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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. 151
    Mike says:

    Re Dennis no. 61 (theories from other areas of science that lay people don’t go round arguing about)

    How about: DNA is a double helix

    It is well established science, but like all scientific theories not without nuances. For example, it is known that more complex DNA structures are possible and present within cells (ie: cruciform DNA) and that DNA segments from different chromosomes can contact each other and perhaps form structures.

    However just because certain segments of DNA may not be in a standard double helix at all times doesn’t mean DNA is not a double helix generally. Thankfully molecular biology does not suffer from “helix skeptics” claiming that the presence of cruciform DNA means that all atomic structures of DNA and of proteins interacting with DNA are wrong and evidence of some mass fraud.

  2. 152
    dhogaza says:


    If they are talking about attribution of recent warming to human activity they are fine. The only error is when people either pro or con overextend such statements to encompass the whole scientific enterprise.

    Maybe they could be trained to say “enough of the science is settled”.

    After all, the science regarding lung cancer and cigarette smoking isn’t “settled” – we still can’t attribute each individual case to smoking or some other cause (unlike some cancers where the cause can be positively attributed).

    Yet we know that smoking – even second-hand smoking – increases the odds of lung cancer to the point where it makes sense to not smoke. Enough of the science is settled to make it clear that not smoking is an intelligent choice.

    More Gavin:

    Lindzen is declaring that any degree of uncertainty (no matter how small) should be enough to prevent any action. This is not an argument anyone would use in any other field

    Lindzen’s a smoker, come to think of it, and opposed taking action on second-hand smoke if I’m not mistaken …

  3. 153
    Svempa says:

    The climate warming matter has turned into an issue of good and bad – we and them. And in that battle the quest for scientic clarity has almost disappeard. I say: Michael Mann and Gavin Smith send all your data and data models to Steve McIntyre for verification. If you believe that the AGW matter is the most vital question of our generation you should take every effort to remove all possible doubts. Everything else would show that you really don’t believe in what you are saying.

    [Response: All my code and output is online. Mike’s latest paper came with 20mb of supplementary data and code. So now do you believe what we are saying? -gavin]

  4. 154
    Ike Solem says:

    By the way,on the deviation from tree-ring thickness from the recent instrumental temperature record, see this report:

    The rising level of atmospheric carbon dioxide may be fueling more than climate change. It could also be making some trees grow like crazy.

    That is the finding of a new study of natural stands of quaking aspen, one of North America’s most important and widespread deciduous trees. The study, by scientists from the University of Wisconsin-Madison and the University of Minnesota at Morris (UMM) and published December 4 in the journal Global Change Biology, shows that elevated levels of atmospheric carbon dioxide during the past 50 years have boosted aspen growth rates by an astonishing 50 percent.

    If this phenomenon is widespread (clearly, water and nutrients also have to be present in adequate supplies in each case) than it would seem to account for the deviation from the instrument record over the past 50 years, wouldn’t it?

    I think this is where Phil Jones and Michael Mann did make a big blunder – rather than looking for an explanation for the deviation in tree ring thickness, they just truncated the dataset at the point where the deviation began and then stuck on the instrumental record.

    By the way, Michael Mann’s efforts to distance himself from Phil Jones on this are a bit silly. Destruction of emails is quite common these days – maybe Jones thought there was no problem with it:

    White House: Millions of e-mails may be missing, April 13, 2007

    “I wouldn’t rule out that there were a potential 5 million e-mails lost,” Perino told reporters.”

    I wonder how many of those emails related to efforts to sabotage climate science (Triana and other satellites), block scientists like Hansen from speaking to the public, and so on – and on – and on?

  5. 155
    dhogaza says:

    If the high school student is recreating the famed work of Galileo but instead attaches a parachute to one of the rocks therefore concluding that Galileo was wrong, we would simply throw out that data as obviously not following the methods required to test the hypothesis. The teacher would likely award poor grade to the student as well.

    If I were the student, I’d scream and find myself a new teacher.

    After all, we have no evidence that Galileo did the experiment. But he did come up with the following thought experiment:

    Imagine two objects, one light and one heavier than the other one, are connected to each other by a string. Drop this system of objects from the top of a tower. If we assume heavier objects do indeed fall faster than lighter ones (and conversely, lighter objects fall slower), the string will soon pull taut as the lighter object retards the fall of the heavier object. But the system considered as a whole is heavier than the heavy object alone, and therefore should fall faster. This contradiction leads one to conclude the assumption is false.

    Well, if I attach a parachute to a rock, then, the string *will* soon pull taut, something every parachutist is thankful for every time they jump. Galileo’s claim is false.

    Of course, Galileo would be right if the tower was in a vacuum but he never mentions that.

    On earth, where we have an atmosphere, it’s actually very common for lighter objects to fall more slowly than heavier objects …

    Things aren’t as simple as you imagine.

    The same should be done for the work of those involved in the East Anglia scam – throw out their work and move on.

    Most assuredly not.

  6. 156
    Peter says:

    Please, please tell that to the politicians – especially those over here in the UK. Hardly a day goes by that we don’t hear, ‘the science is settled!’

  7. 157
    dhogaza says:

    When AGW’er (whatever that means – I only know what it means in context of its usage above) start admitting the warts of the climate models in something other than private and hidden emails

    Wow, I never realized the various IPCC documents like AR4 were hidden from the public and policy makers in private and hidden e-mails.

    Ya learn sumthin’ every day ’round here! :)

  8. 158
    isotopious says:


    That’s a policy statement based on known science (a response based on science).

    There is still a huge amount of uncertainty in climate science, which needs to be reduced. The critical distinction is that a decrease in uncertainty may lead to the IPCC statement becoming more uncertain.

    That’s science.

  9. 159
    Mesa says:

    Gavin – Thanks for all the answers and post monitoring. Quick question, if we all agree that there is more work to be done, if you were to double your research budget, where would you put the extra money [ie computers, researchers, etc]? Also, what additional instrumentation would you like to see in terms of climate monitoring? What would that cost? It seems to me that there is some high utility money to be spent right now in terms of moving the debate forward….letting time slip by without accurate data gathering seems pretty silly at this point (not that some isn’t being gathered, but maybe we need more).

  10. 160
    pete best says:

    The scientific picture is all said here:

    This email saga is now once again distracting us from tackling the task of reducing emissions. If we project BAU scenarios of 2.5% annual growth in fossil fuel usage then by 2045 we would have released an additional 1.5 trillion tonnes of CO2 into the atmosphere. Sinks have wekened 5% according to report although perhaps the jury is still out on this subject (be nice to get an update on this subject)but I will take the reports value so its around 900 trillion tonnes left in the atmosphere almost which 4.5x that which has been left in the atmosphere so far by us.

    Thats 250 ppmv of CO2 added and hence its must mean over 3C of average atmospheric warming.

  11. 161
    Ike Solem says:

    Unfortunately, WAG, cap-and-trade will do nothing to reduce fossil fuel CO2 emissions. This is why Hansen suggested that failure at Copenhagen this year is necessary, because the proposed solutions – such as cap-and-trade and coal carbon sequestration, which are being heavily pushed by the U.S., Canadian and British governments – are deceptive nonsense.

    He has irked some environmentalists by espousing a direct carbon tax on fuel use. Some see that as a distraction from rallying support in Congress for cap-and-trade legislation that is on the table.

    Such environmentalists are either fools or frauds – but Hansen’s suggestion for a carbon tax should be rephrased as a feed-in tariff / renewable energy-linked carbon tax, used to guarantee rates for renewable energy investors and producers. In this scheme, fossil fuels are taxed and those taxes then delivered to renewable power producers in the form of guaranteed rates – and this removes market volatility from the equation, so investors feel safer dumping hundreds of millions of dollars into projects that pay back over 10 years or so.

    Yes, governments SHOULD intervene in markets when there is an obvious social benefit to doing so – I mean, that’s why we have the FDA and other regulatory agencies, right? Drugs that kill people also get removed from the market – is that also a violation of “economic science principles”?

    P.S. I made an error in that coal carbon dioxide estimate…

    A conventional 1 Gigawatt pulverized coal plant burns 416 metric tons of coal per hour and generates more than 127 metric tons per hour of solid and liquid wastes.

    The difference there is about 300 tons per hour, yes, but there’s a big error in that mass estimate – guess what it is? I neglected the fact that it’s not pure carbon exiting the smokestack, but rather carbon dioxide – for each carbon atom there are two oxygen atoms so the mass ratio of C:CO2 is 12:44, or 3.66

    Thus, one ton of carbon is converted to 3.66 tons of CO2; hence 300 tons of carbon dioxide is very wrong; the real answer is closer to 1100 tons of CO2 per hour!

    As an amusing example of how ridiculous the whole project is, the NYT and other press outlets have been championing some coal project in West Virgina:

    West Virginia carbon-capture test gets $334 million from DOE, December 4, 2009″

    They are going to capture 1% of their emissions, but they are not going to report what % of the power plant output that requires… now, that’s clearly distortion and deception, if not outright fraud. It’s highly unlikely they could even break even – and who is going to audit the data? It’s a private concern, so it probably doesn’t have to report anything, just like FutureGen. As noted, the emails and correspondence surrounding this would be far more interesting to read than the CRU hack.

    If anything ever needed an independent scientific review by an outside agency (NAS, maybe), these DOE coal projects are it.

  12. 162
    Andy says:

    Re: 111

    The snow was nice today in Houston. My kids loved it. But read this: NCAR report – record highs beat record lows. Says it all.

  13. 163
    MalcolmT says:

    Re Mike (151) and Dennis (69):
    I have been thinking about about the slow general acceptance of some scientific knowledge recently, prompted by reading Dawkins’ ‘Greatest Show on Earth’. The book lays out the evidence for evolution but is peppered with Dawkins’ attacks on creationism (he says he doesn’t want to repeat ‘The God Delusion’ but it reads as though he can’t help himself).
    Evolution is 150 years old and still 40% of Americans reject it outright. Relativity is 100 years old and, as far as I know, everyone accepts it. Genetics is 90 years old and universally accepted. The toxic environmental effects of DDT were noticed 50 years ago and everyone not only accepted the evidence but acted on it. Climate change is 50 years old (I date the first public knowledge of AGW to Revelle and Keeling) and still rejected by about half the population, even without religious obstacles.
    Why are evolution and climate change special?
    (1) They are too slow to observe directly, so they are deniable by ‘common sense’.
    (2) They require a very deep rethinking of our relationship with the world. Evolution said we’re not really all that special, but are just smart(ish!) animals – a huge blow to our self-esteem as well as a near-fatal blow to established religion. Climate change says we’ve got to stop treating the world as an infinitely exploitable resource and start caring for it – and that will cost serious money as well as forcing us to accept responsibility for our actions.

  14. 164
    David B. Benson says:

    Steve Smith (133) — Ok, here are my amateur estimates:
    insignificant risk, anyway small and advocated as an upper bound in Hanson et al., 350 ppm CO2;
    no risk, anyway very small, 300 ppm CO2ewa (CO2 equivalent with aerosols);
    pre-industrial revolution, about 270 CO2ewa (but I think there are more risks when that low).

    Michael(134) — Web trawling finds “Web definitions for Denialist: Denialism is the term used to describe the position of governments, political parties, business groups, interest groups, or individuals who reject propositions on which a scientific or scholarly consensus exists.”

    Brian (138) — But on at least five occasions in the remote past, it was most dire. For the end-Perian mass extinction, read Peter D. Ward’s “Under a Green Sky” to note that BAU might well lead to similar conditions once again.
    In any case I do encourage you to read “The Discovery of Global Warming” by Spencer Weart, linked on the sidebar, first under WSccience links.

    Joseph (141) — Here are some resources regarding GCMs:

  15. 165
    pointer says:

    Jim H — Can you clarify your point? You seem to imply that political advocacy by scientists is a bad thing, but when scientists leave the advocacy to Al Gore, that’s also a bad thing?

  16. 166
    Andy says:

    RE: 114 – why the glaciers are melting quicker than rising temps should predict? Well, the cat’s out of the bag. Each year the AGU (American Geophysical Union) holds their annual meeting in some glacier-rich hotspot. During the first evening social, once everyone is well souced and impervious to cold, they hike up into the mountains and melt glacial beast’s icy hearts with battery powered blowdriers. All scientists must blow and melt until the batteries are dead. This is required for the initiates wherein newcoming scientists are given their pointy tinfoil hats so as to better pick up their alien overlord’s instructions.

    Sorry, I’m sure your question was serious but for those of us who have to work with research scientists, the whole conspiracy thing is absurd.

    I think it has something to do with temperatures being expected to rise more quickly at elevation (another AGW prediction proving up quite well). Maybe there is a blog entry in the archives – Lonnie Thompson, I think is the glacier guru.

  17. 167
    SecularAnimist says:

    I’m a non-scientist who doesn’t understand most of what the climate scientists are talking about, and I certainly can’t judge for myself the merits of what they say, but I do know that I dislike Al Gore, so I guess I’ll just go with that and conclude that the scientists must be wrong.

    Also, if scientists do sincerely believe that global warming is a serious problem that threatens the lives and well-being of billions of people and maybe even threatens the continuation of human civilization, they most certainly should NOT publicly advocate policies to do anything about it, because that would be “political”, and that makes me think of Al Gore again, who as I mentioned I don’t like.

    You know, we’ve been through these baseless “political” scare tactics before. I remember back in the mid-twentieth century hearing scientist types going on and on about these supposed “nuclear weapons” that could destroy the Earth. Well, THAT never happened did it? Just another hoax to scare us all, and there never were any such things as “nuclear weapons” after all. It was just made up, to scare us into giving up our freedom. Now here we go again with “global warming”.

  18. 168
    Vendicar Decarian says:

    “I would not worry so much about persuading people. Just educate.” – Jonathan Fischoff – 147

    By now it should be clear to everyone that you will have zero success at educating the wilfully ignorant.

    Isn’t it said that the definition of insanity is continuing to do the same thing and expecting a different result?

  19. 169
    Jim Galasyn says:

    Jeffrey Davis says of my blog: “There’s a disturbing novel by Kevin Brockmeier called The Brief History of the Dead that has an absolutely horrifying conclusion. Reading ‘Desdemona Despair‘ reminds me of that book.”

    Jeffrey, that’s just about the nicest thing you could have said; you made my day!

    As to getting desensitized to Doom, that’s a very interesting observation. I try to pick visually compelling images to show what’s at stake. I’ll have to give your comment some thought…

  20. 170
    Jim Galasyn says:

    Oh heck, italics fail in my last post. :(

  21. 171
    Firkas says:

    I have this feeling that there is some heavy trolling on this blog.

    For example, #150 starts off as a somewhat reasonable post, and then it concludes with a jab against Al Gore.

    This pattern, the starting off with claims that the poster has scientific degrees, makes effort to understand and concludes with a denialist attack, is terribly suspicious.

    For me, this would be reason to research for organised trolling.

  22. 172
    Paul says:

    What I learned from redaing RC this week: 1. The word “settled” is the most contentious word in the English language, followed closely by “denialist” 2. Despite all appearances to the contrary, American Mass Media is liberal. And most dumdfounding,3. If society does nothing to ameliorate or mitigate AGW, it’s the fault of climate scientists, because they were so mean to skeptics.

  23. 173
    Chad says:

    Hey Gavin,
    OT if I may. I noticed that there were some data issues with GISS EH/ER. I’ve updated my data for GISS EH2 for 20C3M and A1B from data contained in the modelE-H2a/modelE-H2b folders on the GISS FTP site. I see that GISS ER has a misspecification of stratospheric ozone depletion and that the models were re-run for 20C3M. Is there an update for the A1B runs for GISS ER? I looked around on the FTP server and didn’t find anything that would indicate a re-run of the model initialized with the end conditions from the new 20C3M runs. Does such data exists?

    [Response: Sorry, no. -gavin ]

  24. 174
    Tim Jones says:

    What I don’t understand is that if roughly half the world’s supply of fossil fuels, at least coal and oil created over 100’s of millions of years by the sequestration of hydrocarbons in the ground have been dug up, drilled up and burned in the last 160 years of industrial civilization, the resulting CO2 well recognized as a heat trapping gas and climate forcing agent, how anyone could rationally imagine that human kind is not the primary, nay virtually exclusive cause of current global warming, especially absent the proof of any other significant climate forcing during this period. I think the science is quite well settled except for exactly how many minutes will occur at the rate we’re going before our goose is cooked.

  25. 175
    Radge Havers says:


    “What exactly is a “denialist”? I can’t find that in the dictionary.”

    I guess you could call it a kind of clueless social pathology that causes lacunae in reasoning.
    “What is Denialism”

    “Unified theory of the crank”

    “How I found glaring errors in Einstein’s calculations”

  26. 176
    Radge Havers says:

    Jim Hanson (a different one)@150

    “…Al Gore…the makings of political advocacy all over this subject.”

    That makes a sort of sense just with hindsight. But then any attempt to address AGW that shows signs of being effective will come under intense fire. While one should always be ready to re-examine one’s position and where it went wrong, you should also avoid indulging in self-flogging. That’s just another distraction.

    We’re still learning how to build good firewalls between science and policy. That said, it is perfectly legitimate for people with policy expertise and communications skill to present to the public where, why, and how they think the science should influence political decisions. I’d argue that they’re obliged to do so. Al Gore isn’t a lightning rod because he’s a fat liberal. It’s because he’s articulate and not merely glib.

    The other, other Jim Hanson has taken his share of lumps too, btw, and just about every other climate scientist with a public voice I dare say, starting well before Gore weighed in.

  27. 177
    Rob Bradley says:


    You said (comment#2):

    [Response: No. The standard range is well supported by paleo-climate studies and a small sensitivity is not. Lindzen’s latest paper will not turn out to be robust (I predict), and even Roy Spencer has said he can’t get the same results with only modest differences in approach. You might like to think that a single paper from Lindzen overturns everything, but it doesn’t. – gavin]

    This response misses my point. I am not saying that Lindzen’s paper is right and that the sensitivity is 0.5C. I am saying that Spencer is also below 2C and that a partially right Lindzen falsifies the whole IPCC range.

    Jerry North at Texas A&M is right at 2C, the very bottom of the iconic range.

    To pretend that sensitivity is ‘settled,’ even within a range, is a pretense of knowledge given how little we know and the temperature records that might have to go through a reconstruction.

    By the way, a take by an economist on the real climategate debate that you are missing by attacking the ultra-skeptics is here:

  28. 178
    Garrett Jones says:

    Gavin, this is a bit of a personal question, but you are sort of putting yourself out there…. Do you receive research funding or consulting fees from “Big oil and gas”?

    [Response: Not even little oil and gas. ;) -gavin]

  29. 179
  30. 180
    ccpo says:

    Richard says:
    4 December 2009 at 9:07 AM

    I think you’re guilty of your own brand of misrepresentation here. “Settled Science” in the cited WSJ article almost certainly refers not to AGW as established fact but rather a degree of certainty sufficient to justify large-scale policy change.

    Even if so, they would still be wrong. Apparently, we need to start teaching risk assessment in grade school. See if this informs you at all:

    Of more than 250 experts surveyed, more than half said the 2C target could still be achieved but only 18 thought that it would be. By the end of the century, most thought average temperatures would rise by some 4C.

    …The Guardian poll merely highlights a belief that the warning has simply failed to penetrate. As one said: “I think a full understanding of what must be done quickly, and the consequences of insufficient action, is lacking among the policy makers and the public.” Another said: “Current government actions are playing into the hands of … an electorate that doesn’t quite understand how serious climate change is.”

    Survey respondents were promised anonymity. Many scientists are reluctant to admit publicly that the 2C target is unrealistic, and several warned that simply raising the subject was sensitive.

    Here’s a companion slide show. A little scarier than the above quote.

    The BASE science is settled. Deal with it.

  31. 181
    bcoppola says:

    What’s with all the pearl-clutching about scientists “advocating policy” anyway? Aren’t scientists citizens too? Last I heard, citizens of democracies have that right.

  32. 182
    Llama Cheese says:

    Sorry for coming to the discussion late, but I have a few questions that I would like someone to answer; terribly sorry if they are redundant. I obviously fully support the brilliant scientists at CRU and almost everything I’ve read supports their honesty here.
    My questions:

    1. Sources differ from “Phil Jones lost data in the 80’s”, to “CRU releases 95% of its data”, to “The other 5% is from the arctic”, to “The other 5% wasn’t even recorded/was thrown out”, to: “All of the processed data has been made public, but not the raw data”.

    Can Gavin or someone else please explain the exact state of CRU’s data?

    Was any thrown away, and if so, why?

    What isn’t being made public and why?

    Is the 95% of data released figure true, and does this apply to raw data or processed data? What exactly is the difference between the two?

    Is the 5% from the arctic region? I’m confused on this; one source tells me that CRU does not have arctic stations, and the other source tells me that CRU does not release the arctic data.

    2. Can someone please explain the exact state of Phil Jones’ FOI request problems? What requests did he decline, exactly? Were there valid reasons? How does the situation look for him right now? What will probably be the outcome of the independent review of the emails?

    Thanks, I really hope someone can answer these.

  33. 183
    ccpo says:

    I would argue that this business of calling people “deniers” is unfair and unreasonable to ANYONE.

    I realize “deniers” are pretty much immune to logic. After all, we aren’t really wired for it, as studies often show. But here goes, anyway. It is eminently fair. There is a reason deniers (of all varieties) never discuss physical, observable changes, right? You can’t blame that on biased scientists (97% is bias? Sounds like consensus to me.) You can’t blame it on climate models. You can’t blame it on bad data. So you don’t talk about it. 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. For your pleasure:

    If you can show where any of the above are false, I’ll listen. (Not really. I prefer the ice measurements, etc., to denying reality.)

  34. 184
    walter says:

    I love this site. It is always goog for a chuckle before bed.

  35. 185
    Jim Hanson (a different one) says:

    165, 171, 176: I’ll elaborate, but be patient; I want to squirt a magnum opus in here about cultural conflict.

    For 171 / Firkas: Nope, not a troll, nor a denialist. I am who I say I am. Never posted here before, never been to a denialist website, blah, blah, blah. I am a sceptic, however–of a sorts. Meanwhile, I am trying to get up to speed on intelligent discussion here, so I am off to 183 / ccpo’s link to the Oreske’s video…

    Jim H.

  36. 186
    Mark V Wilson says:

    Why not invest in more thermometers?

    If 100 (or so) thermometers would be enough, why not publish a list of the 100 (or so) thermometers that would, putatively, be sufficient and then track their results versus the total set of extant thermometers?

    Referrring to this comment discussion –

  37. 187
    Dan says:

    [Response: What is it with people refusing to stop playing semantic games? – gavin]

    Good question. Take your opening post, stating that the science isn’t settled, but you want to act like it is… Words mean things, people who write papers know that, and use words for specific reasons.

    If you truly believe that the science is not settled, then I think a letter stating as such – and providing the logical follow-on that more study is needed before drastic measures are taken – would go a long way towards rebuilding trust in much of the public’s eyes.

    Science is to be skeptical, and unless the evidence is conclusive, actions should be taken with care and trepidation. If you’re so sure that action is demanded and what that action should be, then apparently – as a good scientist – you believe the evidence IS conclusive. Meaning the science is settled.

    So which is it? Is it settled, or not?

    [Response: I write a whole post about why binary distinctions are misleading, and you respond by demanding I make a binary choice. Oh the irony. – gavin]

  38. 188
    ccpo says:

    Mesa says:
    4 December 2009 at 1:12 PM

    I keep coming back to the intrinsic variability argument… If the answers are some combination of inaccurate temperature record and/or natural variability (which they seem to be, as CO2 is the only large positive forcing in the GISS database), then it’s understandable why there are a lot of questions about the sensitivity estimates.

    Again, the obvious escapes a poster: Do we care overmuch about history when current experience has observed natural events outpacing the sensitivity? In other words, you’re standing next to a river that was supposed to be at flood stage according to the science we have thus far, but is 5 feet over that, and asking whether the measurements taken in 1940 were correct. The question is, why are we seeing things we didn’t expect to see for decades, or even centuries?

  39. 189
    Whit Blauvelt says:

    The American opposition to science is simply a matter of immaturity. It’s the belief in manifest destiny: that God gave us a good continent with a good climate. A God who would give it to us just a couple of centuries ago, and then snatch it away – that’s worse than accepting astronomical space-time scales or evolution. In both of those perspectives there’s still nothing that forces an acceptance that we are not the children of some being quite larger than us that will love and protect us. This, more than anything suggested by science, requires we be ready not to be children any more.

    Science asks us to grow up. Political and business “leaders” ask us to be children. It’s the converse to their taking on their “leadership” positions, as it were to either side of God. (There are no true religious leaders in this age. It’s all politics and business. Perhaps the Dali Lama’s the only exception.) The implication of the denialists is “Don’t worry, children, God will never let the climate get out of His control.” The motivation is the denialist leaders don’t want us to get out of their control, to grow up and take over the running of the adult world from them. They say as much, accuse us of conspiracy to do that. Let us openly engage in that conspiracy. Anything less is childish.

    And they are themselves childish. Many scientists are too, individually. Still, the step to maturity is scarier for many people than is utter destruction, than is death itself, even for their own children. We must push them to maturity anyway. We must be without mercy in this, except in dealing with the elderly, whose battle this will not be anyway. I’m not speaking as a scientist. Humanly though, this is where we’re at.

  40. 190
    dhogaza says:

    The toxic environmental effects of DDT were noticed 50 years ago and everyone not only accepted the evidence but acted on it.

    Actually, they’re still fighting it, and indeed, some of those who fight it also fight modern climate science.

    That should tell you something, no?

    (if you want an example of someone who is both a DDT and AGW denialist, go to

    (if you want an example of a global warming and HIV/AIDS denialist who is also a far right wingnut, go visit Eric Raymond’s blog)

  41. 191
    Bernie says:

    Apparently the Met Office has decided to reassess its temperature records. It is also promising that this time it will do the reconstruction in a more open and transparent way. It seems like somebody has been taking a close look at what was actually being done at CRU. They say that the reassessment will take them about 3 years.

  42. 192
    ccpo says:

    John S says:
    4 December 2009 at 2:34 PM

    IPCC ar4:

    “Most of the observed increase in global average temperatures
    since the mid-20th century is very likely due to the
    observed increase in anthropogenic GHG concentrations.”

    With “very likely” defined by the IPCC as >90%.

    So then the science is isn’t settled, it’s just “very likely” settled?

    [Response: Whatever. – gavin]

    Quite the distinction, Gavin.

    Yet another who asks so little of every other danger they face, but asks the highest possible – absolute certainty – of the one risk that can actually end civilization.

    Chance of death in car accident: roughly 1 in 100.

    Airplane: In general your chances are about 1 in 10.5 million.

    Fire: 1 in 1,062

    Earthquake: 77,326

    All of these have insurance available, some are mandatory. I’m betting you have some or all of these. Most ***who can afford it*** do. Yet, about Anthropogenically-forced Climate Change, which is essentially guaranteed to disrupt society and very likely to cause its breakdown if not mitigated, nothing should be done till we’re more sure. Even though
    the odds are far greater than any of those above.

    If that’s not denial, what is?

  43. 193
    ccpo says:

    Stephen Gloor (Ender) says:
    4 December 2009 at 5:54 PM

    ccpo – “I’m hoping this whole e-mail thing has awakened the Average Scientist to one simple reality: You’re going to have to come out from behind your desks and engage the public actively, and critics strongly, if you (collectively) wish to help avoid the 6C scenarios.”

    Who then does the research. I am sure that this foolishness has cost climate researchers much time and on his job.

    There are a LOT of climate scientists. A concerted effort – after all, the misrepresenters are utterly organized – would also go a long way. I’m serious. We need a few hours of TV time, live broadcast, led by the President, lots of scientists, even the handful of legitimate(?) naysayers, and show the public why the naysayers are misleading the public. This needs to include the well-documented funding and support as outlined by Oreskes, et al.

    Besides, we know all we need to know as far as how big the risks are. Beyond a certain point, it’s an academic issue. After, say, 4C, do you really think things will be anything like they are now?

  44. 194
    jyyh says:

    Thank you Gavin for your endurance on answering the issues raised over this widely publicized and endorsed criminal activity (also known as CruHack). But here you say now the science isn’t settled. So what are the non-settled issues? Is one of them by any change the observed lack of day-time and summer-time warming over the last 10 years? Has the ‘natural variability’-factor in the climate models been underestimated? If not, how are the limits of ‘natural variability’ on the models determined? I presume they have something to do with the vorticity of the dynamics in the system, so could there be an error on the way the models treat f.e. the deep ocean? I’d like to see these things written out somewhere, there once was a page on NASA that described some of the problems in climate models, but since it was moved or deleted I’m somewhat at loss discussing about the models with people interested on them. I know the simpler models people built during the first half of the 90s have been replaced by more accurate ones, but are there still some problems arising from the beginning of the climate modelling that have not been improved? I was pleased to find Taminos explanations on very early statistical (two-box) models but could there be a story (or a set of stories?) of a more complex (intermediate?) model, explained with as little maths as possible, if that’s possible? Again, thank you.

  45. 195

    The most unsettled science, the greatest unknown, lies with the human psychology and perception. … Humans have blind spots, lapses in hearing, and a general unwillingness to face the unpleasant. Compared to other animals, our senses are limited, while our hubris is unlimited.

    This is not meant to trivialize — the unknown and undiscovered aspects of global warming are now due to human reticence, fear, and political unwillingness to face the issue.

  46. 196
    Glenn says:

    “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.”

    Silly hyperbola and obfuscatory rhetoric, Gavin.

    From: “Michael E. Mann”
    “In this one respect (sea level rise) I agree with today’s Journal editorial that the science is not yet settled.”

  47. 197
    Mike says:

    Re MalcolmT (163)

    I think a lot of it has to with evolution and climate change butting heads with deeply held ideologies, be they economic, political or religious.
    After all the evidence for evolution is overwhelming and it underpins huge areas of science, including areas which people who deny evolution probably accept such as DNA testing, the emergence of drug resistant diseases etc. But a lot of people deny it.

    I don’t know if it matters whether people understand it, I doubt many people understand relativity but everyone agrees Einstein was a scientific genius.
    And I would argue that climate change is occurring fast enough for people to observe it (take the melt of the arctic ice for example). Although the western lifestyle does insulate us somewhat from changes in our environment.

    The denial industry is good at PR and has fairly successfully painted areas of science and perhaps science itself as a left vs right political issue. Personally I think if your personal or political ideology is incompatible with the laws of nature it’s time to change your ideology. But for someone who mistrusts science already and can find people who will tell them what they want to hear, then I’d imagine ideology will always trump the laws of nature.
    How else to explain the denial of evolution, one of the most fundamental aspects of modern science, 150 years after its discovery?

  48. 198
    just-curious says:

    Looking at the data from, there has been no warming for 10 years. My question is how many years do we have to go without warming in order for climatologists to conclude that global warming has ended?

  49. 199
    Dick Veldkamp says:

    Because the meme ‘The Earth has been cooling since 1998’ is becoming more wide spread again (even otherwise sensible newspaper articles seem to feel obliged to add a sentence like ‘but scientists cannot explain the cooling over the last 10 yeasr’) I would like to ask a question to the experts here.

    As I understand it, the fluctuations we see in yearly temperature are mainly due to the fact that we measure the atmosphere’s temperature only. The atmosphere is exchanging heat with the oceans, which have a much larger heat capacity. Heat exchange is dependent on things like weather and El Nino. Therefore the atmosphere’s yearly average temperature is somewhat random.

    Now it seems to me that if we could somehow integrate the total amount of energy in atmosphere, land mass and oceans, this energy (or some average equivalent temperature) should show a steady rise, because yearly solar input is approximately constant (apart from some influence from cloud and ice cover).

    In fact I would contend that this average temperature must be monotonously rising, and cooling is impossible as long as the amout nof greenhouse gas goes up.

    Is this correct?

  50. 200
    Nick O says:

    Thinking a bit more about ‘warming’, I wonder to what extent the climate system shifts by going through a series of step changes, rather like the step-pool sequences one observes of streams and rivers in upland regions.

    In this respect, it seems to me that ‘warming’ can be taking place without much noticeable change in temperature – sensible heat – because much of the heat is going into changing phase i.e. melting ice into liquid water, or changing liquid water into vapour. I wonder therefore whether the apparent cessation of ‘warming’ over the last ten or so years, which the skeptics like to cite so often, is actually the system adapting by a series of phase changes for a while; once these have occurred for a period, the warming then is made evident again by temperature changes, then again a while later by phase changes, and so on, stepping from one energetic manifestation to another. A bit simplistic, I know, but looking at the changes in Arctic ice, and the recent data on Pine Island and more recently in the Eastern Antarctic ice sheet, I susupect that’s where we are at the moment. If this is correct, at some point, the temperature warming trend will be resumed, possibly with quite a large jump compared with what we experienced during the 1990s.