Strange Bedfellows

There are multiple strands of intellectual incoherence here. Firstly, people who have argued that there really hasn’t been a significant rise in CO2 since the 1800s, now accept the ice core results that show there was a much smaller rise from 8000 yrs ago. Secondly, those that argued that the 20th Century CO2 rise cannot be anthropogenic, appear to accept that the post-8000 BP change was. Thirdly, those who argue that the current increase in greenhouse gases has no significant climate effect, now appear to believe that the much smaller changes in the pre-industrial prevented an ice age.

This is like someone who believes the earth is flat buying a round-the-world ticket for their vacation.

Let me make it a little clearer. If one accepts Ruddiman’s hypothesis, one implicitly agrees that: i) CO2 and CH4 can be affected by human activity, ii) greenhouse gases have a significant forcing role, and iii) climate sensitivity is in the ballpark of mainstream estimates. (The opposite is not however true, one can agree on those three points (which is pretty much the IPCC consensus) without necessarily thinking that Ruddiman is correct). One must therefore conclude that those contrarians who have warmly welcomed Ruddiman’s thesis have now come around to mainstream opinion. Hmm…

But wait, they might say, we don’t believe any of those things, but we accept that we may be wrong, in which case, Ruddiman’s theory still implies that we should not do anything about increasing CO2 . No. At minimum it might indicate that reducing CO2 below pre-industrial levels might not be a good idea, but that is far from saying that any amount of further increases are beneficial. It certainly doesn’t follow that if a little bit of CO2 is good for the climate, then a lot more is better.

I think a more obvious explanation is that, for some critics, any argument will do – regardless of its coherence with the argument they had before, or the one they will pick next.

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60 comments on this post.
  1. Grundt:

    Good post!!
    Is Carter suggesting we keep on devastating biodiversity?
    Promoting desertification?

    Does he think in what he is suggesting with:
    “ is clear that for the moment the status quo and “do no harm” is the preferred option. A much better understanding of natural cycles of climate change and of the magnitude of human effects on climate are needed before we consider implementing global mitigation measures.”!!!!

    I think you are absolutely right, the fanatics “..have now come around to mainstream opinion”

    I like this ” This is like someone who believes the earth is flat buying a round-the-world ticket for their vacation.”

    This is not the first time somebody is aware that since the dawn of agricultural activity man has been altering the environment.

    I wonder what new misconstructed argument will pop-up in the mind of these geniuses.

  2. DrMaggie:

    Re “This is like someone who believes the earth is flat buying a round-the-world ticket for their vacation.”

    They could still be aiming to travel around the circumference – which, IMHO, still would qualify as “round the world”…

    Joking aside, as a complete amateur on climate issues, I am having great difficulties with accepting the Ruddiman hypothesis – if for no other reason that the Earth is so large, and 8000 BP, there were pretty few humans around, especially compared to today. I actually thought, naively I’m sure, that it was (regional) climate change events that governed the behavior, and perhaps also the success, of early cultures, such as the megalith builders in Europe – and not, as it were, the opposite…

  3. Barry Phease:

    The other thing is that IF Ruddiman’s thesis is true and that continuous emissions of GHGs is necessary to avert catastrophic cooling, then that is more reason to conserve fossil fuels. There is no doubt that the oil/coal will run out if we keep using it and then we will have no cheap way of maintaining the temperature. OTOH if we reduce our rate of usage then we have longer before we have to find some other method of keeping the heat up. :)

  4. tom:

    Shorter version. Minimal amounts of GHG cause climate change, so maximal amounts are necessary to maintain what the minimal amounts created. The only thing I can conclude is that these people need carbon the way a vampire needs blood.

  5. dave:

    You can’t agree with anthropogenic forcing from 8000 kya to now and disagree with such a forcing during the industrial age. I think the magic words for Idso and other skeptics are “spiral to full-fledged ice-age conditions.” Carbon emissions forcing the climate and warming up the Earth is preventing an ice age – that’s the common thread with Ruddiman. As soon as you bring up ice ages, they come out of the woodwork like … termites? Sorry, thinking methane there.

    Speaking of methane, I have a serious question.

    From Ruddiman et. al 2004, the gist of his argument, or so it seems to me.

    Over the last 8000 years, the CO2 concentration gradually rose to a level of 280-285 ppm during an interval when trends observed during the three previous interglaciations suggest that it should have fallen to 240-245 ppm (Ruddiman, 2003). Similarly, CH4 concentrations rose to 700 ppb during the last 5000 years, a time when weakening monsoons and cooling of boreal regions at the 22,000-year orbital precession cycle predict a continuing decrease to about 450 ppb. The anomalous CO2 rise is attributed to massive early deforestation of Eurasia, and the anomalous CH4 increase mainly to irrigation for rice farming in southeast Asia, as well as increases in biomass burning, livestock, and other sources (Ruddiman and Thomson, 2001). The equilibrium warming estimated from these anomalies (about 40 ppm CO2, about 250 ppb CH4) is 0.8 °C on a global basis and 2°C in polar regions, based on the IPCC sensitivity estimate of a 2.5 °C temperature change for a doubling of CO2 concentrations (IPCC, 2001). [Italics added]

    The effects on atmospheric carbon levels from landuse changes are highly uncertain, as I’m sure Ruddiman knows. I’m not so sure about methane (major sources include rice agriculture, landfills, domesticated animals and biomass burning). See methane sinks and sources.

    However, the claim in that last sentence in the quote, is that right? It seems too strong. That doesn’t seem consistent with the last 150 years. Could you comment on that?

    [Response: It’s about right. The forcing is about 1.1 W/m2. The key is that this is an equilibrium response. The forcing over the last 150 years is around 1.6 W/m2 (including cooling effects from aerosols and land use change) but the climate is not (yet) in equilibirum, and so the full temperature response has not been acheived. – gavin]

  6. Joseph O'Sullivan:

    The critics of climate science who use any argument to support their position are not doing something new. Much of the criticism comes from people who have a financial stake in the debate. If the mainstream and well-supported scientific claims (that the global climate is warming, the warming is at least partially caused by humanity’s release of greenhouse gases, and this warming can be harmful) are accepted, the next step is to take action. This would require a reduction in the release of CO2. Because most CO2 emissions come from the burning of fossil fuels, limiting the emission of CO2 would require a reduction in the use of fossil fuels. Petroleum and coal companies would not make as much money and therefore use any argument to dispute climate change science. These companies are supported by people and organizations who share their ideology and who sometimes also have financial connections to the companies.
    An editorial in the New York Times written by a professor at Yale’s business school noted that in today’s corporate world the only thing that matters is profits, and harmful or dishonest practices are accepted if they are profitable. An analogy that the environmentalist community uses compares the behavior of companies that fight environmental regulation to the behavior of tobbaco companies. Tobacco companies claimed for decades that cigarettes were not addictive and not bad for your health. They claimed to have science that proved this and disputed any science that did not. As an ex-smoker I know, as everyone else does, that cigarettes are addictive and deadly. The same tobacco companies later said they should not be sued because people made sick by smoking knew that cigarettes were proven to be unhealthy before they started. Many critics of climate science are using the same tactics. They are using any argument to get what they want.
    It reminds me of joke that lawyers tell: a lawyer defending a man accused of a crime claims, all at once, that the defendant wasn’t at the scene of the crime so he couldn’t be guilty, the defendant was at the scene but it wasn’t him, and the defendant did commit the crime but is not guilty due to insanity.

  7. Dano:

    for some critics, any argument will do – regardless of its coherence with the argument they had before, or the one they will pick next.



  8. Gary:

    This just goes to show that if we can stop a ice age by accident. Then surely we can stop global warming by doing something about it. The only problem is, getting everyone to sing from the same song sheet. This my be our downfall and mother nature does not take prisoners as we have ALL seen. The truth is she,s already got a firm grip and our ignorence is not helping. Sorry to sound all doom and gloom but all a see is a lot of talk and no action and accidents DO happen.

  9. Henri:

    I think with the point of view of a mathematician.
    Since the beginning of the industrials times, we can see that the curve is as an exponential ( you see e^x?!?). And Ruddiman’s thesis is the begennin of the curve!
    I think! Or i guess!
    But what will happen, noone knows!


  10. Peter J. Wetzel:

    Well, it’s fun to watch Gavin gloat. But the arguments he targets are so obviously beyond the bounds of scientific reason, that he seems to be shooting fish in a barrel.

    Political tactics that have no respect for factual consistency or objective reality do not fool anybody but the fools. It doesn’t hurt to point out these tactics, but it’s probably not necessary to get worked up about it. The only people who respond to such arguments are the certifiable political hacks who wear their agenda on their sleeves. I continue to have faith that even the relatively uninformed average citizen who carries no agenda can see through this sort of patently obvious spin-mongering.

    There is a spectrum of scientific “reality” (as oppossed to a fixed single path of truth), and within it there is a range of plausible uncertainty which must be accepted, if science is to represent itself responsibly. In my opinion, Ruddiman’s hypothesis does potentially fall within this “error envelope” of our understanding of climate. Surveys of the maximum age of lichen on Baffin Island shows that there was quite a considerable expansion of permanent snow cover during the Little Ice age in the higher elevations (particularly around the Barnes Ice Cap). One can argue that this was a local effect, but who can convincingly argue that the onset of global glaciation during previous stadials did not begin with a local effect?

    Frankly, today’s orbital forcing seems to be marginal at best, in terms of its ability to support Ruddiman’s hypothesis — present-day summer high latitude radiation forcing *is* sufficient to sustain an existing ice age, but it falls rather far short of the minima which seem to have been required to initiate glaciation during past glacial cycles.

    Ruddiman’s idea is worth discussing. I’d rather focus on the human influence on land-use change as the primary cause rather than rely entirely on the early release of GHG’s. I believe humanity mastered fire early enough to affect land cover by 8000 years ago. And human induced species extinctions (e.g. sabertooth tiger, mammoth) were well under way by that time. It is thus plausible that our species could have begun to have an influence on climate as well.

    [Response: Unfortunately, if you follow the links, people actually are making these arguments. It surprised me too! I agree though that Ruddiman’s idea is worth discussing. I disagree that the current orbital forcing could sustain an ice age had one been initiated, and I seem to recall a paper showing that (but I’ll need to track it down). – gavin]

  11. ml:

    I had thought precisely this – that we had to be able to control the level of CO2 to steer between the two risks of overheating and preventing the now-overdue ice age. But then this paper in Nature

    came out last year, suggesting that rather than being overdue, the next ice age was likely to be around 15,000 years off.

    Two points – nice for Nature apparently to give us a free kick for once, unlike the generally worse and worse outlook which has been emerging;and in Ruddiman’s most recent paper the Nature paper is not referenced, so I can’t tell from this what he thinks it means for his theory.

    I agree with all the points showing that for some critics any argument will do.

  12. Grundt:

    ml, thank you for the link.
    All this is illustrative of no matter how much research is done, respected scientists don’t have the same kind of “thinking structure” in the brain, or have different color glasses (not everything has to do with who gives the funds..).Logic is difficult to define.. in such an illogical context.. Well, it seems that our ignorance surpasses all accumlated knowledge of Mankind.
    Gary, it’s true for every situation: “The only problem is, getting everyone to sing from the same song sheet” . funny comments, yours, about our “accidental” success in stoping the next Ice age .And the ones by Henri’s, Tom, Barry and the others.
    Bingo!, Gavin, as Dano says.

  13. david:

    From an evolutionary standpoint there is no reason why we didn’t start agriculture during the last interglacial. 1) People haven’t changed genetically since then and 2) during this interglacial we started agriculture on separate continents using many different plants without the assistance of global communication (ships, planes, pigeons, satelites, or internets).

    So . . .

    1) Is anyone looking for unusual charcoal and pollen signals in the old world that might be proxies for slash and burn agriculture during oxygen isotope stage 5E?


    2) Did the lack of new world slash and burn agriculture doom those ancient old world cultures? Did they fail to pump enough CO2 and CH4 into the atomosphere to prevent a return to harsh and variable glacial climates?

    Anyway . . . digging around in 120,000 year old lake sediments might be a good past time for retired physicists and eccentric tycoons.

  14. Silent E:

    Ruddiman 2005 runs an experiment on models without the paleoclimate anthropogenic forcing he described in his 2003 paper. He finds that there would be persisent ice-sheet cover on Baffin Island and in Labrador – but no “run-away” glaciation.

    Even there, the skeptics have to take enormous liberties with his findings.

    Note that, in addition to the Nature paper cited above, a commenter provided this nice page a few weeks ago (from the “Global Cooling Myth” thread of Jan 14, #43). It illustrates that the orbital forcings of the next 100,000 years will not be as strong as those of the last 100K because the orbital effects will be more out-of-phase – i.e. that even in the absence of anthropogenic forcings, orbital forcing would have been much less likely to trigger a new ice age.

  15. John Cross:

    This was published last year Eight Glacial Cycles and indicated that our current interglacial period can be expected to last another 12,000 (without anthropogenic forcings).

  16. dave:

    Re: Holocene Climate

    This Ruddiman stuff gets more and more interesting. Here’s a short news summary from New Scientist about the theory Early farmers warmed Earth’s climate.

    Now, if it’s true that the equilibrium warming from the CO2 and CH4 anomalies is 0.8 degrees C globally and 2 degrees C in the polar regions over the last 8000 years, and given that the CO2 and CH4 records are accurate (regardless of the causes of the increases as they depart from the solar insolation data), then my question is this: does the Holocene paleoclimate record this temperature change? Ruddiman et. al (2005) seem to base their conclusions on the Vostok Antarctic record for previous interglacials and their GENESIS climate model. But what about the Holocene temperature data as currently understood? Does it show the temperature increase? On the other hand, is it supposed that the decrease in solar insolation somehow “balances out” the CO2/CH4 forcing and so the Holocene record would not necessarily reflect it? Is there some other explanation? Is the data inconclusive? Have I asked a good question?

    I don’t see any supporting data at the IPCC TAR How Stable was the Holocene Climate page (for example, the Greenland data) nor anywhere else I’ve looked. Either a 2 degrees C warming at the poles, even over several thousands of years, would be directly reflected in the Holocene paleoclimate data or there’s a good reason why it can’t be seen or hasn’t been noted (in sources I’ve seen) prior to Ruddiman’s work.

    Just trying to figure out what’s going on here…. I was not familiar with this hypothesis before your post.

  17. Pat Neuman, Hydrologist:

    Are scientists paying enough attention to global warming adding to the destruction of the stratospheric ozone layer? Could that destruction be more severe to Earth’s biota than temperature change? How important was the loss of ozone in contributing to extinctions in Earth’s past?

    Excerpt: “Scientists Studying Wintry Ice in Summer Clouds”
    … Because of their high altitude, ice clouds touch the tropopause,
    the region between the troposphere (the atmospheric layer closest to
    Earth) and the stratosphere. When the rising air on a summer day is
    hot enough, it can move fast enough where it “punches through” the
    tropopause and into the stratosphere. This “overshooting cloud top”
    brings water vapor into that layer of the upper atmosphere, where it
    contributes to destroying the “good ozone” that protects us from the
    Sun’s harmful ultraviolet (UV) radiation. …

    [Response: the idea that GW could make OD worse *is* studied – though the mechanism I know of is different. It is: GW will cool the stratosphere. A colder stratosphere can support more polar stratospheric clouds (there is a temperature threshold for their formation), and PSC’s are a vital part of OD. At the moment, the Antarctic strat is colder than the Arctic, hence most OD there. But people study whether the Arctic might cool enough to develope proper ozone holes of its own. Its a balance, I think, between GW (or cooling, in the strat) and the slow decline of ozone-depleting chemicals – William]

  18. Wolfgang Flamme:

    There’s another problem with Ruddiman’s thesis: There’s no sign of a strong population increase that should certainly have taken place if vast deforestation and agricultural development would have been so very beneficial for mankind.
    So probably deforestation was caused by natural climate changes and mankind was forced to compensate for the losses of stock by ‘inventing’ agriculture?

    One of Ruddiman’s main arguments says: Human activity has to be the relevant forcing since our present models cannot see purely natural causes for these changes.
    But it might as well mean our climate models are doing a bad job.

  19. Grundt:

    If Ruddiman is right (at least in part) , then we, some environmentalists, were not mistaken, for decades, assuming Human role is important in Global Ecosystem Earth.
    When we see what means catalysis for some processes; the maybe yet not discovered synergistic processes, , many of their components unknown, not studied. All other factors already so well mentioned by many of you and Jeff elsewhere.
    It means, we will never know, I am sure, what is really taking place, how was it exactly in the past.

    I respect tremendously all of you who know enough mathematics to work with models. I know you are aware that models help to understand, but maybe will never reflect every influence.

    –Gavin : “…If one accepts Ruddiman’s hypothesis, one implicitly agrees that: i) CO2 and CH4 can be affected by human activity, ii) greenhouse gases have a significant forcing role, and iii) climate sensitivity is in the ballpark of mainstream estimates…”

    —Dave.” You can’t agree with anthropogenic forcing from 8000 kya to now and disagree with such a forcing during the industrial age…..”
    Here in Venezuela emergency declared in the major part of our territory…
    Rain – more rain, high sea waves, landslides, floods, evacuations, people trapped in non-accesible zones. This is expected to continue for some days.. Never seen this in February.. Colombia, other countries with similar conditions..


  20. Stephen Nodvin:


    Interesting. Last summer George Will cited news sorties and articles from 30 years ago that had suggested that another ice age was due to denigrate today’s climate scientists and say they are full of “Hot Air” on global warming.


    [Response: See The global cooling myth – William]

  21. Silent E:

    Re #17: “There’s another problem with Ruddiman’s thesis: There’s no sign of a strong population increase that should certainly have taken place if vast deforestation and agricultural development would have been so very beneficial for mankind.”

    1. Ruddiman points to the effects of historic catastrophic disease-caused depopulations: 35-40% depopulation of Europe in Black Death; 90-95% depopulation of Americas following contact with Europeans.

    2. Ruddiman argues that free land fills up very quickly. Even after 35% depopulation in Europe that led to massive re-forestation in 1350-1420, the population recovered within 100-200 years and most of the new forests were re-cleared for agriculture.

    3. In the Americas, settlement patterns following the arrival of humans about 20Kya ago reveal that humans expanded through both continents within 1000 years.

    4. Agriculture was not “very beneficial for mankind” – it was marginally superior to the alternatives for each person that undertook it, and competitively superior for the particular societies that did so. Jared Diamond (and others) made this point in Guns Germs & Steel that the process was gradual, but that agricultural settlement patterns and societies possessed competitive advantages over nomadic or pastoral societies, mostly due to substantially faster population growth.

    5. Faster population growth (e.g., more surplus food, birth spacings of two years instead of four) + free land to anyone who can clear and plant it = massive, accelerating deforestation and rice-paddy farming.

  22. Grundt:

    ‘Political’ Science: The Rise of Junk Science and the Fall of Reason–An ENN Commentary
    February 10, 2005 â?? By Peter H. Gleick, the Pacific Institute

    “….In theory, science is non-partisan. The Earth is goes around the Sun, gravity is a constant, smoking causes cancer, whether you are a Republican, Democrat, conservative, or liberal. In practice, however, as Galileo and many others discovered, science is not always pure or certain….”
    “….Unfortunately, in recent years, the creation of deceptive science and false information has become a thriving industry at a time when independent government research budgets are being threatened and cut…”
    “..One of the most important examples of this kind of scientific abuse can be seen in the arguments over climate change…”

  23. Lynn Vincentnathan:

    I just read a news story about an article in Nature (Feb 10, 2005 – which I don’t have yet) claiming larger climate variability in N. Hemisphere over the past 2000 years, and that perhaps more of the warming in our time is due to this natural variability. I’m sure the skeptics will glom onto that.

    On the other hand, they do claim the greater changes were perhaps due to forcings & factors (solar radiation & volcanos), so would this then show greater climate sensitivity both to nature & us?

    [Response: The paper is Moberg et al. You can read my personal take on it, which includes links to the exect ref. I think its an interesting paper, but there are some concerns. Mostly, there is a possible problem with the scaling. What they do is use a wavelet method to combine low frequency signals from non-annually resolved proxies (lake sediments) with high freq signals from tree rings. This ends up with a non-dimensional signal which needs to be scaled against its overlap with the instrumental record in order to provide a signal that has units of temperature. But… the paper is slightly vague about how the scaling is done; and if we’re talking about the low-frequency signal, it has about 1 1/2 d.o.f. (or 3? its 80+ y signals, over the 120 y period 1859-1979) in the overlap period. Since much of the interest is in the size of the past fluctuations, which depend linearly on the scaling, this deserves a bit more attention – William]

  24. Grundt:

    Re # 17 Thank you for the links.

    Yes, I remember reading in 1998 and later about feedback Global Warming-Ozone destruction.
    Personally I think that what you suggest: –” Could that destruction be more severe to Earth’s biota than temperature change? ” — needs far more attention from Scientific community.

    Biological adaptation to harmful UV is, it seems, a lot more difficult than adaptation to Temperature changes alone, (not taking in account radiative effects, which I understand are forcing factors in Climate terms)

    Of course, Global Warming carries within a Pandora box. The concomitant events for temperature changes are a furious beast, as a renowned scientist, pointed reffering to playing with Climate .

    Which is more important today…?

  25. dave:

    Re: March Scientific American

    As usual, realclimate is on the cutting edge! Next month’s Scientific American features an article by William Ruddiman “How Did Humans First Alter Global Climate?” (sorry, no link). At least it clearly answers a question I asked in #16:

    How did the dramatic warming escape recognition for so long? The main reason is that it was masked by natural climatic changes in the opposite direction. The Earth’s natural orbital cycles [precession] were driving a simultaneous natural cooling trend, especially at high northern latitudes.

    I am also puzzled that this hypothesis is still argued strongly despite the data from latest Antarctic ice core which show (from Schmidt et al, “A note on the relationship….”, link provided in the post):

    The preliminary gas concentration analyses from the Dome C record, while not yet complete, indicate that methane levels were stable during MIS 11 at around 650 ppbv, extremely similar to pre-industrial values seen in Vostok 640-665 ppbv [EPICA Community Members, 2004]. Additionally, the duration of the MIS 11 is clearly longer than one precessional cycle, demonstrating that, during periods of low eccentricity, not all precessional minimal lead to significant methane decreases.

    The EPICA Dome C record is described in Eight glacial cycles from an Antarctic ice core.

    In general, if Ruddiman’s results don’t withstand scrutiny, then the skeptics using the hypothesis become even more incoherent – if that is possible.

    [Response: In the interests of full disclosure, I should state that Ruddiman does not agree with our assessment of the EPICA results, and so it may be premature to quote me as proving anything. It is an ongoing discussion, as they say…. – gavin]

  26. dave:

    Re: #25

    OK, Gavin, I quoted your paper since you had made the point and linked it in. I can see why Ruddiman would dispute your interpretation of the Dome C results. The EPICA team remarks are made in this passage from “Eight glacial cycles…”:

    The most striking feature concerns the relative timing of the CO2
    and CH4 increases compared with younger terminations: whereas
    CH4 started to increase concomitantly with CO2 (and Antarctic
    temperature) during the last four terminations, at Termination V it
    leaves its glacial background 4 to 5 kyr later than CO2, by which time
    the latter had already increased by about 50 p.p.m.v. Similarly, the
    rapid jump of CH4 punctuating the second part of its transition
    takes place when CO2 approaches its maximum. Note that this is
    also the time when Antarctic temperature starts a slow decrease, that
    is, a typical expression of a bipolar see-saw as observed during stage
    3 and possibly Termination I. Following its rapid jump at
    the end of the termination, CH4 continues to increase by about
    100 p.p.b.v. for 2 to 3 kyr, another unusual feature when compared
    to the CH4 trends during the early part of MIS 1, 5, 7 and 9.

    If I am reading this correctly, Ruddiman’s argument is with the preliminary EPICA interpretation of their own results that show “greenhouse gas peculiarities” in MIS 11 with respect to the younger interglacial periods Ruddiman uses to support his hypothesis. I understand that this data and its interpretation requires further scrutiny. I am assuming the similarity of the “low eccentricity and consequently weak precessional forcing” in the current interglacial and during MIS 11. (both quotes from “Eight glacial cycles…”).

  27. Joseph O'Sullivan:

    A little background info
    Science (I started my career as a biologist) is rational discussion. Facts are examined and the complexities are understood. It is an orderly process and there are accepted standards and ethics. I later went to law school (to become an environmental lawyer) and I saw a very different world. Environmental law is a very political process, and politics is a very rough and tumble world. There is a win-at-all-cost atmosphere, especially in conservative pro-industry groups.
    Modern environmental law started in the late 1960’s after a grass-roots popular movement called for environmental protection. Industry countered by saying the the environment involved complicated political, economic and scientific issues and the hippy kids in the environmental movement weren’t sophisticated enough to understand. Environmental organizations quickly became sophisticated and mainstream environmental organizations are now usually better on science issues than industry. The public started to back environmental protection and the laws that are the current basis for environmental regulation were enacted.
    Industry and their political allies didn’t like losing the political power they were used to having. They needed to cut public support for the environmental groups because popular support is the basis for environmental movement. Industry and proindustry groups started a negative public relations campaign against environmental protection that continues today. The EPA was labeled the “Gestapo”, environmentalists called “communists”, and now environmental activism is equated to “eco-terrorism”. Scare tactics about environmental regulation ruining the economy and causing huge layoffs were and still are used.
    Science unfortunately is included in this negative PR campaign. The spectrum of scientific reality is ignored if the science against environment regulation is weak, and the normal uncertainty in even the strongest scientific evidence is always emphasized if the science shows the need for environmental regulation. In the worst cases anti-environmental groups knowingly use misleading science or scientific evidence that is clearly wrong.
    It is very important to make sure that the public can get accurate science. I admit even environmental groups sometimes get it wrong. Because environmental protection is a political process which involves the public making decisions the public should be well informed. Sources like this web site that give even-handed and accurate scientific facts are a necessity.

  28. Florens de Wit:

    It is indeed a sorry thing that some people who call themselves skeptics just seem to jump on any argument that is controversial and not mainstream. Those people are trying to sound scientific for the wrong reasons; just like environmentalist pressure groups are.

    Still the use of the term skeptic and skepticism is even more peculiar.
    Skeptic should be a label of choice for scientists and is being misused to dismiss at least part of the critics out of hand, and is used to associate some badly done criticism with people that are trying to inject some reason in environmental policy.

    A real climate skeptic is probably best described as someone who increases his criticism roughly proportionally to the uncertainty that surrounds the science and policy (maybe augmented by the level of computer processing necessary to arive at a result). So no jumping on bandwaggons, and no dogmatism when it comes to particular studies.

    Science done to prove a point is a sorry thing anyway. It never comes up with interesting points, and only serves an interest that was known beforehand.

  29. Eli Rabett:

    There is a word (actually two) for what Florens de Wit wrote, disinterested skepticism. That exactly fits what de Wit is describing in his penultimate paragraph about how a real climate skeptic would behave. It is precisely because those attacking climate science are not disinterested, better put they have strong political and economic interests, that they descend into scepticism.

  30. Dusty Bradshaw:

    Scaim ran a great lead article on global warming about which I am sure all of you are well aware. In it the author of the article purports that when fossil fuels run out in 200 years, the level of CO2 will begin a natural downward trend- mostly absorbed by the oceans. Why is his fixation only on C02 and CH4, when it is known that several varieties of CFC’s have far higher heat trapping coefficients? Thier levels are increasing as well and are not mentioned once in the article. By the way, this site is awesome and I want to let you all know that we have had many (to the detriment of our readership) global warming articles and will continue to, until some sane plan of action is set upon. Peace.


    [Response: Take a look at the IPCC TAR table 6.1. CFCs are powerful molecule-for-molecule but because their abundances are less, their radiative forcing is currently small – the biggest, CFC-12, is only 1/10th CO2 (which is actually more than I thought it would be…). Also, the Montreal Protocol means that levels of CFC-12 will be declining in the future, albeit slowly – William]

  31. Florens de Wit:

    There is no such thing as disinterested skepticism.
    Skepticism requires an inquisitive and curious attitude about the pro’s and con’s of a thesis (actually about anything you think you know). This includes the theses held by many – sometimes indeed religion and political thought – and also things many scientists may agree upon. It’s about evaluating things for oneself instead of taking someones word for everything. That is why skeptics often like to replicate results.

    In the context of climate change I am skeptical of the use of the term “skeptic”; it is used often to dismiss people for criticising. Often it is also used to attribute the most extreme example of disbelief in climate change to a people that probably are just a little more critical of, for example, computer modelling results, as those crafting the models.

    Computer processing often reaches such a high level of complexity that only experts can tell exactly what the result means. Generally speaking (not knowing the nuts and bolts myself) independent replication would make the reliability much clearer; seems common sense and also very much in line with experimental scientific tradition.

    Some so called climate skeptics are indeed politically and economically motivated; so are environmental pressure groups. I wonder if this means that anything said by anyone with a political or economic interest (which is indeed basically anyone on the planet that can talk) is necessarily suspect in a discussion about science. Besides just pointing out that someone has particular interests doesn’t constitute an argument fore or against anything.

  32. Alan Gorton:

    Why ain’t this simple? Does global warming exist or doesn’t it? Please don’t post comments, respond yes or no. Let’s see where the consensus lies. If the response here is > 95% that global warming exists, doesn’t it concern people that those who think global warming is wrong don’t visit sites like this? If global warming exists, you guys need to get into marketing/politics/business/power. Little point saying I told you so in 60+ years time. Act or shut up.

    [Response: Note that this post has been edited for profanity, which is not tolerated. With someone less patient, you’d simply get your comment deleted.

    As to the point: the current consensus is that GW is occurring; read the back posts on this site. But its *not* a simple matter – as the posts here should also make clear. In essense, IPCC ’95 reported a “balance of evidence” of evidence verdict on human impacts on climate – which is the English civil-law expression, as opposed to “beyond reasonable doubt” which is the criminal-law expression. IPCC ’01 “strengthened” that verdict. The room for “reasonable doubt” is closing and is (IMHO) just about gone; but even that leaves many issues – e.g. the size of future warming – to settle – William]

  33. Daniel Johnston:

    I’ve recently taken an anthropology course on ‘Society and Nature’ at Aberdeen University and the idea that humanity might already have affected climate had occured to me also. The important idea to grasp is that humans have been controlling their environments (though far more subtly than now) in various ways for a very long time. Burning has been a frequently used tool in this arsenal – releasing much carbon that would otherwise have been sequestered. For instance – Stephen Pyne in his book ‘Firestick History’ relates how pollen records show an increase in burning in Australia after humanity’s arrival. Species on the continent evolved to deal with it – i.e. eucalyptus is an ash friendly plant. Even today aborigines decry overgrown areas of habitat as somehow untidy and in need of burning. This pattern is repeated over other areas of the world such as native America and Brazil – wherever, in fact, fire is a useful tool for native peoples. Such behaviour leads me to think there may well be some truth in Ruddiman’s theory.

    Leading on from this is something else I had wondered. Would the widespread use of photovoltaics reduce the amount of radiation returned to the atmosphere and if so how much – and would this have positive or negative affects in a global warming scenario such as we are probably soon about to experience?

  34. Joseph O'Sullivan:

    Florens De Witt is correct when stating the term “skeptic” is being misused. The mainstream positions held by scientists usually are based on the strongest evidence and minority or contrary positions that might have weaker evidence should be examined and not rejected just because they disagree with the majority opinion.

    My comments have been about the politics of climate change science. Conservative anti-environmental politicians and the think tanks and media that support them use extreme tactics. Tom DeLay (Republican Majority Leader in the U.S. House of Representatives) has called the EPA the “gestapo”. Fox news and the conservative think tanks Cato and the American Enterprise Institute have compared the environmental movement to terrorism and communism. These are mainstream republican politicians, conservative political groups and a major media company, not just some fringe extremists. They also label climate science as “junk science” (as U.S. Senator James Inhofe, Republican from Oklahoma, has), but only if it shows that the climate is warming, the warming is caused by people and this warming is potentially harmful. Science that contradicts these conclusions is almost automatically deemed valid and used to oppose climate change regulation. These are not isolated examples either, the same things have been done in nearly every area of environmental regulation and to many supporters of environmental protection.

    The majority of environmental groups do not act so badly. They don’t use such degrading and baseless insults to describe people and groups that oppose environmental regulation, and environmentalists don’t tell such outright lies. Calling someone a skeptic is relatively mild. Environmentalists are far from perfect. They can be alarmist about the potential negative effects of climate change, and sometimes use scare tactics. The environmentalist’s aim is to tell the public that there is a problem and the public needs to act. The more serious the problem is the more likely it is for the public to speak up and tell the government to pass laws, so environmentalists put too much emphasis on the potential negative effects of climate warming. But even considering that, the majority of environmentalist’s climate change claims are based on well-supported science. I reviewed the climate change sections on their websites. They often cite science journals (like Nature and Science) and research reports (Like the IPCC reports) for their conclusions. They word their positions carefully to reflect what is known and what is more speculative. The moderators of realclimate obviously know climate science better than I do and I would like to know if they think environmental groups (like NRDC, Sierra Club, Environmental Defense and the Nature Conservancy) accurately use the climate change science.

    Lastly, the worst thing about the fighting in the climate science discussion is it makes it much harder to get policy agreed upon and regulations enacted. The negative tactics cause alot of bad blood and mistrust. “Poisoning the well” was a phrase I heard that described such a situation. The interested parties are less likely to sit down and try find a workable solution to the problems. It would be tragic if global warming did cause serious problems that could have been prevented if we just had a better and more civil dialogue.

  35. Joseph O'Sullivan:

    There is something I forgot to put in my last post. James Inhofe, the U.S. Senator from Oklahoma and Chairman of the Senate Committee on Environment and Public Works on January 4, 2005 in a floor speech in the U.S. Senate titled “an update on the science of climate change” made some questionable claims. It is on the web site of Frontiers of Freedom, a conservative think tank funded by corporations like Exxonmobile. After calling the threat of global warming “the greatest hoax ever perpetrated on the American Public” said “the climate change debate should be based on the principles of science”. He then refers to “Dr. Crichton, a medical doctor and scientist” and his work of fiction “State of Fear”, and says this book is “designed to bring some sanity to the global warming debate”. The Senator then goes on for about a full page on the virtues of the “State of Fear”. He uses quotes from the book (“nobody knows”) to show that climate change science is based on mere guesses. The use of a fictional tale based on questionable science is not debating “based on the principles of science”. Senator James Inhofe, like Tom Delay, has consistantly fought environmental regulation. Both of the congressmen receive substantial campaign donations from petroleum companies and other groups opposing environmental protection.

    [Response: I’m not going to comment on the political aspects, but we pointed out some of the scientific errors previously. – gavin]

  36. Tom Rees:

    Gavin, not really relevant to this thread but can you give your opinion of the ECHO-G simulations of the past millenium, as referred to in the recent Moberg paper?
    I know you’ve done some modelling of the LIA yourself, and found that your model ‘overestimated’ temperature change compared with MBH99.

    [Response: The ECHO-G model has a climate sensitivity that is within the standard range of the models considered by IPCC (around 2.6 deg C for 2xCO2 I think). This is roughly half what we had in the model used in Shindell et al (2001, 2003) (around 5 deg). However, the runs reported in Zorita et al (2004) and von Storch et al (2004) had forcings that were larger, hence the bigger response. The point is that given the uncertainties in the forcings, the sensitivity and the response, it is difficult to rule out much when thinking about the real world. Our conclusions related to the ‘over-estimated’ response could be dealt with using a 2x decrease in the assumed forcing, or a 2x decrease in the climate sensitivity, or a 2x increase in the low frequency change in the proxies (although not all at once!). Improving the situation here is going to take, I think, a bigger focus on the patterns of regional changes, improved reconstructions (with smaller error bars hopefully), and a better consensus on the size of the forcings. All of these are pretty difficult, but are all ongoing in various places. – gavin]

  37. Lynn Vincentnathan:

    Regarding comments #31 & #32, I really think we have to look at the issues involved in order to decide what level of certainty is required re GW, and what type of skepticism is good or bad, and when we should start abating GW.

    I started reducing my GHGs back in 1990 when scientists wrote (in a 1987 article) how the precipitation belt shifting from Africa to Europe (causing drought, famine, & massive death) fit GW, if and when GW might be scientifically proven. They had not then reached even a “balance of evidence.” I was ready to sacrifice, spend some money and lower my living standards to help abate the problem, but what I found is that I am saving money without lowering my living standards, by reducing GHGs by 1/4, then 1/3, then 1/2 – and now I’m plowing in a few dollars more per month for 100% wind generated electricity, but still have a net savings of $100s per year. There is NO economic argument against abating GW down to 75% GHG reductions (see and for advanced nations such as the U.S.

    If skeptics simply debate the science, but agree that we should do all we can to reduce GHGs on what meagre evidence they do agree with (or on no evidence at all, but just to humor us), then I have no problem. If, however, they are saying we should not reduce GHGs (esp. in cost-effective ways), then it seems to me they are immoral and stupid (for not going after the money-savers).

    As an anthropologist, I find some merit in #33 that humans may have been impacting the climate for a very long time (I think burning has been used as a hunting technique since the time of Homo erectus), though in such a tiny way that science may never be able to detect it. In that case, we wouldn’t have a completely pure pre-industrial baseline for comparison. The upshot would be that anthropogenic GW might be a tad greater than we think.

  38. Joseph O'Sullivan:

    Thanks Gavin for pointing out the earlier post about Inhofe.
    I recently discovered the Realclimate site by clicking a link on The Earth Institute at Columbia University website. I immediately liked it, but I didn’t have a chance to look at the entire site. After I posted my comment about Inhofe I took a good look at the entire site and I saw the section about Inhofe’s speech. Hope I wasn’t too repetitive.
    Realclimate is great for giving accurate information about climate science and for providing a forum for public discussion.

  39. Florens de Wit:

    One more thought on environmentalists versus non-scientific climate skeptics (like some conservative think tanks). It is not easy to compare their attitudes towards rational thought, but both are adherants to the method of “proving a point by finding (only) supportive evidence”, which is not scientific but more like the legal mode of argument. This is why some scientists are quoted out of context and the word skeptic is used as a way to dismiss some.
    There is no way that any side of this completely political debate can be called more rational than the other because they happen to have different ethical and political views besides their views of the science of climate change, and the diversity of views within each group is enormous. In fact their scientific view is often simply a projection of the ethical and political view onto research results available. It’s like having two kids looking at clouds independently and having them tell what they see; their result is bond to be colorful, creative and above all different just like the two kids are. Neither will (likely) be a rational depiction of the clouds shape and properties.

    Also one more thought on science and skepticism.
    I do not agree with McIntyre and McKittrick’s claims that their re-analysis of the Mann et al 1998 climate reconstruction shows that the Kyoto protocol is based on quicksand. One must see that Kyoto is based on a lot more than “the hockeystick”, whether you agree with it or not.
    I do like their suggestion to inject a bit of the audit system into the process of trying to support policy by scientific assessements. Many tend to forget that public policy is about spending a lot of (our?) money so we are entitled to demand that it is high quality data that our government bases its decisions on, just as investors are in the commercial world.
    Requiring an independent replication (or reproduction) of a study used in policy support is an expression of skepticism that is reasonable I think. I hope IPCC looks through the political issues and picks up on this.

    It would also be good for science to facilitate reproduction of results in general, simply because it solidifies the work done, and improves the quality of information. Maybe one could focus on the most cited papers first and check if they “check out” after re-doing the calculations and checking if these were done correctly.
    I certainly do not think that peer review is corrupt overall but would be enriched and strengthened by a independent replication effort. It also would make life for IPCC easier, because they would not need to do the work.

  40. Joseph O'Sullivan:

    Again Florens de Wit is correct, we really can’t compare attitudes. But there are things we can do. The scientific method involves examining facts and drawing conclusions based on the facts. In law verdicts are based on evidence. In the commercial world investments are made based on financial data.

    In the politics of climate change science we can examine the actions of the involved groups and draw conclusions based on these actions. People and groups that oppose regulation concerning climate change catagorize people who favor climate change regulation (and the people who just accept the science that shows the climate is warming, this warming is caused by human actions, and this warming can create problems for society) as environmentalists. The climate change science opponents have said explictly or implied for years that all, not just one or two, environmentalists are:
    Communist (for example Steven Milloy on Fox News Online), Elitists who don’t care about the poor (Sallie Baliunas on Heritage Foundation website, and Senator Inhofe), Racists who either intentionally hurt minorities or don’t care if they do (Senator Inhofe has insinuated this and I was at a lecture where a oil corporation lobbyist said flatly “environmentalists are racists”) Anti-american (Senator Inhofe has again insinuated this and Timothy Lynch on Cato’s website) Nature-worshiping religionists (Inhofe again and Robert Hahn of the American Enterprise Institute on the Cato website) and Wackos/Extremists/Alarmist/Hysteric (these accusations are legion, look at Inhofe, right-leaning TV like Fox News, conservative newspapers like The Washington Times, talk radio like Rush Limbaugh, and conservative and libertarian think tanks and political groups.
    People who truly are these things are very, very bad people. So bad, that anything these bad environmentalists (remember that according to anti-regulation forces this means all environmentalists) say is also bad and should be ignored. There should be no discussion of climate change.

    This is a rhetoric technique sometimes called “killing the messenger”. It stops the discussion before it starts. Without discussion, there is a victory for the status quo and therefore also for the opponents of climate change regulation who want no action taken.

    I took the time to look at media and websites of the generally conservative groups who oppose the majority of climate scientist’s conclusions. I was suprised by the negativity directed at environmentalists on TV news, talk radio, think tank websites and in politician’s speeches. There were many baseless and often deeply offensive acccustations that often flew in the face of reality and historical facts. It seemed crazy to me. In a “eureka!” moment I realized that there was a method to this madness. These accusations were character assasination, a form of “killing the messenger” being use to stop the debate. The skeptics of climate science do not want any debate on the topic, probably because they are afraid they might lose. If they lose, the corporations that they have political, ideological and sometime economic connections to would not make as much money. Losing profits is not acceptable. As can be seen by the skeptic’s actions extremism in the defense of profit is no vice, and moderation in the pursuit of profits is no virtue.

  41. Florens de Wit:

    Joseph O’Sullivan seemingly agrees with me and then just restates his opinion that right wing think tanks and other organisations demonize anyone who disagrees.
    Though he may partially be right, it is totally irrelevant to the attitude, rationality or ethics of true scientific skeptics. I have stated several times already that these think tanks are as much skeptical as any pressure group (which includes environmentalist groups) and true scientific skeptics are left out in the cold because of the lack of understanding of the distinction. I am sad to see that O’Sullivan didn’t get the point.

    When he states “the skeptics of climate change do not want to debate the topic, probably because they are afraid they might lose.”, he does exactly what he accuses those he calls ‘skeptics’ of: dismiss all opponents by labeling their opinions irrational, biased and extremist.

    There ARE skeptics that are rational and just have a different view of the role of science in policy which makes them skeptical towards current policy choices. They don’t call their opponents names, nor do they jump on any bandwaggon that seems to support their view. They critically consider the factual evidence and come to a different conclusion. This is exactly what science is about.

    Part of the science versus policy relation depends on the ethical views of scientists concerning their role as “self appointed advisors” of public and policymakers.
    As long as this isn’t considered also in the public debate, political, economic and other non-scientific interests will keep hijacking this issue and the public will be worse off because important issues will be missed.

  42. Joseph O'Sullivan:

    I have made Florens de Wit sad by not getting the point. I don’t want Florens de Wit to be sad so I must respond.

    The use of the word “skeptic” in my comments is acceptable. In common usage skeptic means someone who has “an attitude of doubt or a disposition to incredulity either in general or towards a particular object”. In a narrow and in somewhat esoteric way relating to science I may be using the word incorrectly. However my and Florens de Wit’s comments have been largely about climate change science policy and politics, and in this context the use of the word skeptic is accurate and is not implicitly or by implication negative. When I say “skeptics” I mean the people who are the most dominant and vocal opponents of climate change science with the goal of stopping any climate change laws and regulation, not scientists with legitimate questions about climate science. The skeptics tactics are what I deplore, not the skeptics themselves. These skeptics have referred to their opponents in environmental and climate science politics as “un-american”, “communists”, “the gestapo” and “wackos”, just to state a few of the slurs used by the skeptics. Calling someone a skeptic is in comparison a compliment.

    The commotion over calling someone a skeptic is another rhetoric technique. It is an attempt to equate the people called skeptics to an unfairly oppressed minority. The objective is to publicly appear as a sympathetic victim. Environmental regulation opponents have used this tactic for years. The “gestapo” label has been used by Tom Delay (the Majority Leader of the U.S. House of Representatives) and others to compare the corporations that are required by the EPA to reduce the level of their pollution to reasonable levels to the victims of a genocidal dictatorship, Nazi Germany. Using a comparison with one of the greatest tragedies in human history to score political points is patently offensive. In the climate science debate Senator Inhofe’s aides, after asked why the Senator chooses not to accept what nearly all climate scientists are saying, replied “Galileo wasn’t mainstream”. Senator Inhofe is as the Chairman of the Senate Committee on Environmental and Public Works one of the most powerful and influential forces in the climate science politics debate. In the very respected and widely read Wall Street Journal an editorial has stated that scientists opposing the established science are “treated as heretics” and feel “their careers might be put at risk if they question the orthodoxy” and Dr Mann is trying to “shut down the debate”. This is an attempt of the skeptics to paint themselves and the scientists as visionaries who are punished for saying the truth, like Galileo.
    Why are the skeptics doing this? Martyring themselves gets them public attention. Science and scientists that might not be credible and would be otherwise ignored are put in the spotlight. The skeptics want to be seen as being innocent victims and want the proponents of the majority of climate scientists to be seen as bad oppressors. This achieves two goals of the skeptics. It makes the proponents of climate change regulation appear as bad and dishonest so they will lose credibility. It also pours doubt on climate science, and strengthens the skeptic’s incessant claims of uncertainty (uncertainty is the major topic in the climate change science discussion on conservative groups websites). The attempts by the skeptics to block climate change regulation are aided if the proponent’s of climate science and climate science regulation public support is removed or reduced by these negative tactics.

    Related to the “skeptic” issue is Florens de Wit’s claims about peer review. The peer review is a critical and necessary part of modern science and proven it’s worth many times, but it is not perfect. Florens de Wit’s claim that peer review is not “corrupt overall” is another rhetoric technique. This claim, put in plainer language, is: peer review is CORRUPT, but just not all the peer review is corrupt. How much of the peer review in climate change science is corrupt? Florens de Wit recommends that the inquiry “focus on the most cited papers first” and “check if they ‘check out’ after re-doing the calculations and checking if these were done correctly”. The papers that are the most cited are generally the papers most accepted by the scientific community and are based on the strongest evidence. If this is first, what is next? Should every climate change science paper be checked? Florens de Wit recommends that when these papers are re-examined the focus should be checking if they are correct. This is an attempt to disparage climate science by suggesting that really all climate change science might not done correctly or may be based on corruption.
    A policy analysis on the Cato website predicts “climate-related pressure” is “likely to subside” and “lose its ‘scientific’ urging”. This is a long established technique of the skeptics. Constantly and publicly cast doubt on the science. Constantly question the accuracy. Focus on the uncertainty. The call for climate change regulation is based on the well-supported science that shows that the climate is warming, this warming is at least partially caused by people, and is potentially harmful for society. If there is enough public doubt about the science the call for climate change regulation will stop or be reduced, and climate change regulations will not be passed. That is what the skeptics want.

    I hope Florens de Wit is not still sad.

  43. Florens de Wit:

    On #42:

    There are people who use any argument to further their claims while being ignorant of consistency, balance of evidence or even plain good manners of debate; lets call this group A. There are also people who are critical towards some generally held views and would like to have their views considered in a atmosphere of rational inquiry even if this requires some effort of their opponents; this would be group B.
    I think group B qualifies to be called skeptic, while calling anyone from group a that would be an insult to group B.

    That is the point I am trying to make (concerning the term “skeptic”) and no other.
    To be entirely clear;
    group A contains any kind of activist while group B contains both “climate skeptics” (except, of course, those who fit in group A) and people supporting the general paradigm of “global warming/antropogenic climate change” (again not those in group A).

    I do not claim that skeptics (out of group B) are right in their claims and doubts. I am also skeptical towards anyone from group A – whatever their claims – because they lack quality of argument to convince me.

    Peer review is of the highest value for science, but, as O’Sullivan points out, it is not perfect. It would be improved if it would just be made possible for any interested scientist to be able to replicate results. I would like to point out that replication is generally considered a very valuable scientific practice and has shown this value in finding unreliable results in the past.

  44. Florens de Wit:

    An addition to my previous post (#43):

    Though I think that science would be better of with some extra efforts beyond peer review I also think this isn’t necessary per se. For purely scientific interests the experiments, studies and calculations will be done again in time. Science proceeds to refine our knowledge of the world around us and mistakes will be corrected in due course, I’m sure.
    I would still like to see more replications done of scientific studies (doesn’t matter what subject), just because I am curious. This could teach us about uncertainties and relevant sources of bias and possibly refine the original.

    What I do think is necessary is a complete replication and check of methods, data and conclusions when scientific work is used to support public policy. I would think this isn’t a unreasonable demand since it concerns public funds not private investments and considerable amounts of those too.
    This is about accountability of governments, and specifically the parliamentary check on the executive government, not about discrediting science. Governments should not be allowed (by parliamentary committees and such) to hide behind science and/or uncertainty when they should have taken the time to check wether the studies they used to back up policy were valid (in the particular case considered) and substantial enough to support policy decisions upon. They should be able to show that indeed the reasons they used for their decision are valid and can be proven to be so up to a high standard.

    I especially feel strongly about this because there have been several instances where executive government officials in my country have selectively ignored scientific advice and proceeded with costly projects, to find out in the end that the fragmentary advice used to back up the plans was not nearly substantial enough; and they got off lightly most of the times (i.e. neither was forced to step down) while it often does reflect back badly on scientists involved.

  45. Joseph O'Sullivan:

    In response to #43
    Labels are sometimes just convenient. “Skeptic” is a lot easier to type then “people and groups who are the most dominate and vocal opponents of climate change science with the goal of stopping the enactment of any climate change laws and regulations”. Skeptic might not be the best label.

    I had for years an academic and professional involvement and a personal interest in environmental regulation and politics, but in the past few years only a personal interest. Some of the posts on RealClimate made me curious and I did some research.
    In the past environmental politics was basically environmental groups verses industry and there was public relation spin and bias on both sides, but it only went so far. When I looked at recent developments I was shocked. The environmental groups stayed moderate, and if anything became more moderate.
    The anti-environmental regulation side has become dominated by far-right and very conservative think tanks and people who have very machiavellian values. Their tactics cross ethical lines that in the past would not be crossed. They use many lies, mischaracterizations, insults and the abuse of science. To paraphrase Barry Goldwater: extremism in the defense of far-right and very conservative agendas is no vice and moderation in the pursuit of far-right and very conservative agendas is no virtue.

    I am frankly outraged by these extreme tactics. They are counter to democratic and scientific principles, and I think these tactics need to be publicly exposed. That is why I have made numerous and lengthy comments on RealClimate. I hope I have not been uncivil or too political. I noted that in Florens de Wit comments there were some aspects of the tactics the anti-environmental regulation forces use. I thought this need to be pointed out, but I do not think Florens de Wit is part of the anti-climate regulation movement.

    Replication of science is potentially a good idea. If regulations that are potentially complex and expensive (like climate change regulation) are based on science, making sure the science is sound is in theory a wise practice. There is the potential for abuse. Will some of the opponents of climate change regulation who have shown a pattern of dishonesty and abuse of science use the call for replication to delay or stop regulation that is beneficial, but they just do not agree with?

    The Center for Progressive Regulation (CPR), an organization of law professors from around the country, has commented on their website on the Data Quality Act. The Data Quality Act was slipped in as a rider on another bill in 2001. There was no debate in Congress or in public about it, and the Center for Progressive Regulation notes that it was reportedly pushed by the Center for Regulatory Effectiveness, a corporate sponsored think tank. Ostensibly its goal is for federal agencies is to “ensure and maximize the quality of information that they disseminate and to establish an error correction process”. The CPR shows how in practice it has been used by corporate supported think tanks and political groups to “censor information available to the public”. In the climate science debate the Competitive Enterprise Institute (CEI), another corporate funded think tank, has used the Data Quality Act to attempt to force the U.S. government to “cease dissemination of the National Assessment on Climate Change”, a report by the federal government on climate change. The CEI alleges that two of the climate change models in it are not reliable, but the National Academy of Science says these models are “well-regarded”, the models were peer reviewed by over 300 scientific and technical experts, subjected to a 60-day public comment period, and assembled under the supervision of a panel of experts convened by the President’s Committee of Advisors on Science and Policy.

    As Florens de Witt notes, the call for replication is being made by McIntyre and McKitrich. I am not sure if Florens de Wit knows that McKitrich is connected to the Fraser institute, a conservative think tank. McIntyre is associated with the George C. Marshall Institute, yet another corporate funded think tank.
    This post “Strange Bedfellows” started on February 8, in response to the use of the Ruddiman studies by climate change science contrarians to try and dispute climate change science and how this violates common sense and scientific standards. One of the groups doing this is The George C. Marshall Institute. On the Marshall Institute website under the “Climate Issues and Questions” section there are multiple statements that the warming climate is not due to people’s release of greenhouse gases and mentions that “global average surface temperatures rose, then fell, then rose again in a pattern that showed no relation to greenhouse gas concentrations”, but the website has also mentions the Ruddiman studies that show human released greenhouse gases have changed the global average temperature (“Man Made Gases Saved the World from an Ice Age”). This is an example misusing science to get a result that you want by The Marshall Institute (which has been funded by Exxonmobile), and what it wants is to block climate change regulation (that will reduce Exxonmobile’s and other companies’ profits). It makes the call for replication of climate change science by McIntyre who has connections to The Marshall Institute highly suspect.

  46. Peter J. Wetzel:

    Science is not militant.

    Nor is science adversarial.

    The futile rhetorical sparring of the militants and their adversaries completely flounders in an atmosphere of scientific reason (such as this web site strives to maintain).

    Florens — sign me up for group B, please.

    I’m of the opinion that policy makers should tred cautiously, and act not on what I’ll call “primary” peer reviewed science, nor even on “secondary” peer reviewed science, but on those scientific results which have passed the muster of “tertiary” peer review. A peer reviewed journal publication has passed the primary stage. A paper which is widely accepted and cited (in a factual, rather than a confrontational context) by subsequent publications in peer reviewed journals has passed the muster of “secondary” peer review. A conclusion from the original paper which has been reproduced (in your terminology, “replicated”, by subsequent independent peer-reviewed journal publications — revisiting and improving upon the original methods and procedures, testing against the original data and further testing against newly available data) has finally achieved the status of “tertiary” peer review, and can be reasonably concluded to be a sound conclusion upon which to base rational policy decisions.

    Your conterpart in the debate here, whom in my individual personal opinion appears to fall into group A, has made a statement which I find to be revealing. I quote:

    “Replication of science is potentially a good idea. If regulations that are potentially complex and expensive (like climate change regulation) are based on science, making sure the science is sound is in theory a wise practice.”

    I am left wondering if your counterpart has a scientific background. For his benefit, and that of the lay public, let me emphasize with clarion amplitude: There is no more fundamental tenet in science than reproducibility. None. Period. A study that cannot be independently reproduced is simply NOT science. I cannot be more emphatic on this point.

  47. Joseph O'Sullivan:

    Response to #46
    My comments have been about the politics of climate change and environmental laws and regulations. Replication is of course a tenet of science. There should be the highest level of replication of science that will be the basis for regulation, but there must be measures to make sure that this requirement can not be abused. I try to shorten my already long comments, but in the process some of the meaning I intend to put in may get lost.

    My science background is a B.S. in marine biology and meiofaunal analysis in professional life. Science isn’t adversarial, but law and politics are. Sometimes I regret leaving science to go to law school and become a lawyer because of the hostility inherent in the field.
    I don’t know about your knowledge of the use of science in the courts, but any lawyer knows he can get an expert witness with a science degree, even a Phd who is an active scientist, to say anything the lawyer wants if the price is right. Lawyers have crude jokes about this practice. I strongly dislike this misuse of science.
    I have worked in environmental law in industry, government and a law firm that represented environmental groups, but I have moved on to other areas. Since I left environmental law the politics have become much more negative and aggressive. I am not being biased, just stating a fact when I say the increased negativity and aggression is from the most dominate and vocal opponents of environmental regulation. There is discussion within the environmentalist community about what to do about this change in tactics.

    Questioning and examining potential regulations and the science that supports them is absolutely necessary. I strongly support the use of the highest level of replication of the science to ensure that the science regulations are based on is sound, but there must be measures to ensure that it is not abused by people who are opposed or for the regulation and who are from industry, environmental groups or anyone else.

    The groups leading the opposition of environmental regulation are in legal terms “bad actors”, that is people or groups who have a pattern of dishonest behavior. These groups have taken measures to suppress science that they disagree with. The Union of Concerned Scientists sent 1400 surveys to scientists at the The U.S. Fish and Wildlife Service. The administrators told the scientists they were not to complete the survey even on their own time. 400 scientists did complete the survey and many said they were pressured to change science to protect industry. If the Union of Concerned Scientists is too biased an EPA internal investigation found that scientists in the EPA were pressured to produce science that supported pre-ordained mercury emission regulations. These are examples of what political scientists call “industry capture”, when individuals from a regulated industry become administrators in the agencies and ease regulations on the industries. I have seen this in the agency I worked in. The Center for Regulatory Effectiveness (CRE) sent a letter to the American Association of University Professors and to several universities warning the universities that the CRE was aware of research that in the CRE’s words had “significant omissions, inaccuracies and manifest biases” and the universities should update their policies to comply with the Data Quality Act. The act according to a former EPA chief was introduced by the CRE, an industry advocacy group. CRE was using a law passed supposedly to improve the quality of the data to suppress science it didn’t like by threatening litigation. This is what lawyers call a SLAPP (strategic lawsuit against public participation) suit. This is a tactic used by industry to intimidate a weaker party into stopping an action that industry doesn’t like by threatening the weaker party with potentially expensive litigation. Because of the demonstrated willingness of some groups to suppress science they just do not like, I can not support the call for the highest level of replication without measures to make sure it will not be abused.

    RealClimate is a science website. This post “Strange Bedfellows” is about the politics of climate change science. I know my comments are very long and I hope they are not too political or uncivil. I sometimes worry that my comments might taint RealClimate as a pro-environmental site.

    RealClimate puts out accurate climate change science facts. It would be better if climate change science could stay in the scientific world. But unfortunately climate change is highly politicized. There are political tactics that are being used in the debate that I think are wrong, and I think people should be made aware of them. Not everyone agrees with me, but that is what discussion is for.
    I know some say it’s probably not necessary to get worked up about it, but if you do nothing in a conflict you will lose by default. In political debates negative tactics are very effective. That is why they are used. RealClimate has been subject to these negative tactics by the Wall Street Journal and I thought that these needed to be pointed out, so RealClimate would not be branded as biased and lose credibility.

    I must note on some statements in #46 that seem to be some of the rhetoric techniques I have mentioned in other comments. Rhetoric techniques are tactics in a debate or argument. Lawyers use them constantly. I think the use of the word “militant” is highly suspicious. There is a statement about the discussion between “militants” and “adversaries” apparently refers to the discussion between Florens de Witt and me. I hope someone doesn’t think Florens de Witt is a militant. But then again, maybe someone thinks I’m a militant. Maybe I’m a militant because I’m speaking up and not everyone likes what I say. If so, that is “killing the messenger” an old trick. I should be ignored by other readers and stop making comments because I’m a militant and because militants are bad and dishonest.
    I’m not lying, I support the claims I make, and make conclusions based on facts that I don’t think are unreasonable. I criticize the tactics but not the people. I have said environmental groups tactics are better, but I’ve never praised or recommended them. I’m not a member of an environmental group. I think laws should be based on the best available science and the precautionary principal (taking action before a problem arises). Climate Change regulations should be based on market principles when possible and new technology should be encouraged. The tactics in the debate should respect the scientific method, be honest, civil and transparent. Referring to me as a militant would be wrong, in fact knowingly wrong and would be publicly broadcast with an intent to cause harm. I wonder if it did cause harm. I can’t remember what that is called. I seem to remember a comment on another post insinuating RealClimate may be funded by an environmentalist group and insinuated an environmentalist bias. I can’t remember who made the comment.

  48. Peter J. Wetzel:

    My comment “futile rhetorical sparring of the militants and their adversaries” refers to politicized policy discussion in general.

    Scientists as individuals, doing their very best to advise policy makers, will always be vulnerable to having their comments dragged into the political arena by the militants or their adversaries (it really doesn’t matter which side is identified as militant — the roles shift from one issue to the next). But it is a personal choice (and a wrong one, in my opinion), if the scientist reacts in a militant or adversarial way to having their scientific advice politically skewed and/or skewered.

    The very reason for the existance of this site is to provide scientists a chance to react *without* being militant or adversarial — by sticking to the science. It is a lofty goal, not always fully met. I think every scientist has their moments of frustration when they just wish they could hire a slick PR man and move in to “slash and burn” along with the best of the politicians. Perhaps that sort of longing was what led the founders of this site to seek the help of professionals in establishing the site. As an “armchair quarterback” I can blithely say that I might have done it differently.

    The reason that this site is so valuable, and the reason that the discussions between politicized militants and their politicized adversaries is “futile” (particularly here) can be stated fairly simply. In the end, “the truth will out”.

    At the foundation of scientific reasoning there is supposed to be an objective reality which is difficult to deny because it is “universally” reproducible. The more well peer-reviewed a scientific finding becomes, the closer it comes to becoming unimpeachable. In times of frustration, the scientist can call upon this foundation to find the strength they need to resist crossing the line into the political arena; and s/he can reconnect with this foundation in order to instead focus his/her energy on strengthening the scientific basis for the conclusions that are being politically attacked.

    We are all here on this site because many of the climate change scientific issues have not yet reached the point of being unimpeachable. There are scientific issues to debate and this topic is rooted in one of those scientific debating points. The political sparring over this issue by the militants and their adversaries is a particularly amusing one, so I’m glad it was also mentioned in the post. But I particularly like the scientific issues that the discussion raises. Here’s another slant: What if man’s early alteration of land use using fire and agriculture actually began to cool climate (the albedo effect and the effect of increased daytime outgoing thermal radiation both cool climate)? What if this cooling actually helped to trigger the Little Ice Age? What if the more recent increase in CO2, (perhaps aided by a fortuitous increase in solar output) then “rescued” us from a potential man-made glaciation?

  49. Joseph O'Sullivan:

    I know I’m jaded, maybe too jaded. Science is based on the facts and when done correctly the truth comes out. Unfortunately in law and politics, as I have seen, the truth doesn’t always win out. It’s a jungle out there and sometimes science and the truth get lost. My comments are made to try to cut through the political tactics to get to the science and truth, but I don’t always do great job of it. Climate change regulation is ultimately a public policy question so the public needs accurate science to be informed. I will leave the climate change science mostly to the scientists. It is very interesting and I get the basics, but it can be a little challenging. It’s the math, I was a biologist and as one of my professors said, biologists are scientists who don’t like math.
    The discussion on Realclimate should focus on the science, but I think the politics and the tactics occasionally need to be discussed. This is civil and rational public discussion and that is one of many values of the RealClimate site.

  50. Michael Tobis:

    Thanks to Joseph O’Sullivan for his comments, with which I am largely in agreement.

    I believe that Peter Wetzel is displaying a rather misty-eyed idealism. For instance:

    let me emphasize with clarion amplitude: There is no more fundamental tenet in science than reproducibility. None. Period. A study that cannot be independently reproduced is simply NOT science. I cannot be more emphatic on this point.

    is a fine point in the philosophy of science, but in practice is honored mostly in the breach. Very few studies are replicated, and very little effort is placed on allowing others to replicate such studies. I absolutely agree that science can and should do better, and I believe the impetus for doing so should come from science.

    Nevertheless, make no mistake. We are in a political environment where tricks that would once have been considered unconscionable are commonplace. It’s extremely likely that the high-sounding demands for replicability that seem so benign in theory will in practice amount to another obfuscatory hurdle in clarifying the facts of the matter to the public and the political process.

    I think it’s reasonable to give Florens his due and call the unfair and political obfuscators something other than “skeptics”. On usenet sci.environment we have taken to calling them “denialists” or occasionally in our sourest moods “septics”.

    It’s understandable that people who find politics distasteful are looking for a place to discuss science, but in this case that sort of intelelctual purity isn’t feasible. Ultimately this site is necessary *because* of the political charge to the material. If people weren’t being willfully confused there would be little need for an unfunded volunteer effort to clarify the science in an accessible way.

    By all means let’s welcome and engage real skeptics.

    Still, I hope that no one will ignore the fact that organized obfuscation is an important part of the context in which we operate when communicating with the public. In practice clever manipulators, typically denialists, will show up in the guise of real skeptics. Others will have been presented skewed views of the evidence, so will echo the denialist position in good faith. Fair minded people need to tread carefully in these minefields.

  51. Peter J. Wetzel:

    While obviously true that very few studies are actually replicated, the more valid rubric is their reproducibility as judged by peer review.

    Scientific resources are limited. The most important results are being reproduced/replicated over and over — witness the “hockey stick” genre of reconstructions of global temperature over the past millenium. But the vast majority of scientific studies fall in the category of “obviously reproducible” and/or “highly specialized and narrowly focused” — so science finds its resources better spent elsewhere.

    Political debates centered around scientific topics tend to have fairly short shelf lives, dissipating or morphing as new science emerges. As one person, with a finite attention span and energy, I’ve made some choices about how to most usefully devote my time. What matters to me is the search for clues as to which bits of the science knowledge gleaned during our time will remain valid and useful a century or more from now.

  52. Grundt:

    Maybe all of you, the last 10 or 20 or more posters, are right..
    Prof. Wetzel, you are right, but, then, almost no one is making real Science..

    For example, in Catalysis (Science), you might never reproduce an absolutely well designed experiment, no matter how well you think you are planning it.

    Once happened -(maybe thousand times different things happen this way)-,
    that a group of chemists obtained an extraordinary compound or result, I´ll call it the X experiment..

    Never more they could reproduce it, despite all the care and dedication, effort, money, etc.

    After months of countless experiments, it was noticed I don´t know how, that the flask in which the X Homogeneous Catalysis experiment was done, a molecular intrusion or wathever, so small that, obviously, you could only notice by elecron microscopy, was the factor that allowed such a very interesting and extremely important result.

    So, Science is sometimes a black box, unless for some experiments scientists can have information about even every atom involved. Not easy.

    That´s why it is so difficult to draw conclusions easily from models, appearance, etc.

    Climate? A very difficult monster to understand, it seems.

  53. Dan Allan:

    Hmm… thought we were supposed to be discussing Ruddiman in this section. But allow me to jump in. I agree in large measure with Peter Wetzel (though I have sparred with him previously), but would add a few thoughts:

    It is really counter-productive to question the motives of scientists based on who funds them, where they speak, who they are friends with, etc. The fact that one’s scientific views and one’s political are aligned does not mean that one’s political views precede and drive one’s scientific views. Nearly everybody believes that their scientific views are borne of the evidence, that they are *right*, and practicing objective science.

    I would draw an analogy to another field that demands objectivity by look at “Bush versus Gore”: Probably every Supreme Court justice believed that his or her decision was basely purely on objective legal reasoning. Yet what a funny coincidence that the conclusion each justice reached matched exactly his or her political leaning!

    In the end, questioning motives implies that we understand this very complicated concept of *motive*. No doubt some scientists are persuading themselves of their scientific views, consciously or subconsciously, or unconsciously, in order to align them with political views – just as the Supreme Court justices did. But to what extent does this unconscious or semi-conscious self-deception mean someone’s motives are tainted?

    Motives are multi-faceted, unknowable and immaterial. If Lindzen is mistaken, he will ultimately be refuted with evidence and science – not with aspersions because he spoke at the evil Cato Institute.

    Second point: there is a natural tendency among humans, and especially humans who become scientists, to want to be right. Thus, once a side is taken in a debate, many of us tend to dig in our heels deeper and deeper, try harder and harder to prove our points. As evidence supporting our view grows weaker, it only makes us more desperate and therefore more emphatic. This is especially amplified in a public, scientific debate. The wish to have be right, and the even more fundamental wish not to suffer the perceived public humiliation of being wrong, causes many scientists to quickly lose their objectivity and deceive themselves regarding their motives and beliefs. It would serve the scientific community well to recognize this, take a rhetorical step back, and go out of one’s way to be receptive to – or at least courteous in responding to – opposing views.

    One area I might disagree slightly with Wetzel: he says that ultimately, “the truth will out.” Maybe so. But it seems to me we are still debating evolution, at least in public and political spheres. I wish the truth would out already! I suppose “the truth will out” in the scientific community. Not so optimistic about the rest of society.

    – Dan

  54. Joseph O'Sullivan:

    The climate science debate has two aspects that unfortunately can’t be separated.

    There is the pure science part. RealClimate is great on this. I was interested in the concept of thresholds and the discussion (Moberg et al post started Feb. 15) was very illuminating including the comments by Peter Wetzel. I may digress, but the potential effects of climate change on coral reefs are something I am also interested in. That is one of the reasons I put in the link to the study of ocean warming at Scripps in an earlier comment. Coral reefs are among the most diverse and complex ecosystems on the planet. They are also very sensitive to abiotic environmental conditions, like temperature. Recent el nino events that warmed the tropical Pacific Ocean caused large scale, but temporary, coral die-offs. Will climate change cause large scale coral die-offs? As far as I know this this is a real possibility but it’s still pretty speculative. This is a purely scientific question: what does current science say about the potential effects of climate change on coral reefs?

    Politics is the other part of climate change science. When science goes public, out in the wide world as William says, it gets political. Climate change science is a prime example of this. On RealClimate, in my opinion, political aspects should be occasionally brought up but should definitely be a sideline to the science. A path needs to be cut through the political jungle so the accurate science can come out. Thanks to Michael Tobis for the comment that supported me. I think RealClimate has also done a good job on the political side too. A short statement or two on the politics while allowing political discussion without getting involved is the best course of action.
    Analogous to climate change science is the politics of evolution science. Thanks to Dan Allen for bringing this up. Polls have shown that about half the people in the U.S. do not believe in evolution, and President Bush has said “the verdict isn’t in” on evolution. As a biologist I almost gag when I hear this. I knew evolution is a proven scientific fact, but out of curiosity I read Darwin’s “Origin of Species” a few years ago. This book showed overwhelming evidence for evolution nearly 150 years ago, but people still don’t accept it as fact today. In the public mind evolution is not a matter of scientific fact but more as a philosophy that is a matter of opinion and personal choice.

    Now I will go back to the politics of climate change science (I’m sorry I just can’t help it). Senator Inhofe, by calling climate change science an “article of religious faith”, wants climate change science to be seen as a matter of opinion or personal choice and an extreme one at that, but not as scientific fact. This is again about stopping action on climate change laws and regulations. To put it glibly the position is: “If it’s not a fact you must not act!”

    Everyone is entitled to their own opinion but not their own facts. Everyone needs to hear the facts. RealClimate can and does help people get the facts of climate change science.

  55. Grundt:

    Excellent discussion, all of you are real Scientists.
    A pity I cannot express as I would like in English (I can do it only in Spanish)
    It is very fortunate exists.

    It is hard to hear ” ..President Bush has said “the verdict isn’t in” on evolution..”, and all this nonsense about “climate change an article of religous faith”!!

    Well, I feel we are still in the Caves Era…..depressed today..
    We are having disaster after disaster with climate and lack of prevention and lack of common sense here in Venezuela, and all around the world… I have not great hopes for the Future.

    But we will keep trying to understand what to do. Until the end.

  56. Peter J. Wetzel:

    I thought “articles of religious faith” were beyond reproach, handed down from an omnipotent deity, requiring and demanding action on penalty of eternal damnation. Perhaps the senator should think twice about elevating climate science to such a lofty pedestal. (wry smile)

    That’s about as close as I’m going to go to playing the political rhetoric game.

    Religion can be scientifically proven to be an important factor in the course of human affairs. Humans act (often to great effect) on all manner of beliefs that are simple to refute scientifically.

    Greed and self-interest play an equally important role in human dealings. Acting on no belief whatsoever, but simply for individual gratification, monarchs and dictators have shaped the affairs of men arguably more than democratic processes have.

    The balance of forces which defines human nature and human motivation arguably only has room for so much science. And balance is a good thing. A world driven entirely by science would be unbearably stifling.

    The balance on this site is defined by the lead paragraph which appears on the upper right of every page we read here. In practice, “commentary” necessarily involves a dabbling in politics. So I do fully subscribe to Joseph O’Sullivan’s moderate view: “On RealClimate, in my opinion, political aspects should be occasionally brought up but should definitely be a sideline to the science.”

    On the issue of coral bleaching, I wonder how much is known from proxies about how often this phenomenon occurred in the past. And how did coral ecosystems tolerate the much warmer climates of 50+ million years ago?

    [Response - Good question. Basically the loss of the symbionts by the corals (=bleaching) does not leave any track behind, although maybe altering the geochemistry of the corals (through the loss of photosynthetic activity). The other problem is that during the last 50 million years, both symbionts and scleractinians evolved. Because the long term trend of the last 50 or so million years was toward a cooling, the modern corals and symbionts seem to be better adapted to cool temperatures than warm ones – see for example the paper by Tchernov et al. in PNAS . So even if we had some good ideas of how did the corals were reacting to warmer early Cenozoic temperatures, the difference of coral and symbiotic communities would make it tricky to apply to modern changes. (Browsing the references databases, I did not find anything on the coral reefs during the Paleocene thermal maximum, which could be useful.) -thibault]

  57. Joseph O'Sullivan:

    How coral ecosystems handled warmer climates in the past is a good question. I’m not sure. I have not been active in the field for several years and I consider myself to be a well-informed but amateur naturalist.

    If I remember right most of the modern coral species are the result of an evolutionary expansion that occurred after the warmer climates about 50+ million years ago.
    I know in general ecosystems shift geographically in response to climate change. Coral reefs require a narrow range of environmental conditions e.g. water depth, temperature, salinity, clarity and nutrient level, so their ability to shift is limited. Another related question would be the rates of past climate change. Coral ecosystems react slowly to change and a rapid temperature change would be harder to handle.

    At present corals are effected by a range of man-made activities like coastal construction, pollution, fishing and possibly introduced diseases. In the Caribbean some coral bleaching has been caused by pathogens not native to the Caribbean and are more common in terrestrial ecosystems. Climate change adds another level of complexity to these issues.

    A science comment without politics, I am proud of myself!

  58. Richard Harvey:

    Gavin, I have not read all the posts so forgive me if my question is a repeat from an earlier post.

    The question that concerns me and that has not been addressed in the posts I’ve read so far is that Ruddiman has not provided estimates of the required land-use change and GHG emissions that would back the plausibility of his hypothesis in a *quantitative* manner. Granted forcings of 40ppm CO2 and 250ppb CH4 should lead to DEL(T)=0.8C globally given a climate sensitivity of 2.5-3C for 2XCO2 (see post #5 above), but are those forcings even plausibly attainable through human intervention with pre-historic technology? Could, say, a few tens to hundreds of millions of people back then have added almost half of today’s CO2 emissions, this time due to billions of people?

    And even if we admit to this hypothesis, there remains puzzling questions. For example, the methane “anomaly” shown to rise above the “normal” downward trend 8000 yrs ago resembles a similar departure from orbital forcing about 230 Kyrs ago (Ruddiman, 2003; Fig. 1). In addition the latter has about the same magnitude as the more contemporary one, but it occurs at a later phase, when the orbital forcing it lower than today’s. Why isn’t he also looking at explaining this departure? And why doesn’t he start by carefully ruling out mechanisms in natural methane cycle changes before even thinking about a human-induced change? He focuses too much on orbital forcing while minimizing the role of possible (and complex) feedbacks between methane and the rest of the climate system. Millenial-centenial climate variability is *not* only caused by orbital forcing!

    To be sure, his statistical correlations are interesting and worthwhile to investigate, but his hypothesis is largely based on circumstancial evidence that still keeps him on shaky grounds. All the hoopla he shows in his recent papers are premature.

    Am I being too critical?

    [Response: Well, you aren’t alone in being sceptical of the details and the points you raise are good ones. These are being addressed in the literature, but I think the most tactful statement is that the jury is still deliberating… – gavin]

  59. Joseph O'Sullivan:

    Anyone interested in the potential effects of climate change on coral reefs can look up a new publication released by the Pew Center, “Coral Reefs & Global Climate Change” a summary of the current science on this issue at:
    The Pew Center is not an environmental group like Sierra Club, Environmental Defense and the NRDC. Pew is a non-partisan philanthropic foundation focusing on education and is similar to the Carnegie and Rockefeller foundations. The Pew Ocean Commission, made up of republican and democratic politicians, environmental groups, commercial fishermen and scientists, released a report on the state of the oceans that is highly respected.
    The commentator mentioned at the start of this post, the Greening Earth Society (a fossil fuel company funded advocacy group that emphasizes in their words “the scientifically sound” perspective on CO2 and global climate change), has misrepresented the science on coral reefs and climate change. It cites three studies that show that some corals have demonstrated some resilience to warming, and then extrapolates that there is no need to be concerned about climate change’s effects on coral reefs. This is another case of twisting science. Some resilience is not the same as complete or even substantial resilience.

  60. Stewart Longman:

    As has been pointed out many times above, there are skeptics, and there are those who appropriate the label skeptic. In history or biology (think evolution), we would call them deniers. Is the science at a point now where it is irrefutable? Some people will still deny the reality of climate change as some deny evolution, or the Holocaust,, while scientists will still work on the details, models, etc., just as evolutionary biologists and hisotrians are still hard at work. No one asks a university (or news program) to represent diversity by appointing creationist biologists and denying historians, and Flat Earh Society members are not invited to give their opinion about the International Space Station. If the time is right, and the science is firm enough, then it’s time to call these people, who are advancing a definite agenda (‘Burn More’) what they are: climate change deniers, nothing skeptical about it.