Talk:Climate change/Archive 13

models have systematically higher albedos than the observations!
By reflecting too much solar energy into space, models parameterized to match the warming of recent decades would attribute warming caused by that energy to something else, probably attributing to greenhouse gasses, warming that was actually due to solar energy. Here is a quote from the abstract:

"Yet, given the present calibrations, a bias is found between different estimates of α, with modelled global albedos being systematically higher than the observed."

Can anyone find access to the full text? The effect of this model bias is probably to increase model sensitivity to CO2 doubling, since the CO2 is having to match the temperature record and has to do it by trapping less solar energy than is actually available. The albedo of deserts and snow cover appear to be particular problem areas. You should not be surprised when results that are in conflict, such as the model and paleo climate sensitivities to greenhouse gases and solar activity, start to converge in later work. Physical reality is supposed to make sense, and such conflicts are natural areas for further research in an attempt to either explain or correct the conflicts. --Poodleboy 12:53, 28 April 2006 (UTC)


 * By reflecting too much solar energy into space, models parameterized to match the warming of recent decades would attribute warming caused by that energy to something else, probably attributing to greenhouse gasses, warming that was actually due to solar energy - sorry, don't follow your reasonning. And it is *your* reasonning - no? Not in the article. So not in wiki either, thanks William M. Connolley 20:29, 28 April 2006 (UTC)
 * It is basic science william, if you fit a model to warming data with one warming contribution underrepresented you must be overrepresenting other warming contribution(s). I hope you are not going to be obtuse.--Poodleboy 01:02, 29 April 2006 (UTC)
 * Nope! The albedo estimates may have been wrong from the beginning, i.e. even for pre-industrial times. That means that the whole temperature balance of the earth shifts a bit, but not necessarily the warming (which is a delta on top of the "natural" balance).--Stephan Schulz 01:07, 29 April 2006 (UTC)
 * The warming is not being questioned. This isn't about paleo data, the albedo of the models is being compared to the satellite data for the same time periods.  What the models failed to attribute to the Sun, they must be attributing to something else.  Even with the bloated predictions, global warming never was the threat to humanity that near earth objects are. Perhaps, this will provide some impetous to getting our priorities straight.--Poodleboy 01:30, 29 April 2006 (UTC)
 * This paper isn't about attribution. Please read WP:NOR. And what does fit a model mean? William M. Connolley 08:09, 29 April 2006 (UTC)
 * There is no getting around it. The paper is about the models being wrong, and reflecting too much solar energy.  To say that doesn't have anything to do with attribution is denial.  The models were parameterized to fit the 20th century data.  Since they are wrong on solar, they can't be right on their ability to model the recent warming without also misattributing.  To claim the attribution is still correct is denial and worse than original research.--Poodleboy 16:57, 29 April 2006 (UTC)
 * The bottom line is that, as NHSavage said below, we won't know what effect this actually has on the models until we take the time to correct it and rerun the models accordingly. To claim to know anything about how this changes GW predictions is OR. We clearly can't run the complicated mathematics in our head. From what I can tell from the abstract, the authors make no speculation about what effect this has on the overall phenomenon, and neither should we. E WS23 | (Leave me a message!) 17:06, 29 April 2006 (UTC)


 * Note also that the abstract does not mention the size of these biases. I might be able to access this from work next week but it should also be noted that the article states "models appear to over-estimate the albedo during boreal summer and under-estimate it during austral summer" so this is not a simple question of over estimating it everywhere. If the albedo is lower than in the GCMs then more energy is absorbed at the surface. This means there would be more (not less) IR and so the sensitivity to CO2 would be greater not smaller (CO2 hardly absorbs in the visible). So this is the exact opposite your argument Poodleboy. Having said that, my hand waving is almost certainly wrong given the complex dynamics of the climate system and the fact that there seem to be differences between hemispheres and the fact that it is only hand waving and not a calculation. The real test would be if someone put these revised values in a GCM and did some experiments (which for all I know is the authors next paper).--NHSavage 21:21, 28 April 2006 (UTC)
 * I've read elsewhere the the biases are towards a 1 to 2% higher albedo, i.e. 1 to 2% more of the Sun's energy as a global annual average is being reflected off into space by the models than is observed by the satellites. The effects are very regional because the errors in the physics are regional.  The models are doing somethings well.  In certain regions the albedo may be lower, but it is the higher global average that gives the net effect.  Please let us know what you find in the full text.  It will be interesting to see the responses and corrections of modelers.  I how much they will be able to fix before the next IPCC report, they should fix things if they want any credibility.--Poodleboy 01:05, 29 April 2006 (UTC)
 * The credibility of the models does not depend on them being able to reproduce one specific set of measurements. Model validation is about how well they are able to reproduce a very large set of observations both of specific things like El Niño and observational records over various timescles see for example chapter 8 of IPCC TAR or this page at Real Climate . What happens is that when the models and observations do not agree is not that the models are simply changed to fit the data but both the models and observations studied in greater detail. This often leads to a better understanding of the physics of the system which is then used to improve the models. This paper on albedos is just the latest example of this process in action. As for the details of the paper the first thing which needs to be understood is that this paper it is about the overall albedo. The differences between the models and the observations is therefore connected to the vegetation, snow cover, clouds and aerosol (plus other processes I am sure) in the models and not just the albedo of specific types of land for example. This means it is not as simple as just 'fixing' the albedo. Which part of the models do you suggest is changed to fit this dataset and how does that impact on other parts of their performance? A couple of final points: the difference between the 2 satellites is also very large which indicates that there are significant uncertainties assocaited with the  measurements - as the authors note this "illustrates the insufficient accuracy of albedo levels that currently available measurements can supply". This is why their conclusions are twofold: that they hope this work facilitates the improvement of GCMs and that the observations will be refined. In summary the authors do not say "models are wrong" but that there are problems with both observations and models and that this is liekly to be a highly productive area for future research. Oh and no - the models will not be changed before IPCC4 - these model runs are the ones used to support that report. It is far to late to make changes for IPCC4 as the first draft underwent expert review in late 2005 and the second draft is now undergoing simulataneous expert and goverment review (until June 2). After that a final draft will be prepared, be sent to governments for review and then approved by the working group with line by line approval required for the summary for policymakers. It will finally be published in 2007. --NHSavage 15:13, 30 April 2006 (UTC)
 * Thanx for the details about the paper. I suggest that the modelers make the albedo fit the satellite data, and then they should change whatever else they have to, to fit the other data we have.  The models are not doing ab initio physics, they are doing parameterizations of the physics to fit they experimental data in all areas that are thought to impact the climate.  The satellites results may differ from each other, but they differ less from each other than they do from the average of the models and some of the models are real outliers on albedo.  The credibility of the models is effected, yes their credibility is helped by exhibiting climate like behavior, such as el Nino's and seasons.  But this report impacts their credibility on solar/GHG attribution, and their credibility is hurt by over 2 fold variation in sensitivity.  Maybe the IPCC4 beaurocracy is going to chug forward with bad data, but their conclusions about attribution, and any predictions based on CO2 scenerios should be significantly muted.  I am participating in the WG1 process, so I am privy to other publications which also are bear on these matters.--Poodleboy 17:54, 1 May 2006 (UTC)
 * So getting the temperature, rainfall or other parameters right don't matter then? Why is albedo more important than all these other parameters? Why do you say the models are wrong and the satellites right when the paper just argues that they are inconsistent? Actually one set of satellite data overlaps the the bottom end of the modelled values so it is misleading to say that the satellites differ less from each other than from the the models. All climate models are based on the basic physics of the system not parameterisation. Why do you think they are just parameterisations? Have you ever studied the way a climate model works and the physics they include? Do you care? Yes all models are imperfect and constantly being improved but to pick one set of data and argue that the models are therefore useless is bizare. The IPCC4 is not using bad data but state of the art climate models which will thoughtly evaluated as part of the report. If the models were completely wrong they would totally fail to be able to reproduce the climate of today, let alone the last glacial maximum and other paleoclimate climate data.--NHSavage 18:31, 1 May 2006 (UTC)


 * I say they are parameterized, because except for the fluid flows, mass and energy balances and some thermodynamic constraints, they are not modeling the actual physics. I am not saying it is a useless process, but modeling the climate is still in its infancy as these and other huge errors indicate.  Things like the albedo and vegetation are highly parameterized, even though they vary as a function of the climate.  The forest, in winter snow and in the summer is represented by parameters, the trees and the snow on the branches right after a storm are not modeled, although these subtleties could be parameterized also. Yes I have studied modeling of the ocean as well as chemistry, seismic, electromagnetic and shock hydrodynamics.  The models reproduce the climate of today because they have been fitted to today's climate, but because you can make the energy balance by compensating for errors in solar, with errors in GHGs, aerolsols, etc does not mean that modeling will be right in predicting a future in which one of these erroneous components doubles.  Perhaps you and I just have a different definition of "physics".  Do you really think the models are doing electromagnetic calculations of of the interactions of sunlight with sand and hot air in order to get the albedo of the surface and reflection off the mirages caused by thermals?  Or do you admit the albedo is parameterized?  It is a rhetorical question.  We both know the answer.--Poodleboy 19:52, 1 May 2006 (UTC)
 * OK now we are getting somewhere. You say the models are not modelling the actual physics 'except for the fluid flows, mass and energy balances and some thermodynamic constraints' in other words most of the key processes! All processes in all computer models including those used for weather forecasting and for sending satellites into orbit are approximations. That is not the question. The question is are the climate models appropriate for predicting future climate given certain scenarios on future CO2 etc. They are not as you assert just 'fitted to todays climate' - they are tested against today's climate but in the TAR it is stated "A reasonable simulation of a limited set of past climate states (over the past 20,000 years) has been achieved using a range of climate models, enhancing our confidence in using models to simulate climates different from the present day." and it is certain they will have improved further since then. As you admit the central processes are based on well understood physics. There are simplifications and parameterisations of some processes of varying degrees of sophistication. However just because a model contains approximations and parameterisations means it is invalid. The different models contain different parameterisations and so we gain insight into the sensitivity of models to these parameterisations due to the different model approaches. That is why this article does not state that temperatures will increase by 3.6 °C between 1990 and 2100. It is very clear: "global temperatures may increase by 1.4 to 5.8 °C between 1990 and 2100.". The models are approximations to the real world but they are not just tuned to 20th century climate as you keep asserting (without proof) but have a basis in well understood physics and have been evaluated with multiple sets of observations (not just albedo) and against past climates. If you want Wikipedia to say that because the climate models don't include the effects of mirages the errors make them untrustworthy please find a reference for this not just your own arguments.--NHSavage 20:54, 1 May 2006 (UTC)
 * I think the parameterization is necessary and will eventually produce something useful. The models produce realistic seeming behaviors, that even give insight into some phenomena, but they still can't reproduce the multidecadal ossilations, and over the last 20000 years, CO2 is not as important to the climate as it will be for predictions over the next 100 years.  It is the law of small numbers.  With smaller amounts of CO2 the errors are smaller, and so the approximate agreement with a paleoclimate which is itself known with less certainty than 20th century data is not that surprising.  Yes, the physics is in the most key processes, so something that looks like climate results.  But if you put bad data  into those key processes via erroneous parameterization you still get bad predictions. For the uses the people want to prematurely put the models to, you can't be throwing away 1% or more of incident solar energy.  The predictions might well be good, if the scenerios were just continuations of the forcings the parameterization was fitted to.  But that would be just predicting todays climate.  It might also be easier to get the albedo right during a glacial period.--Poodleboy 21:25, 1 May 2006 (UTC)
 * "I think the parameterization is necessary and will eventually produce something useful" - so I assume you never look at the weather forecast then? Why are you rejecting the conclusion of IPCC TAR that "Coupled models have evolved and improved significantly since the SAR. In general, they provide credible simulations of climate, at least down to sub-continental scales and over temporal scales from seasonal to decadal. .". Are the authors mad, bad or corrupt in your opinion? I also notice all the points you make seem to be your own opinion, can you provide any evidence to support your opinions?--NHSavage 21:33, 1 May 2006 (UTC)
 * I think weather forcasts are great, the 7 day forcasts are right surprisingly often, although not nearly as good as the two and three day forcasts, what is your point? I agree with the particular IPCC TAR statement you quote.  The models were much improved, and produced realistic looking climate, and I will go beyond that, the models are much better now than then, but much better is still neglecting a lot of solar energy, and they have produced a wide range of CO2 climate sensitivities, that are too difficult to reconcile with the paleoclimate senstitivites, and the model sensitivities are even difficult to reconcile with each other. For evidence to support my opinion, look at the wide range of model sensitivities cited in this very article (from the TAR), a factor of over 2.5. Solar and orbital variability explains most the paleo climate record.  Even within this article there is peer reviewed work, where the solar attribution of late 20th century warming is as high as 36% based on models and varies by a factor of two.  This is well before this paper we are discussing found that too much solar energy is being reflected into space by the models.  Which of the evidence I have cited do you think is "opinion"?  You can read it for yourself.  Perhaps you are not used to evidence that is as forceful as opinion.--Poodleboy 07:35, 2 May 2006 (UTC)
 * The point about weather forecasts is that the forecast models and climate models have very large parts of their code in common. "they have produced a wide range of CO2 climate sensitivities" - indeed this is true and is in the article. However I fail to see what your point is. The article makes this range of sensitivity clear. Please answer my original question - what evidence do you have to refute the statement in IPCC TAR that the models are credible (not perfect, not even as accurate as would be desired but credible). If you accept the models were credible then and are now further improved (and will continue to improve partly by addressing this albedo issue) then what is the problem with the article?--NHSavage 20:26, 2 May 2006 (UTC)
 * You are extremely interested in an ambiguous statement. One would not formulate a testable hypothesis with the word "credible" as a key part of it.  In my mind the models became credible (in a sense) when they started independently reproducing certain features of the climate, such as el Nino's and monsoons.  They became useful for formulating hypotheses based on possible insights gleaned from their behavior.  Agreeing that they are credible at this level, is a far cry from agreeing they can make credible predictions about the future based on scenerios where one small component such as CO2 is blown up to more than twice current levels, and they are especially incredible in light of evidence that they have errors in the basic physics larger than the changes in results they are trying to elucidate.--Poodleboy 02:09, 3 May 2006 (UTC)
 * Fine lets use a less ambigous one - "We consider coupled models, as a class, to be suitable tools to provide useful projections of future climates.". IPCC4 will almost certainly strengthen this statement because, as you admit, they have improved further. Do you have a peer reviewed reference which refutes this statement?--NHSavage 07:27, 3 May 2006 (UTC)


 * restart indent Now you're talking.  That is the statement that would be premature, even today.  How can you explain or defend it?  Yes, we know more today about how wrong the models are, but back then there were many clues about how little they knew, yet they speculated anyway.  We know already that models reflect too much sunlight when compared with observations, yet there are suggestions that aerosols may be twice as reflective as the physics currently parameterized in models, so when they correct that the models will have even higher albedo.  How wrong does the physics have to be to arouse a little more healthy skepticism? --Poodleboy 03:30, 4 May 2006 (UTC)
 * The point is not that I have to prove this statement because it is published. I do not publish original research in wikipedia. You have to provide a reference which says that this conclusion from IPCC TAR is wrong. Please remember this is wikipedia not a discussion group.--NHSavage 07:06, 4 May 2006 (UTC)
 * I think you confuse the IPCC process with peer review. The people who wrote that statement are stating their opinion of the state of the science.  While in part of the process they receive comments on the statements they propose, the can and do ignore many of those comments.  The product of a committee such as this is not peer review.  Now, I have been discussing the science, and you have been repeating IPCC statements like mantra's.  If you read the IPCC TAR at all you will see that even at that time they knew that cloud physics a weak area, that the fit of the models to the data was much better with solar data, even though the models were also telling them that solar variability accounted for little of the warming, they knew that they did not have much information about the impact of the thermal inertia of the ocean, they knew that the climate sensitivity to CO2 in the paleo record was much lower than what the models showed over much shorter time frames, so they knew  that on some time scale there must be feedback mechanisms that moderate CO2s effects.  Yes, perhaps the models could be right over these shorter non-equilibrium time frames, but they don't know that the feedback mechanisms don't work over shorter time frames as well.  Despite, all this which they acknowledge in the separate reports, the committee at the top decided to make the statement you repeat.  Obviously, the opposite conclusion could easily also have been made, so I am not surprised you are unable to explain it.  Note, that I criticise the statement based on evidence they knew and acknowledged (or at least lower committees in the political hierarchy acknowledged) at the time.  The statement is now out of date, there have been improvements in the models, yet we have even more information about how wrong and at variance with each other and the data they still are.  They are remarkable achievements, yet still are not ready to be trusted with attribution or predictions.--Poodleboy 07:27, 4 May 2006 (UTC)
 * The threshold for inclusion in Wikipedia is verifiability, not truth. This means that we only publish material that is verifiable with reference to reliable, published sources.. I have provided this - can you?--NHSavage 13:33, 4 May 2006 (UTC)
 * You know, I did start this thread with reference to a peer reviewed article. You can also find a reference to the Nature article on the reflectance of aerosols perhaps needing to be doubled, in the article.  I've read that Nature article, although the cite given in this article is to a Chinese newspaper that discusses that article, and I've read much of the tar. I've also read several of the full text journal articles discussed in this article.  Yes, going with peer reviewed results rather than just the opinions of the IPCC committee is more about truth.  But you will also find that peer reviewed results should be a little more verifiable, than "We consider coupled models, as a class, to be suitable tools to provide useful projections of future climates.",  which is pure opinion and not verifiable at all.--Poodleboy 18:55, 4 May 2006 (UTC)
 * Look you have clearly a strong opinion on this. I am not disputing there are significant errors in the models. What I want to know is a) what change do you think should be made to this article and b) what publication which supports this change do you want to cite?--NHSavage 19:55, 4 May 2006 (UTC)
 * I'm not shy, I don't have a change ready for the article at this time, when I do, I'll make it. I am waiting for a prepub article I am familiar with from my WG1 work to be published. The work has been presented at various conferences, but I want to be able to use the peer reviewed versions.--Poodleboy 09:44, 5 May 2006 (UTC)

look at the wide range of model sensitivities cited in this very article... not sure which you mean. Can you be more clear? Late solar... nah, implausible. If you want to quote text from the paper, fine, but you're not, you're drawing your own conclusions, which is not fine. William M. Connolley 08:55, 2 May 2006 (UTC)
 * There are a couple external references to climate sensitivity articles in the intro. But the figures I had in mind are actually referenced on the Climate sensitivity article: "likely to be in the range of 1.5 to 4.5°C".  I conclude that 4.5 is more than 2.5 times 1.5.  Follow?--Poodleboy 11:43, 2 May 2006 (UTC)
 * I thought that was likely your mistake. The article gives no values at all for clim sens - 1.4 to 5.8 °C isn't, for example. 1.5-4.5 is *not* a range of sens from modern GCMs. Though I will grant you there is scatter from them William M. Connolley 20:56, 2 May 2006 (UTC)

Hi, I'm not really tracking the details of this discussion but it strikes me that some part of the above discussion should be added to an appropriate Wikipedia article, perhaps climate models or global climate model?
 * --Richard 20:08, 1 May 2006 (UTC)


 * Providing the original research is left out... William M. Connolley 20:28, 1 May 2006 (UTC)

Please review "Geoengineering" section in Mitigation of global warming
Hi guys,

Someone recently made an edit to the "Geoengineering" section of the Mitigation of global warming. Frankly, all of this sounds like pseudo-scientific fantasy to me. What bothers me is the references to IPCC and NAS in this section. I'm not knowledgeable enough to say that it is or is not tripe. It just smells fishy to me. Can someone more knowlegeable take a look and evaluate how encyclopedic this stuff is? At the very least, verify whether references to IPCC and NAS are valid and appropriate.

Thanx.

--Richard 17:59, 4 May 2006 (UTC)


 * It is a speculative proposal that is being evaluated. Probably a better cite should be found.--Poodleboy 19:04, 4 May 2006 (UTC)
 * Section 4.7 of the IPCC WGIII report does mention these options but without including costs and hardly any detail. That report references the NAS report: NAS (National Academy of Sciences), 1992: Policy Implications of Greenhouse Warming: Mitigation, Adaptation, and the Science Base. Panel on Policy Implications of Greenhouse Warming, U.S. National Academy of Sciences, National Academy Press, Washington DC, USA.--NHSavage 19:12, 4 May 2006 (UTC). The NAS report is online aleit in a nasty format.--NHSavage 19:23, 4 May 2006 (UTC)


 * Please check out my comment on Talk:Mitigation of global warming. I think the text that has been recently added to the article is getting a bit unencyclopedic in tone and lack of citations.--Richard 19:26, 4 May 2006 (UTC)
 * I've decide to revert. See talk page of that article.--NHSavage 19:44, 4 May 2006 (UTC)

Water Vapour
Even if users don't believe that WV is a prominent cause of our (reported) recent increase in temperature, it is a greenhouse gas in that it contributes to the greenhouse effect (keeping the planet warm). If all of the H2O were to be removed from our atmosphere, we would be very cold indeed, and I believe that this decrease in temperature would prevent (or slow down substanstially) the evaporation of more water from the oceans to replace this lost water. It works the other way as well - when we get more H2O in the atmosphere, the temperature of the land and atmosphere itself is increased, so less precipitation will occur (water needs to cool and condense to precipitate - (see water cycle). As stated on other talk pages, excess water in the atmosphere doesn't just "fall out of it as rain or snow" - how can it if the temperature has risen to such an extent that little rain occurs?  I belive that a mention of WV in the "Greenhouse Gases" section of this article is required, both for the reasons stated above, and the fact that it is cited as a greenhouse gas on Greenhouse gas, which this page should surely agree with in order to avoid substantial confusion on the part of the researcher. Martinp23 21:26, 4 May 2006 (UTC)


 * Ah good, the clearlight nonsense is gone. But, how about reading the GHG page? That explains the position clearly, and that in turn explains why WV isn't mentioned here - its a feedback not a forcing, so there is no point talking about it in terms of explaining recent warming. This page is long enough as it is without bringing in irrelevances designed to confuse William M. Connolley 21:34, 4 May 2006 (UTC)
 * (edit conflict) Water vapour is in a dynamic equilibrum in the atmosphere. It's predominant state at the range of temperatures and pressure we have on Earth is liquid (or even solid). That means that the relative humidity of the atmosphere is more or less constant. Under normal conditions, excess water does indeed fall out in the form of precipation, and missing water vapor is quickly replenished by evaporation (after all, 70% of Earth's surface is covered by water). That's why we say "water has a short atmospheric life time", unlike e.g. CO2, which is a gas and mixes with the atmosphere in any concentation. Now, as you have stated, water vapour is a potent greenhouse gas. If temperatures increase, the air can carry more water at the same relative humidity, and hence the absolute amount of water vapor increases, and with it the greenhouse effect. Thus, water vapour does tend to amplify a pre-existing warming trend, it does not cause it. Moreover, the overall effect is limited, because the atmosphere is already fairly opaque at the frequencies water vapor absorbs (William, do you have some something about the details?). --Stephan Schulz 21:44, 4 May 2006 (UTC)
 * While naming water vapor as a greenhouse gas would not be wrong, it would be tremendous understatement of its role in the climate. Because water undergoes phase changes in the temperature regime of earth's climate, it has a central role in both vertical and horizontal energy transport, both in its liquid and vapor forms, and equally important for albedo, in clouds, ice and the oceans, and plays is a key intermediate input in the parameterization of the feedback responses of vegetation to climate.  Climate is determined not just be temperature, but by precipitation and the seasonality of both.  So, water vapor and its phase changes are what is being studied and modeled in climate science.  Don't think for a moment that anyone is ignoring it.--Poodleboy 10:06, 5 May 2006 (UTC)

Potential positive effects - bleech
Can somebody read this section and evaluate whether it is as bad as I think it is? My attention was drawn here by the latest edit which was to add "It will likely increase global biomass." By itself, the edit improves the text but that's like arguing that whipped cream will improve a burned caserole. Whipped cream improves everything but it can't save a burned casserole. The text about increasing global biomass seems to be a hopeless mess in need of rewriting.

Or frankly, the whole section on biomass should be deleted unless someone explains why an increase in biomass is a positive effect. I think the idea is that increasing CO2 increases biomass which absorbs CO2 and thus mitigates global warming. If that's the point, then the section should be rewritten to say that up front.

As it is, the section seems to be a back and forth debate between two or more sides of the issue. It reads like a conversation, not an encyclopedia article.

Would it be too much to ask for some sources and citations?

Fix or delete, please.

--Richard 16:53, 6 May 2006 (UTC)


 * Actually there isn't enough evidence to determine whether increased CO2 will increase biomass. This is based on the assumption (a) that plants are primarily carbon limited (as opposed to nutrient limited), (b) that increased biomass won't be balanced out by increased herbivory and (c) that space won't limit increased plant growth.  But, it's true, that people have claimed that increased plant growth will be a "benefit" of GW, so it should be in there (albeit with an explanation).  Guettarda 17:00, 6 May 2006 (UTC)
 * It is more multi-factorial than this, for example, increased CO2 helps conserve other limiting resources such as water, through reduced transpiration losses, or increasing growth for the same amount of water.--Poodleboy 14:50, 7 May 2006 (UTC)
 * ...at least for one kind of desert plant analysed in one study, unless I'm mistaken.--Stephan Schulz 15:22, 7 May 2006 (UTC)
 * There was just recently a report (letter?) in Nature on increased river flow worldwide, explained as a result of this effect. Abstract. Graft 05:03, 8 May 2006 (UTC)

It's far more complicated than that, which gets back to my original point, that there isn't enough evidence to determine whether increased CO2 levels will cause increases in biomass. Part of that relates to the issue of WUE. Pb is correct - increased CO2 levels result in an increase in the amount of carbon fixed per water transpired. Higher CO2 levels allow plants to fix more carbon. The prediction of increased biomass is based on the idea that the plants will funnel this increase in carbon into growth. The alternative is for the plants to close their stomata sooner. Under ambient CO2 levels, plants have to leave their stomata open a certain amount of time in order to fix enough carbon for their needs. While their stomata are open, they are losing water. Increased WUE means that the plants are not increasing their carbon fixation directly in relation to available CO2. Instead they are saving water.

It might seem that increased WUE is a good thing, because plant grown is limited in many circumstances by water availability. However, transpiration is also a major driver of rainfall - if they plants are putting less water into the atmosphere, there's less convective rainfall.

With regards to the issue of plant growth being limited by carbon availability - if most plants were carbon limited, they would not react to fertilisers. Plants that respond to fertilisers are limited by something else, other than carbon. N, P & K are far more likely to limit plant growth (hence NPK fertilisers). While it is possible that some plants might react to increased CO2 levels by allocating more to root foraging and the rhizosphere community, this is, at present, quite speculative. Guettarda 04:52, 8 May 2006 (UTC)


 * You guys are missing the points I was making. Maybe I didn't state it clearly enough.


 * 1) Let's skip over the question of whether or not increased CO2 results in increased biomass and just assume for the moment that it will. Why is increased biomass a positive benefit?  Is it clearly a positive benefit, possibly a negative result or maybe just a big unknown?


 * 2) What is the projected benefit?
 * 2a) That crops will produce better yields? Why?  Is the amount of crop planted limited by carbon or by the nutrients in the soil?  Are you saying I'll get more bushels per acre?
 * 2b) That wild foliage (e.g. in the Amazon jungle) will be more lush? Why is this a benefit?  Because the increased jungle biomass will consume more CO2 than is being produced thus creating a steady state equilibrium?  Or are you saying this is a mitigating factor so that global warming won't be as bad as projected?


 * 3) Also (and this the major reason for my "bleeech") the article reads like the above discussion. In other words, it sounds like it was lifted from a Talk Page.  A asserts X, B counters with Y, A responds with Z.  In a word, "unencylopedic".  Somebody fix it please or I'll delete it and challenge those who want it in to write it in an encyclopedic way.


 * More biomass could be a benefit because we are very dependent on plant biomass - be if food crops or timber production. Crop breeders/plant geneticists play with biomass allocation in plants to increase crop yields (however, most of the green revolution focused on increasing yield without increasing nutritional quality).  So, if it were true, it might be reasonable to consider it a benefit.  Humans appropriate over 40% of global net primary production.  Absolute amounts of photosynthesis are important to us.  Guettarda 06:02, 8 May 2006 (UTC)


 * OK, I put what Guettarda wrote into the "Biomass" section. Now the first part of the article scans a bit better but the tail end of the section is still not quite there.  I am now concerned that the satellite data doesn't "prove" a link between increased CO2 and agricultural production.  That statement seems to infer causality where there might be only correlation.  Are there better sources of evidence to prove a causal link between increased CO2 and agricultural production?


 * --Richard 06:55, 8 May 2006 (UTC)

30 or 33 °C
The introduction says

"The natural greenhouse effect keeps the Earth about 33 °C warmer than it otherwise would be; adding carbon dioxide to a planet's atmosphere, with no other changes, will make that planet's surface warmer."

The causes section says

"Indeed, greenhouse gases create a natural greenhouse effect without which temperatures on Earth would be an estimated 30 °C lower, and the Earth uninhabitable."

Which is it 30 or 33°C? Should some uncertainty range be put on it eg 32°C +/-x°C? What is x? Is the repetition appropriate? Does 'no other changes' exclude negative feedback effects? Would it be better to say 'in the absence of negative feedbacks'? A mention of feedbacks may be a good idea. crandles 11:45, 8 May 2006 (UTC)


 * There is a calc over at greenhouse effect I think..., nope, how about climate model then..., yes. That seems to say 35 degrees. Ha. But of course that depends on the value of the albedo, which would really be totally different sans atmosphere... So the exact value doesn't really matter much William M. Connolley 12:31, 8 May 2006 (UTC)


 * Ok if the value doesn't matter much, how about mentioning the most major component - water vapour (obviously together with some explanation that water vapour is a GHG but not a climate forcing)? crandles 15:25, 8 May 2006 (UTC)

How much would the oceans rise?
I've been curious about the answer to this question for some time. Assuming Global Warming, or some other factor, caused the glaciers and polar ice caps to melt, how far would ocean levels around the world rise? I would love to have a theoretical picture of the earth in such a state, but if anyone could point me in the direction of where I might find even just the simple numerical answer. I'd appreciate it. It should probably also be in the artcle, since I did not see it (Maybe I'm blind?) Thank you. Elijya 17:37, 8 May 2006 (UTC)


 * That's not an easy question to answer, since there are many factors involved. Most of the sea level rise is not due to melting of ice, but to thermal expansion of sea water. If the Greenland ice cap melts completely, we are talking several meters in sea level rise. If Antarctica melts, it will be much more. See the seperate article on Sea_level_rise. --Stephan Schulz 22:35, 8 May 2006 (UTC)

Global Warming
Hi! I thought I would help you guys out as your were buried in references that needed to be cited, and as the footnote citations are the standard used, i created them. please do not revert them, since they took several hours to complete and doing some other kind of formatting will be a waste of time, since you will eventually have to do exactly what I have done to the article. You wont get through the FA without this format. Thanks! :) Judgesurreal777 08:55, 9 May 2006 (UTC)
 * It's appreciated (the effort by all, the result by some ;-). I think we will hash this out. Reference style has been part of a rather acronymous editing war a while back, so people are still jumpy. --Stephan Schulz 08:58, 9 May 2006 (UTC)

To Do's
By the by, I placed all of the FA objections or "work points" into the box at the top of the page, so they are clear and not jumbled like most FAC pages become after a while. All of the issues are there, to make it easier for you guys. Judgesurreal777 10:17, 9 May 2006 (UTC)

Please STOP editing for now
We are getting in a real mess due to the controversy over the citation style this article should use. Can everyone stop doing anything until we have resolved this one as otherwise it will get extremely messy.--NHSavage 10:44, 9 May 2006 (UTC) Well as this request is being ignored I might as well withdraw it.--NHSavage 14:24, 9 May 2006 (UTC)


 * Actually, I think we have at least a temporary rest of arms ;-) --Stephan Schulz 14:27, 9 May 2006 (UTC)

New section, as my proxy acts up.
(My proxy server here freaks out on large uploads (i.e. editing large sections). This is in reply to William's comment. If someone moves it up, thanks! In that case, strike this comment) ::For inline links there is no real connection between the link and the references section. What do you do with a printout that say "Global warming has been proven a scam perpetuated by Nazi UFOs via mind control rays.[1]"? At best you can guess that this corresponds to the reference (Einstein, A, Knuth, D., Hawking, S., "Nazi UFOs and the Inner Earth", Crosstime Publishing, 2311). This is also a problem with the Harvard system, albeit to a lesser degree. The link is there, but only maintained manually. This is worse than LaTeX without BibTeX - this is typewriter technology. The s are at least maintained by the computer.--Stephan Schulz 11:32, 9 May 2006 (UTC)

Fresh start

 * On the issue of copyediting, what do you guys thing should be done? They seem to want it summarized, made easier to read, and perhaps divided into new articles.... Thoughts?Judgesurreal777 20:48, 9 May 2006 (UTC)


 * I'll redo the "positive effects" section once more (I wrote the core of the current stuff, but it got Frankensteined bit by bit). In general, it's hard to strike out much more while leaving the substance... --Stephan Schulz 21:18, 9 May 2006 (UTC)


 * I'd vote for +ve and -ve "effects" to be combined and shortened William M. Connolley 21:22, 9 May 2006 (UTC)
 * If you ignore what they want, perhaps they will go away! This FA effort is being used for wholesale POV gutting of the article.  Please ignore the FA suggestions.--Poodleboy 21:33, 9 May 2006 (UTC)

Is methane forcing from forests natural or not?
William has deleted a section, apparently objecting to methane releases from forests being characterized as part of the natural GHG effect. This is arguably true, at least to the extent that the forests are the natural vegetation for the area, even if there was intervening decades of agriculture that was abandoned. Perhaps the new forests are monocultures, but there is no reason to believe they are different from the original in the characteristic being discussed.--Poodleboy 21:37, 9 May 2006 (UTC)


 * Um, actually you're right to complain about this, I'd got myself confused. The bit is:


 * Recent evidence suggests that forests may also be a source (RC) (BBC). Note that this is a contribution to the natural greenhouse effect, and not to the anthropogenic greenhouse effect (Ealert). 


 * Yes, it *is* natural, except to the extent that we've changed patterns of forests. I haven't restored it to the article (though I won't object to people restoring that bit) because I'm not really sure its important enough to be mentioned in the summary. It made a lot of noise when first published, but for all the wrong reasons, as the eurekalert makes clear William M. Connolley 21:48, 9 May 2006 (UTC)

the current high level of solar activity is relevant and referenced.
William apparently just pulls the excuse of "irrelevance" out of thin air without justification. If the probability of the current high levels of activity being sustained is low, it undermines all predictions of the models that are based on constant high solar activity. Recent work on errors in model albedo's make this even more relevant. Does William have a reason he can actually justify?--Poodleboy 21:41, 9 May 2006 (UTC)


 * You're harping back to albedo? Such a pile of talk, to no effect at all. What a waste. I don't rate S's work - in the sense that I don't think it has had much if any scientific impact on the GW science in general. Current predictions are based on the (correct) idea that there is no good way to forecast solar variations over the next 50+ years, and that those variations are very likely to be minor compared to GHG forcing anyway William M. Connolley 21:53, 9 May 2006 (UTC)
 * If there is no good way to forcast solar variation, there is no reason to assume constant solar activity, in light of evidence to the contrary. Several scenerios should be included.  I rate the result very credible and relevant.  Also, you evidently don't realize the size of the albedo errors in the models, they are much larger than the increases of GHGs in some ways.  It is complex of course, because while larger, they vary with latitude and time of day.  An error in albedo obviously has less effect at high latitudes, at night and in the morning and evening. Overall, there is still a lot of potentially warming energy being reflected by the models that in the real climate contributes to the warming.--Poodleboy 22:01, 9 May 2006 (UTC)

cross reference to Crichton page is relevant and not egregious
As a literature and notable popularizer and communicator of science, Crichton is notable, and Global warming is discussed in the article, so it is encyclopedic to cross-reference to it.--Poodleboy 21:44, 9 May 2006 (UTC)


 * No. Crichton has nothing at all of value to say on GW. If we're corss-listing *people* there are thousands above him on the waiting list. William M. Connolley 21:49, 9 May 2006 (UTC)


 * Name a few, and see how many are familiar to the general audience. As a familiar skeptic, there should probably be discussion of the pros and cons of his arguments on this page.  A reference to his page, is a poor second.  I haven't examined his arguments, perhaps they are dated? Or are more valid today?--Poodleboy 22:06, 9 May 2006 (UTC)
 * All of his arguments are worthless. If you think otherwise, feel free to advance some worthwhile ones William M. Connolley 16:24, 11 May 2006 (UTC)


 * Certainly Crichton doesn't belong here; he is a novelist, and his scientific arguments on the issue are woefully uninformed and have been shredded repeatedly. If we include Crichton, why not TC Boyle for his global-warming-catastophic novel A Friend of the Earth?  Neither is a relevant source for a scientific article.  bikeable (talk) 22:11, 9 May 2006 (UTC)


 * (edit conflict) Crichton is neither a popularizer nor a communicator of science. He is a novelist (not the worst, but far from the best), and, after his last book, a propagandist. He is simply not qualified to be a relevant "sceptic". An encyclopedic article is not a monograph. We have to make cuts somewhere. He can go into global warming controversy, but we decided that this article should concentrate on the science. Crichton is totally irrelevant for that. --Stephan Schulz 22:18, 9 May 2006 (UTC)
 * If you want Crichton, then why not: Al Gore, David Bellamy, James Lovelock, David King (scientist) to just pick four off the top of my head? Wht is Crichton so special?--NHSavage 22:41, 9 May 2006 (UTC)
 * Questioning the powers that be is a little more valuable than parroting their line. However, there is plenty in the published literature, so Crichton's viewpoint is not that special, if the primary sources are not also censored. --Poodleboy 15:42, 11 May 2006 (UTC)


 * I'm pretty sure Crichton used basic scientific literature to explain how dinosaur DNS can be transferred into frog or so eggs as in Dino Park, and that he needed a basic understanding of IT issues to create a killing swarm of nano particles as in Prey - and thus he needed basic scientific literature to create his spooky novel about some maniac "eco-activists". Not to forget, creators of SF tv series use to refer to "Crichton science" when they want to explain something very weird. What's the point in here anyway? Hardern 16:01, 11 May 2006 (UTC)

The basic issue is that Crichton is to science like Dan Brown is to religion. Much like the Da Vinci code meshes fact and fiction-made-to-look-like-fact to create his books, Crichton's work is full of fiction presented to look like fact. Read Crichton and you know less science than you did before, because he will have filled your head with misconceptions. Probably the worst "populariser" you could come up with. Guettarda 16:30, 11 May 2006 (UTC)
 * You reverted more than just Crichton, you've got some explaining to do.--Poodleboy 22:46, 11 May 2006 (UTC)

I disagree. "The State of Fear" used very strong, and effective arguments. It is worth mentioning, because major scientific application was used. —Preceding unsigned comment added by 70.253.99.146 (talk • contribs) 21:28, 21 May 2006 (UTC)


 * SOF is junk. If it had anything of value to say about climate, the thing to do would be to add it there before discussing it here. Still, if you can remember any of the "strong and effective arguments" you could mention them in talk here, and we can have fun ripping them to shreds William M. Connolley 21:37, 21 May 2006 (UTC)
 * That, and it seems to have a place on Global warming controversy. Perhaps that information should be added there? &mdash;Viriditas | Talk 21:40, 21 May 2006 (UTC)
 * Crichton quotes and cites his (very reputable) sources. If it makes you happy I can dig them up when I get home and post them in the article. -BeboGuitar 23:16, 2 June 2006 (UTC)

I've always believed in Global Warming since the term was first used, not because I understand its complexities, but because it seems that a large majority of experts without axes to grind believe in it. I just read State of Fear knowing nothing in advance about its agenda to rebut Global Warming. I still believe strongly in Global Warming, but ignoring the fiction that is the rest of SoF, the argument trying to rebut Global Warming appears quite serious and I think it would be foolish to dismiss it out of hand (the situation is utterly unlike The Da Vinci Code). You can always say "It's junk" -- but that's not going to convince anyone.

I went to Crichton's website where there are some discussion groups, including one about this novel. I found it extremely suspicious that the discussion was allowed to run from about Dec. 20, 2005 - Jan. 31, 2006 and then all further discussion on the subject of SoF was banned.

I would love to see a very careful point by point rebuttal of Crichton's argument by an expert with no axe to grind. I don't think Wikipedia should ignore it, but mention it as an attempt to rebut Global Warming (an *influential* one, fer crissakes -- it got the attention of our highly intellectual president, alas, who is more convinced than ever that Global Warming is bogus!). And refer to a point-by-point refutation of Crichton's argument. Surely some expert has written one by now, no????

Above all I want to say I am incredibly impressed with the expertise and level-headedness with which the Global Warming article is written!!!!!Daqu 04:45, 16 June 2006 (UTC)

C-randals GHG explanations.
User:C-randles has added a more detailed description of the contributions and mechanism of green house gases. I think it's a) to detailed for this article and b) not precise enough overall. It could nicely fit into greenhouse gases, but not here. I've reverted it. Feel free to comment and complain... --Stephan Schulz 23:40, 9 May 2006 (UTC)


 * There is a better explanation in the greenhouse gases pages already. I am not really complaining about most being removed (and certainly not if that is the general view). However, I do think a 'Causes' section should be about causes and not discussion of what the debate is about and the level of committed warming. I also think that if CO2 and methane are going to be mentioned then the most important GHG (water vapour) should be mentioned else it gives credence to a standard septic point that water vapour is ignored. Also, uncertainty over feedbacks seems another important topic to mention. I certainly accept that what I wrote could be improved, referenced better etc. etc. crandles 10:14, 10 May 2006 (UTC)
 * This article is already to long for many people, so I would leave peripheral material out. It is, e.g., very irrelevant that complex molecules have more modes of vibration and hence can absorb more different frequencies. We can just name the major greenhouse gases and state this property as given. Someone who understands energy states of molecules typically will have a solid scientific unserstanding anyways. For everyone else, this reduces a simple property to a complex explanation. This is unlikely to be helpful. Whoever wants to know more can go to the GHG article.
 * Now water vapour is a bit of a sore topic here (see the discussion above). While it contributes to the greenhouse effect, it does not cause global warming (neither do "natural levels" of other greenhouse gases - they just prevent cooling). The problem seems to be that the terms "greenhouse effect" and "global warming" are often used interchangably, although they really are not. I'm not certain we need to go into much details here, but moe reluctant than on the first point.--Stephan Schulz 12:11, 10 May 2006 (UTC)
 * WV deserves something like "WV is not a cause of global warming; see greenhouse effect for details" but no more. I agree the rotation stuff is too detailed. William M. Connolley 15:26, 10 May 2006 (UTC)
 * The paragraph describing the natural greenhouse effect should certainly contain a reference to the WV. Feel free to add that humans can't effect amount of WV if you wish.
 * It seems a little odd, I didn't mention anything about 'modes of vibration' or rotation yet this seems to be one of the main reasons for rejecting what I wrote. I know I did mention different bonds so nitrogen and oxygen are not greenhouse gases and a bit about absorbtion of outgoing radiation. I am happy to accept a consensus that what I added was too much. Can we reach a compromise that what I wrote should be boiled down to something like:

"Water Vapour is the most significant greenhouse gas but it is not a cause of global warming; see greenhouse effect for details." crandles 20:56, 10 May 2006 (UTC)


 * The committed warming paragraph is an effect not a cause. Should this be moved and where to? Should there be a new section for discussion of size of the effect(s)? The other title that I am not happy with is 'Responses' which (only looking at the index) could easily be misunderstood to be reponses of the climate system. Would Mitigation and Adaptation be a better title for that section? crandles 21:08, 10 May 2006 (UTC)
 * It is a bit unnatural to separate causes and effects so completely. The text reads better and the explanations make more sense if cause and effect are related to each other somewhat.--Poodleboy 15:36, 11 May 2006 (UTC)

Kerosene lighting
I have created the article Light Up the World Foundation, and there is a section of relevance, which someone may wish to incorporate or link to from this or other articles; or of course, edit the Light Up the World Foundation article. The section is copied here:

"The LUTW website cites a Lawrence Berkeley Laboratory paper, which argues that replacing kerosene lamps with LED lights helps reduce greenhouse gases. The paper says:
 * The single-greatest way to reduce the greenhouse-gas emissions associated with lighting energy use is to replace kerosene lamps with white-LED electric lighting systems in developing countries; this can be accomplished even while dramatically increasing currently deficient lighting service levels. - Mills, 2002

However it should be noted that Mills does not discuss the one-off contribution to greenhouse gas emissions from the production of componenets such as solar panels."

The external link is: Global Lighting Energy Savings Potential - by Evan Mills, Lawrence Berkeley Laboratory, 2002

Cheers --Singkong2005 16:21, 12 May 2006 (UTC)

Christian Aid says 184 million in Africa could die due to GW
Climate change a 'deadly threat' -- BBC News: I think this should be incorporated into the article, but as much bickering as goes on here, I'm not going to be the one to do it. 71.132.158.128 08:37, 15 May 2006 (UTC)


 * I don't think this should go into this article. First, we concentrate on the science of global warming here. Secondly, it's just a single source and not recognisably peer-reviewed. I'd suggest to put it into effects of global warming, clearly marked as an estimate. --Stephan Schulz 10:51, 15 May 2006 (UTC)


 * I agree. There are lots of different numbers, and it should be marked which figures are quite reasonable and which are not. Hardern 11:39, 15 May 2006 (UTC)

"Many" Scientists Dissent From View That Humanity's Activities Are An Important Source Of Recent Rises In Temperature
The use of the word "many" is unjustified. The overwhelming majority of scientists take the opposite view. And only five scientists are listed as dissenters. So use of the word "many" exagerates the disagreement and would mislead readers. The truth is closer to "a few scientists" or "a small minority of scientists" or "some scientists." But in the interests of NPOV it's probably better to omit any characterization and simply say "there are sceintists who..." So I suggest we continue to refrain from using the word "many" until much greater documentation can be produced that would justify use of the term. I think "many" implies at least a signifcant minority opinion (perhaps 25% or more) -- which is not the case here. —The preceding unsigned comment was added by 74.12.75.164 (talk • contribs).


 * No, NPOV requires that we characterize the tiny group of dissenters as such. "Let's hear all sides", "teach the controversy" are common fallacies that obscure the scientific position. --Stephan Schulz 12:41, 19 May 2006 (UTC)


 * Somehow, "a few" got lost when the absurd "many" got inserted. I've re-inserted the "few" William M. Connolley 12:46, 19 May 2006 (UTC)


 * I agree that "many" implies a significant minority although I would say 10% would be enough to qualify for "many". Presumably, we are talking about less than 10%.

-::: However, I think we are seeing that the "few/many" dispute could and probably will go on forever. The problem is that both "few" and "many" require a judgment as to the number of dissident scientists that is significant enough to be called "many". Can I suggest that you defuse this problem by changing the text to read "A number of scientists advocate a minority position which is..." and then either in-line or in a separate article, list the scientists who advocate the minority position by name. This list might be 5 or it might be 100. As long as the number is less than 10%, it seems reasonable to argue that it isn't "many". However, by not insisting on characterizing it as "few" which has a negative connotation, you sidestep the entire "few/many" debate or at least stand on higher moral ground when someone comes along and tries to insert "many" again. I'm really tired of that debate, aren't you?
 * --Richard 14:23, 19 May 2006 (UTC)


 * I disagree with most of that. "many" implies a majority - which is why it makes no sense at all. Secondly, there *is* no minority position (other that "we dont like the consensus) - only a series of dissident views. There *is* a separate article: list of scientists opposing... well I forget what its called. As to the debate... its been settled, on "few", for a long time - why is it being re-opened now? I agree with Stephan, above William M. Connolley 15:30, 19 May 2006 (UTC)

I agree that the above referenced "few/many" dispute could go on forever. It was just in 1975 when there were countless articles and research warning of "Global Cooling"; and in 1950's there were same sort of alarm about "Global Warming"; at the onset of the 1900's there was wide spread publicity and research once again warning of a return to the ice age...or similar climate of the cold temperatures experienced in the 5 centuries following the Medieval warm period. The article is here: http://www.businessandmedia.org/specialreports/2006/fireandice/fireandice.asp I'm just an outsider, but I think you scientists need to rethink your entire WIKI Global Warming entry to reflect the current non-consensus status of the Global Warming. It is only a theory and should be addressed as such. —The preceding unsigned comment was added by 57.68.138.132 (talk • contribs).
 * That article you point to is, to put it mildly, garbage. In the 1970s there was a small popular media blitz about global cooling - it's one of William's hobbies, so he might tell you more about it. It never was scientific opinion, much less a strong consensus as we have now. The older references are also to isolated reports, mostly in the popular press. There currently is a strong consensus about the core theory of anthropogenic global warming. As always, scientists are refining it, but it has not been seriously challenges in years, if not decades. And in science, a scientific theory is the best, most strongest statement you will ever get about anything. --Stephan Schulz 18:02, 25 May 2006 (UTC)

Hasn't 80% of the earth's geolocical history been at temperature's (based on core samples) higher than those temperatures of today? I was looking at this entry http://en.wikipedia.org/wiki/Temperature_record It just seems intuitive that our temperatures would trend back to "climate optima" in time. I have also not seen a breakdown of percent contributors of CO2. I read in a journal once that volcano's alone contribute 10 times as much CO2 as humans do. Neal Benoit (User:57.68.138.132 )


 * Over geological time periods, the temperature of the Earth depends primarily on variations in solar output (the Sun is getting hotter, but very very very slowly) and on the configuration of the continents on the surface - serious amounts of land in high lattitudes leads to glaciation, which increases albedo and hence reduces temperatures, potentuially leading to more glaciation. Distribution of continents also affects ocean currents, which profoundly influence climate. Indeed, large parts of Earth's history have been warmer and had a lot more CO2 in the atmosphere. The carbon in the fossil fuels we are now burning originally comes from the biosphere/atmosphere. None of this is relevant in the (geologically speaking) short term. We've been in a geological ice age for 40 million years, and in a stable interglacial of this ice age for 12000 or so years. Without human intervention, this should go on for at least a few thousand years, and then temperature should drop once more due to certain variations in Earth orbit. CO2 emission by volcanos is negligible compared to fossil fuel burning over human-scale times. Over billions of years, (nearly) all CO2 comes from volcanoes. But currently, we are outdoing volcanoes (and all other net CO2 contributing processes) by a huge margin. --Stephan Schulz 16:22, 31 May 2006 (UTC)


 * One of rather obvious problems with stating the "amount" of scientists who do or do not support global warming theories is that only a handful of "scientists" are qualified to comment on it. As with a lot of other discussions it seems that once one has reached the lofty position of being a "scientist" then your views on a wide ranging series of issues are deemed to be significant when this is clearly not the case.

Comment
To take into consideration regarding "SEPP editing": The Richard Lounsbery Foundation, the biggest monetary contributor to Wikipedia, has also funded global warming skeptic Fred Singer. -Dna4salE 04:44, 20 May 2006 (UTC)


 * Well, they were right on one count, wrong on the other. Happens to the best of us ;-). Seriously, that is an interesting factoid, but should not influence us in any way. --Stephan Schulz 08:12, 20 May 2006 (UTC)

sol var?
I'm with Stephan on PB's:


 * Solanki, et al (2004) found that solar activity for the last 60 to 70 years is at its highest level in 8000 years, and based on the assumption that previous high levels of solar activity are typical, they estimate that there is only an 8% probability that this current period of high activity can last another 50 years. Muschele, et al (2005) argue that periods circa 1150AD and 1600AD have comparably high activity. Solanki, et al. (2005) point out errors in Muschele's analysis, and show that their 2004 reconstruction is more consistent with other published proxy reconstructions.

I think Solanki, et al. (2005) point out errors is probably POV - more likely they just disagree - but I haven't read either yet. But the main point is Stephans - this is too much detail for the GW article, since there is a separate sol var article to handle details. Its also too much, because its doing its best to imply some relevance, which it doesn't have. Sol var, as far as is known, is too small to explain much William M. Connolley 10:28, 20 May 2006 (UTC)
 * I have read both and they are peer reviewed. And they don't disagree much, with Muschele's reconstruction also finding the current level high, only comparable twice in the period Solanki analyzed.  The other reconstructions that compare well with Solanki's are in the references and would have been known to the peer reviewers, so his statements must be considered supported.  You have been deleting the probability estimate of sustaining this level of activity, and along with it the reference Solanki 2004 notation that is the source of the 8000 year figure.  Do you have a reason to delete th is other than you uncomfortableness with the implication of current unusually high solar activity levels?--Poodleboy 10:39, 20 May 2006 (UTC)

PB: "why do you join William in reverting that element?"
Just read your suggested text. This is "he said/she said/he said (and we are waiting for her again, if we are not bored to death)". But more substantially: This is supposed to be an encyclopedic article. It gives a broad overview of the state of knowledge in a reasonably self-contained manner and restricted to a few pages of text. It's about the lenght of one typical Journal article and has to summarize hundreds of them. By comparison, the IPCC WG1 TAR, already extremely condensed, has 900 pages. We have to concentrate on the core, not on the very latest articles that improve (or fail to improve) the bleeding edge of our understanding. That's what journals and conferences and preprints are for! And note that the current climate reconstructions and predictions do include solar variability to a good deal - either explicitely, or as part of the ranges given. This is not a killer paper that shoots out all support from the IPCC position (even if it turns out to be correct) --Stephan Schulz 10:49, 20 May 2006 (UTC)
 * The journal Nature competes for the most significant research, so they must have thought it had some killer elements. William's reversions should provide you with evidence of that.  You forget that the IPCC work itself points to gaps in their knowledge, and several more recent papers are mentioned in the article that fill in some of those gaps.  There is no reason for this article to be so general that it is wrong.  The solar section currently is biased, putting disclaimers of knowledge first before results shedding insight on solar variation and influence.  Most attribution of GHG vis'a'vis solar is based on models, which now have been shown to have significant problems in their albedos.  Science moves forward and an internet encyclopedia does not have to be static.--Poodleboy 11:07, 20 May 2006 (UTC)
 * Ah - now I see: anything I revert must automatically belong in the article? And/or anything Nature publishes on climate automatically belongs? The solar section starts, correctly, by pointing out that the level of knowledge of solar forcing is low (or at least if did before NH rewrote it - will have to think about that). Your opinion of models is your own, and doesn't belong here William M. Connolley 11:43, 20 May 2006 (UTC)

Rewrite of whole section
I have never liked this section and I have now tried to present a coherent flow in the article - partly to address concerns of PB about starting with the disclaimer. I have also gone with the shorter version of the Solanki et al story - this can only be a short summary. Probably everyone will hate it though.--NHSavage 11:33, 20 May 2006 (UTC)
 * Thanx, I think you have made an improvement. However, the first paragraph is still too political, talking about what the majority of scientists believe, instead of the discussing the evidence that leads them to believe it.  The evidence should be discussed, and then perhaps it might make sense to report what the majority of the scientists conclude from that evidence.  Readers should come out of the article informed about the evidence and not about the opinions.--Poodleboy 00:01, 21 May 2006 (UTC)
 * This is dangerously close to original research. The consensus opinion of nearly all qualified scientists is much stronger evidence than any selection of primary facts, except to someone extraordinarily qualified in the very field under discussion. That's why we have experts in the first place! --Stephan Schulz 00:28, 21 May 2006 (UTC)
 * Facts and conclusions in peer review journals, have been subjected to expert review, so we get the benefit of both original research and experts. Keep in mind that recent peer review articles have the benefit not only of the latest research, but of non-peer reviewed work such as the IPCC TAR.  So, since when is citing peer reviewed journal articles, "original research" under wikipedia standards?  I thought such citation was encouraged.--Poodleboy 01:10, 21 May 2006 (UTC)
 * Ermm...the IPCC TAR is peer reviewed, and with much more scrutiny then any standard conference or journal paper I've seen in my life. The TAR is an academic publication, with the individual chapters written and reviewed by independend scientists with normal academic positions, not something that the UN ordered from some hirelings to further their nefarious purposes. Citing peer-reviewed literature is indeed fine and encouraged. But not everything that is peer-reviewed is automatically a useful addition to an article. --Stephan Schulz 01:35, 21 May 2006 (UTC)
 * No, the TAR wasn't peer reviewed. The writers get comments on their preliminary versions, but they are free to ignore those comments and write what they want.  In peer review, the authors have to address the concerns and requirements of the peer reviewers or they don't get published in that journal.  Yes, if the writers of the TAR wanted a FAR funded they had to please the governments involved, but that is not peer review.--Poodleboy 05:46, 21 May 2006 (UTC)
 * You don't know what you're talking about. Still, you make your biases clear William M. Connolley 09:46, 21 May 2006 (UTC)
 * You are making a mere assertion, can you support it with some information? I made my biases clear with the near earth objects comment above.  You make yours clear by your reverts.--Poodleboy 11:30, 21 May 2006 (UTC)
 * This has to be one of the more bizarre comments I've seen in my life. Is it really your position that "the danger form NEOs is bigger than the danger from global warming, hence we should lie about GW so that more resources can be spent on reasearch on and defending against NEOs"? This is not how science works for me. Science is about getting the best possible understanding of an issue. Then you set your priorites and make your decisions. On another topic: I've been author,  programme chair (for workshops), programme committee member (for minor and major conferences and workshops), reviewer, editor of workshop proceedings and editor of journal special issues.  Your understanding of peer review is at best incomplete. For may publication venues, there is one round of reviews. If the paper is accepted, the authors are asked to take the referee reports into account for the final version, but no second round of reviewing takes place. What keeps authors from substituting Mickey Mouse comics is scientific integrity and peer pressure, not the revieving process. For journal publications, there may be multiple rounds of reviewing, but again the very final version is not usually reviewed again, unless the editor is very suspicious.--Stephan Schulz 12:30, 21 May 2006 (UTC)
 * Where did you get the "lie" part? My positions are empirically based, not on the fundamentalist belief that any disagreement is treason.  The paleo climate record makes it clear that all forcasts are survivable by humanity, and are projected to be smaller in magnitude than much less technically advanced cultures have already survived.  NEOs are a far larger and more certain threat to human lives, unless we find them and do something about them.  Can you stick to discussing evidence and not attacking character?--Poodleboy 08:52, 22 May 2006 (UTC)

(<left) Why else bring unrelated bias up if not because you think it leads to people acting against their better knowledge when editing the article (in short, "lie"?). Anyways, if you dislike the phrasing, I apologize. I'd suggest you try to assume good faith, too.

I'm not in fear for humans as a species - they will most likely survive both global warming and a even a major impact event nicely. If humanity and civilization do is another question. For us in rich western countries, global warming is unlikely to be an existential problem. But that does not hold for e.g. a peasant in Bangladesh. But this is totally of topic. Whatever the risk from NEOs, it does no affect our knowledge about global warming one bit.

And it's a fallacy to assume that mitigation of global warming somehow has to be traded of against research into and protection from NEOs. Indeed, I see huge synergies. Burning less fossil fuels will also lead to clearer skys, making astronomical observations easier. Cheap and efficient solar panels are just as valuable for space propulsion as they are for energy production on earth. Saving a large supply of readily available energy for an emergency instead of buning it in a binge also will help us to deal with extraterrestial danger. Better understanding of the climate requires space observations and hence a viable space programm...and so on. --Stephan Schulz 20:13, 23 May 2006 (UTC)
 * Economics is the study of the allocation of scarce resources. NEO research and mitigation of global warming compete for scarce resources.  More important than that is the impact of some global warming proposals on economic growth.  Research and charity are luxuries enabled by surplus wealth.  Perspective is needed for good decision making and the risk of NEOs is just one example of providing perspective, if one is going to fear monger, then at least fear monger where the evidence shows there is a real threat.  There are far more productive uses of wealth than reduction of global warming.  The Bangladesh will benefit far more from addressing health and clean water needs, than global warming, and a poorer world will be less able to afford helping them.  Don't confuse perspective with "bias".  We can avoid "bias" and "lieing", by assuring that the best evidence and arguments for various theories pro and con are presented and not reverted.--Poodleboy 00:28, 24 May 2006 (UTC)
 * Hold on, a second.  There is a basic problem with one of the premises being discussed here.   Many strategies for mitigation of global warming actually save businesses and economies money rather than costing money.  For instance, conservation, energy efficiency, co-generation, use of renewable energy in remote areas, use of hybrid cars, etc. are all cost neutral or save money.   And in terms of quality of life on this planet, is there any doubt that everything possible should be done to help China and India produce power without building enormous numbers of old-fashioned, high-polluting coal power plants?   If you need to see some discussion of this, see a book by Dr. Joseph J. Romm called "Cool Companies", discussing how businesses have saved money and increased profits by using green technologies and conservation.  --Ssilvers 05:38, 5 June 2006 (UTC)

Species that rely on cold weather conditions such as gyrfalcons, and snowy owls that prey on lemmings that use the cold winter to their advantage will be hit hard?
Is it the lemmings or the predators that use the cold winter to their advantage?--Poodleboy 06:42, 21 May 2006 (UTC)

Image sizes
While I was travelling some miracle occured and global warming became a featured article. Congratulations everyone.

I haven't looked over all the changes that were made in the process (not even close), but there is one that stands out and I would like to express my opposition to. Specifically, someone removed the size designators from all the images. Since I am the author of roughly half the images in the article, I'm probably not a neutral party here, but I think it is important to keep the images at a size where the major labels are visible whenever practical. Unlike some articles where images are used primarily for identification (e.g. a mountain, a tiger, an historical figure, etc), the images here are not merely window dressing but really are an important part of the information being conveyed by the article. As such, the information they convey should be reasonably legible to readers without forcing them to click through to the image page. I realize that increasing the image size could be inconvenient for the roughly ~1% of web users that use screen sizes below 800x600, and that setting a value interferes with the preference settings of Wikipedians, but I think we need to focus on choosing an image size that is legible to the majority of readers. Dragons flight 02:54, 22 May 2006 (UTC)


 * Hi DF! Taka a look at the discussion at Featured article candidates/Global warming. In short, someone pointed out (correctly, in my opinion), that thumbnail size is user-configurable, and that setting it absolutely (as we did) is less than optimal. Its fixable via Special:Preferences->Files, but I don't know if that is satisfactory. Idealy, Wikipedia would support different inline image sizes (small, medium, large, at 1X, 2X, X magnification). I'd suggest to wait for a few more comments.... BTW, I converted most of the images (and I think all of yours) to PNG as part of the FA process.  --Stephan Schulz 07:03, 22 May 2006 (UTC)


 * Seems the problem is that Joe average user has no clue about preference setting and therefore the majority of viewers of the page see tiny unreadable graphs. The article is not written for wiki-addicts, it is written for Joe. I suggest the graphical images should be fixed at a reasonable size readable for all the Joe's out there. Vsmith 12:19, 22 May 2006 (UTC)


 * I don't have a strong opinion on this, but with regard to the default-settings bit: people are not going to change their settings to be larger, just so they can see the GW graphs, even if they know the option exists (which few do!). I would tend to agree that if the graphs need to be at least X pix to be useable, they should be sized that size. I guess it would be nice if the image markup could say "size X, unless user prefs set, in which case...". Is is possible to xfer some of the text info into the caption? William M. Connolley 16:57, 22 May 2006 (UTC)

Done it. I used 280px 'cause that seems best for my res. Vsmith 16:32, 23 May 2006 (UTC)


 * I was traveling as well, but may I say how pleased I am? Congratulations everyone. Walter Siegmund (talk) 05:25, 24 May 2006 (UTC)

Positive/Negative effects?
Why are the effects divided into positive and negative? Positive and negative to whom? I think that they should just be merged into one section: "Effects of global warming" and listed in order of relevance (which I believe to be the current order, minus the subheadings. savidan(talk) (e@) 09:31, 22 May 2006 (UTC)


 * I suspect that this was done for political reason. This way, the deniers can mostly have their own section (positive effects) to tell us how, when they're proven wrong about their claimed non-existence of global warming, it will still be shown to be "good" for somebody somewhere.


 * Atlant 11:50, 22 May 2006 (UTC)


 * No one has objected to my proposal in a week, so I'm going to go ahead and do it. Wikipedia must be neutral toward all events, including the possible extinction of our species. savidan(talk) (e@) 12:57, 29 May 2006 (UTC)

Semi-protection?
Seeing as this article is the #4 hit on google for such a controversial topic perhaps semi-protections isn't uncalled for. This page is getting vandalised a *lot*. TimL 11:19, 23 May 2006 (UTC)
 * See here, but you raised a good point that has not been noticed so far. Hardern 11:24, 23 May 2006 (UTC)

Theory Removed?
Why was "theory regarding" removed from the opening sentence? GW is a scientific theory, as it is yet to be undeniably proven as fact. Seems like POV to me... —The preceding unsigned comment was added by 24.208.158.6 (talk • contribs).
 * There are no "proven facts" in the strict sense anywhere outside mathematics. Global warming has been directly observed, and is a "scientific fact". Not even Singer denies it anymore. The global warming theory is a scientific theory explaining the fact of global  warming. But that sentence does not refer to the theory, but to the observation. P.S.: Please add new stuff at the end! --Stephan Schulz 07:01, 26 May 2006 (UTC)
 * I think you over simplify. Yes, globally averaged rises in temperature data have been observed.  A massive amount of sophisticated peer reviewed work has adjusted for confounding factors such as heat island effects and found a warming trend in the land, sea, satellite and other data.  A result that is well confirmed in the literature.  While, technically, global warming is a theory and not a simple fact or observation, calling it a theory whenever it is mentioned would be overly didactic and so obvious and unnecessary that it is deprecated.--Poodleboy 08:20, 26 May 2006 (UTC)
 * Nice to see that we can agree on something, even if for different reasons ;-)--Stephan Schulz 08:49, 26 May 2006 (UTC)

Maybe it would be better to say that the causes GW consist of theories, rather than calling the existence of a warming trend a theory? It's getting warmer, obviously, but the "theories" are as to why it's happening? Dubc0724 12:19, 26 May 2006 (UTC) WC
 * Isn't that what I wrote? --Stephan Schulz 12:28, 26 May 2006 (UTC)


 * Not sure. Maybe. —The preceding unsigned comment was added by Dubc0724 (talk • contribs).

Whether "theory" should stay or go probably depends on whether we're speaking to scientists or the common person. Scientists know what "theory" means but as has been proven time and again by Creationists, the common person thinks theory=crackpot or untested idea. At this point, I'd remove "theory" from this article.

Atlant 12:56, 26 May 2006 (UTC)


 * What follows is an expansion of what Atlant wrote. Any duplication is a result of the fact that we composed our responses at the same time and mine comes after his because of an "edit conflict".


 * First, historical warming is a fact. Theories about causes lead to predictions about whether the warming will continue and for how long.  GW is a theory that suggests that, in the absence of a change in human behavior, warming will continue.  The theory is popularly used to include predictions of what the warming will do to the climate and the ecosystem.  However, these predictions are arguably a separate set of theories and that global warming could occur without all the dramatic negative effects that are predicted.  Do we want to make that distinction?  We sort of make the distinction by the structure of related articles (e.g.Effects of global warming) but we don't consistently use two different phrases to differentiate the two.


 * At the risk of stating the obvious... not all theories are equal. It is true that every assertion about causality is a theory.  However, we cold argue that it is a theory that the sun warms the earth and that if the sun were to suddenly stop radiating energy, the earth would freeze over and most life on it would die.  That is a theory but most people treat it as a fact.  There are lots of other theories that we treat as indistinguishable from fact.  The argument to characterize GW as theory is dependent on the extent to which we argue that it is or should be treated as equivalent to fact.


 * It's one thing to say that GW is a theory early in the article. However, if the word "theory" is appended to "global warming" everywhere that it is used, it serves as a signal that the GW theory is more theory than fact.  It may be the leading theory but the addition of thw word "theory" adds a sense of challenge which is why opponents of GW like to insist on saying "GW theory".  We don't say "evolution theory" but "evolution" even though we all know it's a theory.  Opponents of evolution insist on saying "the theory of evolution".  We don't say "quantum mechanics theory" and "relativity theory" because nobody is seriously challenging those theories.


 * So, do we say "GW theory" as an NPOV sop to the opponents or do we assert that GW is closer to accepted fact and just say "global warming". I'm in favor of acknowledging early in the article that it is a theory and then just using "global warming" throughout the rest of the article.  That, I believe, is the way we are doing it now.


 * --Richard 13:04, 26 May 2006 (UTC)

"Theory" is an excellent word to avoid, because it has at least two highly distinct meanings in science, and sometimes this ambiguity is used for decepive purposes (e.g., "Evolution is only a theory"). Just to be extra clear: one meaning is a hypothesis of one sort or another (Democritus had a theory that matter is composed of indivisible elements, which he called atoms; physicists once had a theory that space is filled with a substance they called ether.)  On the other hand, another meaning is a coherent body of established facts generally supporting each other and explaining a large aspect of science (the theory of evolution; the theory of relativity). I recognize I haven't said anything y'all didn't already know, but this ambiguity -- since many readers will not have a good scientific background -- is a good reason to avoid this word.Daqu 05:04, 16 June 2006 (UTC)
 * At least the Aether Theory of light propagation was not a simple hypothesis, but a normal scientific theory. It was supported by observations ("waves" move in it) and was falsifiable - and Michelson and Morley did indeed refute it (or at least gave it a heavy blow). Democritus really is to early for "science" as we understand it. But in principle you are right. Plain, unadorned "theory" will be misunderstood. "Scientific theory" is better. --Stephan Schulz 06:16, 16 June 2006 (UTC)

Increased light?
First sentence of "Positive Effects": "Plants use solar energy to convert water, nutrients, and carbon dioxide into usable biomass using photosynthesis"

Global warming has nothing to do with the sunlight hitting the earth's surface, it has to do with the temperature. As far as I know, photosynthesis relies on light. And on the contrary, a related effect global dimming has caused a reduction of solar irradiance which means less photosynthesis.

Maybe increased temperatures can allow greater distribution of phytoplankton in the sea and plants on land, but they aren't helped individually. 134.215.197.202 15:17, 26 May 2006 (UTC)


 * Read on a few sentences. The increase in carbon dioxide can stimulate plant growth. Also, the warming can increase the growing season in high latitudes. Wether the overal effect is a net increase in biomass is uncertain, and this is stated in the article. Note that "global dimming" is not caused by CO2, but by other pollutants (which are often produced by the same processes that create CO2). --Stephan Schulz 15:21, 26 May 2006 (UTC)

Equilibrium scenarios & transient scenarios
This part of the Climate Change 2001: Working Group II: Impacts, Adaptation and Vulnerability page (linked from Increased biomass production section) describes "transient scenarios", but I'm not sure if this means the changes over decades, or changes occurring over shorter periods, after global warming has taken hold:
 * Crop modeling studies that compare equilibrium scenarios with transient scenarios of climate change report significant yield differences. The few studies that include comparable transient and equilibrium climate change scenarios generally report greater yield loss with equilibrium climate change than with the equivalent transient climate change. Even these few studies are plagued with problems of inconsistency in methodologies, which make comparisons speculative at this time (see Section 5.3.4).

Can someone shed some light on this? Thanks --Singkong2005 01:47, 27 May 2006 (UTC)

rewriting Biomass production
I'm doing some work on rewriting Biomass production - I've removed this bit, though some of the points are there in other forms. But feel free to add it back (or rewrite and add, with sources) if appropriate.


 * However photorespiration rates increases with temperature more rapidly. Therefore, while an increase in carbon dioxide would increase carbon fixation rates in plants, the temperature rise caused by global warming might cause that carbon to be broken down again into CO2 and oxygen without a net energy loss to the plant.

The last bit (which I've bolded) is kind of interesting, but needs a good source. --Singkong2005 02:01, 27 May 2006 (UTC)

Solanki and Muscheler disagree? about what?
William wants to specify that Muscheler "disagrees" but doesn't want to specify about what. I have no doubt because of Muscheler's opinions dismissive of the importance of solar variation that he disagrees with Solanki a lot. But in his published results he only specifically mentions two other periods that compare with the current unusually high levels of Solar activity, and Solanki has published responses to those. Muscheler does not mention any disagreement with Solanki's statistics supporting only an 8% probability of the current high level of activity continuing another 50 years, so the text should not misleadingly imply that the "disagreement" is broader than it is. I've no objection to detailing the evidence on both sides, but we should not broaden Muscheler's "disagreement", when his published analysis is in broad agreement on most of the general outlines of the reconstruction, and where his analysis, where it disagrees is also disputed in published/peer reviewed detail.--Poodleboy 07:11, 28 May 2006 (UTC)


 * Well, you can read it. They think that S's claims aren't justified. Removing the M response also isn't justified. As a copromise, I've moved it a bit William M. Connolley 10:47, 28 May 2006 (UTC)
 * I don't think that stating that M disagrees is an informative characterization of M results, although that is M's opinion. Perhaps before peer review M had more results to support their opinion, but with what survived in the published results, there is still no higher solar activity in the last 8000 years, although two other periods are comparable, and NOTHING in the M results disputes the historical duration statistics for high activity periods that S uses.  There can be little doubt that M et al did their analysis to dispute S's results, but in what survived peer review in Nature, M's analysis did little to change S's results, and S's response appears far stronger in both detail and substance.  You placement of the disagree narrows its scope, partially addressing my concern. Thank you for that.  However, I think more detail would still be an improvement.  The paragraph was already a run-on statement, that has been made worse by both of us.   Better sentence structure is probably needed.--Poodleboy 13:41, 28 May 2006 (UTC)
 * This senstence doesn't read well. What does Muscheler disagree with? The sentence actually seems to imply that he agrees solar output is high, but that it won't last for much longer. But who said it owuld last for much longer in the first place? None of this is clear from the article. TimL 15:58, 28 May 2006 (UTC)
 * His published work shows that current solar output is unusually high. He disagrees that this is important, but the most he can do is show that two other past periods were comparably high.  Not as strong statement.--Poodleboy 12:55, 29 May 2006 (UTC)
 * Thanks, you're edit makes things much clearer. TimL 15:48, 29 May 2006 (UTC)

There Should be...
There should be a section about the history of global warming as a theory (If I remember correctly, it was first proposed by Arrhenius in 1904 or 1905?), then when it was first proposed that global warming is happening in the present (as opposed to in the past), and when it finally started to get acceptance in Europe and North America, where it was treated less as a fringe theory and more as an accepted fact (i.e. where the turning point or tipping point was; which if I remember correctly was in 2003-4 for Europe, and 2005 for the US). Maybe something like a timeline would be good. I have no clue about the timeline of theory --> acceptance in Asia or other parts of the world though, but for purposes of completeness, they should be included as well.


 * Ermm...the IPCC first assessment report was published in 1990. It summarized exisiting research, and clearly described global warming and the greenhouse effect. The scientific debate about the basic facts was over by then, and popular opinion (as far as it existed) in Europe had largely accepted this as well. Kyoto was negotiated in 1997 and closed for signatures in 1999. This is not brand-new science, but well-established.--Stephan Schulz 19:37, 28 May 2006 (UTC)
 * Ermm...ermm...by citing the 1990 report you are more than a decade early. The debate about the basic facts wasn't over until the gap in satellite temperature results closed a bit.  There is still a lot of debate about attribution and predictions.  The disagreement between model results and predictions is much greater than the "disagreement" between the results of Muscheler and Solanki.--Poodleboy 13:00, 29 May 2006 (UTC)


 * "The balance of evidence suggests a discernible human influence on global climate" was a 1995 Second assessment report conclusion. "We calculate with confidence that: ...CO2 has been responsible for over half the enhanced greenhouse effect; long-lived gases would require immeadiate reductions in emissions from human activities of over 60% to stabilise their concentrations at today's levels..." was a first assessment report conclusion though it also said "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." You can see this and more from Intergovernmental Panel on Climate Change. The closing of the gap in satellite records was important as solving the most criticised aspect of models but the range of evidence was much greater and not all defeated by a disagreement of data and model over upper troposphere temperatures. 1990 is possibly a little early but not by more than 5 years. If we have a history section, I think it can be kept quite short by having reference to the Intergovernmental Panel on Climate Change page. crandles 13:35, 29 May 2006 (UTC)
 * Your quote says "balance of the evidence". That is a different and less extreme standard than the "debate about the basic facts was over" standard being applied by Stephan.  The satellite discrepency meant there was still debate about the basic facts.  Facts should fit a valid theory.  Many of us are uncomfortable when they don't.--Poodleboy 15:20, 29 May 2006 (UTC)


 * I stand by my description. Maybe we disagree about what exactly are the basic facts. For me, they are that a) humans are adding significant amounts of CO2 (and other greenhouse gases) to the atmosphere, b) this increases the greenhouse effect and hence c) leads to global warming. The 1990 IPCC FAR states (emphasis by me) "We are certain of the following: there is a natural greenhouse effect...; emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases: CO2, methane, CFCs and nitrous oxide. These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth's surface. The main greenhouse gas, water vapour, will increase in response to global warming and further enhance it.". The satellite data were just one minor problem played for much more than it was worth by the sceptics. --Stephan Schulz 15:45, 29 May 2006 (UTC)

I nominated this for the main page
I had to create a brief summary that could fit on the main page. The nomination is at Today's featured article/requests. Feel free to modify as you see fit, I had to cut out a lot of things. Elle vécut heureuse à jamais  (Be eudaimonic!) 01:22, 29 May 2006 (UTC)


 * I tweaked it a bit. Maybe use the obs pic rather than the prediction? William M. Connolley 08:43, 29 May 2006 (UTC)


 * Obs pic? I used the one with the globe on it because it seemed better for the main page, since a graph isn't readable at that point, but a warming globe can be expressed at 180 pixels ;-). Elle vécut heureuse à jamais  (Be eudaimonic!) 17:30, 29 May 2006 (UTC)


 * The proposed main page summary for this article is written in a more neutral manner than the actual article itself. If the main article introduction had all along been written as well as the proposed main page summary, I think a lot of time and energy that was spent in edit wars and heated discussion would have been saved. Cla68 16:36, 30 May 2006 (UTC)

Clear Bias on this Page
There is not a scientific consensus for human-caused global warming. Saying so is a flat out lie. The number of scientists who believe in human-caused global warming is only a small minority. A few extremist vigilante leftist environutjobs are using this page to further their fascist anti-reality beliefs. —The preceding unsigned comment was added by 24.165.87.40 (talk • contribs).


 * If you actually click on the links about the scientific opinion on climate change, you'll find this is thoroughly cited and well-referenced. Also, this is an old moot point that was dealt with long time ago. This article is on the verge of being on the main page, anyhow. As for your allegations of leftist polemic sabotage, I suggest you read Civility. Elle vécut heureuse à jamais  (Be eudaimonic!) 02:40, 29 May 2006 (UTC)
 * There is a scientific concensus that the earth is warming. This article is about all the theories as to why, and which theories have gained widest acceptance. There are some wild claims in the media aobut the effects of global warming (abcnews.com recently had a piece purporting scientists predict rises in sea level of 30 feet over the next century and that global warming has created the need for a "Category 6" for hurricanes) but I don't see any wild claims here. TimL 15:54, 29 May 2006 (UTC)


 * "The number of scientists who believe in human-caused global warming is only a small minority." That's only true if you consider the group consisting of all climate scientists and all Neo-Cons. There are far more Neo-Cons than climate scientists... :) Count Iblis 17:20, 29 May 2006 (UTC)

PB edited the start of the solar section" to better reflect IPCC". His source is:


 * Summary We conclude that climate forcing by changes in solar irradiance and volcanism have likely caused fluctuations in global and hemispheric mean temperatures. Qualitative comparisons suggest that natural forcings produce too little warming to fully explain the 20th century warming (see Figure 12.7). The indication that the trend in net solar plus volcanic forcing has been negative in recent decades (see Chapter 6) makes it unlikely that natural forcing can explain the increased rate of global warming since the middle of the 20th century. This question will be revisited in a more quantitative manner in Section 12.4.

I don't think his edit does what he says. Just adding the first sentence suggests greater effects than by including the rest of the para, in particular it might be better to start the section with The indication that the trend in net solar plus volcanic forcing has been negative in recent decades (see Chapter 6) makes it unlikely that natural forcing can explain the increased rate of global warming since the middle of the 20th century, perhaps? William M. Connolley 18:38, 29 May 2006 (UTC)
 * Your text is not supported by the reference at all. Where do you see support for:


 * "The majority of scientists believe that direct variations in solar output are too small to have substantially affected the climate"


 * In the cited IPCC reference or your quotes above? The reason natural forcings are a net negative, is because they are lumping solar and volcanic together, and of course because they are discussing changes in net forcing.  On an absolute basis solar forcing is positive for the next few dozen billion years.


 * Note that "have likely caused fluctuations in the global and hemispheric mean temperatures" is quite different, in fact some might say the OPPOSITE of the text you reverted to "too small to have substantially affected the climate." Why not improve the text instead of reverting to something wrong?--Poodleboy 05:43, 30 May 2006 (UTC)

What if we had two separte Global Warming pages, each with their own view? Those who believe that Humans are the sole cause use one page and those who don't use another page so we limit the amount of edit wars over global warming. Lord_Hawk 07:25, 1 June 2006 (UTC-8)


 * Wiki doesn't allow such bifurcation, sorry.


 * Atlant 14:33, 1 June 2006 (UTC)

Possible Causes
I changed 'Causes' to 'Possible Causes', because after all, we are dealing with theories regarding the cause of the rise in temperature. Please explain any reverts here on the talk page.Dubc0724 12:46, 30 May 2006 (UTC)


 * Go read the Theory article, then come back here. I believe you don't understand the scientific meaning of the word "theory".


 * Atlant 20:03, 30 May 2006 (UTC)


 * I concur that we should use "Causes" not "Possible causes" to reflect the view of the vast majority of scientists. Formally, yes it is a theory, and may be overturned by new evidence.  But as with the Germ theory of disease, the evidence is sufficiently overwhelming to convince the vast majority of scientists in the field.  We should not say humans may be responsibe for warming the climate any more than we should say bacteria may be a causitive agent in some diseases.  To introduce doubt where there is none is misleading.  --TeaDrinker 20:14, 30 May 2006 (UTC)


 * I've reverted this again. The scientific consensus is that these are the causes, not the "possible causes." TeaDrinker summed it up well, so I won't go into any more detail. E WS23 | (Leave me a message!) 20:20, 30 May 2006 (UTC)


 * I read the Theory article, specifically the theory of gravity. All theories are not created equal, would you agree?  Now, it seems to me that if you don't know for a fact that A causes B, but you're pretty sure it does, good judgment dictates that you say that B is a possible (highly probable, even) cause.  These little things are the things that add up to POV.  Some scientists believe that humans are causing GW.  Some Christians believe that Jesus Christ is the only true Lord and Savior, regardless of what any other religion (theory) says.  Now if I were to post on some article about Christianity that there is no doubt that Jesus Chris is the absolute Lord and Savior, how long would that stand?  I'm neither a theologian, nor a scientist.  But if we accept one theory based on the intensity of its proponents' beliefs, then we should state all theories that have ardent support as fact.  I'm not here to bash GW.  I'm here to learn, just like everyone else. But I do become irked when one's gut feelings, however well-substantiated and well-intentioned, are passed off as undisputed fact.Dubc0724 23:03, 30 May 2006 (UTC)


 * Then let`s stick to the facts and you will find out that anthropogenic global warming is NOT an issue of religious belief. Jesus... Hardern 10:53, 31 May 2006 (UTC)


 * Nobody said that the theory of "anthropogenic" GW had anything to do with religion. You completely missed my point. It had nothing to do with religious beliefs. It was an analogy that apparently you missed in the midst of your knee-jerk reaction.  Maybe I should have used a different example. (This is the exact kind of overreaction I predicted, by the way.)  Thanks for proving my point, although I'm not sure you got it.  Good grief.  Dubc0724 12:32, 31 May 2006 (UTC)


 * But if we accept one theory based on the intensity of its proponents' beliefs, ... But we don't, the theory is accepted based on evidence in support of it. Your proponents beliefs bit said a lot about the religious connection you were making. Please be civil with your comments. Vsmith 13:18, 31 May 2006 (UTC)


 * I wasn't making a "religious connection". There is no religious connection.  I was illustrating the point that we cannot state theories as fact, no matter how many people believe in them.  Again, religious beliefs are irrelevant, other than as I used them to illustrate the point.  I wish I had used some other analogy.  And I've been as civil as anyone else here. Dubc0724 13:37, 31 May 2006 (UTC)


 * See, you've just illustrated the problem I've been trying to point you towards: to a scientist, "theory" is about as certain as you ever get. Scientists really don't believe in "facts" as in "things we believe with absolute certainty". But to a layman, corrupted by bad (sloppy) science reportage over the years, "theory" means "unproven but possible explanation" while "fact" means "proved". When a scientist tells you that it is a theory that the current round of global warming is being caused by human activity, that doesn't mean that it's only one possible explanation among many. It means that all the testing so far has supported that hypothesis and it has advanced to what a lay person would call a "fact".


 * A lot of politicians and media pundits in America today exploit this difference of definitions for their own ends (both here and in the "Creationism/Intelligent Design" debate). But this isn't a case where "words mean just what I say they mean"; there are real, broadly-accepted definitions here and there are real experiments that tested the hypothesis before it was accepted as a theory, and no matter how much Rush Limbaugh, or George W. Bush, or the president of Exxon-Mobil objects, it's not going to change reality: The earth is warming as a direct result of human activity.


 * Atlant 14:27, 31 May 2006 (UTC)


 * (edit conflict) Have you already read the above discussion about theory and fact here? I think there it's settled quite well. Hardern 14:29, 31 May 2006 (UTC)


 * I never said that it was simply one "possible explanation out of many". I even said it could be presented as the overwhelmingly probable cause.  So I question the foregone conclusion that the only way to explain any gradual increase in temperatures is to blame humans (Americans?) and now I'm either a right-wing sycophant or a religious fundamentalist zealot.  In actuality I'm far from either.  I'm not even saying anthropogenic GW doesn't exist. I'm just someone who is tired of the arrogance displayed by presenting working theories as incontrovertible facts.  Call me a layperson if you need that kind of reassurance, but there is still a difference between a theory and a fact. Cheers! Dubc0724 15:35, 31 May 2006 (UTC)


 * Which is exactly? Hardern 17:24, 31 May 2006 (UTC)


 * Theory ...... Fact.  Dubc0724 17:33, 31 May 2006 (UTC)


 * With that reply, you get points for terseness, but not for clarity. Here's a statement from the lede of the Theory article:


 * It follows from this that for scientists "theory" and "fact" do not necessarily stand in opposition. For example, it is a fact that an apple dropped on earth has been observed to fall towards the center of the planet, and the theory which explains why the apple behaves so is the current theory of gravitation.


 * This statement seems to support my (and Hardern's, etc.) claims about the scientific meanings of the words "theory" and "fact".


 * 17:40, 31 May 2006 (UTC)


 * Ah, clarity is overrated anyway. :-) I'm giving up, because I really don't care anymore, and I know I'm not making this any clearer by arguing. I do think I had a valid point, though.  It's funny, over the last few days when I Googled global warming, how many articles are written by right-wing groups denouncing GW and how many are written by left-wing groups holding GW as the most serious issue in the world.  Honestly, this can't be a party-line issue. There's got to be some middle ground backed up by science that hasn't been bought & paid for.  As for me, I'm more confused than I was when I started looking at this article.  Good luck.  Dubc0724 18:10, 31 May 2006 (UTC)

Actually, to a scientist, theory ≠ proven fact. Although "'theory' and 'fact' do not necessarily stand in opposition", they don not necessarily stand togehter, either. A more scientifically accurate set of definitions would be:

Hypothesis = "unproven but possible explanation" Theory = Possible explanation that has some experimental data backing it up, but which has not yet been conclusively proven. Law = Theory which has stood up to repeated experimental scrutiny and, therefore, has been generally accepted by objective scientists to be a proven fact.

Examples: Laws Newton's laws of motion the combined gas law the 1st 2nd & 3rd laws of thermodynamics Theories the Germ theory of disease is still a theory because debate still exists, as evidenced by the final paragraph of that wiki entry evolution is still called a theory, because no one has lived long enough to gather sufficient observational data to conclusively prove it (see Scientific method for more on how this works) GW is a theory because debate is still ongoing about many possible explanations for the increase in global temps including -- but not necessarily limited to -- natural cycles, increased solar activity, increased vulerability to solar activity due to earth's weakening magnetic field, human causes or a combination of any/all of these.

Oh... and so that no one confuses my words as the uninformed babblings of a layperson, my background is in microbiology & biochemistry, so I am a scientist. — Preceding unsigned comment added by 130.36.62.129 (talk)


 * I disagree somewhat. "Law" is used to describe a relationship, generally mathematical, even if that relationship is empirical.  "Theory" is used to describe a set of explanations that have been supported by observation.  There isn't a simple "law -> theory" heirarchy.  For example, we have a "Law of gravity" (empirical, Newton) and a "Theory of gravity" (including relativity, due in part to Einstein and later developments) which encompasses the "law".  This does not mean that "laws" are proven and "theories" are not.  The "germ theory of disease", for example, is not called a "law" because there it doesn't state a mathematical relationship, not because it's not "proven"; it will never advance to a "law".  (Also, please sign your comments with four tildes, thus: ~ .)  bikeable (talk) 17:32, 13 June 2006 (UTC)


 * I disagree quite a lot, and agree much more closely with what bikeable said. For example, Newton's laws of motion are passe, supplanted by Einsteinian notions of curved spacetime.


 * Atlant 17:41, 13 June 2006 (UTC)


 * Here we go again, and I can't help but jump in. The example of the theory of gravity keeps getting used.  It's said - "hey it's a theory, but everyone agrees it's true."  How about the Single Bullet Theory?  It's a theory supposedly supported by some empirical findings, but something along the lines of 80% of the population doesn't buy it.  I'm making this analogy this quite tongue-in-cheek, mind you, but it does beg the question: Are all 'theories' created equal?  Dubc0724 17:56, 13 June 2006 (UTC)


 * No, all theories are not created equal. But scientists simply do not have a word for "theory-which-is-known-to-be-true", which I think is what you are looking for.  That may seem strange to a nonscientist, but it's easily explained by two facts: First, you can't prove a theory true (you can only falsify hypothesis, at least in a Popperian view of science); and second, any theory can always be replaced by one which has more explanatory power.  Even a theory which fits all the data, which you might want to call "theory-which-is-known-to-be-true", could be replaced by a broader theory which offers better explanations for more predictions.  So scientists just use the word "theory", and it is clear enough to people in the field where the various theories fall in terms of explaining data.  This is, arguably, a shortcoming of scientific terminology and a failure to properly communicate things to the public; but you won't find a stronger term than "theory".  bikeable (talk) 21:56, 13 June 2006 (UTC)


 * OK, if GW is a theory, and you're OK with that, why does everyone bristle when the word theory gets introduced into the article? If "you won't find a stronger term than 'theory'", why is this such a big deal? Nowhere in the article is GW referred to as a theory. Call a spade a spade. Dubc0724 12:23, 14 June 2006 (UTC)


 * Your very first edit at the top of this section explains that: its the way the word "theory" is used William M. Connolley 15:59, 14 June 2006 (UTC)


 * All I said was that we are dealing with a theory regarding GW. Is that not true?  In fact I think the whole argument about this 3+ weeks ago stemmed from the fact that "theory" isn't being used in the article.  If you search for the word theory, it only comes up in reference to theories other than anthropogenic GW.  And global warming itself is not referred to as a theory.
 * I understand your contention that the average layperson doesn't understand the "true" (scientific) meaning of the word theory, but correcting that misconception is (or should be) the purpose of the Theory article. There are lots of things that the average person doesn't understand, but that doesn't mean we can ignore them.  Dubc0724 16:12, 14 June 2006 (UTC)


 * Three reasons, off the top of my head. First, if everything in science is a theory, why bother putting that in here?  We know it's a theory.  The page on Magnetism doesn't say "theory of magnetism", it just describes what magnetism is.  Which leads me to the second point, that it introduces a needless abstraction: the article is not about the scientific theory, it is about the process of warming itself.  (Having some content in the article about historical development of our understanding is totally appropriate.)  (If it's not clear what I mean by "abstraction", consider changing the page to say, "'Global warming' is a phrase used to describe a theory that...".  Then the page would be about the phrase, not the theory or the process of warming itself.)  Finally, and most importantly, most people don't use the word "theory" to mean what it means to scientists, so adding "theory" creates misunderstandings, as you have already illustrated with Single Bullet Theory.  For precisely the same reason, we have to take the phrase "theory of..." out of the Evolution page every few days, because people keep putting it in because they think it is a way of making it sound somehow disputed.  This is an abuse of scientific terminology.  bikeable (talk) 17:49, 14 June 2006 (UTC)


 * First, if everything in science is a theory, why bother putting that in here? We know it's a theory. Who is the target audience of this article?  If it's written by (largely pro-GW) scientists for (largely pro-GW) scientists to read, everything you just said is 100% dead-on right.  But if it's meant to be a true encyclopedia article, then I'm not so sure leaving out the word theory is such a no-brainer.  "We know it's a theory" may not work if you have someone fresh off the street who wants to learn about GW.  (This of course assumes (and depends on) the good faith contributions of all parties, not just here but throughout Wikipedia.) Just my two cents and a little bit of the ol' Devil's Advocacy...make of it what you will. Dubc0724 18:32, 14 June 2006 (UTC)


 * Because, as has been said over and over, "theory" means something different in a colloquial and in a scientific context; and "theory" is inserted into this article (and into Evolution) specifically to cast doubt -- inappropriately, as I (and others) believe. bikeable (talk) 20:47, 14 June 2006 (UTC)