century temperature than giving it a low weight. Given that we must literally have millions more data points for 20th Century temperature than we do for Antarctic temperatures hundreds of thousands of years ago, I find this persuasive. The heating mechanism that causes the initial temperature rise in ice cores remains to be explained; but that does not mean that CO2 cannot be causing temperature rises right now. -- Merlinme 17:31, 13 June 2007 (UTC)

CO2 production is a consequence of global warming: That is what feedback means. Durkin only summarised the scientists and they have never discounted CO2 feedback - they are physicists after all - but it appears to have had negligible effect on past temperatures they say. You should also be wary of the argument that only CO2 can explain current warming. This originally comes from Hadley centre's climate modeling team. Since most of the model parameters were guessed and hence very variable; they tuned them all until the model nearly mapped the surface temperature records. It is circular reasoning with no actual supporting data and quite frankly it is appalling science. Google "Craig Bohren USA today" for a good perspective from the inside. Yes another emeritus! They are the people you can really trust because they don't make money from either side.( JG17 14:35, 15 June 2007 (UTC))

First, you've wandered quite a bit from the original point, which was the argument that temperature affects CO2 but CO2 does not affect temperature. Also, I don't think you understand how the models work. Finally, Bohren makes a number of statements that are flat-out wrong, e.g. "in the atmospheric sciences it is difficult to get grants unless you can somehow tie your work to global warming" (which a quick glance at lists of NSF or NOAA awards will show to be false). Raymond Arritt 14:56, 15 June 2007 (UTC)

The Bohren article is interesting, and seems reasonably well balanced. I'm still not completely sure why you would take the views of a couple of retired professors over the views of dozens of active, researching professors though. Anyway, at no point does Bohren say that he doesn't think global warming doesn't exist. His main point is that he is sceptical of doomsday scenarios, having seen plenty of them fail to happen, which is fair enough. I don't personally believe we're going to get a superstorm going to swallow up entire cities or anything. However, I do believe we're going to get changed weather patterns happening in a fairly short space of time, which will increase stresses on human populations, notably in the third world, and will probably lead to greater problems with migration and conflict over things like water and grazing rights. Bohren implies that he thinks that there are more serious risks than global warming, which is an arguable case. However, he seems unnecessarily defeatist about the possibility of keeping consumption of fossil fuels down- is there no point in even trying? He is also rather dismissive of computer modelling, which he admits is a personal bias; is this a reasonable bias, based on knowledge and experience, or simply that of an old man who did most of his research before computers were everywhere, doesn't like them particularly and doesn't understand people who spend their lives with them? To return to the analogy I use quite a lot, how much do the people who program weather models understand each individual data point? Does that make their weather predictions invalid?

When Borhen admits his bias against modelling, he lists things which he finds more convincing, e.g. longer growing seasons. At no point does he say whether he sees or does not see evidence of this. Really, I'd describe his whole viewpoint as "somewhat sceptical of global warming, sceptical of what we can do about it, and very sceptical of doomsday scenarios". At no point does he say he doesn't think global warming exists. The sentence: "Fortunately [for me], I'll be dead before the consequences of global warming become dire, if indeed they do" is essentially saying he would like to see more conclusive evidence. He doesn't even entirely rule out the possibility that the consequences of global warming will be dire. -- Merlinme 17:31, 15 June 2007 (UTC)

At no point have I disagreed about global warming either, or with man's current contribution. Perhaps the arctic is melting too quick and perhaps it's our fault. I'm just arguing against clearly unscientific and unsound logic from a web page, not a paper, being repeated here. I explained why I trusted retired professors - precisely because they can be trusted. ( JG17 18:10, 2 July 2007 (UTC))

Yes I wandered off the point. However, the GISS model can be downloaded from their site and it is far less complex than the mathematical models which I work with on a daily basis. Actually I criticise fatigue crack growth modeling for exactly the same reason - too many fudge factors make accuracy impossible. Furthermore, most of these climate factors don't seem to be based on hard data and they are admitted to be poorly or very poorly understood. Anyone expressing full certainty in the models, as Hadley centre does, is engaging in pure PR, not science. Bohren obviously meant grants in his own field of climatology. Whether it is false or not I'd suspect he is far more able to say than you.( JG17 18:10, 2 July 2007 (UTC))

Bohren even repeats the tired old global cooling nonsense William M. Connolley 17:37, 15 June 2007 (UTC)

I vividly remember the ice-age stories. It may have been before your time, and it may have been nonsense but it most certainly had a following among certain journalists. It didn't go anywhere only because the earth started warming up. That there were few papers is probably due to the fact that there were very few climatologists then. Bottom line: Bohren was there - you weren't. ( JG17 18:10, 2 July 2007 (UTC))

You're welcome to your stories and to your journalism. I'm talking about the science, and I'd hope that Bohren was, too. If you're interested in the science (the state of it then) tehn I recommend the global cooling article which you might find interesting. Bottom line: I've read the science papers from then; you haven't; it looks like Bohren hasn't either William M. Connolley 19:23, 2 July 2007 (UTC)

Nice free ride for Schneider there. The problem arises because scientists are usually ambiguous in the text, talk up a possibility in the conclusions, concoct a more alarming vision for the papers, then the hacks make it even more alarming and the snowball runs. We all agree this happened for the ice age scare and we can see very often it in the current climate too. When the balloon inevitably bursts the scientist then goes back to the original ambiguous paper and says "it was that journalist who did it, not me". Bohren sees this, I see it and you see it too don't you? But is it science or PR? JG17 14:38, 10 July 2007 (UTC)

I don't believe "Previous research has demonstrated a reduction in cosmic rays between 1920 and 1980, when measurements were stopped. ^[1]". Reading the ref (I presume this [18]) says "Fair-weather potential gradient (PG) observations in Scotland and Shetland show a previously unreported annual decline from 1920 to 1980, when the measurements ceased." which is entirely different. CR measurements continue William M. Connolley 21:10, 12 June 2007 (UTC)

In fact I cut the whole Sven para: "Henrik Svensmark at Danish National Space Center ^[2] contends that low-level clouds (which cool the Earth) are formed when cosmic rays come into the low atmosphere. ^[3]." - the Royal Soc stuff is new, but the rest isn't; and the Royal Soc stuff *doesn't* support the text - only the press release does; but thats nothing post-TAR William M. Connolley 21:10, 12 June 2007 (UTC)

I demand this section be rewritten from a NPOV standpoint. Articles written so as to convey the impression that one side is more credible than the other must not be tolerated. If reference [19] was not good enough, then please someone else rewrite the section, or fix the context in which the reference was used. James Callahan 19:34, 24 June 2007 (UTC)

You're not going to win anybody over by making demands and saying what will and will not "be tolerated." Instead, perhaps try to be bold and make changes to make the article better. I incorporated your reference and rewrote part of the section, but it's clear that the balance of scientific opinion is currently against this theory, and the section has to reflect that. Oren0 20:16, 24 June 2007 (UTC)

"Dismissed" seems a bit strong. From NASA:

"Since the late 1970s, the amount of solar radiation the sun emits, during times of quiet sunspot activity, has increased by nearly .05 percent per decade, according to a NASA funded study.

"This trend is important because, if sustained over many decades, it could cause significant climate change,"

...

"Historical records of solar activity indicate that solar radiation has been increasing since the late 19th century. If a trend, comparable to the one found in this study, persisted throughout the 20th century, it would have provided a significant component of the global warming the Intergovernmental Panel on Climate Change reports to have occurred over the past 100 years," ( [20])

See also: Sun more active than for more than a millenium, Oren0 20:45, 24 June 2007 (UTC)

"Dismissed" is entirely accurate. We have other scientists going on record as saying things like "that's nuts", which is extremely unusual in scientific discourse. His speculations simply aren't taken seriously. Raymond Arritt 20:57, 24 June 2007 (UTC)

Do you believe that opinion should be more important than data? Saying "That's nuts" is unusual in most scientific discourses but it seems commonplace in this particular area. Why is that? Are climate scientists particularly uncivil? Seems so! ( JG17 18:10, 2 July 2007 (UTC))

If you like data rather than opinions, you could provide some. As far as can be told - see solar variation - there is no long-term upwards trend in solar over the last 30 y so its a poor candidate for explaining the warming. Nor is there any sfc T signal corresponding to the (far larger than any trend) 11-y solar cycle. You can also look at fig 4 of the SPM [21] for some attribution stuff comparing natural (inc solar) and GHG forcing William M. Connolley 19:21, 2 July 2007 (UTC)

I was referring to the other chap who quoted NASA's data and was dismissed by the repetition of a juvenile insult from a "climate scientist". Argue with NASA's conclusions not mine! The solar effect does seem to fit the temperature graph before the 80´s doesn't it? The CO2 forcing doesn't fit the temperature as well as solar for that period does it? An unbiased scientist should conclude that it is therefore probable that there is more than one thing controlling our climate and solar effects are very important too. Why is that so difficult for you guys to conclude? Ah yes - bias! One club golfers don't win many matches you know! ( JG17 14:53, 10 July 2007 (UTC))

Basically, no. Attribution isn't done by wiggle matching. As you say, there is more than one thing forcing our climate - this is fairly obvious. Solar almost undoubtedly had an effect (in the pre-industrial, for example). Most attribution studies don't detect solar or only marginally detect it. In contrast to the GHG and aerosol signals which come out strongly. See TAR or AR4 for details. Does The solar effect does seem to fit the temperature graph before the 80´s doesn't it? (which I'm not assenting to) concede that solar doesn't match post 1980? William M. Connolley 17:49, 10 July 2007 (UTC)

If you had a CO2 graph with those wiggles you'd say exactly the opposite wouldn't you? Moreover in that event I'd agree with you because the CO2/temperature relationship would be undeniable. I note that the IPCC says they have a very low understanding of solar forcing so what the TAR or AR4 says is set against a backdrop of little actual knowledge. I readily accept what the data shows (unlike many) but I'd put 3 caveats on it; a) it depends on whose temperature graph is being used and how much it has been "corrected" upwards, b) I keep hearing from you guys that 20 years is too short a time scale to judge climate - except when it suits; c) On an averaged graph the most recent years are partly made up of guesses about the future. By the way, in real life the sun is the only forcing and everything else is a feedback - why not so in the models? JG17 12:09, 16 July 2007 (UTC)

If CO2 perfectly matched solar over the last century, that would be puzzling, because we know other forcings (e.g. sulphate) are important. Fortunately it doesn't match up. This lesson appears lost on the solar folk who are only happy when their wiggles match. Most of the rest we've been through before. In real life, no, there is orbital geometry too, which is more important (at least on ice age timescales, or so people assume, perhaps because it is known). CO2 input from anthro sources is not in any meaningful sense a "feedback" either, so I'm not sure what you mean William M. Connolley 12:43, 16 July 2007 (UTC)

We know other forcings are important but it seems there is a lot of guesswork as to how important they all are. Since all radiative activity can ultimately be traced back to the energy coming from the sun then you could have had just one independent variable instead of several. With appropriate material emissivities/absorptivities and frequency-dependent IF statements, you could have found the effect of the atmospheric gas/particle changes by varying the quantities via a simple lookup table. I would have found that less controversial because the input is well known and the effects are more interdependent. You are being unfair with the solar physicists - do you purport to know more than them about the sun? BTW reference 22 is no longer pointing to the right place so that controversial, non-peer-reviewed website entry (which you possibly wrote in the first place) is now even irretrievable. Shall we remove the paragraph? JG17 13:32, 18 July 2007 (UTC)

If I understand you correctly, what you are saying is meaningless/wrong. You cannot simulate the effects of CO2 variation by varying solar input. Re ref 22: what do you mean? It points to Science. Why would you want to remove the para? William M. Connolley 13:47, 18 July 2007 (UTC)

Reference 22 in the actual text (not the footnote) points to antarctica.ac.uk and refers to the new "feedback argument" we discussed above: It is a dead link. I'd argue for its removal though anyway using one of your own arguments - it's not a proper peer reviewed publication. On the 1st point; yes in the current models it is impossible to do, but since the heat energy radiated from the earth, which is in turn "stopped" by the greenhouse effect, originally came from the sun, it is hence dependent on the sun - albeit with a time lag. I'm proposing a more realistic model: Ok you need to let the model stabilise carefully but it would be more physically correct than the multiple independent variables approach. I say this because in finite element radiation models it is well known that it is always better to use the original source and let the model find the secondary effects because there are multiple interdependendent effects between the various bodies which are totally impossible to calculate by hand. Such interdependance is needed in a climate model too I'd say. Incidentally I think we'd probably agree on green issues more than we disagree. My worry is that already too many people blame CO2 for every ecological problem around and the real land-abuse and pollution culprits are getting a "get out of jail free" card. The CO2-above-all-else dogma is doing more harm than good in a lot of areas. If climate sensitivity to CO2 eventually turns out to be small then it'll be doubly tragic. JG17 17:56, 20 July 2007 (UTC)

Actually I meant tragic in a sense that environmentalists will start to be be ignored again. Obviously if the planet is not at risk then that is good news. JG17 18:02, 20 July 2007 (UTC)

OK, I fixed the link: our website "experts" upgraded the site to have pretty pictures of penguins but forgot the elementary principle of not breaking old links. Sigh. As for your science: that there are many env problems other that CO2 is obvious. That CO2 is the largest driver of current change is the current state of the science. I don't think your stuff about the FE codes has any relevance - if its not the sun thats varying but the CO2 is, it makes no sense to think of it in terms of solar var William M. Connolley 20:58, 20 July 2007 (UTC)

Ah but I wouldn't vary the solar forcing - just the quantity of GHG's and aerosols. The effect of these differences would still pop out. I just think it's more elegant. If I get the time I'll try it.( JG17 10:51, 24 July 2007 (UTC))

Radiation parameterizations in current-generation climate models closely match the results of line-by-line codes, so I'm not sure what you're driving at here. Raymond Arritt 12:18, 24 July 2007 (UTC)

I referred to the fatigue code case above, which has a similar number of parameters, each with an inbuilt error plus cunningly disguised techniques (eg bucket size limits) to give the result we want. Since we have virtual unlimited ability to modify the state of the model and we know that these effects won't interfere with each other then we can easily simulate a known state and give the impression of accuracy when in fact it is akin to guesswork or fakery. By reducing the independent variables and increasing the interdependencies between variables it is harder to tune so it forces us to look for the correct answer, not just the one that fits our hypothesis. If the hypothesis is sound then it doesn't matter, though my way would be less error-prone too. Ultimately though the model reflects the theory but the theory can only be verified by observations of the real world - not by other models.( JG17 14:53, 24 July 2007 (UTC))

Actually William, since you work for the BAS and that reference points there, is this just a disguised POV? You can now point to Hansens "trace gas" paper for an actual peer reviewed paper ( http://pubs.giss.nasa.gov/docs/2007/2007_Hansen_etal_2.pdf) though I'd understand why you'd find that distasteful.( JG17 14:53, 24 July 2007 (UTC))

Update. I see now that there are such models as I described - called "carbon cycle models". They seem to me to be a lot more sensible than the models with CO2 forcing. JG17 11:21, 26 July 2007 (UTC)

This user's last says that the user undid a past version. Yet, the changes are very different. In fact, it seems like the user was just trying to hide a past change that was earlier attempted at least once here. Is it possible to hide edits under the 'undo' function or am I just being paranoid? Brusegadi 23:14, 30 July 2007 (UTC)

It looks like 'undo' works differently and more selectively from a rollback or revert. The 'undo' removed the edit by BenB4 ( this one) without affecting any of the intervening edits. I didn't know it worked like that, but it seems useful when one needs to fix an old edit while leaving intermediate constructive edits in place. (Which is not to say the undo was appropriate in this case.) Raymond Arritt 23:42, 30 July 2007 (UTC)

I think I got confused. Sorry for wasting your time. Anyhow, it is good to know how this things work because some vandals are tricky. Brusegadi 23:48, 30 July 2007 (UTC)

It seems that the following article" contradicts the information on this page. Should it be incorporated?

Burning forests 'is main agent of climate change' Independent, The (London), May 14, 2007 by Daniel Howden http://findarticles.com/p/articles/mi_qn4158/is_20070514/ai_n19113378 User:E.D.R. —The preceding signed but undated comment was added at 19:52, August 25, 2007 (UTC).

Since that very page says The rampant slashing and burning of tropical forests is second only to the energy sector as a source of greenhouses gases... I think you've failed to read past the headlines William M. Connolley 21:46, 27 August 2007 (UTC)

The article clearly states, "Carbon emissions from deforestation far outstrip damage caused by planes and automobiles and factories... [and] the destruction of those forests will in the next four years alone... pump more CO2 into the atmosphere than every flight in the history of aviation to at least 2025." This was printed in the UK's Independent, not some right wing smear job paper. The information in the article clearly contradicts the graph on this page. I am not saying the article rather than graph is correct, only that the two are contradictory. —Preceding unsigned comment added by 76.23.153.173 ( talk) 02:19, 5 November 2007 (UTC)

Carbon emissions from deforestation far outstrip damage caused by planes and automobiles and factories... is dubious. Whether its wrong or not would depend on whether they include power generation. Fossil fuel burning is about 6* deforestation; newspapers are not reliable sources for science William M. Connolley 09:43, 5 November 2007 (UTC)

They do not include the energy sector, as you earlier pointed out. They include "planes and automobiles and factories." Also, as you correctly say, newspapers are not reliable sources for science. However, the article in question refers to a study conducted by an reputable, peer reviewed, and environmentalist scientific body: the Global Canopy Programme. I will leave it at that, as I am not an expert, but somebody who is might consider revising the page to reflect this data, or explain how it is flawed, rather than dismissing it off-hand as "dubious". —Preceding unsigned comment added by 76.23.153.173 ( talk) 04:42, 16 November 2007 (UTC)

The report in question [22] introduces itself with this (the very first sentence in the intro):

Human induced climate change is real and upon us. We cannot avoid dangerous warming without action on deforestation, which causes 18-25% of global carbon emissions – 2nd only to energy.

So chalk it up to bad reporting once more ;-) -- Kim D. Petersen ( talk) 00:17, 23 January 2008 (UTC)

I've moved the recently-added map lower, because I think it carries the wrong implications of "attribution" and shouldn't have priority by being at the top. This page (I assert) is about the attribution of climate change to different forcing agents; not about why countries have caused which proportion of CO2 emissions William M. Connolley 12:29, 1 September 2007 (UTC)

I agree. A necessary distinction, a necessary move. Vinny Burgoo 16:18, 1 September 2007 (UTC)

1. The phrase "The current best answer is..." is incredibly POV and inappropriate for this article. While it is true that some people may believe that it is "the best answer", that doesn't necessarily mean it is and it certainly should be reported as fact when it is opinion.

3. It is absolutely inappropriate to discuss the issue of greenhouse gas emission in the second paragraph without including discussion of the fact that the majority of greenhouse gas emissions has taken place AFTER the reported increase in global temperatures. Anything else is POV pushing.

3. "A summary of climate research may be found in the IPCC assessment reports". That isn't either accurate or sufficient. The IPCC doesn't summarize all climate research, it creates its own summary. So this phrase must be changed to reflect this fact. I suggest something like "An IPCC summary of climate research may be found in their assessment reports".

<My POV> I am currently undecided on the issue of anthropogenic global warming (I have changed my mind about three times today), but I am opposed to any single organisation dominating any given field of research </My POV>. A read through of this article made my POV hackles rise. Five of the top eight references are IPCC. This may as well be titled "The opinion of the IPCC and ridicule of skeptics". If the theory linking warming on other planets to that on earth is 'nuts' (uncommon scientific terminology), why include it? Simply to ridicule skeptics? Article needs NPOV work IMHO, but I'm not going to waste my time making changes that will be reverted instantly. Dhatfield ( talk) 14:32, 8 January 2008 (UTC)

Cl Ch is unusual in that there is one body - IPCC - charged with collecting and collating and summarising resea ch. IPCC doesn't dominate the research enterprise, but it does provide the best summary. And (once again) its work has been endorsed by X, Y and Z. Warming on other planets is different (you're right: it is basically nuts and has no scientific support, its only here because it comes up from the septics). Not making instantly reverted edits is a good idea. As always, you're free to discuss POV-type improvements here William M. Connolley ( talk) 22:56, 8 January 2008 (UTC)

Unusual is one way of putting it. Unique would be another way. Why does the article not reference the fundamental research? Is primary research not preferable to referencing a third party in an encyclopedia? As an aside, is this http://en.wikipedia.org/wiki/Image:Climate_Change_Attribution.png really the best we, as a species, can do? It ends in 1994. Dhatfield ( talk) 10:42, 23 January 2008 (UTC)

Though this discussion seems over, I'd like to point out that at least in this case, secondary research is DEFINITELY preferable to primary, although relying on one source is indeed a problem. In general, interpreting primary research is NOT the job of an encyclopedia, and on Wikipedia qualifies as OR. In this particular case, there are literally thousands of studies that need to be compiled, statistically analyzed, and interpreted; citing individual studies would be useless. As for the graph, I'm not exactly sure what the objection is. Eebster the Great ( talk) 03:41, 21 January 2009 (UTC)

I don't like the current version of the "solar var" section; it reads too much like endorsing it. Quotes from the various articles linked need to be pulled in to make it clear that the people observing this stuff aren't claiming it. It would be nice to find a way to note how weak the stuff is - eg the pluto and neptune stuff is a trend from 2 points William M. Connolley 21:07, 7 October 2007 (UTC)

The section is poorly written. The entire section about the solar variation only speaks about mostly unrelated climatic changes on other planets, which it shouldn't. ~ UBeR 21:17, 7 October 2007 (UTC)

My recollection is that this is a leftover from an old edit war. Somebody put in the nonsense from Abdusamatov when he was in the news, then some of us added the responses, so here it is. Delete as much as you like. Raymond Arritt 21:52, 7 October 2007 (UTC)

Now that section reads like it is totally bashing the concept... I'm totally clueless on this subject matter, so unless it is supposed to read like that (i.e. the concept is just some scientists making crazy assumptions and is ridiculous to pretty much the rest of the scientific community), can someone make it more neutral? wctaiwan ( talk) 14:49, 7 January 2008 (UTC)

Re [23] - I'm with Hermione. This is a science article; CCD is primarily political William M. Connolley ( talk) 13:11, 2 March 2008 (UTC)

I agree, i don't know what i does on the Attribution article, the connection would have to be rather far-fetched. -- Kim D. Petersen ( talk) 19:35, 2 March 2008 (UTC)

William, I realise that you take a special interest here, so would you please reconsider the reversion of edits to make the article consistent with WP:SULF. Normally, I would applaud the use of the <POV> correct </POV> spelling, but global standardisation is a Good Thing. Dhatfield ( talk) 15:14, 2 April 2008 (UTC)

Sorry, but I'm a fanatic on this issue. I'm also a bit sick of having SULP quoted at me, because I can't help feeling that people don't actually read it: it sez quite clearly These international standard spellings should be used in all chemistry-related articles and this is *not* a chemistry-related article, its climate. And Sulphate is the preferred IPCC spelling William M. Connolley ( talk) 21:43, 6 April 2008 (UTC)

Obviously all those atmospheric chemicals have nothing to do with chemistry :) Take away all those pesky chemicals and there'd be no problem - global warming wouldn't exist...

Of course it is a chemistry related subject and no, IPCC doesn't dictate spelling on Wikipedia - WP policies and conventions do.

And, yes WMC and I have discussed this before, rather heatedly as I recall. Now, what is the consensus? Go with WP guidelines and IUPAC on this obviously chemistry related series of articles - or follow IPCC and WMC's personal preferences? Vsmith ( talk) 00:04, 10 April 2008 (UTC)

I'm all for standardization so I'd say follow WP:SULF but I really care very little one way or the other. Oren0 ( talk) 00:36, 10 April 2008 (UTC)

See Talk:Global_warming/FAQ#Water_vapour_is_the_most_important_greenhouse_gas.21 on why water vapor is a greenhouse gas, but not a climate forcing. -- Stephan Schulz ( talk) 08:28, 6 April 2008 (UTC)

To be honest, I don't understand why this edit of mine was reverted: [24]

It was trying to get the point across that yes, water vapour is the dominant greenhouse gas, but no, it's not a factor in recent global warming, which presumably we all agree on. Can we not find a compromise based on that? -- Merlinme ( talk) 08:22, 7 April 2008 (UTC)

I don't know why you were reverted, but one problem is certainly "naturally occurring water vapor". The amount of WV in the atmosphere depends primarily on the temperature. If CO2 pushes the temperature up, is the added WV "naturally occuring"? -- Stephan Schulz ( talk) 14:49, 7 April 2008 (UTC)

Well, I don't know; I wasn't actually particularly expecting my edit to stand unaltered, but I wasn't expecting it to be reverted either. By all means improve it, but NewtonianWiki appears to have a point to me; a) that the section should be called anthropocentric greenhouse gases (or, possibly, forcing greenhouse gases); and b) it needs to be explained to a Wikipedia reader why water vapour is not relevant. My edit was attempting to provide this information. I'm happy to have it improved, but I don't think ignoring the issues raised (by reverting) helps. I'll have a second attempt. -- Merlinme ( talk) 15:42, 7 April 2008 (UTC)

I'm not convinced. Water vapor is a red herring here. Nobody seriously claims that its a climate forcing. It's a standard tactic of sceptics to confuse the overall greenhouse effect with the anthropogenic greenhouse effect and then to claim "look, its all due to water vapor, not CO2". If we start listing things not responsible for global warming, we will have a fairly long list soon ;-). -- Stephan Schulz ( talk) 16:31, 7 April 2008 (UTC)

The relevant point to me is that the section is headed "Greenhouse gases". Red herring or not, water vapour is a greenhouse gas. Alternatively, come up with a section heading which better explains what the section holds. I'd be a bit unhappy with "Forcing greenhouse gases" though, because it's not a term the average encyclopedia reader could be expected to understand. It would need to be explained; simply calling the section "Greenhouse gases" and having a short sentence on water vapour probably deals with the "red herring" quicker. Whatever solution is adopted, I would hope it aids a reader's understanding rather than confuses it. -- Merlinme ( talk) 17:20, 7 April 2008 (UTC)

So then you disagree with the language at greenhouse gas: "water vapor acts as a positive feedback to the forcing provided by greenhouse gases such as CO2." Should I go ahead and remove that? There's a difference between listing everything not responsible for global warming and listing a major greenhouse gas when talking about greenhouse gases and explaining its effect on climate. Oren0 ( talk) 16:40, 7 April 2008 (UTC)

Nope, that sentence is entirely correct. WV is a feedback, not a forcing. -- Stephan Schulz ( talk) 16:43, 7 April 2008 (UTC)

..and now, we state that water vapor "is responsible for 36-66% of the greenhouse effect". While correct, this gives the wrong impression of a wrong uncertainty, while the range does not describe an uncertainty, but rather is caused by the non-additive nature of GHG mixing and depends on which question is asked. -- Stephan Schulz ( talk) 16:57, 7 April 2008 (UTC)

Fine, it's a feedback not a forcing, therefore it's still important to GW, right? The current revision seems to dismiss it outright. As for the 36-66% number, I took it directly from greenhouse gas and RealClimate. Oren0 ( talk) 17:11, 7 April 2008 (UTC)

Indeed. The numbers are correct. Assuming you understand them, do you really think the average reader will understand the fact that which value in that range one picks is more a matter of definition than of uncertainty? Yes, water vapor is a feedback. So I would suggest we describe it as a feedback in a separate paragraph, especially as it amplifies any warming, not just GHG induced warming. -- Stephan Schulz ( talk) 18:19, 7 April 2008 (UTC)

Fine with me. I think that leaving water vapor out was a glaring omission. If you think it can be explained better in its own paragraph, fine. I also don't like the idea of leaving out data because you think the average reader is too dumb to interpret it properly. Oren0 ( talk) 18:49, 7 April 2008 (UTC)

Good thing then that that is not my reason. But everything in its place...there is a good reason why neither The Art of Computer Programming nor Decline and Fall of the Roman Empire are assigned reading for high school students. -- Stephan Schulz ( talk) 19:43, 7 April 2008 (UTC)

Sure, but this is an encyclopedia, not a work of literature. In my opinion it should be possible for a reasonably informed reader to achieve a good basic level of understanding of a subject from reading an encyclopedia. Speaking for myself, I did neither physics nor chemistry past 16, but I take an interest, and I would like to think I have achieved a good basic level of understanding of global warming through reading Wikipedia. To completely miss out water vapour in a paragraph headed "Greenhouse gases" is to do the reasonably informed reader a disservice, because either it leaves them not realising water vapour is a greenhouse gas, or it leaves them wondering why it's been missed out. In either case I would argue not having the subject clarified makes them more likely to believe misinformation on the subject. You don't explain something to someone by ignoring it. -- Merlinme ( talk) 07:34, 8 April 2008 (UTC)

Several footnotes should be attributed to Gavin Schmidt (not "gavin" or "Gavin Smith" or other mistakes). But I cannot figure out how to edit them--they don't seem to show up in the editing page. Haven't been active lately, so have forgotten how to do this.

Jeeb ( talk) 14:28, 27 June 2008 (UTC)

The footnote text is where the reference is made, not in the references section (to be more exact, it's at one of the places where the reference is made, but usually there is only one). -- Stephan Schulz ( talk) 14:33, 27 June 2008 (UTC)

Oh, you are right. I have corrected the references now. Splette :) ^{How's my driving?} 14:57, 27 June 2008 (UTC)

Who the hell decided this article should be called "attribution of recent climate change?" This should be changed to "causes" IMMEDIATELY. I mean, seriously, the English language does not use the word "attribution" in this manner, at least not in America at any sort of reasonable level. I'll wait a few days, if it's not fixed, I'll do it myself. —Preceding unsigned comment added by 140.112.185.129 ( talk • contribs)

Don't William M. Connolley ( talk) 07:03, 22 July 2008 (UTC)

"Attribution" is less loaded than "causes" and seems to imply a more rational and scientific stance.The whole climate change debate is so politicised that the anthropomorphic aspect dominates the subject.If we attribute climate change to human activity, we understand it better than to say we "caused" it, as in accusing ourselves of wrong doing,ignorance,etc etc.Example;Recent legislation in California seeks to make high energy consuming big screen plasma televisions more energy efficient.One clown politician jumped on this and argued that next there would be laws limiting playstation use to an hour a day.USA=the consumers dream continues in the fog of childhood.I note there is no quick link to " Global warming controversy"?Should there be a link to this article found in wikipedia?If so,I don't know the way to enter it.Thanks Ern Malleyscrub ( talk) 06:32, 22 November 2009 (UTC)

Attribution is appropriate process when there are multiple causes to be sorted out. What is unfortunate, is that the article neglects to attribute bias in beliefs as a cause. Zulu Papa 5 ☆ ( talk) 22:41, 27 November 2009 (UTC) This is becoming ridiculous.To state bias in beliefs is a cause is to return to burning witches and superstition;stick with facts and proof.If you have evidence of "bias" state clearly facts to show this.Science disputes "belief" as any influence on the real world except in the minds of believers.Superstition has no place here,thanks. Ern Malleyscrub ( talk) 12:33, 5 December 2009 (UTC)

This sentence needs some clarification:

While 66% of anthropogenic CO2 emissions over the last 250 years have resulted from burning fossil fuels, 33% have resulted from changes in land use, primarily deforestation.

I seriously doubt that there was any substantial impact on CO2 levels from burning fossil fuels during the 18th and 19th centuries. Steohawk ( talk) 22:38, 25 August 2008 (UTC)

Hmm, the sentence makes perfect sense to me. It refers to the the percentage of fossil fuel vs.land change related CO₂ emissions of the cummulative total anthropogenic emissions in that time, regardless of how these are distributed over these 250 years. Of course the last few years contributed the most to that... Splette :) ^{How's my driving?} 23:04, 25 August 2008 (UTC)

I think this article needs more on positive feedbacks. Here's a science summary http://www.eurekalert.org/pub_releases/2009-02/su-ccl021009.php

Unless there's widespread disagreement, I'll start making some edits soon. Andrewjlockley ( talk) 12:19, 15 February 2009 (UTC)

That's a press release, not a science summary. It also mostly affects future effects, not recent climate change. I think most of that (if sourced to better sources) should go into Effects of global warming, which already has a feedback section (and covers most of the material). -- Stephan Schulz ( talk) 12:49, 15 February 2009 (UTC)

Per Stephan, consider this disagreement widespread. - Atmoz ( talk) 15:37, 15 February 2009 (UTC)

The feedback effects are based on peer-reviewed science. Is that not popular in this article? Andrewjlockley ( talk) 17:52, 15 February 2009 (UTC)

Then start with the science, not with press releases William M. Connolley ( talk) 18:56, 15 February 2009 (UTC)

Sadly the science has been edited out previously. Can I assume that I'm now free to include it, now that there seems to be little doubt that the 4th report is, as i have been saying all along, utter rubbish? Andrewjlockley ( talk) 00:18, 16 February 2009 (UTC)

What? -- Stephan Schulz ( talk) 00:25, 16 February 2009 (UTC)

I'm no longer going to put feedback effects in here. The point I was making above was simply that the IPCC report 4 underestimates climate change so badly as to be entirely misleading. 79.65.169.132 ( talk) 17:36, 16 February 2009 (UTC)

You've said that several times, it gets very boring. After asking you to learn to log in, we've replied "do it from papers not press releases" and then you go away William M. Connolley ( talk) 17:57, 16 February 2009 (UTC)

Quit the personal attacks william, I've simply stated that THIS ARTICLE is not the right place, because it's FUTURE impacts I'm talking about. The quote from Field was entirely appropriate, as discussed on the GW talk. I'm just about to edit the GW article now, as per the '24hrs on talk page' policy. So get ready to make some more entirely unconstructive comments and arbitrary reversions. Andrewjlockley ( talk) 09:09, 17 February 2009 (UTC)

The "'24hrs on talk page' policy" is somewhat new to me. It seems like a reasonable idea IF you participate in a constructive dialog during that time. -- Stephan Schulz ( talk) 10:02, 17 February 2009 (UTC)

It seems a good way of preventing an edit war! Andrewjlockley ( talk) 01:38, 18 February 2009 (UTC)

What I'm thinking of is McKitrick, Ross and Patrick J. Michaels (2004). "A Test of Corrections for Extraneous Signals in Gridded Surface Temperature Data" Climate Research 26 pp. 159-173. full text -- and similar papers that discuss the problem of the poor quality of the instrumental record.

The obvious question is: can we really (empirically) detect the signal of AGW in the noise of poor-quality temp records: from Heat-island contamination (McKitrick's argument), weather-station site issues, instrumental-calibration issues, etc.

Thanks in advance for pointers (to the archive?) and comments, Pete Tillman ( talk) 00:11, 12 September 2009 (UTC)

I would suggest to discuss this not here, but at Instrumental temperature record. -- Stephan Schulz ( talk) 00:31, 12 September 2009 (UTC)

I find it very difficult to understand from this article why the major scientific bodies have determined that recent global warming is primarily caused by human activity. It is not enough to just say "most of the major bodies have determined it is so." Why? What is the evidence? Yes, certain gasses have increased in the atmosphere due to human activity, and the planet is warming. But how do we know that these two are connected to each other? What is the evidence? It is really hard for an average reader to gain this information from this article. I get the feeling that the emperor has no clothes. -- Westwind273 ( talk) 16:17, 6 October 2009 (UTC)

We have Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."[2] and 2 is a link to a publically available document. You could read it.

Or you could read further on and get to: Evidence for this conclusion includes: * Estimates of internal variability from climate models, and reconstructions of past temperatures, indicate that the warming is unlikely to be entirely natural. * Climate models forced by natural factors and increased greenhouse gases and aerosols reproduce the observed global temperature changes; those forced by natural factors alone do not[10]. * "Fingerprint" methods indicate that the pattern of change is closer to that expected from greenhouse gas-forced change than from natural change.[11] William M. Connolley ( talk) 16:32, 6 October 2009 (UTC)

....and then there is the link to greenhouse gas that explains the basic mechanism of the greenhouse effect. What is really impressive is that Svante Arrhenius correctly predicted the effect more than 50 years before we had good CO2 measurements or a reliable temperature record. -- Stephan Schulz ( talk) 16:44, 6 October 2009 (UTC)

I personally find the most helpful section Attribution of 20th century climate change. There the article discusses different possibilities for the observed increase in global temperatures. While it is difficult for a scientist to make a definitive statement on something which has so many variables, there is essentially universal scientific agreement on the following things: 1) global temperature is going up 2) human activities (fossil fuel burning, forest clearance, farming etc.) raise global temperature 3) most of the recently observed increase is due to human activities. The evidence for 1) and 2) is enormous; 3) is slightly more contentious, but as the article notes, recent studies by scientists from many different countries (i.e. the IPCC) have concluded that it is "very likely". As I understand it, the evidence for this is mainly that scientific models of the atmosphere which include human components predict the observed increase in temperature much better than those which don't. That's what the graph is about; before about 1950, the effect of greenhouse gases on changes in global temperature was less than that of solar activity. Afterwards the effect of greenhouse gases gets steadily larger, although initially the effect of this was masked by sulphate pollution, which reduces global temperatures. A model which takes into account changes in greenhouse gases, solar activity, ozone, volcanic activity and sulphates provides a good match to observed changes in temperature. It doesn't provide a perfect match, but then no models do. It certainly provides a far better match than models which ignore greenhouse gases, the effects of which have got a lot stronger since 1990. Essentially all the scientists who've done research in this area find this evidence convincing; no-one has come up with a model which can "explain away" the effect of greenhouse gases.

Just because it is complex does not mean that the evidence is not pretty clear; it annoys me when people say "but that isn't the case" without providing any evidence or intellectual justification for such a statement. People say "yes, but theory X has now been shown to be wrong"; true, but that was because theory X disagreed with the evidence, so a theory was created which better fitted the evidence. By contrast, the evidence currently available strongly supports a significant anthropomorphic global warming effect; and there are no plausible competing theories.-- Merlinme ( talk) 17:56, 6 October 2009 (UTC)

I do feel some sympathy though for the view that there is too much "this report supports the view" and not enough actual evidence referenced William M. Connolley ( talk) 20:06, 6 October 2009 (UTC)

Well in the end I got bored of pasting it together from IPCC quotes and just made something up William M. Connolley ( talk) 20:32, 6 October 2009 (UTC)

"Climate models forced by natural factors and increased greenhouse gases and aerosols reproduce the observed global temperature changes; those forced by natural factors alone do not[10]. "Fingerprint" methods indicate that the pattern of change is closer to that expected from greenhouse gas-forced change than from natural change.[11]" Yes, but how? As far as I know, warming is warming. There have certainly been periods in the past where the earth has warmed naturally. What is it about this warming that indicates a human cause? What is the "fingerprint" of this warming that shows it is caused by humans and not natural? This article should not simply pass off such questions to "go read the footnote references". This issue is the whole reason why conservatives say their is no global warming problem. To gloss over these important questions, simply reinforces the conservative argument. I myself seriously wonder whether we have solid evidence that global warming is caused by humans, given that proponents seem to avoid these important questions. Merlinme's #3 is really what this whole article is about. If #3 is contentious, then the whole argument collapses like a deck of cards. -- Westwind273 ( talk) 15:13, 7 October 2009 (UTC)

I don't understand your problem. What is there about Climate models forced by natural factors and increased greenhouse gases and aerosols reproduce the observed global temperature changes; those forced by natural factors alone do not that you didn't understand? That isn't all the evidence, but it is a large part of it William M. Connolley ( talk) 15:29, 7 October 2009 (UTC)

If you can't understand the footnotes, and refuse to accept the word of people who do understand them and don't particularly have an axe to grind, then I'm afraid we're not going to get very far.

Point 3 isn't that contentious. Given my (admittedly limited) understanding of the science, the fingerprint is simply that where there are more of the greenhouse gases being released by humans, we get more warming. We don't get more of anything else known to cause warming (as the article notes, if anything known "natural" factors would be expected to be reducing temperature at the moment). WMC might be able to explain the point better.

If you disagree with this point, then feel free to do your own research into the sources. Hell, do your own original scientific research if you wish. If you managed to find the "missing link" that is natural and causing all this warming, without involving human causes, then you'd probably deserve a Nobel prize. But I doubt that you will. The fact is that every scientist who has done the research thinks that humans are causing a significant amount of the warming (and a large majority would say that humans are "very likely" causing most of the warming).

If you disagree with all these scientists, well I guess that's your prerogative. But in the absence of any scientifically plausible evidence supporting your position, your position is more in the realms of conspiracy theory than scientific theory. -- Merlinme ( talk) 15:34, 7 October 2009 (UTC)

Fingerprints include e.g. the fact that we have stratospheric cooling at the same time that we have tropospheric warming and the fact that the Arctic heats up faster than the middle latitudes. Different sources of warming have different effects, and the effects that we observe are consistent with GHG induced warming and effects from land use. Increases in solar radiation, e.g., would cause stratospheric heating as well as tropospheric heating. But again (and again....and again): We understand the greenhouse effect from first principles. More GHGs means more warming. Even Lindzen agrees with that, he only speculates about some compensating effect via clouds. -- Stephan Schulz ( talk) 15:51, 7 October 2009 (UTC)

The fingerprint stuff actually gets quite tricky and heads off into EOF/PCA land. We link to the TAR section on this [25] for anyone who cares for the grungy details William M. Connolley ( talk) 16:58, 7 October 2009 (UTC)

On the specific issue of previous global warming (which cannot have been caused by burning fossil fuels), it is quite an interesting area, and is discussed in (exhaustive) detail at Paleoclimatology. There are complex effects involving changes in solar radiation, ice, and atmospheric feedback processes. However, to take one of the most recent global examples, the Holocene climatic optimum raised temperature in some parts of the world by as much as 4 degrees C. However the effect on global temperature was probably close to zero, and the warming took place over hundreds or thousands of years. Similarly, the Paleocene–Eocene Thermal Maximum did raise global temperatures by about 6 degrees C, but it took 20,000 years. By contrast, current warming is expected to reach about 2 degrees C after about a century, which is light speed in terms of geological processes. All the available evidence which we have (e.g. measured solar radiation etc.) suggests that natural phenonomena cannot explain the rise, whereas a human cause fits the evidence well. -- Merlinme ( talk) 12:27, 8 October 2009 (UTC)

The number of Americans who believe in global warming has declined by 20 percentage points in recent years. See http://news.yahoo.com/s/ap/20091023/ap_on_sc/us_climate_poll;_ylt=AvXSu6fsBisf5SrVsViFvk6s0NUE;_ylu=X3oDMTMxaG1naWFxBGFzc2V0A2FwLzIwMDkxMDIzL3VzX2NsaW1hdGVfcG9sbARjcG9zAzcEcG9zAzQEcHQDaG9tZV9jb2tlBHNlYwN5bl9oZWFkbGluZV9saXN0BHNsawNwb2xsdXNiZWxpZWY- I think the reason for this decline is exemplified by the rude way my questions have been treated on this page. Those who believe in global warming seem to dismiss as 'stupid' those who want clarification of the evidence. My main point here is to improve the article, which is what this page is for. My main point is that the explanations of why we know global warming is not nature-caused is something too important to simply be dismissed to "go read the footnotes" or "trust the scientists". Those who have commented here have not read what I have been saying all along. It is not that I don't understand the footnotes; that is not the issue. My point is that an explanation of the reasoning for man-caused warming is too important a point to be relegated to the footnotes. I don't know how much clearer I can say it. If you think that those of us on the fence should just read the footnotes or trust the scientists, then you are sticking your head in the sand while public opinion is changing against you. Those who are posting here actually have trouble articulating just what the evidence is (e.g. "The fingerprint stuff actually gets quite tricky"). By sifting through all that was written here, I can kind of pick out a few reasons why the warming is manmade, not global. You seem to be saying that the location of the warming indicates it is only manmade, or the pace of the warming cannot be mathematically attributed to nature. But it is really hard to pick these things out amongst all your misunderstanding of what I am saying. And absolutely none of this explanation is contained within the article. Thus American public opinion continues to slide against global warming. Without a proper and clear explanation of what it is about the warming that indicates man-made, many of us are left with "The emperor has no clothes." -- Westwind273 ( talk) 03:20, 23 October 2009 (UTC)

WMC wrote: "I don't understand your problem. What is there about Climate models forced by natural factors and increased greenhouse gases and aerosols reproduce the observed global temperature changes; those forced by natural factors alone do not that you didn't understand? That isn't all the evidence, but it is a large part of it." WMC, you are not reading what I am writing. In what way do the "observed global temperature changes" of manmade warming differ from the changes "forced by natural factors alone"? Your quoted sentence does not explain this. Are the locations (longitude and latitude) of manmade warming different from those of natural warming? Is the pace of manmade warming different from the pace of natural warming? Does manmade warming happen at different levels in the atmosphere than natural warming? Is natural warming of the past caused by factors like solar flares which are not happening now to explain the warming? I'm trying to help you by throwing out a bunch of possibilities here. The main article should explain this. Otherwise public opinion will continue to slide. -- Westwind273 ( talk) 03:30, 23 October 2009 (UTC)

WMC said "we don't care how many americans believe what". I'm not sure that's quite right; it would be more correct to say "it's not relevant to this article how many americans don't believe in global warming". Westwind, I'm afraid global warming is not easily reducible to a soundbite that will be understood by American public opinion. That does not mean, however, that it doesn't exist. There are plenty of scientific theories which are supported by the evidence but not understood by American public opinion. Quantum mechanics implies that quantum cats can be alive and dead at the same time. I'm not sure that's understood by scientists, let alone the American public, but that doesn't make quantum mechanics any less true, as far as we can tell. The article on "Attribution of recent climate change" reflects the fact that attributing climate change to particular causes is quite hard. Explaining exactly what happened to the Earth's atmosphere millions of years ago is also hard. What do you want us to say? It's easy? How exactly would you explain quantum mechanics in one sentence to the American public? Unless you're prepared to become a specialist in the area, and wade through dozens of scientific papers, you're going to have to take a certain amount on trust; i.e. you're going to have to believe the specialists, especially when they essentially all agree. Alternatively, you are at liberty to become a specialist, understand the papers and correct this article where necessary. Wanting something to become simpler to understand, however, ain't gonna make it so. Regardless of what American public opinion does or does not think.-- Merlinme ( talk) 10:47, 23 October 2009 (UTC)

Merlinme: A Wikipedia article is not a soundbite. If Wikipedia articles can describe things such as Einstein's theory of relativity, then certainly they ought to be able to describe what it is about the current warming that indicates a human cause rather than a natural one. It is quite elitist to say to users of Wikipedia "Global warming is caused by humans, but sorry, you're not smart enough to understand how we know that." Here is the inherent contradiction: You say that "attributing climate change to particular causes is quite hard." If that is true, then why are so many scientists apparently convinced that it is human-caused. It doesn't take a rocket scientist to see that "difficult attribution" and "overwhelming agreement of attribution" are inherently contradictory. This is something the common man can understand. So why leave it out of the Wikipedia article? It only leaves one with the taste of "the emperor has no clothes." I am not saying that the explanation is easy; I am only saying that it is not so difficult that it falls outside the scope of a Wikipedia article. If Wikipedia is simply a matter of "trusting the specialists", then why have an article on relativity at all? Why not just have an entry that says "Relativity -- E = mc2. As to why this is true, just trust the experts." Of course, the article on Relativity says much more than that. So why is it only the global warming articles that refer so often to "all scientific bodies agree" or "because this report said so". Have you ever taken the time to listen to the arguments of those who deny human-caused global warming? My points are precisely what they are saying -- that there is no evidence that the current warming is human caused. So then why would the Wikipedia article stick its head in the sand and refuse to explain why we know the warming is human caused? I am disappointed that you again seem to intentionally misunderstand my point. I don't want attribution of global warming to become simpler to understand; I am saying that, although it may be difficult to understand, it is not so difficult that it should be left out of the article entirely, or passed off to "most scientists agree". I am astounded by the strong resistance that you global warming supporters have to including an explanation in this article of why we know it is human-caused. Your resistance deepens my doubts about whether global warming is indeed human-caused. -- Westwind273 ( talk) 07:33, 24 October 2009 (UTC)

It doesn't take a rocket scientist to see that "difficult attribution" and "overwhelming agreement of attribution" are inherently contradictory.

Would you say it is easy or difficult to launch a human into space safely? If it is difficult, but there is overwhelming agreement it has been achieved, as there surely is, your claim is that everyone is lying about us having launched thousands of astronauts into space? Difficult and impossible are not synonyms. -- 86.129.7.162 ( talk) 17:53, 28 October 2009 (UTC)

Yes. I am not denying global warming is human caused. I just want the article to explain why we know it is human caused. For example, the article on the Apollo program goes into quite a bit of detail about how it was that we got men to the moon and back, even though it was quite difficult. If Wikipedia can explain the Apollo program in all its complexity, then why can't a Wikipedia article explain clearly why we know that global warming is human caused? It is only the global warming articles that are replete with "because all scientists agree" or "because such and such report says so". -- Westwind273 ( talk) 02:59, 29 October 2009 (UTC)

We've spent (wasted) rather a lot of time in the past on this article fighting off the wacko septics. They seem to be pretty well gone now, so I'm happy to agree: this article could do with some work along the lines you suggest. I have, you'll have noticed, begun William M. Connolley ( talk) 09:19, 29 October 2009 (UTC)

I would personally prefer it if the section on, say, the fingerprint of anthropogenic warming, were clearer. Even if the science is gnarly, I would hope that there's a way of at least explaining the main possibilities to a lay reader. That would improve the article. However, even if that can be done, I doubt it will make Westwind happy. I'm not quite sure what will make Westwind happy. He appears to be implying he understands general relativity, quantum physics and rocket science just fine, but can't read and understand IPCC articles on global warming. On the specific area of rocket science, I'm not sure the analogy with the Apollo programme holds. The Apollo programme is forty year old technology which we know worked. Describing that will always be easier than describing current research on something which is very likely but not certain. -- Merlinme ( talk) 20:54, 30 October 2009 (UTC)

A point I'd make is that "scientific method" in this subject is little understood, as the complexity of the research loses most people who do not have the patience for science that involves over a dozen different disciplines.Mathematics,geology,physics,solar radiation,thermal energy,biology involving mass consumption of carbon by sea algae,as well as the oceans ability to transmit and change the Earths atmosphere such as the El Nino and La Nina events to name only two.The comparison with the Moon program reminds me that there are Moon landing deniers who take their prejudice and fears of government "conspiracies" into this subject.The steps taken to develope the technology to get to the Moon over the centuries engaged the public with the event. Science and scientific method are not an everyday experience for the general public, yet this climate change research will change all our lives.When science collides with politics always expect the possibility of hysteria and manipulation of information. Ern Malleyscrub ( talk) 00:54, 28 November 2009 (UTC)

Here are two web pages which contain the best explanations I've seen yet about why we know the warming is mostly human-caused:

http://www.ucsusa.org/global_warming/science_and_impacts/science/global-warming-faq.html#How_do_we_know_that_humans_are_the_major

http://www.edf.org/documents/5279_GlobalwarmingAttributuion.pdf

I would argue that this is not as complicated as everyone is making it out to be, although I will admit that it is more complicated than I originally supposed. Basically the story boils down to this: We know what causes naturally occuring global warming (increased sun activity, etc). These types of causes are not happening in enough quantity to explain the global warming that has taken place during the 20th century. At the same time, we know that human activity has dramatically increased the amount of CO2 in the atmosphere. Given what we know about how the atmosphere works (the effect of increased CO2, etc), it is overwhelmingly likely (90% probability) that most of the observed global warming in the 20th century was caused by human activity. Quite simply, other known natural causes of global warming are not occuring in enough quantity to account for the observed warming.

I think this article should use more of the concrete wording from the above two websites, along the lines that I just wrote. Just my humble opinion. -- Westwind273 ( talk) 06:45, 5 December 2009 (UTC)

excuse me Westwind273,added a link same day,later Ern Malleyscrub ( talk) 13:01, 5 December 2009 (UTC)

see also IPCC link here http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_wg1_report_the_physical_science_basis.htm added later Ern Malleyscrub ( talk) 12:46, 5 December 2009 (UTC)

My point is that someone should not have to dig through a 100-page IPCC report just to understand the main points of why we know that global warming is human-caused. This "gnosis" attitude of "go read the report" is why so many Americans do not see global warming as a problem. It is correct that truth in Wikipedia articles should not be influenced by how many people believe in that truth. But let me say that Wikipedia exists to serve a societal purpose: the spreading of (hopefully correct) information. As one of the outlets for public education, Wikipedia should have a concern that majority of the public does not believe what appears to be true. And it is altogether fitting and proper that Wikipedia should reflect on itself and see if its own articles are perhaps part of the cause of the public misperception. -- Westwind273 ( talk) 16:52, 5 December 2009 (UTC)

Isn't it somewhat redundant to have a section called "Attribution of 20th Century Climate Change" within an article called "Attribution of Recent Climate Change"? After all, isn't this what the whole article is supposed to be about? This seems to be a clever apology for the fact that this article talks about anything but what it is supposed to cover, which is a clear explanation of why we can attribute recent climate change to human causes, not repeated references to "all scientists agree" or "this study concluded". It is so sad that this article is so poorly written, since its topic is one of the most critical of our times. -- Westwind273 ( talk) 23:42, 24 October 2009 (UTC)

Cheers for that constructive criticism. I'm glad to see you're spending so much time making Wikipedia better, despite the efforts of all the rest of us. -- Merlinme ( talk) 20:42, 30 October 2009 (UTC)

Thanks Merlinme. Nice to know that my contributions are appreciated.  :) -- Westwind273 ( talk) 07:04, 16 November 2009 (UTC)

"Recent climate change" is rather vague in my opinion. Given the current obssession with global warming and the nature of the article as dealing primarily with global warming, the definition of "recent" should be something like "from the beginning of the current warming trend" (which, according to even this hockeystick graph, http://en.wikipedia.org/wiki/File:2000_Year_Temperature_Comparison.png, began sometime after 1600 and before 1700, before the Industrial Revolution). In my brief scan of the article, the (relatively) exact DATE of the the inception of the warming trend is not mentioned; it says something about 1750 but that's not what the hockeystick says. I think a discussion on theoretical causes of this pre-industrial warming is warranted. —Preceding unsigned comment added by 69.90.55.168 ( talk) 14:49, 17 November 2009 (UTC) Another obscure piece of information is the link of volcanic activity to global temperature variations.The Pinatubo eruption was significant enough to show the effect of stratospheric dust reflecting sunlight and solar energy.This is discussed in the book "Superfreakonomics" with somewhat fanciful ideas about using sulphur to cool the planet(!).Also complicating the subject is the discovery of enormous areas of the Earths oceans that once become de-oxiginated by trillions of tons of algale blooms that thrived and provided oxygen into the atmosphere & ocean then died and sucked up oxygen as they decayed en masse.These dead zones were covered by sediment and were sealed under the surface to be discovered many millenia later when homo sapiens needed oil.Although brief, this wikipedia article provides all the basics.If needed,hundreds of books containing thousand of pages are available.Let's keep wikipedia succinct and brief, if possible.Thanks Ern Malleyscrub ( talk) 07:02, 22 November 2009 (UTC)

The first citation in the article points to a page that has dozens of megabytes of reports linked. Is that as close as these footnotes need take the reader? Citing so generally is akin to pointing someone to the library and saying, "the answer's in there somewhere." Can the article's writers do better? And if not, why bother with such citations? (If the writer genuinely went to the cited source for the cited information, then a page citation should not be too hard to include. And I was taught that citing material you did not read is unethical.) Thank you, Pcrh ( talk) 22:43, 23 November 2009 (UTC)

This is a Wiki. Feel free to improve the citations. One problem is that older IPCC reports have been on the web in different forms (html, multiple PDF, single PDFs), and page numbers have not always been consistent (or existent). But I agree that sticking to one version and refining the references is a worthy endeavor. If you want to verify a particular statement, though, it's usually pretty fast to search in the document. If you do, please add the page number. And remember, we are all volunteers. With Wikipedia, you get a lot more than what you pay for. -- Stephan Schulz ( talk) 22:50, 23 November 2009 (UTC)

This article neglects to attribute the consensus probability specifically to Bayesian probability. The reader would benefit from a distinction made about frequency observed probability vs Bayesian Probabilities. A link to the Bayesian article should be provided. It is impossible to have frequency probability on a single global event, all the research is conducted in the greater Bayesian context. source [26] Which has inherent objective flaws and is subject to rapid changing views. Zulu Papa 5 ☆ ( talk) 22:03, 27 November 2009 (UTC)

I don't think the article would benefit from this distinction. The distinction does exist, and can affect interpretation. JEB has some interesting posts on Bayesian stuff and cliamte science, e.g. [27]. But it doesn't appear to be a *notable* topic in the field William M. Connolley ( talk) 22:13, 27 November 2009 (UTC)

The subject is taken for granted. I am not saying give the topic undue weight, just fair mention. It likely not very active because their is little to be done about it. It is obvious to me that this is at heart of the debate. Folks are just beginning to measure the consensus changes as scientific study. The Bayesian context is relevant and meaningful to justifying this important issue where there is no realistic proof outside of mind objects. Zulu Papa 5 ☆ ( talk) 22:33, 27 November 2009 (UTC)

It may be obvious to you that it is at the heart of the debate, but (to belabour what I hope is the obvious) your opinion doesn't matter; you'll need to bring in some RS's for it William M. Connolley ( talk) 22:55, 27 November 2009 (UTC)

You obviously missed the source above [28]. This is adequate to justify Bayesian probability for relevant, notable and meaningful inclusion in the article. (I apologize for misleading you with my opinion.) Again, what should be said with a link (and text) is the probabilities are Bayesian. This is not a synthesis, it's just good editing and is what Wikipedia is about with linking. (My opinion matters as much as yours, thank you.) Zulu Papa 5 ☆ ( talk) 23:40, 27 November 2009 (UTC)

A source [29] from IPCC. Zulu Papa 5 ☆ ( talk) 23:52, 27 November 2009 (UTC)

You provided a link to an unpublished paper (or to a pre-print of something that was subsequently published? I'm not sure which). What you have proved is that "bayesian ideas have been used in climatology". Since that was never in doubt, you haven't got very far. Your *claim* is that "it is at the heart of the debate" and you have provided no evidence for that. A small section from WG II doesn't help much either. I think it is clear we disagree. I'll back off for a bit and see what others have to say William M. Connolley ( talk) 00:08, 28 November 2009 (UTC)

Ok, it's better to follow this source [30] from IPCC. I got to break now too. Zulu Papa 5 ☆ ( talk) 00:31, 28 November 2009 (UTC)

Clearly it's not a 90% probability in the same sense that it's a 90% probability that you will roll between 1 and 9 inclusive on a ten sided die. But I would have thought this was (relatively) obvious. Having had a quick look at the links, I'm unconvinced that they would help people understand; I'd have thought there's a high chance they would instead make the article more confusing to read. You make what is a (relatively) intuitive concept and imply that people have to understand quite a technical field before they can understand climate change. People don't need to understand Bayesian probability to understand that the 90% figure is an estimate based on a large number of different factors. It's an opinion, albeit one which has an extremely large degree of support in the scientific community. -- Merlinme ( talk) 09:06, 3 December 2009 (UTC)

A wikipedia search on 'MMGW' redirected me to this article. But this article doesn't even mention MMGW let alone explain what it means. 20.133.0.13 ( talk) 10:53, 4 December 2009 (UTC)

What do you think it means? What were you expecting to find? Assuming it's a global warming related abbreviation, I would guess it's Man Made Global Warming. In which case it should probably redirect to Global Warming rather than here. -- Merlinme ( talk) 11:18, 4 December 2009 (UTC)

He means http://en.wikipedia.org/?title=MMGW&action=history William M. Connolley ( talk) 11:31, 4 December 2009 (UTC)

Well sure, but that just redirects to here. It doesn't give any clues as to what it means, or why it redirects here. -- Merlinme ( talk) 15:19, 4 December 2009 (UTC)

This might be a complete shot in the dark but I guess if 20.133.0.13 knew what MMGW meant, he wouldn't have a need need to look it up in an encyclopedia. The fact that MMGW is complete myth is totally beside the issue. 81.157.131.194 ( talk) 15:26, 4 December 2009 (UTC)

Your shot in the dark may well be right, but doesn't help us work out what it's supposed to mean, either. Although if you know it's "complete myth", then presumably you can enlighten us. -- Merlinme ( talk) 17:11, 4 December 2009 (UTC)

Well I hadn't got a clue which is why I tried to look it up. But then Wikipedia is known for being as much use as a chocolate fireguard - especially in environmental matters. 20.133.0.13 ( talk) 10:20, 9 December 2009 (UTC)

• Fixed by redirecting to AGW, a dab page that includes "Anthropogenic (man-made) global warming." Cheers, Pete Tillman ( talk) 22:55, 28 September 2010 (UTC)

Please note that, by a decision of the Wikipedia community, this article and others relating to climate change (broadly construed) has been placed under article probation. Editors making disruptive edits may be blocked temporarily from editing the encyclopedia, or subject to other administrative remedies, according to standards that may be higher than elsewhere on Wikipedia. Please see Wikipedia:General sanctions/Climate change probation for full information and to review the decision. -- ChrisO ( talk) 03:01, 2 January 2010 (UTC)

I reverted CD [31]. Given points 1 and 2 there seems little point adding "and natural" to point 3 William M. Connolley ( talk) 20:19, 27 March 2010 (UTC)

http://epa.gov/climatechange/endangerment/downloads/RTC%20Volume%203.pdf is useful. Its got Mars and all William M. Connolley ( talk) 21:15, 9 May 2010 (UTC)

Also the recent RC article http://www.realclimate.org/index.php/archives/2010/05/on-attribution/ William M. Connolley ( talk) 11:27, 27 May 2010 (UTC)

The paragraph is clear that the 18% figure refers to anthropogenic emissions, but this isn't obvious in the bullet points – "9% of global carbon dioxide emissions" etc. From ftp://ftp.fao.org/docrep/fao/010/a0701e/a0701e03.pdf this section of the cited document] these all refer to anthropogenic emissions, and I've edited accordingly. My browser couldn't find the server for the link in the citations, but a search brought up Livestock's long shadow: environmental issues and options which gives links to sections as well as the complete pdf. Should we change the link in the citation? . . dave souza, talk 07:12, 13 September 2010 (UTC)

Seems reasonable, though its a bit ugly to repeat it thrice. I removed "Scientists attribute..." cos that language always annoys me, its a bit peacocky. Who else could possibly do the attriution anyway? William M. Connolley ( talk) 09:03, 13 September 2010 (UTC)

I already posted this on the wikipidia talk page "Climate Change and Agriculture" but it is relevant here as well. This article states that livestock agriculture contributes 18% of greenhouse gases. This seems to come from the article "Livestock's Long Shadow"<ref>{{cite web|title=Livestock's Long Shadow|url=http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CHEQFjAB&url=ftp%3A%2F%2Fftp.fao.org%2Fdocrep%2Ffao%2F010%2Fa0701e%2Fa0701e00.pdf&ei=MNseUPmkAe30iwKzuoGwCw&usg=AFQjCNFW_mqPCkFzRvJ6-mhgII0_a9CQdA}}</ref>. However, the EPA states that the production of greenhouse gases by agriculture as a whole is 14% ^[4]. The wikipedia article on "Livestock's Long Shadow" also notes problems in the the methodology behind the 18% number ^[5] .

Could we have an expanded and more up to date section on "fingerprinting"? I always thought it was an important part of the attribution, and I believe there's been some recent progress; if I remember correctly there were a couple of big studies in the news which reported that fingerprinting supported an anthropogenic cause. Currently the article is vague as to what fingerprinting actually is, and it seems to point to 2001 reference. -- Merlinme ( talk) 11:00, 13 September 2010 (UTC)

Would be nice. Its on my list of things to do once peace breaks out again. Though I don't suppose I'll be able to do it then. Never mind, I'm sure one of the inexhaustible supply of experts that arbcomm appears to believe in will suddenly pop up and do it William M. Connolley ( talk) 22:49, 28 September 2010 (UTC)

That's a shame. I was considering doing it myself based on news reports and whatever linked research I can dig up, but obviously it would be better coming from a scientist. I'm quite busy at work at the moment, and now my evil Freeholder seems determined to tie me up in legal applications, so I can't really see me having the time in the next month or two. But if and when I have a chance, maybe I'll try to do something and you can correct as necessary. -- Merlinme ( talk) 07:55, 29 September 2010 (UTC)

I was going to base what I wrote on AR4, which hopefully lays it out clearly. But I haven't checked yet William M. Connolley ( talk) 19:57, 29 September 2010 (UTC)

A new paper [32] in Nature suggests that an abrupt shift in Atlantic sea-surface temperatures around 1970 may offer an alternate explanation for the puzzling "pause" in global warming from about 1940 to 1975. This decline has been conventionally ascribed to the influence of man-made aerosols. The new work suggests that changes in circulation-patterns in the Atlantic, perhaps influenced by the Atlantic Multidecadal Oscillation, may better account for the observed cooling. See When the North Atlantic caught a chill (Nature Science News) and A Sharp Ocean Chill and 20th Century Climate (Andrew Revkin, NY Times) for discussions and speculations. Plenty more in the blogosphere, if you're curious.

This is more a heads-up to work-in-progress, but perhaps our aerosol section here might need a caveat. Interesting work. Best, Pete Tillman ( talk) 22:02, 28 September 2010 (UTC)

explanation for the puzzling "pause" in global warming from about 1940 to 1975 - are you sure? It looks like it only talks about ~1970. But as you say, not yet. Let it settle William M. Connolley ( talk) 22:47, 28 September 2010 (UTC)

Eduardo Zorita has a nice discussion of this paper at Klimazweibel, and there's lots of chatter in the technical blogs comparing (forex) the 1910-1940 warming to 1970-2000 -- here's one by Judith Curry. Interesting stuff, but way too preliminary for here. Best, Pete Tillman ( talk) 20:21, 7 October 2010 (UTC)

Eduardo " Jugula" Zorita? No, I wouldn't call that nice. But even EZ is talking about 1970s, not 1940-70. And Curry isn't talking about this paper, so I'm rather puzzled by your refs William M. Connolley ( talk) 20:49, 7 October 2010 (UTC)

What I've been trying to point out, perhaps not very well, is that the scientific attribution of recent climate change is in a state of flux. Pete Tillman ( talk) 21:10, 7 October 2010 (UTC)

Oh, now I see what you mean. I think you're rather over-egging your pudding William M. Connolley ( talk) 21:27, 7 October 2010 (UTC)

Solar activity would have to be considered one of the dominant contributers to the warming, especially if deforestation and black carbon are included. Models do attribute most of the warming to the greenhouse gasses. But the language that previously listed was not only POV but incorrect. The IPCC considers the NET natural contribution to be negative, since it considers the cooling contribution of volcanic aerosols to be greater than the solar warming contribution.-- Africangenesis ( talk) 11:25, 21 October 2010 (UTC)

Looking at your description of this, it looks like you might be justifying a personal synthesis so I've reverted it now for a more complete explanation. Are you saying the IPCC believes solar forcing to be dominant but does not state so openly? Tasty monster (= TS ) 12:06, 21 October 2010 (UTC)

I doubt "dominant" was an IPCC term. The IPCC will just list a forcing contribution from solar that is in the range of those that this introduction was calling "dominant". Was "dominant" supported by the source for all the entries listed? I notice you did a complete revert, even of things you probably know are correct. How much do you review the sources before doing a revert? When you speculate that I might be justifying a personal synthesis without reviewing the supporting references, are you assuming good faith, or are you engaging in a personal attack? Am I the only one that should assume good faith? -- Africangenesis ( talk) 12:34, 21 October 2010 (UTC)

A quick look at AR4 didn't turn up the word 'dominant', but the summary here is pretty clear:

How do Human Activities Contribute to Climate Change and How do They Compare with Natural Influences?

Human activities contribute to climate change by causing changes in Earth’s atmosphere in the amounts of greenhouse gases, aerosols (small particles), and cloudiness. The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere. Greenhouse gases and aerosols affect climate by altering incoming solar radiation and out- going infrared (thermal) radiation that are part of Earth’s energy balance. Changing the atmospheric abundance or properties of these gases and particles can lead to a warming or cooling of the climate system. Since the start of the industrial era (about 1750), the overall effect of human activities on climate has been a warming influence. The human impact on climate during this era greatly exceeds that due to known changes in natural processes, such as solar changes and volcanic eruptions.

(my bolding). Squiddy | (squirt ink?) 12:59, 21 October 2010 (UTC)

They are lumping solar and volcanic together again. Notice that they didn't say solar "or" volcanic. Their listings of the actual radiative forcings have CO2's postive forcing and aerosol's negative (cooling) forcings as the highest, but nothing else is as high as solar or volcanic, certainly the list deforestation isn't.. "dominant" is POV. Please restore the changes. -- Africangenesis ( talk) 13:17, 21 October 2010 (UTC)

Perhaps the solution is to remove our non-IPCC terminology and see if we agree on whether that resulting statement reflects the source. -- TS 13:59, 21 October 2010 (UTC)

Africangenesis, you keep explaining stuff to us, like here what can and cannot get lumped together, but this is no use to us to improve the article. What we need is page-referenced quotes from reliable sources where notable scientists or mathematicians have said that you can't lump these things together, or that you must say 'or' instead of 'and'. No matter how good your explanation gets, it will never help improve the article until we see what you want to say printed in a well-cited, peer-reviewed article. See WP:RS, WP:V and WP:OR. -- Nigelj ( talk) 14:16, 21 October 2010 (UTC)

Based upon your pattern reverts and comments that miss the point, I agree that it is no use trying to explain things to you, and will explain things for benefit of others instead.-- Africangenesis ( talk) 19:19, 21 October 2010 (UTC)

We're all here to try to improve the articles, not to explain things to each other. If you have a suggestion to help improve the article, it needs to be backed by verifiable reliable sources. The quality of the sources is much more important than the explanation. -- Nigelj ( talk) 19:24, 21 October 2010 (UTC)

No you aren't, you are just reverting. You put the feedback article back in a state known to be incorrect and expect me to fix it, presumably because I am so much more knowledgeable. But if you aren't knowledgeable enough to at least leave it in a correct state, perhaps you shouldn't be reverting.-- Africangenesis ( talk) 19:31, 21 October 2010 (UTC)

OK, now you seem to be getting personal and incivil. Please see WP:CIVIL and the notice re 'Wikipedia general sanctions' at the top of this page. I was trying to be helpful by explaining to you how to put your case more effectively, but as far as I am concerned this conversation is now over. -- Nigelj ( talk) 20:41, 21 October 2010 (UTC)

How about if we compromise by adding "except solar." to this. We could use the IPCC FAR quote: ^{[1] [1]}

-- Africangenesis ( talk) 22:49, 21 October 2010 (UTC)

Can someone fix the reference please!-- Africangenesis ( talk) 22:54, 21 October 2010 (UTC)

I don't really understand why you think that quote means we should change the article the way you want us to (or why you think the article is incorrect). The article is saying that the combined effect of all natural forcings over this period is net cooling. The quote you want to use agrees with that. If you think that this could be stated more clearly in the article, then suggest a better wording; but you appear to be under the misapprehension that the article currently is trying to say that "all natural forcings are negative", whereas in fact it is trying to say that the sum of all natural forcings is negative. At no point does it say "solar forcings are negative". -- Merlinme ( talk) 13:37, 22 October 2010 (UTC)

I am redirected to http://guide.opendns.com/main?url=ipcc-wg1.ucar.edu/wg1/wg1-report.html —Preceding unsigned comment added by Jackminardi ( talk • contribs) 09:28, 1 December 2010 (UTC)

The website has apparently been taken down, and your DNS provider is lying to you to grab advertising dollars. That, unfortunately, is not infrequent today. I've updated the reference to a proper reference with a link to the official version at the IPCC. And I strongly wish all Webmasters would read Cool URIs don't change. -- Stephan Schulz ( talk) 12:51, 17 February 2011 (UTC)

"The dominant mechanisms to which recent climate change has been attributed all result from human activity" Where is the reference? Highly disputable! Solar emmission (not diffusion, not absorption) alone could cause this, yet the evidence is still lacking. This should not be offered as a statement of fact. There is plenty of naysayers still to be found. -- 71.245.164.83 ( talk) 03:12, 17 February 2011 (UTC)

I've removed this bit from the opinion section:

Some scientists noted for their somewhat skeptical view of global warming accept that recent climate change is mostly anthropogenic. John Christy has said that he supports the American Geophysical Union (AGU) declaration, and is convinced that human activities are the major cause of the global warming that has been measured.[22]

I don't see that this information is of great importance. If Christy hadn't changed his mind, then it might be worth noting his opinion alongside those of others, like Lindzen. But since he has changed his mind, he's now part of the consensus, and therefore not notable. Enescot ( talk) 03:09, 20 May 2011 (UTC)

I've added a new background section on some key concepts used in the article. I feel that the article should explain these concepts before using them. Ideally these definitions would be integrated into the main article, but I didn't feel up to doing this.

I've removed the picture of per capita GHG emissions. I don't see how this picture is directly relevant to this article. I've replaced it with a picture of rising CO2 levels.

Findings that complicate attribution to CO2

I've retitled the section "Findings that complicate attribution to CO2" to "Difficulties in attribution". CO2 is not the only GHG. I've also moved the content of this section. The part describing CO2 acting as a feedback is now in a new section called "Earlier climate changes," while the sub-section "Warming on other planets?" is now in the list of scientists opposing global warming consensus article.

I've done this because I felt that the previous revision was not consistent with the IPCC report. As far as I'm aware, the main uncertainty in attribution is distinguishing human activity from internal climate variability. The previous revision of the section could give the impression that the CO2 forcing/feedback issue and "warming on other planets" are the principal scientific uncertainties. I do not think that these issues reflect mainstream scientific thinking in respect of attribution.

I do appreciate why these sections had been included in the way they were. However, I do not think it is appropriate for an encyclopedia article to read like a skeptic's FAQ. Issues discussed in this article should focus on mainstream scientific thinking, and not give undue weight to minority viewpoints. Enescot ( talk) 16:26, 14 June 2011 (UTC)

Why on Earth are you moving it to a list of views by specific scientists? Is it a view of a specific scientist? If it should go anywhere then it should be to an article. The controversy article is the one at the top of my mind - but another subarticle might be better. Alternatively remove it completely. -- Kim D. Petersen ( talk) 16:49, 14 June 2011 (UTC)

I moved it to the list article because Abdusamatov was cited as a source:

Over the last two decades, proxy evidence of local or planetary warming has been observed on Mars,[1] Pluto,[2] Jupiter,[3] and Neptune's largest moon Triton.[4] It has sometimes been asserted in the popular press that this points to a solar explanation for the recent warming on Earth.[5] Physicist Khabibullo Abdusamatov claims that solar variation has caused global warming on Earth,[6] and that the coincident warmings "can only be a straightline consequence of the effect of the one same factor: a long-time change in solar irradiance."[7] This view is not accepted by other scientists. Planetary physicist Colin Wilson responded, "His views are completely at odds with the mainstream scientific opinion," and climate scientist Amato Evan stated, "the idea just isn't supported by the theory or by the observations."[1] Charles Long of Pacific Northwest National Laboratory, who studies radiative transfer, says "That's nuts ... It doesn't make physical sense that that's the case."[8] Jay Pasachoff, an astronomy professor at Williams College, said that Pluto's global warming was "likely not connected with that of the Earth. The major way they could be connected is if the warming was caused by a large increase in sunlight. But the solar constant—the amount of sunlight received each second—is carefully monitored by spacecraft, and we know the Sun's output is much too steady to be changing the temperature of Pluto."[2] Instead, scientific opinion is that these changes are caused by other factors, such as orbital irregularities or (in the case of Mars) changes in albedo as a result of dust storms.[9]

Personally I thought that the list article could be expanded to explain the various non-consensus viewpoints. I'm not a supporter of the controversy article. In my opinion, any controversies regarding particular issues, e.g., climate sensitivity, should be explained in the relevant articles. I don't see why a dedicated article is required.

I'd be happy to restore the section to this article. The reason I moved it was because I thought it would be better placed in the context of other non-consensus viewpoints, e.g., Lindzen. My preference would be to restore the text but retitle the section "non-consensus" or "non-mainstream viewpoints". Since Abdusamatov isn't the only scientist with a non-IPCC viewpoint, an expansion tag might be added to the section as well. Enescot ( talk) 19:55, 17 June 2011 (UTC)

I agree with Kim. I've undone the change to the List article. Please either find a better home for it, return it to this article, or give a reasoned argument why it should be removed completely. -- Merlinme ( talk) 09:02, 15 June 2011 (UTC)

I'm happy to restore it to this article provided that the section is appropriately retitled. I'm aware that the section does take the trouble to make the point that "warming on other planets" is a view that other scientists do not share. However, I feel that this should be further reemphasized by retitling the section (see my response to Kim D. Petersen). Enescot ( talk) 19:55, 17 June 2011 (UTC)

Add Portal:Global warming. 97.87.29.188 ( talk) 19:08, 14 July 2011 (UTC)

Un-Redline Clim-Past-Discuss.net ( Climate of the Past Discussions) please. 99.181.140.243 ( talk) 05:08, 15 July 2011 (UTC)

This section states, "Over the past five decades there has been a global warming of approximately 0.65 °C (1.17 °F) at the Earth's surface". However, the accompanying graph indicates that the .65 metric is for the past century. One of you special editors should fix that.-- 184.240.56.237 ( talk) 06:19, 16 July 2011 (UTC)

The IPCC citations here are woefully incomplete and unspecific. I can't do much about the latter, but in line with Stephan's response to a query two years ago (" This is a Wiki. Feel free to improve the citations.") I shall be replacing the IPCC citations with a revised form, such as now implemented at Global warming. As using {{ Harv}} templates will be a lot easier for me, and I think a significant improvement in citations, I query: anyone strongly enough opposed to want to clean all this up themselves? :-) _ J. Johnson (JJ) ( talk) 23:41, 14 September 2011 (UTC)

Largely done. Many of the IPCC citations were non-specific, and I have tagged them with "page needed". If anyone is looking for something to do it is quite straightforward to search the indicated source for the particular quote or material, then add the location to the citation in a manner consistent with other citations. This could also be done with several citations of the NAS report (I may come back and build a suitable reference for that). There has also been a start in converting citations to {{ Harv}} templates; it is, again, fairly straightforward to move a templated citation/reference from the text to the References section, replacing it with a Harv citation. Ask if you need help. _ J. Johnson (JJ) ( talk) 20:49, 26 September 2011 (UTC)

Beware Climate Change Risk from A/C, Fridge Gases: U.N. "Soaring use of man-made gases used in refrigerators, air conditioners and fire extinguishers risks speeding up global warming and industry should adopt alternatives, a U.N." Scientific American November 21, 2011 by David Fogarty; excerpt ...

On average, HFCs survive in the atmosphere for 15 years and are about 1,600 times more potent in trapping heat in the air than CO2, underscoring growing alarm about these compounds. Combined with rapidly growing CO2 emissions from fossil fuels, this will make it even harder for mankind to try to limit global warming to 2 degrees Celsius -- a threshold that risks dangerous climate change, scientists say. "In the future, HFC emissions have the potential to become very large. This is primarily due to growing demand in emerging economies and increasing populations," said the report by the United Nations Environment Programme released in Bali, Indonesia. ... HFCs are also used to make insulating foams and aerosols. ... HFCs do not damage the ozone layer, which shields the planet from cancer-causing ultra-violet radiation.

See China, India, Brazil, Montreal Protocol,

97.87.29.188 ( talk) 23:56, 21 November 2011 (UTC)

The climate change attribution figure should be removed. It dates back to 2004, and significant diagnostic literature has been published since then that show that models had errors larger than the phenomenon of interest. Stroeve and Scambos described the models as 30 years behind the melting of the Arctic ice cap. Andreas Roesch showed a positive surface albedo bias that amounts to more than 3W/m^2 globally and annually average, and Wentz in the journal Science (2007) showed that none of the models produced even half of the increase in precipitation in the observations. This result was recently confirmed, showing that even the most recent models haven't fixed their under representation of the acceleration of the water cycle.

"The result also suggests that the water cycle is intensifying quickly under global warming—twice as fast as climate models have been predicting." [33]

-- Africangenesis ( talk) 06:57, 28 September 2012 (UTC)

Which 2004? The one in Non-consensus views? William M. Connolley ( talk) 08:02, 28 September 2012 (UTC)

The one that was based on the models later shown to have significant diagnostic issues of course: http://en.wikipedia.org/wiki/File:Climate_Change_Attribution.png -- Africangenesis ( talk) 08:25, 28 September 2012 (UTC)

I took this out ( [34]) twice.

This is the "Attribution of recent climate change" article, and 100 kyr type changes aren't obviously relevant. As I understand it, the T-dust-CO2 correlation comes from desertification and exposure or sea beds and the like during the depths of the ice age, and that isn't clearly relevant to recent change William M. Connolley ( talk) 21:23, 18 October 2012 (UTC)

---

There is no causal relationship inferred by the data or information added. However, the long term data clearly illustrates an inverse relationship between dust(aerosol) and the levels of CO₂ and termperature. Long-term data in considering the attribution of RECENT climate change is absolutely necessary for context and the complete absense of it on this page indicates a clear and consistent effort to use it to present a point of view rather than a complete set of facts.

All aspects of climate change are relevant to recent climate change. One person making a determination that long-term change has no relevance to recent change is not acceptable. The effort to keep objective and complete data off of this page makes it a point of view, which is not appropriate.

"Desertification" refers more specifically to land that is transfomed by deforestation and inappropriate agriculture and is irrelevant to the addition of long term data. Mitigation of desertification is done through land reclamation and the introduction of biodiversity, and not related directly to the long term data. Furthermore, with the exposure of sea beds changing over both short and long term it is relevant to both, but since this is only one factor and one thoery, excluding additional data based on it is inappropriate and further serves to present a point of view. Valid data on climate change, even if it doesn't support the point of view of one person, needs to be evaluated objectively, and it's removal makes this article inaccurate and based on edits/removals on the page, largely the opinion of one William M. Connolley.

You were deleting my edits as I was making them. Please be more considerate of new and accurate information, even it you don't agree with the potential conclusions to which it leads readers. The fact that it was being deleted (twice) while I was editing it shows inadequate level of respect for the input of others on this topic.

And with that, I'm hoping you won't delete it a third time.

--- Mhannigan ( talk) 23:56, 18 October 2012 (UTC)

All aspects of climate change are relevant to recent climate change - no. This is wrong, obviously. And you present no evidence above to suggest it is relevant here. As for "respect" - maybe you should try some yourself? See WP:BRD William M. Connolley ( talk) 06:37, 19 October 2012 (UTC)

--- No, William, that statement is correct, obviously. All aspects of climate change are relevant to recent climate change. I did provide more than sufficient reason to include the data. I'm sorry that you don't agree, but that isn't a good enough reason to remove valid data - what is your reason for removing it?

I understand WP:BRD, which you have not followed: "BRD is not an excuse to revert any change more than once. If your reversion is met with another bold effort, then you should consider not reverting, but discussing."

The first thing you stateed was that you reverted my changes "twice". They disappeared AS I was editing - twice. The avoidance of this type of confusion is one of the reasons you should follow it. And certainly the only justification you've provided is that it's "obviously" not relevent. That's not a proper argument. You haven't offered on real reason for reverting the edit - "obviously" isn't a reason. — Preceding unsigned comment added by Mhannigan ( talk • contribs) 23:49, 22 October 2012 (UTC)

I will explain again - The short term cannot correctly be considered without the CONTEXT of the larger picture. What you say is not logical. There is no way to attribute short term changes without climate change data that can potentially provide a baseline from which one can determine the short term data that is actually anomylous. Your logic is flawed - if we consider very short term data - say two years - if the two years were alike, we could conclude that climate change doesn't exist on any level and therefore there's nothing to attribute. If the years are vastly different, we could conclude something totally different. However, if we put that in context and found that the temperature was the same every other year for 50 years - average A on the even years, Averag B on the odd, the conclusion is completely different and more meaningful. How can you possibly justify removing the reference data? I think that you bear a bit more burden for explaining why you would REMOVE data that in and of itself does not provide a conclusion of any sort, but which may bear relevance to the topic. What is your evidence that that long term climate change offers absolutely no insight into short term climate change? I would love to know.

Under what situation could you justify removing contextual data in a scientific observation? That seems more "anti-science" and the promotion of a point of view. --- Mhannigan ( talk) 23:42, 22 October 2012 (UTC)

--- William - I just saw this link from your user page. You have it linked as "I am famous". http://www.conservapedia.com/William_M._Connolley It reads: William M. Connolley is a British Wikipedia editor known for his fanaticism in promoting the theory of anthropogenic global warming (AGW) and in censoring the views of critics and skeptics. He is the ringleader of the infamous global warming cabal at Wikipedia, a powerful pro-AGW group that has an iron grip on global warming-related articles. Any editors that attempt to introduce factual information that is against their point of view are ceaselessly harassed until they are forced to quit or are banned. Connolley--a Wikipedia editor since 2003--and the group enjoy tacit support from the Wikipedia hierarchy, who often turn a blind eye to the group's misdeeds. This certainly would explain why you are removing factual data.

It has also come to my attention that you are currently under Sanction from Wikepedia regarding reverting changes to Climate Change Related articles? ^[1] Aren't you currently in violation of those sanctions by doing more of the same? --- Mhannigan ( talk) 00:19, 23 October 2012 (UTC)

No, the sanctions have been lifted for non BLP articles. And I would not pay too much attention to attack articles written elsewhere, repeating content from them is not exempt from rules on no personal attacks. Given this dispute is only a few days old before trying mediation why not wait for others to get involved here? I suggest you outline the changes you are proposing on talk first, since the general topic attracts attention, and we can discuss them. -- BozMo talk 05:51, 23 October 2012 (UTC)

It's not intended as a personal attack. Nor is it something I wrote. It is quoted because it is linked directly from the users page as "I am famous". At the risk of overuse of the word - this and other factors provide "context" for the issue at hand - the user has a history of removing valid information that doesn't support his position on global warming. Mhannigan ( talk) 19:23, 25 October 2012 (UTC)

FWIW reading the content, your addition would not appear to be relevant to the article title and more likely to confuse the reader than help. Presumably this content is somewhere else on WP already? -- BozMo talk 05:56, 23 October 2012 (UTC)

Confuse the reader? In what way? By introducing doubt into the conclusion that Global Warming is caused by humans?

Is there any source for the proposed addition? Neither the claim itself nor the relevance seem obvious. Eyeballing the graph, there may be some statistical correlation, but it seems to be a lot more complex than an "inverse relation". -- Stephan Schulz ( talk) 06:45, 23 October 2012 (UTC)

The source was cited in the proposed content. Of course there is more to the story - it's very complicated. An inverse relation does not address a causal relationship - it merly indicates that there is an inverse relation in the data. And I think we agree - you say there may be some statistical correlation. Because it is complex is not a valid reason for exlcuding it, IMO. Mhannigan ( talk) 19:23, 25 October 2012 (UTC)

How far back are you proposing to go in terms of "context"? The climate is a complex system where the long-term is millions or even billions of years; to take this to a deliberately absurd conclusion, the weather we see now presumably is a direct result of the geology and mass of the Earth and its distance from the Sun, however no-one suggests we should go into that in great detail when discussing attribution of recent climate change. Saying "this is relevant to the context" is not sufficient in itself; you have to show why what you are proposing to add is relevant enough to what we are experiencing now to be worth talking about in this article.

What do you mean by no-one suggests we should go into that great detail? No one who? What does No one mean here? No one of the already active editors on this page? I'm suggesting it, so no-one suggests... is no longer accurate. The key word here is "presumably". The long term data, by definition, IS the context. Intentionally eliminating the context is illogical. By this reasoning, let's try to answer your question. What is recent? And where do we draw the line? Using a desired conclusion as a basis for the parameters is bad science. So, what is recent, and can recent data be studied accurately in total isolation? Some Global Warming Advocates choose to use 20 years as recent, some use 50, some use 100. We can change the entire trend to global cooling if we reduce it down to 1 year. The same is true if we 'choose' to study 1940-1950, where the trend reversed for a decade. And you want me to show why it's relevant enough to what we are experiencing now? Self research? Mhannigan ( talk) 19:23, 25 October 2012 (UTC)

That is not to say that long-term trends are irrelevant; they may be. Merely saying "this provides context" is not enough though, there is a burden upon you to demonstrate to other editors why what you are proposing to add is relevant to recent climate change. Please make your case here. And please avoid making personal attacks. -- Merlinme ( talk) 08:33, 23 October 2012 (UTC)

Actually, it was removed because because it is not relevant. Shall I challenge every piece of data on this page by removing it until someone can prove sufficiently to me that it IS relevant. Mhannigan ( talk) 19:23, 25 October 2012 (UTC)

• This seems to be an issue for the #Earlier climate changes section of the article, which itself looks to be in need of revision with more up to date sources. For example, recent studies have investigated the relationship between temperature and CO₂ increases at the start of ice ages. Also, why are we citing The Great Global Warming Swindle as though it has any credence? It might work to rewrite this section to appear earlier in the article as context, but it clearly follows after the explanation of forcings. . . dave souza, talk 10:14, 23 October 2012 (UTC) p.s. should we mention the PETM as a comparable earlier abrupt increase in CO₂ levels, a comparison made by Hansen? . . dave souza, talk 10:18, 23 October 2012 (UTC)

Note that I put the data in the part of the article that states, With virtual certainty, scientific consensus has attributed various forms of climate change, chiefly cooling effects, to aerosols... My original intention with adding the graph is that it SUPPORTS this existing information. That was my original intention. I didn't expect such a backlash from anthropogenic global warming advocates to supress valid data. Look - the data is accurate, it MAY be relevent to recent changes (it's not up to me to decide that), and I added it to support EXISTING information in the article to make it better. I've never seen/experienced this kind of effort to keep valid, pertinent information out of an article. I don't have a dog in this fight. I was just trying to improve the article. I don't have more time to waste arguing with the anthropogenic global warming advocates that are watching over this page. I can't win here regardless of how important the information is to providing the truth. That's why I started the dispute process and that's where I will have to continue. Mhannigan ( talk) 19:23, 25 October 2012 (UTC)

Are you kidding me? Three or four different editors ask you to state your proposal clearly and argue your case, and you write walls of text, treating us if we are all opposing any changes at all, and then say you will be invoking dispute resolution before we've even had a chance to respond? It's not even been clearly demonstrated that there is a dispute, all that's happened is you've decided (without any discussion) that we are The Enemy. WP:NOTBATTLEGROUND springs to mind. Please let us know when you are actually prepared to discuss your proposed changes. Merlinme ( talk) 08:03, 26 October 2012 (UTC)

This is my point, right here. I've written "walls" of text explaining why this data belongs here. And as your response indicates, it doesn't matter what I say in support of it. All I get are comments about how I'm not supporting it correctly, that I shouldn't dispute it, etc. Not a single intelligent thing has been said about why the data should not be included. The fact is that the editor who removed my edit while I was writing it has been under sanctions for the exact same thing for the exact same topic. So when a handful of editors that also maintain this page as a POV jump in and side with his inappropriate removal of the information (twice), I'm not very hopeful that there will be an objective evaluation of the very small addition I made to the article which support what is already there. Note that you didn't address that. Note that not a single person has addressed why they don't think it should be there - though there is no shortage of people making personal attacks. If you would like me to take your comments seriously, please relate them to the arguments I've put forward for the inclusion of the data rather than focusing on reasons why my (cited) additions are invalid by default based on process, procedure, etc. Part of "dispute resolution" is "third party opinon" which is the ONLY part of the process that I engaged. And I think it's appropriate, don't you? Enemies? Merlinme, seriously, it would take a great deal more than a discussion on Wikipedia to make you or anyone else here my enemy. At the risk of sounding like a context advocate (made up), let's keep this in context as well. I mean nothing here to be personal in any way and my opinoins have nothing to do with being an ally or enemy of any sort. The immediate and devisive response I saw from my one edit here is not something I have seen before, and I found it unusual enough to persue. The dispute is that I've tried to have discussion, but there has been no real response except to discourage me. I'm not naive. I'm a big boy. If you do have something to say about my proposed addition, and if you'd like to tell me how we can justify considering the short term data in isolation, I'll be happy to hear it. And if you convince me, I will propose different changes to remove all references to long term data. Mhannigan ( talk) 22:01, 31 October 2012 (UTC)

I asked you if there is a source for the claimed relationship and its importance. You wrongly claimed that the original addition was sourced - what was there was a description of where the image came from, but no source that either supports your interpretation, nor its relevance for recent climate change. Unless you can bring useful sources, I see no basis for a discussion. -- Stephan Schulz ( talk) 22:16, 31 October 2012 (UTC)

Please state, briefly: 1) what you want to add or change in the article; 2) how it improves the article; 3) your source or sources for the proposed change. -- Merlinme ( talk) 08:51, 1 November 2012 (UTC)

Old: http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts/global-climate-change New: http://academic.evergreen.edu/z/zita/articles/climate/ModernGCC03KarlTrenberth.pdf ?? — Preceding unsigned comment added by Paxik ( talk • contribs) 07:21, 9 May 2013 (UTC)

A study has been performed by P.V. Forster in 2007 that utilises the fact that CO2 emitted from anthropogenic sources such as the burning of fossil fuels and deforestation have a lower average mass number than those emitted from natural sources. The study determines the amount of CO2 in the atmosphere that has been emitted from human sources by measuring the average number of neutrons in atmospheric CO2 molecules. The study conclusively showed that most of the CO2 in the atmosphere was produced by anthropogenic sources. This study was extended by G.J. Bowen and others in 2009, which involved measuring the lateral variation of atmospheric CO2 to determine zones of major CO2 sinks and sources.

I would like to propose that this information is added to the Fingerprint studies section for this page. I have several figures and of course references which can be supplied to support these statements. — Preceding unsigned comment added by Michael Dello-Iacovo ( talk • contribs) 11:08, 27 November 2013 (UTC)

You have the wrong page. This one is about attributing observed change to human-released GHG's. There's no doubt at all that the increase in GHG's is human-cuased, so no need for the study you mention.

Technically, your "The study conclusively showed that most of the CO2 in the atmosphere was produced by anthropogenic sources" is wrong, but I think I know what you mean William M. Connolley ( talk) 12:48, 27 November 2013 (UTC)

Land use change has affected CO2 and other greenhouse gasses but is no longer considered a net driver of climate change. This is stated in a number of ways in AR5. Specifically that afforestation has low confidence in mitigating climate change and that land use changes have forcings that offset whatever greenhouse forcings have been created. -- DHeyward ( talk) 17:27, 9 February 2014 (UTC)

D, as I already pointed out, the talk page guidelines frown on starting new threads to argue the same thing at multiple places. See WP:MULTI. It's ok to cruise related pages to post a pointer back main thread on this issue, however. NewsAndEventsGuy ( talk) 18:59, 9 February 2014 (UTC)

These are different statement. GW conflates net effects (wrongly, I might add) of warming. This article states it specifically as a climate driver. This was a change from AR4 to AR5. I thought I'd give editors a chance to read and understand before I made the change and citation. Also, the argument for not changing it was that it could not be cited. It now can. -- DHeyward ( talk) 20:55, 9 February 2014 (UTC)

OK, but if you don't provide greater detail and the citations you can't assume silence is tacit approval. NewsAndEventsGuy ( talk) 21:32, 9 February 2014 (UTC)

From the previous time you brought this up: AR5 WG1 SPM says, in the summary to section B5 (P. 9), "Carbon dioxide concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions." AR4 says, "Global increases in CO₂ concentrations are due primarily to fossil fuel use, with land-use change providing another significant but smaller contribution." [35] From the un-published body of AR5 we get, "Between 1750 and 2011, the combustion of fossil fuels (coal, gas, oil, and gas flaring) and the production of cement have released 365 ± 30 PgC (1 PgC = 10¹⁵ gC) to the atmosphere (Table 6.1; Boden et al., 2011). Land use change activities, mainly deforestation, has released an additional 180 ± 80 PgC (Table 6.1). This carbon released by human activities is called anthropogenic carbon." Section 6.3.1 Does your argument depend on whether CO₂ in the atmosphere is actually a cause of warming? -- Nigelj ( talk) 21:57, 9 February 2014 (UTC)

Since this is not a WP:FORUM I'm less interested in DHeyward's argument and more interested in the detailed proposals for how to improve the article(s).

The citations are in AR5 and others like here [36]. GHG total emissions in tonnage from 1750 has a large component from land use change (the integral). Currently it is only 10% of emissions. Down from 20% in AR4. In the AR5 Technical summary (page 51, figure TS.4). [37] it is pretty obvious that it is no longer a primary driver for "recent climate change" (i.e. since 1950). There is more as the future RCPs pretty much eliminate land use change as a driver. "In addition, the time evolution of the land use change, and in particular how much was already completed in the reference year 1750, are still debated. Furthermore, land use change causes other modifications that are not radiative but impact the surface temperature, including modifications in the surface roughness, latent heat flux, river runoff and irrigation. These are more uncertain and they are difficult to quantify, but they tend to offset the impact of albedo changes at the global scale. As a consequence, there is low agreement on the sign of the net change in global mean temperature as a result of land use change." (page 55, TS.3.4), That includes GHG emissions (which are rather negligible to concrete and fossil fuels). Land sinks have grown since 1750 just as the ocean has.

"In view of the large spread of model results and incomplete process representation, there is low confidence on the magnitude of modelled future land carbon changes. {6.4.3}"

And Box 1.1, Figure 3. The removal of land use CO2 emissions to compare the older AR4 SRES and AR5 RCP's. It also is trying to compare emission vs. concentration models.

Figure TS.4 though is the definitive emission driven case that land use CO2 is not a driver of recent climate change even thought it is a significant source of GHG's since the industrial revolution (1750 with 0 fossil fuel use). Land carbon sinks are also significant. Albedo and non-forcing effects add even more uncertainty but it's pretty clear land use isn't a significant driver of recent climate change (since 1950) and is not expected to be a significant contributor going forward. -- DHeyward ( talk) 00:15, 10 February 2014 (UTC) Picture File:Emissions_ar5.jpg

Dopey me. Yes indeed, page 51 Fig TS.4; NewsAndEventsGuy ( talk) 08:18, 11 February 2014 (UTC)

Ah ha! Does the picture make sense in terms of what are the current/recent drivers of climate change? This is the hard part because the realities of the science of WMGHG's and their sources don't extend favor to traditional allies but still show fossil fuels and cement as the the main culprit. Planting a tree doesn't do squat in regards to the current problem and some research has stated that trees in certain locations are actually worse. IPCC is never going to tell policy makers to not plant trees but if you google statements by timber industries and environmental orgs you will see press releases that state mid-latitude "forest management" reduces global warming (timber industries) and tropical rainforest preservation and afforestation reduces global warming (environment groups). Both are technically correct but they are fighting for crumbs on that graph. The graph is the "Big Picture" of what and where the problem is and it isn't land use, it's fossil fuels and cement. Make sense or am I missing something? -- DHeyward ( talk) 11:42, 11 February 2014 (UTC)

Fighting over crumbs, you say? Some folks think we need all the crumbs we can get. Such folk observe that 1 "climate wedge" out of the many that are needed equals ~14 new nuclear power plants, and say we shouldn't sneeze at mitigation efforts that seem puny, because its the net effort that matters.

But more to the point is that we are wikipedia editors. We need to report what the sources say, not interpret them. I still need to look at the TS in detail. NewsAndEventsGuy ( talk) 12:39, 11 February 2014 (UTC)

Land-use is not clean energy. Clearly replacing fossil fuel usage is top of the chart (they even put it the top so you can see it). Land use contributions to CO2 today and going forward are declining and largely inconsequential. The "crumbs" aren't small pieces, it's statements that tend to throw a bone at group that has been an ally but is not really relevant any more. Both the timber industry and forest preservation groups claimed vindication with recent IPCC reports. They claimed it over the crumbs of CO2 striving to remain relevant when they are no longer so. Both vie for subsidies to support their industry/views and take money from other mitigation efforts like nuclear/wind/geothermal/solar. So look at the chart again and ask what "policy statements" should be made when the science is viewed objectively? The sources say land use is relatively inconsequential and would not do much of anything even if we reverted 260 years of land-use change to 1750 levels. The sources say dialing back fossil fuels only 30 years to 1990 levels would be HUGE. So do we really want to attribute recent climate change to "land use changes such as deforestation" when the sources show nearly no ROI and most likely a much worse "food insecurity" if that did happen? I like and support tropical rainforest conservation and I like trees but because I like them, I am not simply going to ignore the science and pretend it's a realistic mitigation strategy for climate change nor listen to organizations that get money for promoting those non-scientific views. Those groups get their talking point bone of the integral ("Since 1750, the largest contributors to CO2 are.... So send us money to plant a tree and help save the world from Climate Change.") while they ignore the underlying science. Subsidizing tree farming, rainforest protection or people buying carbon credits by planting a tree to pay for fossil fuel is not mitigation. It's nonscientific, special interest fluffery. -- DHeyward ( talk) 19:03, 12 February 2014 (UTC)

One climate wedge out of the 15ish that the RSs say are required means building ~15 or so nuclear plants a year and replacing several others. IPCC says land use is 10% of emissions. It wouldn't be hard to standardize those units (climate wedge vs 10% actual emissions). Point is, to offset land use would take a bunch additional nuke plants, and my saying so is for illustration purposes only... the idea is to demonstrate that 10% of total emissions due to land use is still a whopping load of emissions, even if the gross emissions from land use really are less than they used to be. More importantly we don't pass judgments here on what policy statements should be made. Instead we follow sources. Since land use appears in IPCC AR5 WG1's SPM as one of the main emission sources (after fossil fuel and cement manufacture) your claimed expert opinion isn't going to trump that RS, sorry. Even the figure you posted shows IPCC still attributes 10% of emissions to land use changes. And I don't see IPCC saying "stop worrying about land use", nor does any other source you have cited say "stop worrying about land use". Instead we have your spin about what the sources say, e.g., where you interpret them to mean "Land use contributions... going forward are .... largely inconsequential." Show us RSs that say that please because I'm not really interested in your personal predictions. NewsAndEventsGuy ( talk) 19:30, 12 February 2014 (UTC)

(Somewhat later) it occurs to me that if you are interested in the efficacy of individual actions of various sorts (e.g. tree-planting), there are plenty of RSs that talk about that subject. Have you considered working on that topic at Climate change mitigation? NewsAndEventsGuy ( talk) 00:20, 13 February 2014 (UTC)

In an earlier comment in this thread, DHeyward wrote "land use CO2 is not a driver of recent climate change even thought it is a significant source of GHG's since the industrial revolution". However, the sources seem to say that CO2 has a very long lifetime in the atmosphere... if I understand it all correctly, plenty of 1750 CO2 emissions have escaped the various sinks and are still in the air "driving" climate change today. NewsAndEventsGuy ( talk) 19:55, 12 February 2014 (UTC)

I never said it wasn't an emission source. I said it's not a driver of recent climate change. Fossil fuels are. Lifetime of CO2 has to do with permanent uptake for sequestration in the long carbon cycle. You can see the bi-annual difference (and diurnal) in the fast carbon cycle in CO2 N Hemisphere respiration in the Keeling curve. There are also carbon dating of atmosphere as living things that respire replenish carbon while fossil fuels and lime do not. Land use change is generally living organic matter already part of the cycle. Fossil fuel and lime sources are not living. One of the "fingerprints" of anthropegenic CO2 is the change in isotope levels due to fossil fuels and lime. And oldie but a goodie is here. The key thing to take away from that is atmospheric carbon cycles back and forth rapidly so no volume of CO2 stays in the atmosphere. Once in the atmospheric cycle of life, carbon dating can be done because of that cycle. In reality, probably 90% the atmospheric carbon "excess" from 1750 is from fossil fuel and lime (cement). They don't even notice radiocarbon footprint (or warming) until 1850 which is expected. If you want simple maths, in the SPM, page 12, land use change added 180 GtC to the atmosphere and land reuptake was 160GtC (so net 20GtC since 1750 - maths not work this way, but okay for BOE). There's 240 GtC of anthropogenic CO2 remaining in the atmosphere. 20GtC out of 240 GtC is roughly 9% (which is the emission percentage). That's exactly the kind of number you'd expect in a rapidly respiring world. Here's another source showing the fraction of carbon that remains in the atmosphere from anthropogenic emissions is relatively constant at 43% (sinks are proportional to emissions as shown on the graph) over short time spans (annual). The fast carbon cycle (up to 100GtC cycled through the system per year) keeps up with emissions at that rate leaving the 43% remainder in the atmosphere. This will tend to force the fractional concentrations from sources to equal their fractional emissions very quickly. What that means is if the emissions from land use are 10%, their fractional component of concentration will be 10% depending on the rate of mixing (100GtC/yr or about 100x the rate of land use emission). Make sense? -- DHeyward ( talk) 01:58, 13 February 2014 (UTC)

The point here isn't that land-use change emits CO2 (it does). The point is there are no sources that say it's a driver of recent climate change. It's declining in both percentage and tonnage of CO2 emissions and has large error bars and low confidences on net values. Coupled with other land-use change effects, the sources quite clearly say it's around 0 W*m^-2. I've pointed that out many times. 0 W*m^-2 isn't driving the climate anywhere. Page 13 of the SPM title "Drivers of Climate Change", 10% of 1.68 W*m^-2 is about 0.168 offsetting albedo surface changes of 0.15. (I'll the exact "as likely as not" quote I've cited before. ) -- DHeyward ( talk) 02:29, 13 February 2014 (UTC)

Section: "Effect of cosmic rays"

Henrik Svensmark has suggested that the magnetic activity of the sun deflects cosmic rays, and that this may influence the generation of cloud condensation nuclei, and thereby have an ******affect****** on the climate.

(should be "effect")

Fixed, thanks. -- Merlinme ( talk) 10:43, 3 March 2014 (UTC)

We can use page 5 William M. Connolley ( talk) 21:06, 5 March 2014 (UTC)

Also available as http://royalsociety.org/policy/projects/climate-evidence-causes/question-2/ William M. Connolley ( talk) 21:09, 5 March 2014 (UTC)

FYI this article was mentioned at Talk:Global warming#Should "Evidence of global warming" really redirect to "Attribution of climate change"? NewsAndEventsGuy ( talk) 18:30, 20 March 2014 (UTC)

The following sectionhas been erased,

• At the time of establishment of the United Nations Framework Convention on Climate Change UNFCCC, there was as yet no indication of a clear signal of anthropogenic warming in the observations, as per the IPCC First Assessment Report (FAR) in 1990. Thus the observed increase could be largely due to this natural variability; it wasn’t until the IPCC’s Second Assessment Report in 1995 that the IPCC consensus maintained a ‘discernible’ human influence on global climate.

What is being deemed wrong with it? Serten II ( talk) 00:00, 17 December 2014 (UTC)

Well, it wasn't just that edit you made, was it? You made quite big changes to a controversial article without testing consensus first. Your edits included a spelling mistake and some debatable grammar changes, which isn't going to help.

If you want to argue for the inclusion of that particular paragraph, please explain: a) why it's necessary and helpful to the article; even if it's true, does it make the article clearer or less clear? b) If it is helpful, is it needed in the lead? c) Please could you provide a good source for your summary of the IPCC First Assessment Report. I just had a quick look at the Wiki article, which says e.g. "emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases: CO2, methane, CFCs and nitrous oxide"; "Thus the observed increase could be largely due to this natural variability; alternatively this variability and other human factors could have offset a still larger human-induced greenhouse warming. The unequivocal detection of the enhanced greenhouse effect is not likely for a decade or more." So as far as I can see they said they were confident that humans were causing an enhanced greenhouse effect, however they weren't certain how much, and they couldn't unequivocally attribute the enhanced greenhouse effect to humans. Is your paragraph a reasonable summary of that? I'm not sure it is. The difference between the First and Second reports seems to mainly be a matter of certainty, they thought humans were almost certainly causing warming in 1990, but they were even more certain in 1995. -- Merlinme ( talk) 10:39, 18 December 2014 (UTC)

Ask scholar: [38]. First two entries the reports itself, third (first secondary source / third party) R. Grundmann - Environmental Politics, 2007. That would be a suitable scholarly source. Crutzens “Anthropocene” as of 2006 is on the same line, as well Paul N. Edwards and Stephen H. Schneider The 1995 IPCC Report: Broad Consensus or “Scientific Cleansing”? Ecofable/Ecoscience 1:1 (1997), pp. 3-9, quote Nevertheless, the balance of evidence suggests that there is a discernible human influence on global climate. (in the SAR) marked the first time the IPCC had reached a consensus on two key points: first, that global warming is probably occurring (“detection”), and second, that human activity is more likelythan not a significant cause (“attribution”). That said, the difference is rather distinctive: The FAR did not acknowledge a discernible signal beyound natural variability, but urged for action based on the precautionary principle. A discernable human signal started to be identified with the SAR, but not earlier. In so far I ask to reinstall the entry. Serten II ( talk) 02:02, 19 December 2014 (UTC)

As Serten appreciates, the [draft] article is now at User:Serten II/IPCC consensus for improvement. The topic is covered rather better at Weart's history, the point is that studies in the 1990s tackled the attribution, with Santer's "fingerprint" approach convincing climatologists followed by the arguments to get IPCC member governments to accept that human influence was "appreciable", watered down in negotiations to "discernable". [39] . dave souza, talk 16:32, 19 December 2014 (UTC)

So what? Spencer R. Weart provides some details and confirms e.g. Jean Goodwins finding on the role of the Villach meeting in developing and using the consensus in the political realm. You stay in the tekkie realm with that. Point is, international politics got aware of the greenhouse effect as early as 1969, take Nixons Nato initiative 1969, confirming the Collins & Evans' rule on scientific consensuses. Weart has no background or idea of that. Just another physicist. Serten II ( talk) 21:07, 19 December 2014 (UTC)

Really? You seem to have access to information but give the unfortunate impression that you're just another social scientist trying to fit everything into a political realm. Let's try showing the scientific development first. Got detailed proposals? . dave souza, talk 21:29, 19 December 2014 (UTC)

Changes a while back in the CS1 templates resulted in some error messages in the Attribution of recent climate change#Notes section. Stamptrader recently made some changes to suppress those messages. However, these changes were sub-optimal, so I have reverted them, pending a deeper look into this to find a better way. To be continued. ~ J. Johnson (JJ) ( talk) 23:13, 10 March 2015 (UTC)

There's a nice pic at http://www.realclimate-backup.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/?wpmp_switcher=desktop that we could perhaps use ( http://www.realclimate-backup.org/images/attribution.jpg to be specific) William M. Connolley ( talk) 22:49, 8 December 2015 (UTC)

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