main_climate_skeptics

The Climate Deniers vs The Consensus

Monday, December 7th, 2009

A visual map of the arguments for and against human-caused global climate change. I’m fascinated by climate deniers.

How could anyone deny the climate change is happening? What evidence is there? Surely it’s unambiguous? Curious, I investigated the key statements made by climate denialists and sought out the counter-views, as presented by climate research scientists. The result is this image. (This a new and updated version of the spread on Climate Skepticism from my book The Visual Miscellaneum)

Method

I researched this subject in a very particular way. I deliberately chose not speak directly to any climate experts or leading scientists in the field. I used only publicly available web sources. Why? Because I wanted to simulate what it’s like for people trying to learn about climate change online. My conclusion is “what a nightmare”. I was generally shocked and appalled by how difficult it was to source counter arguments. The data was often tucked away on extremely ancient or byzantine websites. The key counter arguments I often found, 16 scrolls down, on comment 342 on a far flung realclimate.org post from three years ago. And even when I found an answer, the answers were excessively jargonized or technical. Most of the info for this image is sourced from Realclimate.org. It’s an amazing blog staffed tirelessly by some of the world’s leading climatologists. Unfortunately, the majority of the writing on there is so scientific and so technical, it makes the website nigh on useless to the casual, curious reader. This has got to be one of the reasons why scientists and leaders are struggling to convince sections of the populace that the threat of climate change is real. Because they’re doing such a terrible job explaining it. (Saying all that, I would like to express my gratitude to Gavin A Schmidt, one of unsung heroes of the web IMHO. His sterling and patient replies to comments, on RealClimate.org in understandable English, have really helped this process.)

Runaway Feedback

This image was a mammoth undertaking, especially for someone like me, unschooled in climate science. So I appreciate your understanding if any errors have crept into the process. If you spot any, please get in touch and I’ll will correct them on the double. In every case, wherever possible, I went back the original data. (I’ve included a ZIP of all the data I’ve collected plus a spreadsheet of all the sources). And all the graphs in the image are generated from the original temperature records and other data sources. Feel free to rifle through and check everything. RealClimate.org are (now) keeping an archive of all the data – if you want even more! http://www.realclimate.org/index.php/data-sources/ UPDATE 1 (12th Dec 09): There have been a few complaints about the legibility of the image. So I’ve created a version on white instead of black.


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Show Comments ( )

  • samuel black

    The explanation for CO2 lagging the temperature is a little weak.

    The periodic nature of the temperature changes suggests an astronomical root cause; some kind of periodic fluctuation in the orbits, or in the sun’s activity. Unless one can think of a direct astronomical cause of CO2 release (or some other periodic reason CO2 should be released), it would be very surprising to see the CO2 levels leading periodic temperature changes.

    The data show that warming temperatures, whatever the initial trigger, cause the release of CO2.

    The question is whether the release of CO2 produces a positive feedback and increases the amplitude of the cycles. Here the failure of well-understood astronomical calculations to account for the amplitude of the temperature changes suggests such a role for CO2.

    It’s no slam-dunk, but the implausibility of CO2 leading periodic temperature change should be emphasized.

  • Rick

    The best place I have found to get info from the skeptics is http://climateaudit.org/

  • Creemer

    Maybe I missed it, I haven’t read all the posts here. But why is there so little mention of the (supposed) fact that all planets in our solar system are heating up? Seems to me a point worth consdidering and investigating in the muddy light of this endless debate.

  • http://blogjack.net Glen Raphael

    The key problem with this whole endeavor is that your info discovery process was guaranteed to produce confirmation bias for your existing views, to incorporate as wisdom the claims made by random anonymous blog commentators, and to exclude the possibility that the “denialists” might be right in any aspect. You wrote:

    I investigated the key statements made by climate denialists and sought out the counter-views, as presented by climate research scientists.

    I would be interested to see what would happen if you were to make a second chart based on doing the exact reverse process. That is, investigate the key statements presented by climate research scientists and seek out the counter-views, as presented by the most credible skeptics you could find. Present the statement on the left, response on the right, appropriate graphic in the middle.

    [Thanks a great idea. Can you do it and show me? You needn't do the graphics. Just the text would be good. Thanks! David]

  • Karl

    Great piece of work. I have been perplexed for some time by the ‘consensus’ side’s unwillingness to engage with the debate in anything other than the shrillest of terms. It plays into the skeptic-seeded doubts about the ‘consensus’ motivations and transparency, and does them no good. This is one of the few efforts I have seen to provide sober, sourced rebuttals. Thanks!

  • Adam

    Creemer raises an argument common among skeptics which should be addressed. Climate change similar to Earth has been observed taking place on Mars, Pluto, Triton, and Jupiter.

    Another important fact brought to light by the Climategate e-mails (also not addressed in this article) is that the last 150 years of the sole, raw climate data from the world’s leading climate change research organization has been deliberately thrown out, leaving only adjusted / synthesized / “value-added” temperature data for the world’s scientists to go on.

    Finally, in the 1970′s, there was a scientific consensus surrounding global cooling, of all things. That should be addressed as well.

  • http://www.thinkinginanutshell.com Chris Wenham

    Please use the terms “denier” and “skeptic” consistently and correctly. In the Title element you use the term Denier, and then in the body you use Skeptic.

    These terms are not interchangeable.

    A climate skeptic doesn’t deny AGW, they just demand the evidence and process is made public before believing in something.

    I’m a climate skeptic and I don’t have a problem with the conclusion that there is a warming effect, nor that this effect is due to human activity. I simply insist on seeing the evidence and the process first.

  • http://www.ORWW.org Bob Zybach

    Nice work — Thanks!

    Other commenters have provided good inisghts on biases and other weaknesses in the presentation, and (to your credit) you have addressed their concerns.

    Keep up the good work!

  • http://blogjack.net Glen Raphael

    Thanks a great idea. Can you do it and show me?

    As you said, it’s a lot of work. And not my top priority. But the fact that you had to resort to obscure 17th-page-of-realclimate arguments might have given you pause to consider that perhaps the counterarguments you found were justifiably obscure. For all you know, there might have been an even better counter-counter-argument on some 4th-page-of-climateaudit that blew your chosen counterargument away, but your methodology – start a claim, find a counter, then stop – would never find it. You were only searching to *enhance* the counter, not the original argument. So the more searching you did, the better the counter looked.

    I can’t invest the time to do the whole thing, but there are a few I can address off the top of my head, so let’s start with that. Item #1: the “hockey stick”. You show two charts with confusingly different – and hence not really comparable – horizontal axes, *neither* of which goes back far enough to address the skeptical claim about the stick. The consensus prior to MBH98 was that there was a cold Little Ice Age(LIA) and a warm Medieval Warming Period(MWP). The big news about MBH was that it had a stick that went – not just back to 1880 like your chart shows – but far enough back to wipe out the MWP. The shaft of their stick – the one under dispute – went back more than a thousand years. It’s primarily the flat long shaft, not the existence of a steep blade at the end, that is being questioned. So a “stick” that goes from 1880 (your chart on the left) or even from 1400 (your chart on the right) doesn’t speak to the question. What you want to show is the 2000-year trend. There aren’t many reconstructions that long. Until recently all the ones there were got their shaft – and some of the blade – from tree rings, and the skeptic consensus is that tree rings are not reliable long-term temperature proxies. Why not? Because specific trees don’t *stay* temperature-limited over a period of centuries even if they were during your “calibration period”. (Look up “inverted-U growth response curve” and the recent work of forest ecologist Craig Loehle). There are reconstructions based on boreholes and sediment layers that show a much wider variance and a very warm MWP. This is important because if the MWP was about as warm as present – which seems likely – then (a) current temps aren’t provably “unprecedented”, and (b) there’s more “natural variability” than is reflected in the current models.

    There’s a *lot* more to be said about the climategate letters – read the last dozen Climateaudit posts for more detail. The main thing you miss is on “hiding the decline” – the fact that the reason for divergence is “unknown” (according to your own text!) implies it might have happened before. The idea that the post-1960 decline was human-caused is a *guess* – there is no proven mechanism. An at least equally-plausible guess is that trees aren’t good proxies as the temp increases, which implies doubt about what the tell us regarding the MWP.

    That’s enough for now…

  • woodsy42

    I would agree with you about the difficulty of finding honest unbiased information. Any honest science has by now become so overlaid with vested interests, political manouvering and commercial profit that nothing you hear or read can be entirely trusted. And it’s not a simple situation anyhow. Virtually everyone realises that climate changes over long periods, it always has. The key question is whether CO2 is the most important factor? If so is it ‘our’ CO2 and can we control it? Even then should we even try because it’s hiddeously expensive and maybe won’t solve the (maybe non-existent) problem? Indeed if warming has ended we may be entering a cooling phase – and that’s really dangerous because of its effect on crops and energy needs. By comparison being warmer is actually a bonus to much of the world.
    Science can point a direction or even identify a problem but as yet climatology, a new science, cannot answer the subtle question of ‘how much’ nor should science ever try to define the social/political response. All we can say is that the alarmist scaremongering now being used to brainwash our children and politicians is certainly grossly exagerated by the people set to gain from it. There are many problem in the world, from deforestation to famines through fires and floods. They were around before global warming and arguable are way more important and urgent than a potential (but unproved) increased sea level in 100 years because people are dying now this very minute!
    As you also note much of the genuine honest scientific thinking takes place on specialist sites which make few concessions to an ordinary person’s understanding. That too makes much sensible opinion inaccessible to many people.
    But you need to be very aware that Realclimate.org are a very one-sided propaganda site. They may seem very reasonable and understandable but it was set up deliberately by members of the ‘man-made global warming’ community to push their own agenda. Look more carfully at some of the ‘put-downs’ and you’ll see how many questions are glossed over. Likewise much mainstream media is very biased on its coverage and there is a row currently about Wikipedia coverage having been hijacked by an ‘evangelical’ extremist environmentalist.
    As Glen suggested try doing the exercise the other way around, your method has a built in ‘establishment’ bias. Start with the premise that nothing unusual is happening and you might be surprised where you end up.

  • Josh Cryer

    See these comments, David? This is why, it’s not that people can’t understand, it’s not that people can’t learn. It’s that herd mentality has pushed more and more people into a cycle of ignorance. The first comment is someone telling you that you are forming your bias before you do your research, when in fact the process of doing the research is having an open mind! No matter *what* someone says on either side of the debate, researching what they say is a necessary condition upon understanding what is going on. The denialists rely on people not doing that research, so you get comments like these. They don’t realize it takes much more effort to actually go and read a scientific paper to understand, for instance, why USGHCN adjusts their data so much (TOD changes, from PM to AM, cooler measurements, biased the wrong way).

  • Josh Cryer

    And Glen Raphael, the reason you won’t or can’t do it from the opposite manner is that there are no accurate counter arguments. You cannot invoke scientific literature to “prove” that AGW isn’t occurring. Instead you would have to resort to blogs. This is why the recent trend in denialism is to try discrediting the scientists, because that’s all you got.

  • http://lesposen.wordpress.com/ Les Posen

    @ Scott A. Mandia

    Are you sure you gave that Powerpoint stack talk in a public setting, not a scientific setting?

    I mean, to members of the general public with little knowledge of scientific method, or knowledge more based on what they perceive of science as portrayed in the mainstream media?

    If it was the latter, you had your work cut out for you! But as I have written elsewhere, you may not have served your cause well by your slide construction. I’m trying to place myself in the shoes of your lay audience, despite having post graduate qualifications in the biological sciences.

    I’ll be blunt here, but if I was in the audience, not matter how smooth your delivery, I would feel like the proverbial goose under going gavage!

    The human brain can only take in so much information at a time, but your slide stack could fill a book, to be read carefully over a number of hours or days. But to take it all in a one hour public session, no matter how good your delivery? I don’t think so…

    Perhaps make an attempt to provide the salient evidence with far simpler slides, one idea per slide, one change/time per graph, which you build up over a number of slides, until you’re sure your audience gets the essence.

    It’s an extremely difficult proposition I know, but for public talks, rather than those intended for peers or students, the message will be more persuasive and you more authoritative, rather than less.

  • PeterD

    David, you point out that:
    <blockquote cite=" [The CO2 precedes the temperature rise. In past cycles, the CO2 has come after the temperature rise - David] "

    Not if the MWP actually existed.

    [Yep - David]

  • elder norm

    First of all, thanks for trying to present a straight forward view of both sides arguments.

    Second. The skeptics really scare me. Its like if they can hide their head in the sand, then its not happening. And if its not happening then they can continue messing with the environment as much as they want. Big business in the US seems to only think of this quarter and stock prices. I plan to live a bit longer and my kids should be around for a while, so I would like to see the world, in general, just focus on facts and not how much they can ignore.

    While I do not think we have all the parts of the equation, we are getting a better and better picture. Burning off the rain forest not only adds co2 … but reduces o2 and leaves a scar on the world for instant profits only.

    Such short term thinking is greed only. Screw up you and everyone else for me only.

    PS that 10,000 acres of floating plastic is real too, but if we ignore it, I am sure it will just go away, ….. eventually,….. right?

    Just a thought,
    en

  • http://blog.monstuff.com Julien Couvreur

    There is an important logical step which may be missing on the “man-made climate change” side of the poster: which step proves that the change is due to CO2 (and thus man-made)?
    If you find out a succinct statement which explains this conclusion, it would be a worthy addition to the poster.

    Since this is the most important conclusion from the IPCC, there should be a logical chain of falsifiable statements leading up to it. I was not able to find that chain explicitly summarized anywhere…

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    The Information is Beautiful website has the full sized version that’s much easier to follow and read. Unfortunately, if I’d put that here, I would have completely screwed the column format – so had to work with the dimensions. This is the first graphic I see that eliminates all the fluff and sticks to facts.

  • Lockie

    I’m *amazed* by the energy of the sceptics, so many of them feel so incensed that they need to comment even though they’ve almost certainly done only a tiny fraction of the reading on this topic versus yourself (or anyone with a genuine background in climate science for that matter)! Never before have I witnessed the uneducated masses (and I say uneducated not in an absolute sense, but in a contextual sense in relation to studying climatology or renewables etc) had so much to say in relation to such a highly technical field based on their (generally) assimilated learnings from various websites and books. The level of vocalism is astounding; people don’t get excited about cigarettes and lung cancer correlation, they don’t get excited about the nuances of competing super string theories, they don’t even get excited about evolution much anymore but suddenly AGW gets under the skin of a whole group of people that would have previously had no discernable interest in the climate. I wonder if they ever ask themselves why they care so much, what really grinds them about this particular topic and not so many other important issues that they could devote their energies towards. David, please be assured that many believers in the consensus are undoubtedly reading this and enjoying your graphic and detailed research as I did. They are just not adding a comment because they don’t have a bone to pick; I only did because of the almost hilarious (if it wasn’t so wasteful and pointless) level of scepticism in the preceding comments

  • woodsy42

    Elder Norm, why do you make the assumption that:
    “Its like if they [skeptics] can hide their head in the sand, then its not happening. And if its not happening then they can continue messing with the environment as much as they want.”
    Can’t you see this sort of simplistic insult is just parotting the alarmist brainwashing process. They would love to suggest anyone opposing them is stupid and anti-social but actually being skeptical of the alarmist CO2 bandwagon does not prevent anyone being seriously concerned about good environmental housekeeping, world resources and care for the environment.
    Indeed if you can just free yourself from the arguments about the role and control of CO2 it’s very obvious that the resources already being used, and the deliberate future reduction in prosperity that will be caused battling CO2, means important and urgently needed environmental action is already being ignored and this will likely have worse serious future consequences than a degree of warming! This Canute-like attempt to divert our resources into trying to prevent the irrelevant (or inevitable) is what scares many skeptics, not a desire to ‘mess with the environment’ as you rather unpleasantly phrase it.
    You mention deforestation – This is a good example because it’s very important as an issue in it’s own right. It deserves support and action for many reasons, not because of CO2 or climate change, so why relegate it to a subset of CO2 management and dream up fancy cabon trading schemes and other complex nonsense instead of getting on with the job and doing something about the trees being cut down now?
    And while I’m here I would also like to pick you up on the other bit of propaganda that you seem to have swallowed and regurgitated. You say: “Big business in the US seems to only think of this quarter and stock prices.”. Well of course they do, business is depressingly obsessed with short term profts and to hell with the consequences. But look behind the global warming rhetoric and you will see that big business is not driving skeptical global warming opinion. Just the opposite. The really big future profits are to be made in ‘green’ technology and especially in trading carbon credits, which is set to become a trillion dollar international market. You’ll find most major banks, energy companies and commerce already have trading divisions ready for the carbon credit feeding frenzy. These are the people pushing ‘cap and trade’ carbon schemes, they won’t help the environment.

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  • http://www.hawrivertrail.org Mike Holland

    Thank you for this monumental task of boiling down this largest of subjects for everyone to digest. This is a great service. You have our great admiration.

    Without saying weather I agree or disagree, let me say that as a scientist I withhold final judgment until the experiment is complete, and we are still in the middle of this, greatest of experiments in terra-forming. IF Global warming is human-driver, the world will become drastically unlivable for the majority of humanity, if we are not the cause, the world may still become unlivable, but in the meantime, what sense does it make Not to Act. We may end up with a world with less pollution, less extractive energy policy and more personal quality of life from making the adjustments needed to counter supposed human causation, so I have to ask what will be the harm; on one hand we have the possibility of saving mankind and on the other we risk supposed significant depression in jobs and economy… I certainly find this an easy choice to make, right or wrong in my belief in human’s culpability.
    Thanks again for your great effort.

    Mike

  • http://midwestoutreach.org/blogs/ Ron Henzel

    Geologist Dr. David Gee, chair of the science committee of the 2008 International Geological Congress and author of 130 plus peer reviewed papers said, “For how many years must the planet cool before we begin to understand that the planet is not warming? For how many years must cooling go on?” (Dr. Gee is currently at Uppsala University in Sweden.)

    These and many, many quotes from scientists engaged in the climate debate can be read in the “U. S. Senate Minority Report: More Than 700 International Scientists Dissent Over Man-Made Global Warming Claims Scientists Continue to Debunk ‘Consensus’ in 2008 &
    2009″ (http://hatch.senate.gov/public/_files/USSenateEPWMinorityReport.pdf).

    Even the most committed global warming kool aid pushers are now reduced to urging cap-and-trade policies as a form of “risk management” because the science has become so unsettled and questionable (cf. http://midwestoutreach.org/blogs/from-the-feckless-to-the-reckless).

  • Nom_de_Guerre

    As someone who lived through- with direct experience- the desinformation campaign by Big Tobacco against public health organizations and NGO’s, and which tried to constantly discredit scientific consensus-driven resolutions by another UN Panel (WHO), while promoting “debate” and fighting “alarmism” and “government control” around restrictions on tobacco consumption, this whole “skepticism” situation seems uncannily similar.

    It’s amazing that our culture is completely unable to learn from experience, when faced with the duty of personal responsibility.

    It is also a complete failure for the credible scientific institutions, who are unable to get acrosss the general public, and especially the UN, who even after being right on their technical assessment of the (un)existence of Iraqui WMD’s and being ignored, at the cost of many lives, still hasn’t gained the trust of American society…

  • Chad Brick

    I thank you for trying David. Unfortunately, you are caught in the same conundrum that the whole media is: How do you present both “sides” of an argument fairly when one “side” out-numbers the other 30:1 among professionals? In your chart, you clearly give equal time to both, but is this just?

    You also have to deal with another problem: It is always easier to make false or misleading claims than to refute them. Skeptics are spin-meisters, often fitting multiple falsehoods into single sentences. If an interview gives them 45 seconds to babble, they can easily fit in half a dozen lies. Then some poor scientist is given 45 seconds to refute them, it is absurdly impossible, as it often takes minutes to make a technically correct refutation of a single point. Neither the audience nor the media has the patience for this, though I would love to see just one interview where the denialist hack was surprised to find out that he was debating THIRTY people, and each one would get equal time to shred him.

    As a note to Gene Mete: As a scientist, I have no problem using the word “denier” for political hacks that know little or nothing about science, but are just spouting their twisted ideology. However, I do use the word “skeptic” for people like McIntyre, Christie, Lindzen, etc who are professionals and limit what they say to at least something resembling the facts.

  • Tilman

    1. On “we don’t even have accurate temp records” you could add that there are satellite temp records too, not only the land-based stations. and the satellite data shows the warming too. additionally, temp-profiles of the oceans are measured, with the result that the heat content of the oceans is rising too.
    2. On “rising CO2 is not always linked with rising temp” you could add that there is natural variation in any measurement of the climate system, for example because heat content shifts in cycles between the oceans and the land surface, and a lot of other effects. That’s why we will always measure “variations + trend” and not only the trend. If the variations in a particular timeframe are -0.2°C and the trend is +0.2°C, you get zero. But if you average over large areas and long timeframes, variations will cancel out and the trend will remain.
    3. Maybe you should add the denier-argument that there is no “direct link”, and counter it with the fact that there are measurements by satellites which show the absorption bands of CO2 increasing over the past 30 years, consistent with the rise in CO2. You could also point out that the stratosphere (a higher layer of the atmosphere) is cooling, which can only be explained by a change in radiative transport due to greenhouse gases, like CO2 and methane. if for example the sun would be the source of current warming, you would have to see a warming stratosphere too, which is not the case.
    4. You could also counter the argument that the CO2 in the atmosphere does not rise because of human influence by the fact that “old” CO2 (from fossil fuels) has different isotope concentrations than “young” CO2 (in contact with the atmosphere). by measuring the change in isotope concentrations, we can measure how much “old” CO2 is pumped out of the ground and added to the atmosphere.

  • Carol

    First of all, thank you for trying to address the topic in a point-counterpoint way, to simplify and compile information gained from your research, boiled down to the sound-bites that people seem to need. Climate change, deforestation, water availability, soil erosion, declines in biodiversity, antibiotic resistance, etc. are all complex issues, to which new information is constantly being applied. New information results in the re-evaluation of the data, methods, and arguments drawn from them. THAT is how science works. Btw, as a former science teacher, I am saddened by the propensity of the American public (and media) to separate almost any analysis into exactly two opposing views. Sadly, it seems that is what is in demand. So I applaud your effort to help those who can’t see a middle, or an interplay of ideas and information.

    Scientists criticize their colleagues’ work, and if it withstands the test of time and criticism (and new discoveries) it persists. It’s not a perfect process, but it enables our understanding to evolve. The strength of the science comes not from a single method, research group, or country. Instead, many types of evidence exist, and analyses of the many natural and human records allow broad understanding to develop.

    Unfortunately, for many people, the fact that scientists disagree (often over the details, not the trends or basic scientific principles) leads some to think that they don’t “know”. They presume we can wait until they do agree, or at least until the scientists are more sure before acting.

    The question for all of us is what steps can we reasonably take to reduce the potential effects of rapid change, and where are those energies best spent? (pun intended). There was probably angst over the implementation of our interstate highway system too. It was a major shift in thinking, which took away some land, used huge amounts of resources, and took years to become fully functional. Does anyone want to go back? Surely we can learn how to be cleaner and more efficient…(at some cost, but also with some benefits). It seems particularly short-sighted to remain dependent upon fuels that we must import from people who don’t like us; or feel a need to remove mountaintops, pollute the ocean, and clog the air with particulates just to do what we have gotten used to doing. That is especially problematic when other options that can also help our economy rebound are within reach.

    P.S. As you know, ice cores provide multiple types of evidence, not just CO2 in bubbles. The gases trapped in the bubbles are dependent on accumulation rates and temperatures in the ice field. The oxygen isotopes (as a proxy for temperature) can usually be determined on an annual basis, however. Then you’re back to comparing CO2 from a variety of other sources with the temperature record. Thankfully, CO2 is well-mixed in the atmosphere, so it doesn’t have to come from the same source.

  • http://www.brainrap.com Michael Coleman

    It seems to me that one weakness in both the for and against arguments is the lack of discussion on the basic equations used in the climate prediction models. In that regard the issues include
    1) The accurate measurement of the current stste of the atmosphere on a global scale This is the starting point for the models use to predict out to 20years or more so it is very important.

    2) How well the equations used in the models represent the various atmospheric processes and their interactions. In some cases the equations can only be solved by making assumptions which means that by using different assumptions the models will produce different solutions

    3) The need more more understanding of the role of feedback mechanisms such as the capacity of the oceans to act as a sink for CO2 and the role of cloud cover and its relation with low-level and surface temperature.

    In summary what I’m saying is that before we get too caught up in the for and against stuff we ought to try to understand how the predictions are made and how reliable they are. It is sometimes argued that if a number of global models come up with the same outcome then that must be accurate. Of course if they use the same equations and same assumptions what else would you expect. However, if one model incorporates, for example, the formation of low level cloud because the temperature is warming the result will likely be quite different from a model that doesn’t.

    If you are interested I have a post on my brain healthblog about climate change and air pollution

  • SLRTX

    Check out this site.

    John Cook, the site owner, has done a good job compiling the arguments, and explaining the science to counter the arguments. Lots of good links to the sources.

    http://www.skepticalscience.com/

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  • Michael

    I love the balanced way you showed the debate. Nicely done.

  • Jez Hunter

    Thanks. Like the site. Keep up the good work please.

  • Sapincher

    My favourite quote from this chart is in reference to tree-ring data showing a decline in global temperature as opposed to increase:

    The decline occurs in only a certain type of tree-ring data (far northern trees). The reason is unknown. But a human cause such as air pollution is suspected. For this reason, tree-ring data is considered unreliable from 1960 onwards. And, overall this tree-ring data is just one of numerous records used to reconstruct past climate.

    Hold on let me translate that for you

    Yeah, it does show decline. But only on half of the planet. We probably did it anyway! Even though we are arguing that we are actually increasing the temperature of the planet… Anyway to make things easier for us we’re just throwing away all of the tree-ring data except the stuff that helps our case! And this is just one of many sources too, so we have plenty of other ones to throw away as well.

    And earlier in the chart it talks about correcting the data for ice samples to account for modern air that leaked into them. And instead of throwing out the obviously unreliable, tainted data, they just “corrected” it in their charts as opposed to throwing it out like the tree-ring data.

    Yes, this chart presents an incredibly powerful argument to those damned-nonbelievers!

  • Nigel

    Great work! This was compiled and presented really well and certainly shows that in reality, no one on either side has CONCLUSIVE evidence, it can always be challenged. I’m still not too convinced on human-induced climate change, it’s cyclical. But, there’s nothing wrong with us all becoming greener, there’s just something wrong with doing it for the wrong reasons and being misled in the process.

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  • Peter

    I had only minor interest on the topic of global warming until a friend posted a link to this chart on his Facebook page.

    Unfortunately the chart put me in the non-believers camp. :)

    1. I noticed that all the warmist counter-arguments focus on “Yeah, our evidence is kind of shaky… but your evidence for the contrary is not conclusive too!”. Hardly a compelling argument on the “consensus”.
    I like best the No Medieval Warm Period argument:
    “Yeah, in Greenland they were growing crops and it was warm north for hundreds of years. But you never know – it might have been cold in Australia to balance things out.”
    Kind of convenient the Vikings didn’t colonize the Antarctic too, just to spite modern environmentalists. :)

    And the C02 800-year lag counter-argument is laughable. So let me get this straight:
    1. Weather warms for 800 years for unknown reason.
    2. CO2 catches up and starts to rise
    3. The unknown reason is no more responsible for warmer climate – it’s now CO2 and it’s a chain effect
    4. As the chain effect grows even stronger yet another unknown reason starts to sharply cool the weather.
    5. 800 years later CO2 gives up and starts going down too.

    Heck of powerful “unknown reasons” if you ask me. Might be good to know what they were before and check for their presence now before we start crying “close the factories”

    2. Made more research and watched these excellent movie series:
    http://www.youtube.com/watch?v=hpWa7VW-OME&feature=related
    Individually the arguments are weak but the sheer ammount is staggering. Of note:
    2.1 The direct correlation between sun and temperature explaining pretty much everything:
    http://www.dailytech.com/NASA+Study+Acknowledges+Solar+Cycle+Not+Man+Responsible+for+Past+Warming/article15310.htm
    2.2 You can’t really argue that man-made global warming research tends to get a lot of funding and attention in the past decade and the sceptical argument didn’t even get a hearing until the current (probably temporary) global cooling trend started.

  • carrot eater

    Getting better. Still some nits to pick. If I’m not mistaken, the post-1960 trick refers to a plot that appeared in a WMO report, not any IPCC report. That WMO report was long-forgotten. The more common practice is to show separate curves for the modern instrument record and the proxy-based data; you should check, but I think it was always done that way (separately) in the IPCC reports.

  • carrot eater

    Peter, there is nothing unknown about the root cause of the ice age cycles. The underlying cause is variations in the earth’s orbit that change how much sunlight gets to the earth. Those changes cause the initial warming or cooling, and then CO2 follows and amplifies the effect. After a while, the orbital variations go back the other way, and the reverse takes place. Please look up the Milankovitch cycles; you’ll see three different modes of variation in the orbit, over timescales of tens and thousands of years, causing predictable changes on Earth. There is still work continuing on some aspects of this theory, such as the exact details of how an initial leading leads to more CO2 coming out of the oceans and land into the atmosphere, but the basic picture is pretty well established.

    This is the danger of such a simple pictorial; it will never be able to answer all the questions somebody might have. But it does give some references for people to follow up on their questions.

  • harry

    Your chart at the top from the Vostok core is most interesting. This core shows swings in past temperature up and down that are much larger than the temperature change of the last few hundred years (I am not saying they are faster or slower, just that the peaks and troughs are well outside modern temperatures). Since there is no reason to believe that the corresponding CO2 changes were produced by fossil fuel burning, there is presumably some natural explanation for the turning points and sustained trends both up and down. From what I’ve been able to read, there are not particularly strongly supported arguments or climate models to explain these historic oscillations, only speculative ideas about them. Since the warming led to CO2 increases, which is claimed to in turn lead to more warming, what caused the subsequent reversals, and why were they sustained in the face of large excess CO2 concentrations?

    More importantly since we can’t adequately explain the past, why should we have high confidence that we can explain the present so well? e.g. conclude that the largest driving force is anthropomorphic? While there are certainly “deniers” who say that it “can’t be human induced,” there is a more reasonable position that the evidence linking it to man made causes is simply not that compelling because there is a lot about what drives climate (and atmospheric CO2 concentration) that is not understood that well.

  • iAN l. mCqUEEN

    It was a mistake to place everything against a black background. The graphs are almost unreadable.

  • http://kaihaanj.com/blog Kaihaan

    WOW – Thank you!

    I’ve been struggling to get a handle on this ever since it blew up in the media. This is head and shoulders above what I have read in the national papers, other websites etc. I think its a very significant contribution for people like me who need help to understand the issues.

  • Jeff Saxton

    I’ve been thinking about climate change and reading all I can on both sides for ten years or so. What I’ve learned is this:

    1. Man-released CO2 might be changing the climate a little.

    2. Lots of other things we do are changing it too.. both ways. (cooling, warming,) but not by much. Now that time has passed, AGW proponent’s predictions are diverging from observed temperature trends.

    3. The climate changes constantly all by itself. It has whipsawed violently even before men existed, and changed as much as the claims for AGW in recent history, and without CO2 forcing.

    4. The anointed climate “experts” seem to be smoothing, biasing and otherwise massaging data to reach a predetermined conclusion… (Disappearing MWP, LIA.) I saw this pattern of behavior before “climate-gate,” which merely helped confirm my suspicions. They appear to be biased and firmly politicized, working in concert with political forces who feel they absolutely must prove the theory of AGW, or at least make us believe they have.

    5. The small increase in temperature they claim to have detected in the last century was obtained from data sets which are inherently too inaccurate (records) and speculative (tree rings, etc.) to be plausible.

    The whole issue has been so politicized and so much propaganda generated that it’s time to step back. It very much appears that the Hadley people have been spending more time trying to blackball and silence detractors than in doing real science. I believe we are making political decisions based on bad science and people with an agenda.

  • Luke

    http://www.youtube.com/watch?v=gZ8wUJWUMCE

    A nice visualization of how much CO2 is in the atmosphere and how much of it is man-made.

  • geronimo

    If you get your information from realclimate.com you are getting,not from a site there to inform on the climate, but a site specifically set up to push the AGW agenda. There is so much wrong, on both sides, with this approach that it would take pages to refute it, here’s one or two. The replicated hockeysticks used the same data as Mann et al. Amman and Wahl’s paper actually proved the results were statistically unreliable, Briffa’s paper was tainted by the selection of 5 trees that had the uptick against 34 nearby trees that showed no uptick. The MWP was real, easily proved and it matters not that it was only in the NH because the original paper from MBH was a reconstruction of NH temperatures anyway, but has been used as global temperatures through the art of teleconnecting. It is simply not true that the proxy data for Briffa ran out in 1960, what happened in in 1960 was that temperatures from the proxy declined, while quite clearly from the instrumental record they had gone up. The “trick” was to take the instrumental records and splice them onto the proxy records. The “sin” was to continue to use the proxy records because they gave the “right” answer, when it was already obvious that they were unreliable.

  • Javaharv

    What I find curious is why do the conservatives and religious refute the data and liberals and non religious accept the data? Is it only a matter of who benefits large corporations that might loose business versus new businesses and technologies?

  • http://www.stromhylden.net Arild Strømhylden

    Great website. Just clicked in to say that your last link to realclimate.org in the article is broken.

  • Denis

    Ice cores are reliable. Ice cores are not reliable. For heavens sake which is it? Scientists doe not ‘edit’ the data, they ‘adjust’ it. Wonder what the difference. You should really abandon Mann’s hockey stick, as the IPCC effectively have.
    Apart from ‘consensus’ having nothing to do with science there is no longer a concensus. Please read the National Academy of Science and E.Weisman’s submissions to the US government committees.
    Mitigation, even on the massive scale recommended by western politicians will be much less effective and even counter productive than a moderate expenditure on adaptation. After all very successful socitnies have flourished in a huge range of climates, from 5 degrees to 30 degrees (Finland and Singapore).
    How come the IPCC et al predictions completely failed to predict the last decade shows no warming in spite of a large CO2 increase.
    Your highly biased page gives only convenient soundbites which will be attractive to the readers only if they have no time to spend finding your opinions are not supported by fact (rather than computer models).

  • Michael

    Nice Image. Here are two more suggestions…

    Show the 30 years of global cooling cited in the 1974 Time Magazine
    http://bit.ly/dz6fuS

    Show the 15 years of non-”statistically significant” warming that Phil Jones mentioned
    http://bit.ly/bi4uzK

    I think those would be much more of a challenge.

  • tobywhc

    On the section about CO2 rise after temperature rise, the global warming cycles are 5000 year in words or 50000 years long in the figure?

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  • Tom

    I commend you for this. I shared it out, but here’s what I posted to my friends:
    After reading the whole “he said/she said” I came to what might be an odd conclusion: they prove each others points.
    Proponents aren’t clear in their message, and this allows the critics to point out flaws. Issue remains murky.

    Again, I commend you for the effort. The “two sides” aren’t even talking to the same points, leading to a very murky, ugly, fight. The proponents need to get it together, as the IPCC report showed.