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Unsettled Science

Filed under: — gavin @ 3 December 2009

Unusually, I’m in complete agreement with a recent headline on the Wall Street Journal op-ed page:

“The Climate Science Isn’t Settled”

The article below is the same mix of innuendo and misrepresentation that its author normally writes, but the headline is correct. The WSJ seems to think that the headline is some terribly important pronouncement that in some way undercuts the scientific consensus on climate change but they are simply using an old rhetorical ‘trick’.

The phrase “the science is settled” is associated almost 100% with contrarian comments on climate and is usually a paraphrase of what ‘some scientists’ are supposed to have said. The reality is that it depends very much on what you are talking about and I have never heard any scientist say this in any general context – at a recent meeting I was at, someone claimed that this had been said by the participants and he was roundly shouted down by the assembled experts.

The reason why no scientist has said this is because they know full well that knowledge about science is not binary – science isn’t either settled or not settled. This is a false and misleading dichotomy. Instead, we know things with varying degrees of confidence – for instance, conservation of energy is pretty well accepted, as is the theory of gravity (despite continuing interest in what happens at very small scales or very high energies) , while the exact nature of dark matter is still unclear. The forced binary distinction implicit in the phrase is designed to misleadingly relegate anything about which there is still uncertainty to the category of completely unknown. i.e. that since we don’t know everything, we know nothing.

In the climate field, there are a number of issues which are no longer subject to fundamental debate in the community. The existence of the greenhouse effect, the increase in CO2 (and other GHGs) over the last hundred years and its human cause, and the fact the planet warmed significantly over the 20th Century are not much in doubt. IPCC described these factors as ‘virtually certain’ or ‘unequivocal’. The attribution of the warming over the last 50 years to human activity is also pretty well established – that is ‘highly likely’ and the anticipation that further warming will continue as CO2 levels continue to rise is a well supported conclusion. To the extent that anyone has said that the scientific debate is over, this is what they are referring to. In answer to colloquial questions like “Is anthropogenic warming real?”, the answer is yes with high confidence.

But no scientists would be scientists if they thought there was nothing left to find out. Think of the science as a large building, with foundations reaching back to the 19th Century and a whole edifice of knowledge built upon them. The community spends most of its time trying to add a brick here or a brick there and slowly adding to the construction. The idea that the ‘science is settled’ is equivalent to stating that the building is complete and that nothing further can be added. Obviously that is false – new bricks (and windows and decoration and interior designs) are being added and argued about all the time. However, while the science may not be settled, we can still tell what kind of building we have and what the overall picture looks like. Arguments over whether a single brick should be blue or yellow don’t change the building from a skyscraper to a mud hut.

The IPCC reports should be required reading for anyone who thinks that scientists think that the ‘science is settled’ – the vast array of uncertainties that are discussed and dissected puts that notion to bed immediately. But what we do have are reasons for concern. As Mike Hulme recently wrote:

[S]cience has clearly revealed that humans are influencing global climate and will continue to do so, but we don’t know the full scale of the risks involved, nor how rapidly they will evolve, nor indeed—with clear insight—the relative roles of all the forcing agents involved at different scales.

The central battlegrounds on which we need to fight out the policy implications of climate change concern matters of risk management, of valuation, and political ideology. We must move the locus of public argumentation here not because the science has somehow been “done” or “is settled”; science will never be either of these things, although it can offer powerful forms of knowledge not available in other ways. It is a false hope to expect science to dispel the fog of uncertainty so that it finally becomes clear exactly what the future holds and what role humans have in causing it.

Dealing with the future always involves dealing with uncertainty – and this is as true with climate as it is with the economy. Science has led to a great deal of well-supported concern that increasing emissions of CO2 (in particular) are posing a substantial risk to human society. Playing rhetorical games in the face of this, while momentarily satisfying for blog commenters, is no answer at all to the real issues we face.

567 Responses to “Unsettled Science”

  1. 301
    Hank Roberts says:

    > just like arguing in favor of no regulation is also
    > an opposing statement in political economy.

    Well, no.

    “… There is no insult I can take seriously from people who are so fanatically devoted to free-market idolatry that they would rather see lives lost and ruined than controvert its sacred principles. People who care more about free market ideology than human life prove themselves remarkably undeserving of either.

    That, I suppose, is the simplest statement of my political philosophy.”

  2. 302
    Hank Roberts says:

    And along the same line:

    “… This video shows the collision, and the driver crash test dummies, between a 1959 and 2009 car. The 2009 car undoubtedly weighed far less than the 1959.

    … there are quite a few climate-related technology issues that exist regarding efficiency of old technologies, or new technologies to develop, that we’re being told would drive companies out of business, cost jobs, and other alarmist statements — as there were in the 50s and 60s regarding automobile safety. Yet the engineers found ways of improving safety even as we drove more, drove lighter cars, and so on. And the companies didn’t go out of business, indeed make quite a lot of money.”

    —– Car crash regulations happened because people organized for their own mutual benefit: ‘government’.

  3. 303
    Ken W says:

    Re: 296
    “That damages (rightly or wrongly) your claims of political neutrality, and compromises (in the mind of the public) your position as an honest broker of the science. ”

    On the contrary, I (being one “mind of the public”) think scientists should take any opportunity they have to communicate good science to the public. That’s a great service and should be encouraged. While I’m sure some will interpret such acts wrongly (i.e. those who themselves are zealously political), unless the scientists speaks politics their service will be construed as information base and not advocacy based.

  4. 304
    Bryan S says:

    I am a scientist who works for a big oil company and lean decisively libertarian politically, but probably hold my nose and vote for some pretty stupid Republicans too often. Does that imply that I am hopelessly compromised? I bet many of your readers would answer that it does. The point is that now that it is out in the open, they get to decide. If you accept the challenge to disclose your own political leanings, then the public can decide on their own if your public science statements are colored by your politics. I tell you, you will feel much better to get it out in the open, and then you can move on and engage in a candid professional discussion of the science (where everyone agrees you have expertise) and your own layman’s opinion on the best policy response (where your expertise may not be much better than the next guy). Just ask your boss.

  5. 305
    David B. Benson says:

    Even HuffPo gets it:
    Decade Of 2000s Was Warmest Ever, Scientists Say

  6. 306

    Matthew L: Roy Spencer… one of the gatekeepers of the satellite temperature record, he seems to be the one sceptic worth at least listening to.

    BPL: Do you listen to his endorsement of creationism as well? How about his unbelievably dishonest argument that CO2 is too small a fraction of the atmosphere to matter, a statement HE KNOWS VERY WELL is not true, since his job requires him to understand Beer’s Law? Still worth listening to? How much of a crackpot does someone have to be before you stop taking him seriously?

  7. 307
    SecularAnimist says:

    Bryan S wrote: “I am a scientist who works for a big oil company and lean decisively libertarian politically, but probably hold my nose and vote for some pretty stupid Republicans too often. Does that imply that I am hopelessly compromised?”

    That depends on whether or not you understand that your political inclinations have absolutely nothing whatever to do with the scientific reality of anthropogenic global warming.

    It’s entirely appropriate for “conservatives” and “libertarians” to propose policies to address AGW that are in accord with their political and ideological preferences.

    That so many “conservatives” and “libertarians” refuse to do so, and instead prefer to pretend that the problem doesn’t exist, suggest that they themselves believe that their ideology has nothing to offer in the way of solutions.

    Is that the case with you?

  8. 308
    Bryan S says:


    The next time you see me drop by and get into a detailed discussion on the Paleocene/Eocene Thermal Maximum or some science issues where I think I may have a little knowledge, you can judge the merrits of my science arguments. The point is that you can now judge them in the backdrop of whether you think my political views are coloring my professionalism. The wonderful thing about this is that you now have the power of full disclosure which can keep me accountable as a scientist to the science. Gavin and the gang have not done this *yet* (they inevitably will), instead choosing to intentionally cloud their political views so that the public is denied this power of knowledge. It is all about influence and power, and they are scared to death to lose theirs.

    [Response: Bollocks. We have no power, and precious little influence. Why you think a declaration of my voting record would make any difference to that is very strange. But if you want to know, I haven’t voted in over a decade. How does that change the credibility of my discussions of climate modelling? – gavin]

  9. 309
    Bryan S says:

    Well bullocks right back at you Gavin. When the New York Times and London Daily Telegraph are calling you up to get your take on issues, you have power and influence, and you love it. They don’t call me. Political think tanks are not hosting me to make public statements at press conferences. Again Gavin, you strain your credibility with these types of humorous statements.

    [Response: You have absolutely no idea what ‘power’ entails. Let me assure you, it is not being on a journalist’s rolodex. – gavin]

  10. 310
    sidd says:

    Since there are so few science articles on these days, I take the liberty of posting on this thread.

    Two papers I read recently raised these thoughts”

    1)Trenberth 2009 (Current Opinion in Environmental Sustainability, v1, pp19-27, 2009) available in many places on the web ( attempts to track the energy imbalance in the various parts of climate systems. The missing energy is on the order of 1e22J over the period 2004-2008, and from Table 1 and associated text, it seems to me that the only possible sink for such an amount is the deep ocean. Although such heating of the ocean ought to reveal itself in sea level rise, Trenberth also points out that the rise might be masked by changes in precipitation patterns due to La Nina, which could result in a 6.0 mm sea level drop. Is this a plausible explanation for the ‘missing’ heat sink ?

    2)USGS (including realclimate’s Gavin Schmidt) just published an estimate for Earth System Sensitivity (ESS) 30-50% higher than Charney sensitivity(CS), which contrasts with Hansen’s estimate of ESS being twice as large as CS. The USGS study is based on the Pliocene, (3 MYr before present) while Hansen uses data from 400Kyr b.p. Is there a simple reason for the disagreement ? The USGS paper is Lunt et al., Nature Geoscience,NGEO 706, doi:10.1038, and the Hansen paper is available on the web at

  11. 311
    David B. Benson says:

    Undocumented Volcano Contributed to Extremely Cold Decade from 1810-1819:

  12. 312
    paulina says:

    But Gavin, what did you eat for breakfast, in that non-voting decade?
    Who did you sleep with?
    When did you get married?
    What’s your favorite color? (Do you have any hard evidence to back that up?)
    How many breaths do you take per minute?
    Did you ever run a marathon?
    Are you left-handed?
    Release ALL your personal data!
    Baby photos!
    School concerts!

    Or else the “public’s trust” will be “damaged” by ALL of YOU having “overstated” the case and “falsified” the data, or at least by the media falsely, shamefully, or rather shamelessly, saying you did that.

  13. 313
    Matthew L. says:

    BPL #306
    I have read many posts on Roy Spencer’s blog and have seen no discussion or endorsement of creationism. I will take another look. If he does have such views it would certainly colour my view of his judgement.

    I have also seen no comment that “CO2 is too small a proportion to matter”. Reading his blog it is quite clear that he fully understands the forcing affect of CO2. His argument is with the effect of positive feedback assumptions used in climate models. This seems to me to be a perfectly valid line of enquiry.

    He clearly has a bias towards ‘scepticism’ but then so do I (in a very general sense – not necessarily related to climate science). I think it is a good thing that there are people out there testing and picking holes in the theory. If the theory is robust it will withstand those tests. It might be good for politicians and policy makers for there to be scientific unanimity, but it is truly bad for science – particularly when dealing with such an inherently uncertain and complex system as the climate.

  14. 314
    sHx says:

    Marc Ambinder of The Atlantic is evidently not a reader of the Real Climate blog. Perhaps, a climate scientist, preferably Gavin Schmidt, should write to The Atlantic editor and remind them that climate science is unsettled.

    Copenhagen: The Science Is Settled; The Policy And Politics Aren’t

    [Response: Actually, that’s a very good article. One can quibble with the title, as you are doing, but it is clear from the text that he and Gavin would have no disagreement on this. Quote: “However valid one’s feeling of exclusion is, it isn’t a substitute for what science does: test and try to falsify. The theory of anthropogenic climate change has not been disproven. It is stronger today than ever before.” –eric]

  15. 315
    phil c says:

    Although no-one is going to deny that the climate changes and has warmed up over the last few decades of the 20th century, there is the question of whether this current phase is unique.

    If it is unique then we can look for a unique driver and human industrial emissions of CO2 fits the bill

    But if the Earth has warmed before industry got started then until we can explain that the more likely explanation is that the earth is doing the same thing – even if we have no idea what the mechanism is.

    History indicates that the Medieval Warm and the Little-Ice-Age were real and significant periods in the last 1000 years.

    Looking at the famous hockey-stick graph these periods are not visible and their absence makes the graph very scary and points towards CO2 as the driving force.

    Although the elimination of these periods comes as a surprise to many historians, if the science of climate reconstruction was very sound then so be it.

    Unfortunately, recent information indicates that the proxy data diverged from the actual temperatures towards the end of the 20th century (re the infamous “hide the decline”). If the proxy data is shown to be divergent in recent years this casts doubt on historical reconstruction from tree rings. Given that the techniques used at CRU have these anomalies and they appear to remove two known historical periods this surely casts doubt as to the validity of the entire historical reconstruction and therefore the impact of Anthropogenic CO2.

    You can tell me I don’t understand the science or that I’m a “denier” but once the MWP and LIC are put back into the temperature records, the case for AGW becomes far weaker and any science that I’d need to understand it becomes irrelevant as there is nothing to understand. With these periods put back into the temperature records then it is your side that has to explain why CO2 is effectively the sole driving force.

    I suspect many people on this site may have criticisms of Jasper Kirkby but I find the lecture at this link far more convincing.

    [Response: Your logic makes no sense. You write: ‘But if the Earth has warmed before industry got started then … the more likely explanation is that the earth is doing the same thing.” This is like saying — after ramming your car into a kid on a bicycle — “well, the last time I saw a kid fall off a bicycle, I wasn’t even driving, so clearly, the cars-knock-over-bicycle theory is wrong.” Get it? No one has ever said “only CO2 can change climate” and no one has ever said “the only way for a bicycle to fall is if a car hits it.”

    As for Professor Kirby, I think the blog post you refer to actually sums up the state of that ‘theory’ rather nicely: “They haven’t completely worked out the mechanism yet…” Uh huh… And I’ve got some stock to sell you. I haven’t quite worked out how the guy we’re buying it from is investing it but… trust me.

    Call us back when you have worked out the mechansism, will ya?


  16. 316
    Matthew L. says:

    Right, I have had a dig around and I can see that Roy Spencer is a ‘born again’ Christian. He also seems to put some credence on the theory of intelligent design. However his views do not seem particularly extreme or ‘crackpot’, or at least no more crackpot than most other Christians.

    It must take a certain amount of ‘cognitive dissonance’ to be both a Christian and a scientist. However, I know several successful and sincere scientists (mainly in the medical profession) who are also Christians and who don’t let their faith interfere with their professional judgement.

    Not being religious, those are not views I would subscribe to, and it does provide a bit of context for his scepticism. Thanks for the heads-up.

  17. 317
    Bryan S says:

    Hi Gavin,

    How about playing fair and posting my reply to your comment for the sake of a very good discussion. I really did not believe all those folks that said you screened comments to shut off discussion, since you have most of the time posted my comments in the past.
    I see your friend Dr. Steig is now replying to callers, so maybe he held it up. Please let him know what a good guy I am, and post my comment.


  18. 318
    phil c says:

    Eric really!

    If the earth has gone through previous similar warming before then it would be a natural cycle – if so why do you need to invoke a new driving force for this one.

    Your analogy is silly – more likely, if the kid keeps coming into the house smashed up with his bike all twisted up I’d say he’d been hit by a car – again.

    I note that you didn’t bother to explain how the MWP and LIA have now been removed from history by Phil Jones etc.

    “Call us back when you have worked out the mechanism, will ya?”
    why- if he can show a strong correlation between cosmic rays, cloud formation and historical temperatures then even without knowing what the mechanism is I’d say that is at least indicative of a possible connection. If you are a scientist, are you not even curious – if not why?

    [Response: Sigh.. You really aren’t listening, but I’ll try once more before I give up. Nobody ‘invoked’ anthropogenic CO2. What is being ‘invoked’ is the cosmic ray / temperature correlation (which in any case is not convincing, even as a correlation. Read up on the basics, please…. -eric]

  19. 319
    Ken W says:

    Re: 304
    Bryan, the ONLY reason you want Gavin to start talking about his politics is because you can’t adquately criticize his science. So you’re trying to get some leverage (obviously you assume he’s liberal leaning) where you can use personal attacks (vs. science) to attempt to discredit him. While that might be a nice debators tactic, it won’t fool anyone that comes here for actual climate science information.

    The motivation of Gavin for studying Climate and reporting on it here is irrelevent. Is his science honest and doesn’t it stand up to scrutiny is all that matters. There have been many great scientists from all over the political and religious spectrums.

  20. 320
    Chris Colose says:

    phil c, is it possible that someone can be murdered by gunshot, and then a month later another person can be murdered by stabbing?

  21. 321
    Ray Ladbury says:

    Phil C., Uh, Dude, you are SOOOOO lost. First, warming is a PREDICTION of climate science when the CO2 content rises. Arrhenius knew it back around the turn of the last century, long before the current, rapid warming. Please, please, please, might I suggest a little history to dilute your ignorance?

  22. 322
    Mr Sh says:

    I appreciate the effort of RC members.

    The term of “scientific” and “uncertainty” have often been abused when decision making is needed. In 1960-1970, Japan experienced many environmental pollution jugments. The defence counsel always insisted that “There are many uncertainties. The mechanism is scientifically proven.” even if the data enoughly suggested the relationship. Minamata disease, thalidmide, etc are all the cases.

    In my view, what is important is “Do we have enough knowledge to give the decision in spite of the remaining uncertainty?”. The climate science has already reached the discussion stage of “mechanism and causality” rather than the “observation and correlation” and provided enough information on AGW though scientific uncertainty remains.


  23. 323
    David B. Benson says:

    phil c (311) — Nobody is claiming that MWP didn’t happen (mostly in the northern hemisphere) and the evidence for LIA is global. It is just that neither was the result of a very large temperature excursion in comparison to the warming of the last century or so.

    Plase do follow Eric’s advice; I suggest reading “The Discovery of Global Warming” by Spencer Weart, first link in the Science Links section of the sidebar.

  24. 324
    Jim Bouldin says:

    I note that you didn’t bother to explain how the MWP and LIA have now been removed from history by Phil Jones etc

    This explains how that works.

  25. 325
    tharanga says:

    gavin, reply to 308: Great, now you’ve just given them another far-fetched idea on how to harass you. It’s a matter of public record whether you’ve voted or not, so now they’ll go scurrying to check up on that, and then put some weird spin on it.

    When can we return to the regularly-scheduled programming of discussing interesting new papers? You could spend the rest of your lives answering the same elementary or ill-posed questions over and over again. The same with the conspiracy theorists. At some point, we need to move on.

  26. 326
    Dale Husband says:

    “1. How do you account for the 1910-1940 warming without CO2.”

    We don’t have to. The industrial revolution began in the mid-19th Century, long before 1910, and human emissions of greenhouse gases due to industry, including CO2, began at that period. The fact that human influence on climate change was being discussed by scientists before 1910 indicates that your question is pointless.

    2. How do you account for the lack of warming over past 10 yrs.”

    The actual lack of warming began in 2006, three years ago, not 10. And at that time, the Sun went quiet, offsetting the increases in CO2 over the past few decades. Again, this would be obvious to anyone who did his homework.

  27. 327
    Robert says:

    It’s a challenge to explain to the public not only the science but the scientific method and what “scientific uncertainty” means.

    I read a “news opinion” article about the so-called “Climategate” (the recent e-mail hack) and there was a forum for the public to post comments, similar to this one. That crowd’s response was mostly negative towards the climate scientists, with opinions ranging from a benign “the science is not settled” to more extreme claims of fraud, data corruption, and scientific misconduct ! Knowing what I do about the culture of science, I realize those claims obviously cannot be true in any widespread way, and it would be frustrating to me if I worked in your field. Maybe it doesn’t matter what some people think, but it is important to have an outreach like this to help the public understand the issues. I appreciate the effort.

  28. 328
    Matthew says:


    Thanks for your responses to my 262.

    I’ll keep them for reference.

    But, What do you think are the most unsettled issues and how do they affect our plans and actions for the future? Do you have them somewhere else that I have missed?

  29. 329
    JEFF LOCKE says:

    I am an educated American but:
    1)Big or small the individual will be affected by the whole.
    2)A “fever” is typically 2-3 deg hotter than those around the sick one.
    3) When the Earth is that hot we all die! – see trapped CH4.
    4)”Smoke” does its damage downwind while its source stupidly profits.
    5) as another inconsequential sig but flies out a window – “FU” it says.
    6) Ignorance is only Blissful to the ignorant!

  30. 330
    Doug Bostrom says:

    Comment by Bryan S — 7 December 2009 @ 4:53 PM:

    Arithmetic is nonpartisan. Chemistry is nonpartisan. Physics is nonpartisan.

    Can you describe exactly how and where you see political leanings manifesting themselves in scientific publications by scientists publishing on climate-related topics? Something more than a vague suspicion with no evidence on offer?

    Every month I get royalty checks from various little divisions of producing oil and gas wells. In your worldview, what does that say about my attitude to AGW and what I’m likely to say about it from my layman’s perspective?

    I thank the clowns driving spotless Range Rovers around town, helping to keep $/bbl as high as possible. I profit from stupidity. At the same time those same bozos paradoxically help to discourage consumption via their disproportionate effects on the part of the economy not having to do with Serengeti Fantasy Island. I think it’s tragic that we’re still stuck w/our love for burning natural resources which could be better used for other purposes. I’m worried about our reluctance to grow up and work on a more permanent means of powering our civilization.

    Which statement do you trust?

  31. 331
    Matthew says:

    300, Lynn Vincent Nathan: and what about all that seafood being harmed by ocean acidification

    Considering how rapidly mosquitoes adapted to DDT, malaria adapted to quinidine, TB and SA adapted to just about all antibiotics, and HIV has adapted to anti-retroviral medications, I’d bet that wildlife will adapt to increased ocean acidification quite well. Random variation, natural selection, and all that. If the results of land studies are indicative, then oceanic vegetation will grow faster with higher CO2 concentrations where low CO2 is the rate-limiting factor. DDT cause problems higher up the food chain because it accumulated and was ingested, but CO2 doesn’t accumulate and ingesting CO2 doesn’t cause problems.

    Even more, shellfish and diatoms use CO2 as the ingredient in making their (exo- and endo-) skeletons, so they have stronger skeletons when raised in CO2-rich water, according to a recently published study.

    Land surface may suffer from AGW, but ocean life will almost certainly adjust, as it has in previous eons.

  32. 332
    Matthew says:

    323, David B. Benson: Nobody is claiming that MWP didn’t happen (mostly in the northern hemisphere) and the evidence for LIA is global. It is just that neither was the result of a very large temperature excursion in comparison to the warming of the last century or so.

    That is a matter that is still disputed. The original Mann “hockey stick” purported to show it, but other analyses (and the most recent Mann et al Science paper) show the MWP to be warmer than the “hockey stick” showed. Depending on which estimate of the temp during the MWP is accurate, and which estimate of future warming is accurate, it may take another half century to a century of warming to achieve the temp of the MWP.

    326, Dale Husband: The actual lack of warming began in 2006, three years ago, not 10. And at that time, the Sun went quiet, offsetting the increases in CO2 over the past few decades.

    Don’t most scientists agree with Kenneth Trenberth that there has been no net warming since 1998? The sun did not, of course, suddenly go quiet — but if it’s continued quiet is that powerful, there may be no new warming for decades. I maintained (and I think Gavin Schmidt disputed) that the relative strengths of the solar and CO2 forcings are not known.

  33. 333
    Lynn Vincentnathan says:

    #304, Bryan & “If you accept the challenge to disclose your own political leanings, then the public can decide on their own if your public science statements are colored by your politics.”

    I actually think folks from the hard sciences might (sans AGW) be a bit more conservative on the whole that us social science folks. I myself started out as a Republican concerned about life, but due to racism and other social evils I eventually became a Democrat. I know of at least one very famous climate scientist who was conservative, libertarian … until the conservatives went (it seems) completely over to the dark side, pro-death, earth destruction.

    The only good conservatives now, it seems to me, are those who really don’t understand climate science, so narrowly focused they are on saving babies from a very narrow range of threats, but not from all threats. The rest of the conservatives seem to me to be misinformed selfish people out to save their own (economic or political) skins, but unwittingly harming themselves…as GW will bring both economic and political hardships and evils we can bearly imagine now.

    …except, of course, for those in the oil and other such industries who are wittingly helping themselves at least for the present.

    The upshot, I think, is that AGW has caused honest & informed folks to change or solidify their politics to the left (which was actually about where the old right used to be — it’s almost as if some folks stayed in place while the politics shifted); politics has not informed their science.

    It’s the denialists who appear to decide their science based on their political views. Which I find very horrible, horrifying….worse than IDIOCRACY.

    Because the AGW science really has been settled for some 20 years now for non-scientists concerned about life of planet earth, the folks who seek to avoid the false negative. (Scientist are such a conservative lot!) We non-scientists have much lower standards for deciding something is threatening and harmful, maybe a p-value of .50, certainly not .05, bec we want to avoid great harms. And it’s good we can also save money and strengthen the economy by mitigating GW, so it’s a win-win, laughing all the way to the bank!

  34. 334
    ccpo says:

    Don’t most scientists agree with Kenneth Trenberth that there has been no net warming since 1998?

    Uh, no. I doubt Trenberth means what you think he means, but I could be wrong. And, do you not understand that by the more complete data set that includes Arctic temps, 2005 was warmer than 1998, and that 1998 was an outlier for obvious reasons?

    Also, the net energy in the system is pointed to by the average for the decade. the present decade has been warmer than any previously going all the way back to the Eemian. Your assertion that the MWP was warmer is, at best, controversial and most likely wrong. In fact, there have been studies this past year saying temps are the highest for at least 1000 to 1000 years, right?

    Let me give you an analogy. Let’s say it’s 85 degrees in your house at 10 AM on a summer day. You turn on the AC for a few minutes to cool the house, but not too long because you want to conserve energy/save money. The temperature drops to, say, 79 before you turn it off.

    Tell me, is it going to be warmer or cooler than 85 in your house by 3 PM?

    The energy is accumulating. We can’t track every calorie of energy, but rest assured, if the balance is + for the system, it’s accumulating somewhere. The average for the decade tells you this is so.

  35. 335
    Tom Dayton says:

    332 Matthew, no, most scientists do not agree that there has been no net warming since 1998. Tamino has a new post on this.

  36. 336
    Patrick M. says:

    The politicians keep stepping on the scientists’ toes, claiming this science is ‘settled’ … Here’s Gibbs today:

    “Gibbs responded, “It shouldn’t, because the science is clear.”
    “And settled?” Gibbs was asked. “And settled.”

    Some smart-aleck journalist needs to ask the followup “if the science is settled, why do we need more research?”

    [Response: And he would have no doubt answered that we still want more details. – gavin]

  37. 337
    Tilo Reber says:

    “Science has led to a great deal of well-supported concern that increasing emissions of CO2 (in particular) are posing a substantial risk to human society.”

    And of course, after making statements that are settled, like an increase in CO2, a rise in temperature, CO2 is a greenhouse gas; you can’t help but jump in with a statement that is not only not settled, but is most likely false.

    No important question is actually settled. For example, how much of a rise in temperature is there. Taking the 5 year average for the beginning of the HadCrut3 record and the 5 year average for the end of the HadCrut3 record shows a 150 year temperature rise of about 0.8C. When HadCrut3 began, we were coming out of the LIA. So some warming could be expected. Additionally, the ENSO charts since 78 shows a dominance of El Nino events, while prior to then La Nina dominated. That could also add to the recent warming. And, the strength of Solar Cycles has risen for most of the 20th century. On average, 20th Century Solar Cycles were much stronger than 19th century Solar Cycles. And we have no idea if the urban heat island effect is correctly compensated for. Given these questions, questions like “how much of that .8C over 150 years is natural” still arise. And that is not a settle issue. Climate sensitivity is not a settled issue. Even the sign of the feedback is not a settled issue. No models have yet been proven to have any robustness for any significant period of time. Their results are not a settled issue. The recent 11 year flat spell in the temperature record is also unexplained by any elements of natural variation. That is also not a settled issue. Given the remainder of the unsettled issues, we have no right to ask the world to shell out trillions of dollars on unsubstantiated claims about future climate disaster.

    [Response: You aren’t parsing the statement right. The issue is that there is a risk. That is well supported – the best estimates for the sensitivity (and even the range) clearly indicate the likelihood of significant climate changes under BAU scenarios. This isn’t a ‘claim’ of future disaster, but rather a warning. (The difference is some telling you that you will be knocked down by a car, and someone telling to look both ways before crossing the road). Your other statements are just wishful thinking; the models are robust over different lengths of time, net feedbacks are clearly positive, and natural variability is expected around any long-term trend. – gavin]

  38. 338
    Patrick M. says:

    #183 – “Anyway, the reason contrarians or sceptics or deniers or just the deluded are treated as, well, what they are is because we know where there opinions come from, and it ain’t science in the vast majority of cases.”

    Really, you know where they are coming from? Without even talking to them about it? You should got to WattsUpWithThat or ClimateAudit or the Blackboard or Peilke’s or Motl’s website and tell those folks that. You might be surprised at the diversity of thought (both sensible and not). Saying it here is like telling a congregation of Baptists how heretical the Mormons are.

  39. 339
    gopakumar says:

    Global concern over climate change cools off but rising in India. Indians are ”very concerned” about climate change, believe that the main responsibility to address global warming issues rests with the government. 54 percent Indian consumers said they were “very concerned” about climate change.

  40. 340
    Tilo Reber says:

    “Don’t most scientists agree with Kenneth Trenberth that there has been no net warming since 1998?”

    I have charts that show no warming for HadCru3, UAH, and RSS since 1998. GISS shows slight warming. I also have an ENSO compensated chart for HadCrut3 which also shows no warming. But they won’t allow me to post the links here.

    “I maintained (and I think Gavin Schmidt disputed) that the relative strengths of the solar and CO2 forcings are not known.”

    Gavin is most likely right on that issue. I think that solar forcing is one element of warming, but it is a very small one. More important is the lack of a strong magnetic field around our solar system when the sun is quiet. This exposes the earth to more cosmic rays which in turn causes more cloud formation that then causes more albedo. The AGW people deny this because of the lag response that happened after solar cycles topped out. But a kettle of water doesn’t rise to the level of heat that you put under it immediatly. It takes time. And the ocean is a big kettle of water.

  41. 341
    Doug Bostrom says:

    331 Matthew:

    Excellent. We just wave our hands and POOF! all the problems go away.

    I’d find still more comfort in your words if you could actually point to some real world evidence to support the abracadabra part, something along the lines of “Here’s the absolute acidification increase we expect to cause and here’s the interval of time during which acidification will rise, and here are some past examples of organisms that have successfully tracked a similar chemical and temporal shift without a die-off that rippled up the food chain causing a geologically transient but in human terms massive dislocation.”

    Can you do that?

    I’m absolutely confident we’re not going to cause anything worse than what a multi-kilometer ET impactor or perhaps a nearby supernova would produce and indeed life has apparently seen its way through a number of such events. It’s a comforting thought really, that we’re no more unkind or stupid than a mindless cosmological catastrophe, worst case. However, if memory serves me correctly that’s the kind of event that would likely stop our supply of fish and chips for a few human lifetimes.

  42. 342
    Lawrence Coleman says:

    I had the fortune of listening to an interview by James Hansen to our ABC Australia on Lateline last night. Went for a good 20mins and Dr Hansen elequently and logically crushed the main contrarians arguments which was presented to him..such as the anomaly regarding whether 1998 or 2005 was the hottest year on record. Simple answer 2005 because that also took into account the accurate temps of both polar regions which the british study failed to include. Also the pathetic one thats keeps cropping up..that water wapor is the main climate driver and not CO2..well stupid ones..listen up..yes water vapour is indeed a potent climate driver but is the ‘direct’ result of a warmer climate caused by an increase in the planet heats up..the oceans warm and evaporate more water vapour near the surface into the atmosphere which results in more severe precipitation..year 9-10 hyrologic cycle homework..did any of these contarians actually attend school??. Oh Yes! this classic..that the temp data is taken from urban areas and so give a distorted dummies! that temp data used by NASA Goddard is taken largely sourced from rural/wilderness and maritime sources..not urban areas which any idiot knows gives an artificially elevated figure. Not only that but the many areas in siberia, alaska, the oceans and about as far as you can get from humanity actually show a disturbing higher than average figure..higher even than most urban areas!
    Dr Hansen said also that all input data used in climate modelling should always be made available to anyone and that that process be kept transparent. That also means reading into it that the data must be kept uncorrupted and ‘uncorruptable’ when it’s stored in university hard drives and data bases. His appearence on lateline was so important as it will hopefully cause program editors to report the science and not some crackpot contrarians misguided view to somehow ‘balance’ the topic. 4500 climate scientists can’t be wrong when whey say with one voice..YES CLIMATE CHANGE IS HAPPENING and that there is a 98% probabilty that it’s cause is ANTRHOPOGENIC.

  43. 343
    Marco says:

    You may wish to read that study on ocean life and exoskeletons again. It noted that several species benefitted, whereas others did not. In fact, there were some examples where the prey would lose out to the hunter. Guess what happens to a tiger when he suddenly is much faster and stronger, and capable of eating all the gazelles and buffalos who got slower and weaker?
    Moreover, the same study noted that it was a controlled experiment, where CO2 was the only limiting factor. Give children in the West extra growth hormone and they will grow faster and bigger. Give children in the Third World extra growth hormone, and you’ll probably see some really freaky effects.

  44. 344
    john byatt says:

    more rubbish from bob carter
    he wants you all dead

    ” only geologists capable of doing the science “

  45. 345
    phil c says:

    Phil C., “Uh, Dude, you are SOOOOO lost. First, warming is a PREDICTION of climate science when the CO2 content rises.”

    except CO2 has risen since 1998 whilst temperatures appear to have stayed level – even dropped
    in which case the prediction has failed.

    I really suggest you watch Kirby’s lecture and then try to dismiss the strong correlations between cosmic rays/cloud formation/climate
    once you’ve watched it, then come back and we’ll talk science which is rather more relevant than history.

    [Response: You should try reading this and then any of this. Then come back and we can talk science. – gavin]

  46. 346
    Lawrence Coleman says:

    As far as Copenhagen goes..trying go get a hard hitting (one that the IPCC say is essential to stabilise the climate) using the due ‘democratic’ process employed in Copenhagen will most certainly fail. Democracy = compromise..trying to find the acceptable middle ground. Surely even Eric can see how ineffective that will be. Climate Change cannot be averted through due democratic process! Put it this way..say there were 10000 huge fragments of a exploding comet heading for the earth..time of impact 12 hours. A hurredly convened meeting of world leaders, polititians, scientists was arranged. But each missile costs $1B a shot..and you will need 10000 of them. America says ‘darn’ we only have enough funds in reserve to launch 4000. China is still undecided..because their findings is that there is a 2.5% chance that they will miss the earth and only commits to 1000..after all they have their booming econmomy to consider. So the result of that meeting only makes available 5000 missiles. 6 hours later the earth is wiped out! There is no difference between that scenario and CC apart from 100 or so years. Can’t anybody see that point and stop clinging so tightly to mommy democracy’s apron strings.

  47. 347
    George Ortega says:

    I’d like to help pull the discourse back to the issue at hand; how will scientists succeed in communicating to the public that the “science” of climate change has been settled for years now, and action is long overdue. Given that banning opposing voices is not an acceptable enough option, what can climate scientists do to reach the public before the warming gets far more serious and far more expensive to solve?

    Addressing this challenge from a scientific perspective, I would first suggest that climate scientists acknowledge that communicating for public acceptance is not within their expertise. There are, however, various scientific disciplines like psychology, sociology, and political science that are designed to far more directly address this communications issue.

    Perhaps it is time for the IPCC and other climate science organizations to recognize that in addressing climate change, the science of public communications of the scientific findings is just as important as the actual climate science. Perhaps it is time for these organizations to actively recruit and form working relationships with experts from these other fields. My understanding is that the IPCC is now comprised of over 2,500 scientists. Does it seem unreasonable that two or three hundred of these scientists be public communications experts who assist climate scientists in dealing with the absolutely indispensable issue of communicating the climate science findings to the public in ways that will earn their understanding and acceptance?

    Doctors determined several decades ago that an integral part of being a good doctor, at least on the level of general practitioner, was to cultivate what they refer to as an effective “bedside manner.” In other words, doctors today are routinely taught not just how to heal their patients, but how to communicate with them in ways that make such healing much more effective.

    I know that climate scientists did not get into the field to study the popular psychology as it relates to distant, unspecific threats of the kind climate change poses. But if the current reality provides the choice between continuing to amass more and more findings that are ultimately ignored by the public and taking on, by collaboration if necessary, the SCIENCE of public communication of climate change findings, it seems that scientific method would highly favor the latter option.

  48. 348
    Greg says:

    #332, Matthew

    The Permian-Triassic extinction event may have related to a massive surge in atmospheric CO2 levels due to volcanism. I’m not an academic or anything, but according this paper, marine extinction patterns were in line with what might be expected if ocean acidification were driving the extinctions.

    It’s an interesting read, either way. A decrease in biodiversity is something we should be concerned about; we are changing the planet at a geologically rapid rate, and even if some of the simpler life forms can adapt rapidly, it’s entirely too likely that many can’t.

  49. 349
    elheebo says:

    The “about” page of this site notes the following:
    “The discussion here is restricted to scientific topics and will not get involved in any political or economic implications of the science.”
    Understandably, the comments get into that, but it’s quite obvious that the initial posts do so on many occasions. You might consider scratching that sentence.

  50. 350
    Jim Prall says:

    CNN just started a week-long series “Global Warming: Trick or Truth?” on Campbell Brown’s 8pm EST time-slot. Last night they had Michael Oppenheimer up against Stephen McIntyre(!) and(!) Chris Horner(?!?). Why two contrarians? This isn’t even false balance. In fact Dr. Oppenheimer held his own pretty well.
    In other segments, they’ve interviewed other climate scientists including Ken Caldeira and Peter Liss. Dr. Caldeira hit back pretty hard; Dr. Liss came across pretty reserved and genteel, giving little sense of the atrocious violation against CRU.
    I think the key point to get across any time someone asks about this is that there is no ‘decline’ to ‘hide’ in the ‘real temps’, only in a few tree-rings. There are over 10,000 stations with direct temperature measurements today, and that’s the data that Prof. Briffa showed to ‘hide the decline’ in the tree ring proxy. If he’d done this the other way around, that would be something to complain about.
    What a spectacle of spin!