RealClimate logo

Technical Note: Sorry for the recent unanticipated down-time, we had to perform some necessary updates. Please let us know if you have any problems.

Are geologists different?

Filed under: — rasmus @ 19 August 2008

rockThe International Geological Congress (IGC) is sometimes referred to as the geologists’ equivalent of the Olympic Games and is an extremely large gathering of geologists from all over the world, taking place at 4-year intervals. This time, the IGC took place in Lillestrøm, a small place just outside Oslo, Norway (August 6-14). The congress was opened by the Norwegian King (before he continued to the real games in Beijing), and was attended by some 6,000 scientists from 113 countries. Even the Danish Minister of Energy & Climate participated in a panel discussion on climate change. In other words, this was a serious meeting.

opera.jpg I didn’t attend the meeting myself, but the scientific programme for the session on climate, shows that the ‘climate contrarians’ were quite well represented. The organizers probably wanted to give room to “other views”. Together with web cast of the panel discussion on climate change (by the way, you may need Windows to view this because of the video format…), the proportion of attendees with a skeptical attitude to the notion of anthropogenic global warming appeared to be notably higher than in other conferences, such as the European Geosciences Union or European Meteorological Society, or indeed the scientific literature. So be it.

Svensmark was there, even though he’s not a geologist, and said that he didn’t understand what he was doing on the panel. He didn’t say much during the panel debate, apart from that clouds are not well described by GCMs (which is true and discussed in the latest IPCC report), and that the 90% confidence in the human influence on recent trends is derived only from models (not true). There is an irony in that, whereas detailed microphysics in clouds are not well understood (hence the uncertainties in the GCMs), Svensmark’s own hypothesis hinges entirely on the cloud response to cosmic rays (which is even less well understood).

Robert Carter said a great deal more than Svensmark on the panel. He made a point of the last couple of years being cold. But he did not appear to understand Jansen’s explanation of the difference between trends and natural variability (see here). What really struck me was not who was saying what, but the intellectual level of discussion: the debate often got stuck at misunderstood trivialities which for a long time have been regarded as solved or explained in the climate research community. When you keep starting at square one, you’ll never make much progress.

Other statements did not have a scientific basis (e.g. Morner popped out from the crowd and said that the sea levels are not rising – not true – and then saluted the panel). Thus the debate seemed to be a step backwards towards confusion rather than a progress towards resolution.

What is going on? Is there a higher proportion of geologists that have a completely different view on climate change, or was this a biased representation of the community? The thought of stifling a scientific debate by insisting on outrageous or ignorant claims also has struck me.

Update: Marc Roberts sent along this mildly relevant cartoon:

314 Responses to “Are geologists different?”

  1. 101
    veritas36 says:

    Milankovitch cycles are “computer” models. (Okay, you can do the math by hand if you have enough time). If they didn’t compare successfully with empirical data, nobody would believe them. (And they weren’t established as a climate forcer until enough data piled up to support them.

    It is always the combination of data and theory that makes science so powerful. Many geologists, as well as weather forecasters and experimentalists, are not comfortable with mathematics and tend to react with suspicion to theories that are heavily mathematical.(As opposed to a simple precept like uniformitarianism).

    I keep thinking of the plate tectonic sessions at the American Geophysical Union in the early 1970′s, where the old geologists used to whisper to each other, “But do you believe in continental drift?” I still know a geologist who does not.

    The inability of some geologists, or other scientists, to absorb the evidence for rapid climate change combined with the basic chemistry and equations behind the predictions of the models would not be significant IF there were not a massive, well-funded public relations campaign to discredit climate change.

  2. 102
    Chris Colose says:

    Bob Carter (# 84)

    Thank you for the reply. Regardless of your feelings on RC or other members, I hope we can continue this exchange. I’d also like something productive so I will spend as little time as possible quibbling over definitions which we should agree are inherently subjective to some extent. If someone said that an asteroid hitting the Earth that wiped out 95% of life was not catastrophic (or “dangerous”) because it happened before, then I might not take them too seriously, but I don’t think I’d be able to argue with them, with just science as a tool. Some may disagree, but I would consider the question outside the domain of science, and into the realm of philosophy. I would not mind your thoughts, however, on Hansen et al (2006) which takes up this question in more detail. However, many consider rapid loss of coral reefs, northern hemispheric ice, ecological displacement, sea level rise, etc to be “dangerous” (even if it happened before) and I am working with the premise that if climate sensitivity is 2 to 4.5 K per 2x CO2, we have something that is worth “doing something about.” Some differences however between now and the past though:

    - As far as I’m aware, there is no example in the paleoclimate record of a global 3 K change in timescales of decades to centuries (and the abrupt changes during the last glaciation are not a supporting example due to the extent of the temperature anomaly). High-frequency information is limited to impossible as you go back much farther (e.g. past the ice core record), but I doubt such a change has occurred so rapidly over the whole Cambrian (if I am wrong, please correct me). Much larger changes have occurred of course, but generally on glacial-interglacial to millions-of-year timescales.

    - There has never been 6.5 billion people on the planet (~9 billion by 2050), with so much invested in the status quo. Civilization began in a stable Holocene, and has not experienced variability outside ~1 degree C since then. Even still, relatively minor bumps in the road proved to matter quite a bit (e.g. to the Mayans or Vikings). Without humans, large and quick climate changes will cause problems, but now that species have limited areas to migrate (e.g. across parking lots rather than open land), and now that there is much more infrastructure and population in coastal and low-lying areas, this only makes things worth. A 2 C temperature anomaly taking place over 100 years would have many more consequences now than if the same thing happened ten million years ago.

    I cannot think of how IPCC WG2 would disagree with me in any of these regards. I have very limited study in biology or ecology, but I would think it near impossible to find professionals in the field who disagreed that large and quick changes can cause problems. In fact, you are right in that climate changes have caused life to thrive, since for evolutionary mechanisms to make any significant “steps forward” you probably need some variability rather than a completely homeostatic system. This is a view I’d support now looking back to previous large changes, but it is not a view I’d support if I was involved in those large changes while they were occurring. Imagine the environmental assessment report those anerobic creatures would have written when the atmosphere was becoming oxygenated!

    Still, I would like a couple of questions answered which summarizes mine and other concerns

    1) how do you propose we go about the attribution effort? If models are to be excluded and we use only empirical observations, then what constitutes sufficient empirical evidence that
    a) The climate is changing
    b) Humans are a significant cause of that warming

    2) What climate sensitivity, or what magnitude of radiative forcing, is sufficient to say the situation is “dangerous?”

  3. 103

    Bob Carter (84): “I am unaware of any empirical (that word again) justification for the assumption that 2 deg. C of warming is ipso facto dangerous.”

    125000 years ago it was 1 to 2 degrees warmer on average than now, and sea level was about 6 meters higher. I know that such a sealevel rise doesn’t happen overnight, but it does show that a temperature change of 2 degrees is at least potentially dangerous in the long run.

    Furthermore, I think the 2 degrees has a basis in that some elements of the climate system are expected to be close to their tipping point at such a degree of warming (a statement which of course has large uncertainties, granted, but they go in both directions, and it’s a matter of risk assessment in the face of (to a certain degree) unavoidable uncertainty).

    Perhaps the difference in opinion here is more about what risks we’re willing to take, than it is about climate science.

    Jules (33): For me (and I assume most people here) the interest is not in blaming any particular profession, but rather in understanding why people are “skeptical” towards anthropogenic causation of climate change. That is important to ponder for the communication and understanding of climate science amongst the public (and amongst “skeptics”) to improve. From your blog, I think you would agree with that.

  4. 104
    Jolly Jest says:

    Climatology and geology separate sciences; earth system a whole. However, geologists little concerned about “short term” climatic change timescale and mock idea that “minor temperature changes” in the gaseoous us envelope can impact on the tectonic system. Moreover, many geologists linked to fossil fuel industry.

    However, hypotheses:

    Increased global warming (of interest to climatologists)causing melting of ice over Greenland. Result, slow secular isostatic adjustment of Greenland crust (of interest to geologists). Greater probability of seismic activity due to stresses and strains on rocks from crustal adjustment.

    Global warming causes greater evaporation from oceans and increased and more intense precipitation over continental land masses (climatalogical fact?). Erosion from continents increases, greater deposition in ocean basins. Positive isostatic adjustment over continent; negative isostatic adjustment in ocesn basins. (Geological fact?) Greater seismic activity and greater volcanic activity levels result? But timescale of global warming – couple of centuries; timescale of consequences of global warming on earth crust – millennia or longer.

    Lesson: geologists need to pay more heed to climatologists’concerns.

  5. 105
    Don Healy says:

    Re: Lynn, #93:

    For a doubling of CO2 from 360 ppm, experiments have confirmed the following (from the link referenced in #89 above):

    “Cereal grains with C3 metabolism, including rice, wheat, barley, oats, and rye, show yield increases ranging from 25 to 64 percent, resulting from a rise in carbon fixation and reduction in photo-respiration. Flag leaves, the ones closest to grain panicles or heads, show a 60 percent increase in photosynthetic rates.

    Food crops with C4 metabolism, including corn, sorghum, millet, and sugarcane, show yield increases ranging from 10 to 55 percent, resulting primarily from superior efficiency in water use.

    Tuber and root crops, including potatoes and sweet potatoes, show dramatic increase in tuberization (potatoes) and growth of roots (sweet potatoes). Yield increases range from 18 to 75 percent.

    Legumes, including peas, beans, and soybeans, show yield increases of 28 to 46 percent. For soybeans, frequently planted not only for their food value but because they naturally fertilize the soil, there is a spectacular increase in biological nitrogen fixation, as will be shown below.”

    Thus, I question the negatives that you at attached to “an experiment”. The results I cite are from hundreds of experiments. Please cite your source.

    Thanks, Don

    [Response: Maybe this one: Long et al, 2006... - gavin]

  6. 106

    It’s instructive that Bob Carter ignores Gavin’s question. Carter claims that he is “unaware of any empirical evidence that dangerous warming, or any measurable warming for that matter, can be attributed to a human causation.” The IPCC is full of empirical evidence, the balance of which supports the conclusion that CO2 is a greenhouse gas, and that humans are responsible for unprecedented levels of CO2 in the system. CO2 of natural origin has warmed the planet in the past. CO2 of human origin can certainly have the same consequence.

    The models are only one thread in the overwhelming evidence for this understanding. What is missing is evidence of some natural mechanism for the warming that is clearly happening. How would Carter attribute the warming if not by relying on models? What kind of evidence is he waiting for? Looking over his opinion pieces, it seems that the only evidence he recognizes is that which confirms his conclusion that there’s nothing to worry about, regardless of the quality of the evidence or the credibility of his sources.

  7. 107
    Brian Klappstein says:

    I’m a geologist….and a skeptic too.

    I think the reason geologists might be more skeptical of human-caused catastrophic climate change is we learn early in our training that the history of the earth is one of ongoing catastrophe, from meteor impacts, to periods of intense volcanism, to “iceball” earth episodes, all going back 500 million years or so. We just find it hard to get worried about the temperature allegedly rising 2 degrees in the next 100 years.

    Plus we know that the most devastating episodes for life on earth recently have been cold periods not warm.

    Regards, BRK

    [Response: That's what I don't understand. It's as if you've seen your neighbour's houses destroyed by termites, sinkholes, floods and runaway trains, and so you know how fragile they are, and yet you are content to watch while someone stokes a unguarded fire under your porch. Doesn't it bother you even a little? - gavin]

  8. 108
    Joseph O\'Sullivan says:

    #84 Bob Carter

    “Local geological records contain countless examples of greater increases (or decreases) in temperature than 2 deg. C. The nearby animals and plants (ecosystems, if you like) did what they always do, i.e. shifted their geographic distributions and/or adapted to the different conditions”

    There are three things that plants and animals always did, adapted, shifted their geographical distributions or became extinct. Claiming that animals and plants only “shifted their geographic distributions and/or adapted” is incorrect. Considering that Bob Carter is a scientist, its unlikely this is a merely an uninformed statement.

  9. 109

    #84 Bob Carter

    Both “catastrophic AGW” and “dangerous climate change” are relative terms. Common sense would lead one to believe that the connotation is related to the human system and its subsystems as well as those changes that fall outside of the natural cycle.

    There is also the geologic time scale to consider. You may certainly argue that the AGW event is neither catastrophic nor dangerous if you so choose and the best way to accomplish this goal is to ignore any impact on human and biological systems. Then you would be more correct in your assertions, at least connotatively speaking.


    It’s most likely, from what I read in your posts, that you just are not aware of, or ignorant of, the importance of such relationships, but if you now continue to ignore the relevance based on what you have heard, that means you are purposefully ignorant of the importance. Not good for one that claims to be a scientist.

    Further, you discuss a meeting regarding “Avoiding Dangerous Climate Change”. A marketing meeting has nothing to do with the science, you should know that already because you are one. You seem to think it relevant somehow though?

    You further go on to discuss greater temperature changes in the past and certainly ecosystems adapted to those changes just as will occur again. The missing aspect of relevance is that the connotative value of ‘dangerous’ directly relates to speed of change, current context and infrastructure as it pertains to human systems and biological systems that human systems rely upon.

    In this context, dangerous and catastrophic are easier to understand. Latitudinal and altitudinal shifts as well as geologic timescale issues of AGW v. natural cycle shifts in combination with human infrastructure and the monetary economic impact thereto. I don’t think it’s that difficult to understand really.

    I would like to hear your answers to Gavin’s questions in post #51.


    There are a lot of people in here that would love to be enlightened with any sound science you can present.

  10. 110
    CL says:

    #84 Bob Carter

    “Local geological records contain countless examples of greater increases (or decreases) in temperature than 2 deg. C. The nearby animals and plants (ecosystems, if you like) did what they always do, i.e. shifted their geographic distributions and/or adapted to the different conditions”

    In addition to J. O’Sullivan’s response… There are international legal agreements to preserve biodiversity, because it was generally agreed that biodiversity is important for a vast number of reasons.

    If there is rapid climate change, there’s no time for species to either adapt or to move geographic range. Some things are just stuck where they are, like coral reefs, species high on mountains, isolated forests, rivers that dry up, etc, with nowhere to got to. For example, Scottish fauna and flora, Capercaillie, Ptarmigan, etc, cannot move further northward. Where are penguins supposed to move to ?

    Of course, on geological time scales, or a God’s-eye view, these things may not matter. But for humans and their children and grand-children, they are relevant.

  11. 111
    David B. Benson says:

    ‘dangerous’ climate change: How about the concentration of CO2 which leads to pulmonary acidoisis? Whatever that level is, it means that everybody will be cronically somewhat ill. This following, rather obscurly published and under-referenced paper states, in effect, that 426 ppm is too much:

    [Response: This is very dubious indeed and should not play any part in these discussions - many city centers have levels higher than this already. - gavin]

  12. 112

    #85 Richard Sycamore

    If I am reading your question correctly you are questioning the climate response time to GHG change. Oceanic thermal inertia is keeping the change rate in check. If we were at equilibrium with the current forcing it would be warmer. I suppose we can all be thankful that oceans heat and cool slowly in relation to forcing, thus allowing time for species adaption in the natural cycle. Of course we are breaking the natural speed limit with this AGW event.

    Other response considerations:

    The GHG change rate has been purported to be dramatically above (thousands of times faster than) natural variability in the paleo record (large asteroid impacts aside i.e. end mesozoic/cretaceous):

    Global climate change progressed faster in the 20th century than at any other time during the past 22,000 years, warn Swiss scientists.

    Climate change threatens a million species with extinction

  13. 113
    David R. Hickey says:

    It’s a pity that so many of the geologists who have posted here are questioning global warming. I know plenty who have accepted it long ago. These must be geologists who work in fields unrelated to those I listed. Most are likely in the petroleum or mining industries. It’s a shame that then the climatologists appear to be bashing the entire science of geology (& many seem here to claim the (climate)science all for themselves when anyone following this topic from the 70s knows better–it’s an area of study integrating many disciplines–glaciologists, & some ‘oceanographers’ e.g., ARE geologists, and many other disciplines as well.) “…geologists can’t understand the basic chemistry and equations”??! Nonsense. All this shows is that you know nothing of academic geologists and the entire range & reach of the science: geochemistry, biogeochemistry, geophysics, marine geology, sedimentology, glaciology, geoarchaeologists, paleontology and paleoecology are among the many geological disiplines where you will find those who have contributed immensely to the current research & without who’s work (& by the way we CAN and DO understand short times scales)there would be no historical basis On which to establish GW but the very short time temperature readings have been taken. Thus, there would be no historical precedents. GEOLOGISTS studying the Pliestocene glaciation and maine geologists & paleontologists are the ones who have contributed the necessary data to show that rapid global climate change has & can happen both rapidly & over long periods of time. We can and DO study short periods of time.

    Re long time periods–without History you are NO WHERE. If you Don’t understand the history of the planet then you can’t understand much of anything about the present.

    Again, many of those geologists still denying GW have only B.S. & M.S. degrees & have ignored research since gaining employment–their vested interest are threatened-or their old world view. Those that speak out againsts it are paid shills in the industry. They have no credibility. But these people do NOT make up the Majority of Academic geologists who DO accept it and the many who have joined this research.

    I was offered a geophysics position by Exon starting at $35K/yr in 81. I’d gone to the interview on a lark. I’ve Never had any intention of working in an industry whose goal was to put a strangle-hold on the world economy-which I realized would happen when still in high school. I gladly went on to obtain my degrees so that I could teach students about the history of the Earth & what it tells us–Anthropogenic GW IS REAL, yet never made more than 25K/yr. And I had a family of Five. The course I offered on Global warming in 90 was the first of its kind among any of the colleges & universities in Michigan’s lower penninsula. And I taught that it had Already Begun, just as James Hansen had said & been ridiculed for in the 80s.

    For the sake of science and public perception, please STop your bashing of geologists! If you really believe some of your outrageous statements, then you need to get another degree or two.

  14. 114
    Hank Roberts says:

    David, 20 août 2008 at 6:14 PM
    I looked up the footnotes to that the paper at that link.

    There is one interesting statement there about one study I could not find, on CO2 levels in classrooms and learning problems. If you can find that I’d be curious.

    But I’m, er, skep …skep … can’t be fooled again.

    This sentence and cite is the key to the impression you have. I think it’s bogus:

    “Office buildings exist which are described
    as ‘sick’, in which workers display symptoms of carbon
    dioxide poisoning8.”

    Look up the cite for that footnote #8 — it says sick buildings have air full of a panoply of nasty stuff most of which can’t be measured. It doesn’t support the statement for which it’s cited, in my amateur opinion.
    Consider this instead, a source that is actually referring to actual carbon dioxide levels:

    “… This document discusses the toxicity and exposure limits for exposure to carbon dioxide gas (CO2). We give references and explanation regarding Toxicity of Carbon Dioxide …”

    “… a Drager colorimetric gas detection tube used to test the CO2 levels in air. In an indoor air test (in our laboratory) the detector found that the CO2 level was about 600ppm which is typical of indoor air and is an acceptable and safe level.”

  15. 115

    #84 Bob Carter
    #94 Crust

    (This was, I think, the same meeting that determined the change in media usage from “global warming” to “climate change”, which was similarly promulgated for cynical marketing-the-message reasons).

    I am unsure how to address the idea of ‘climate change” v. ‘global warming’ scientifically. However, I use the term ‘global warming’, because ‘climate change’ is something that both, goes up and down in trends based on forcing, and occurs in natural full cycle.

    ‘Global warming’ on the other hand is only half a natural cycle. Putting aside any marketing reasons, I believe the more accurate term to be either ‘global warming’ of ‘anthropogenic global warming’ or ‘human caused global warming’.


    1. We are warming, not cooling, in the trend.

    2. We are warming outside of the natural variability due to anthropogenic imposed forcing caused by increased GHG’s imposed via industrial processes.

    In my understanding ‘climate change’ is not a sufficient reference to something that is in an uptrend warming specifically and anthropogenic in cause.

    I am more concerned that ‘climate change’ increases cognitive dissonance rather than decreases, since it has the ambiguity of warming and cooling potentials within it, while we are clearly in a warming event.

  16. 116
    dhogaza says:

    I think the reason geologists might be more skeptical of human-caused catastrophic climate change is we learn early in our training that the history of the earth is one of ongoing catastrophe, from meteor impacts, to periods of intense volcanism, to “iceball” earth episodes, all going back 500 million years or so. We just find it hard to get worried about the temperature allegedly rising 2 degrees in the next 100 years.

    That’s senseless. Just senseless. The next 100 years is when your children and grandchildren will be living. You suggest we should be unconcerned about our actions making their lives more difficult because once upon a time we had snowball earth?

  17. 117
    Hank Roberts says:

    Here’s a double-whammy paper.

    Yes, migratory birds are showing up earlier (first arrival date is earlier) over the past 30 years).

    But there are a lot fewer of them — they’re more scattered out in time. The mean arrival date is later because the cohort size total is smaller.

    Any way you look at it, it’s not good news.

  18. 118
    Hank Roberts says:

    Geologists publishing relevant papers:

    Martin Kennedy, David Mrofka & Chris von der Borch. Snowball Earth termination by destabilization of equatorial permafrost methane clathrate. Nature, 453, 642-645 (29 May 2008) DOI: 10.1038/nature06961;jsessionid=BB6B9E467D46F310D8191AA2C60AABF4


  19. 119
    Eric Swanson says:

    RE: #96 Bob Carter makes reference to my earlier comment # 87 in which I pointed to two instances in which Dr. Carter misused the scientific information. Since he chose to address my use of the word denialist instead of responding to the substance of my comment, I must assume that he now agrees that I was correct to raise those issues. According to both the Spencer & Christy and the RSS analysis of the MSU data, there is a warming trend seen in the so-called lower tropospheric temperature data. There are also other groups who have found a warming trend by analyzing the MSU data. Isn’t that exactly the sort of evidence which Dr. Carter has claimed was lacking in proof of Global Warming?

    But, Dr. Carter chooses to quibble over whether the changes being observed are “dangerous” or catastrophic”, when we know that relatively small changes resulting from volcanic eruptions can indeed produce short term catastrophic consequences. The effects of Tambora, Huaynaputina and Kuwae are clear evidence of the sensitivity of human civilization to small cooling events on the order of a few degrees C. While we do not yet know with certainty how dangerous a few degrees of warming will be, such certainty won’t be fully known until AFTER the temperature has risen, at which point, we will be stuck with the results of our unintentional climate experimentation.

    I think the data suggests that the Thermhaline Circulation may be much more vulnerable than some have suggested, as there is evidence of considerable fluctuations in the flow on decadal time scales. I have seen evidence which suggests that the THC may have weakened (or even shutdown) in the Greenland Sea THIS YEAR, but I have no direct oceanographic measurements to support that view. (Perhaps one of the professional oceanographers out there in RC land could comment on this year’s measurements.) Would a shutdown of the THC be the sort of consequence which Dr. Carter would consider to be dangerous or even catastrophic? If not, what sort of change WOULD Dr. Carter have on his list of “dangerous” changes?

    E. S.

  20. 120
    David B. Benson says:

    Hank Roberts (114) — Thank you for finding such an informative link.

  21. 121

    #113 David R. Hickey

    I did not read all the posts, but I don’t think anyone is bashing all bashing geologists, just the ones that are spreading ideas out of context. I would personally find it hard to believe that the majority of geologists are not aware of the situation as it has developed, especially since so much good reporting on global warming comes from the AGU and like organizations.

    On the other hand, it is appropriate to address and put in perspective the fallacies and shortcomings of those few geologists that have not examined the width and breadth of the relevant science and the contexts of the data and models and understood it.

    There is much as stake and communicating and illustrating the science appropriately is difficult when certain individuals take it upon themselves to narrow their vision to a point that science becomes impossible and then claim that their myopic vision is relevant to a point that people should ignore the relevant science… and then spread such fallacy through the media as if it is some sort of gospel.

    It’s a strange time. I guess in reality we are all just passing though this life, but to trivialize our existence and say it does not matter… because … geologic time scales show that life is resilient… not a very nice thing to say, all things considered.

    I continue to hope the cataracts will fall from those eyes, that they may see the forcing, and the ramifications in time before too much damage is done… but a certain amount of damage is now in the cards and some will pay while others benefit… with any luck, maybe we as a human race will become aware in time to keep it sane?

    Thank you for your post.

  22. 122
    Steve says:

    David B. Benson Says:
    20 August 2008 at 6:14 PM
    ‘dangerous’ climate change: How about the concentration of CO2 which leads to pulmonary acidoisis? Whatever that level is, it means that everybody will be cronically somewhat ill. This following, rather obscurly published and under-referenced paper states, in effect, that 426 ppm is too much:

    [edit--watch the tone!] what is “pulmonary acidoisis”?

  23. 123
    Patrick 027 says:

    Re 107 – “Plus we know that the most devastating episodes for life on earth recently have been cold periods not warm.”

    Well, if that’s true, the present may provide some variety for you.

    I would guess (I’m not an evolutionary biologist) that evolution has some time scale of memory – that is, the species around today have the genetic variations that have survived not just the last generation. So it makes some sense that in addition to size and rapidity of change, unfamiliarity is a factor. That is, if it was just recently 5 deg C colder (how recently it has to be to matter, I’m not sure), a cool down of 5 deg C might not cause as big an extinction as a warm up of the same (over the same time period) – although if it’s fast enough the distinction may not matter, because aside from genetic variation among and within species, trees and soil can only migrate so fast, even assuming there is a route available… (PS notice that other human-caused changes may have made ecosystems and biodiversity even more vulnerable to other changes). Anyway, many humans are not nomads, and the way some of us have become accustomed to living, we have deep expensive elaborate roots in the ground (that will need to be repaired eventually anyway, but still…) and a whole lot of nice baggage that we’d prefer to take with us when moving. The modern way of life currently enjoyed by x % of us has never seen global average surface temperatures outside a narrow range. Whatever combination of changing our emissions and changing the climate, we’ll have to change, the question is, what combination of the two is preferable? (With oil at ~100 $/barrel, solar power doesn’t seem all that expensive anymore, even without carbon taxes.)

    Wasn’t it warming up during the end Permian mass extinctions?

  24. 124
    Brian Dodge says:

    re #84 Dr. Robert Carter
    >(This was, I think, the same meeting that determined the change in media usage from “global warming” to “climate change”, which was similarly promulgated for cynical marketing-the-message reasons).

    Frank Luntz is a Republican pollster known as the architect of House Speaker Newt Gingrich’s 1994 “Contract with America.” Luntz advised Republicans in a secret memo during Bush’s first term on their political vulnerability because of their stand on the environment:

    “Voters believe that there is no consensus about global warming
    within the scientific community. Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly;”

    “Therefore, you need to continue to make the lack of scientific certainty a primary issue in the debate;”

    “It’s time for us to start talking
    about ‘climate change’ instead of global warming and ‘conservation’ instead of preservation.
    1. ‘Climate change’ is less frightening than ‘global warming;’ As one focus group participant noted, climate change ‘sounds like you’re going from Pittsburgh to Fort Lauderdale.’ While global warming has catastrophic connotations attached to it, climate change suggests a more controllable and less emotional challenge;”

    “A compelling story, even if factually inaccurate, can be more emotionally compelling than a dry recitation of the truth.”

    He is also reputed to have said that the key to survey polling is “to ask a question in the way that you get the right answer”

    Yes, the spin from global warming to climate change was “promulgated for cynical marketing-the-message reasons.”
    Just not by people concerned about avoiding dangerous climate change.

    (ReCaptcha: “sad approach”)

  25. 125
    David B. Benson says:

    Steve (122) — Should have written ‘respiratory acidosis”:

    but sometimes ‘pulmonary acidosis’ is used:

  26. 126
    David R. Hickey says:

    re Hank Roberts link posts. I thank you as well for coming to geologist’s defense.

    re John P. Reisman post #121
    Thank you John. You are likely correct about the majority of geologists being refered to in these posts. However, I suppose it comes down to this. The blog post Title reads “Are Geologists Different” and those posting about the viewpoints of geologists w/out identifying them as educated or uneducated in fields relating to GW and those geologists posting objections to the GW as the inescapable concensus conclusion of the great majority of climate scientists (geologists Included) give the impression when reading through the posts that this is a free-for all climate scientists only bash against all geologists and paleobiologists. Yes, the post accompanying the question does give many geologists credit, but cites a few at one conference as representing the whole. Thus, Perhaps it was the very Title/Question posed by the blog that is misleading and should have been clarified initially. Something like “Are SOME Geologists Different?”

  27. 127
    Don Healy says:

    Re: 105, Gavin and Lynn:

    I have read the study you provided in #105 above, (Response: Maybe this one: Long et al, 2006… – gavin] but conclude that it probably supports my position on the benefits of CO2 fertilization more than yours. The experiments cited wheat and rice FACE experiments included nitrogen treatments, but only at lower levels. From the paper “At the lowest [N] (15 to 70 kg of N haj1), the average yield increase with elevated [CO2] was only 9% (28), just over one-third of that of the chamber response (Table 1). Although this N input treatment was considered low by the standards of intensive agriculture in the European Union and United States, these levels exceed the world average and may therefore be closer to the stimulation factor for crop yields across the globe.” And “For example, the major C3 herbage grass, Lolium perenne, also showed a yield increase of only 9% at two locations; and at the lowest [N] (100 to 140 kg of N haj1), the yield increase was an insignificant 1% (table S2)(28).” The justification used above for only considering low nitrogen level appears unwarranted considering that a vast majority of the agriculture products that feed the world are produced with fertilizers of one sort or another.

    Additionally, the paper makes no mention made as to the nitrogen levels used in the experiments for greenhouses, laboratory chambers or field chambers that the FACE results were compared to. Limiting nitrogen levels will certainly reduce the effect of CO2 fertilization.

    There have however, been numerous other FACE experiments that mirror the results of the chamber experiments and also mention the effects of various nitrogen and water regimes. CO2 Science documents much of the work of Dr. Bruce Kimball who has been involved in FACE experiments since their beginning in 1989. A summary of his findings between 1989 and 2002 in many dozens of experiments is as follows:

    “So what did Kimball et al. learn from their massive review of the FACE literature? To what degree were different plant physiological processes and properties altered by a 300 ppm increase in the air’s CO2 concentration?

    With respect to net photosynthesis, the rates of this process in upper-canopy leaves of the several C3 grasses studied were enhanced by an average of 46% under ample water and nitrogen, and by 44% when nitrogen was limiting to growth. In the case of the C4 crop sorghum, however, the net photosynthetic enhancement at ample water and nitrogen was only 14%; but when water was limiting to growth, the CO2-induced stimulation rose to 34%. And when net photosynthesis was measured throughout the entire canopy of a C3 wheat crop, the mean enhancement was 28%.
    With respect to aboveground biomass, three C3 grasses (wheat, ryegrass and rice) experienced an average increase of 18% at ample water and nitrogen, 4% at low nitrogen, and 21% at low water. C4 sorghum, however, experienced a mere 4% increase at ample water and nitrogen, but a 24% increase at low water. Most surprising of all, perhaps, was potato (a C3 forb), which experienced a 32% decrease at ample water and nitrogen. Clover (a C3 legume), on the other hand, experienced a 36% increase at ample water and nitrogen, as well as a 38% increase at low nitrogen. Last of all, woody cotton and grape plants experienced an average 48% increase at ample water and nitrogen, and an average 39% increase at low water.
    With respect to belowground biomass, wheat, ryegrass and rice experienced an average increase of 70% at ample water and nitrogen, 58% at low nitrogen, and 34% at low water. Clover experienced a 38% increase at ample water and nitrogen, plus a 32% increase at low nitrogen. Outdoing them all, however, was cotton, with a 96% increase at ample water and nitrogen.
    With respect to agricultural yield – which represents the bottom line in terms of food and fiber production – ryegrass and wheat experienced an average increase of 18% at ample water and nitrogen, while wheat also experienced an increase of 10% at low nitrogen and 34% at low water. Sorghum yield was unchanged at ample water and nitrogen; but at low water it rose by 38%. And potato, in spite of its 32% decrease in aboveground growth, experienced a yield increase of 42% at ample water and nitrogen.” (From:

    So, it would appear that the study you cited was not conducted with the intent of mirroring the conditions that were assumed for the previous “enclosed chamber” experiments and basically only tested for low nitrogen environments; an unrealistic approach considering our current agricultural techniques.

    Thanks, Don

  28. 128
    Guenter Hess says:

    Dear Rasmus,
    I like to answer your question. No, geologists are not different.
    They are as knowledgeable and as well educated as any other group of scientists. This should be respected. Many of them have given wealth to us or to their countries by finding ore or oil. I think that is also a fact that one should respect and not forget.
    I watched yesterday the webcast of the IGC panel discussion about global warming.
    For my opinion the conclusion of the panel discussion was: It is most likely that there is warming. Moreover, it is most likely that there is a significant anthropogenic factor. There was also a strong argument to take action and make political decisions to mitigate or prevent climate change based on the available model predictions.
    Moreover it was for my opinion a regular panel discussion that could have happened at any scientific or engineering conference about any topic. A spread of different opinions based on different levels of knowledge about the specific topic. I even noticed that ”ad hominem” arguments did not play a significant role. I think, we do not have to worry about this world as long as people voice and defend their opinion, even though we disagree with their opinion or even if they are wrong.

    [Response: Thanks for your comments. In 'different' I referred to having a different view to the other disciplines working in geophysics. I still think there is a problem when fundamental concepts are mixed together, such as natural fluctuations (e.g. the mentioned 'trend' since 1998 and 'cooling' in the last couple of years) and trend issues in the penal debate. One usually expects state-of-the-art matters to be discussed in such panel debates (at least in conferences of this size), unless there is a fundamental paradigm shift. I agree that geologists are as knowledgeable and as well-educated (in their field) as any other group of scientists, and that it should be respected: Obviously, they know their field, but I wonder if they are entirely up-to-date regarding the current climate situation. That is an interesting and legitimate question. -rasmus]

  29. 129
    KW says:

    In the long run, I’m not afraid of a warming planet. It sounds unfrightening to me, really.

    An ice age sounds much more difficult to survive through.

    Those are the deadline facts.

    Now…if you get off on arguing who’s more intelligent or right…then by all means, do so.

    Happiness found in other useful pursuits, is infinitely more important to me than being right about evil humans and all that they do on a planet for an infinitely insignificant speck of time.

  30. 130
    Arch Stanton says:

    RE Steve 122,

    Acidosis (very briefly): The body maintains the ph of the blood within a narrow range optimum for many metabolic functions. It primarily does this through the respiratory and renal systems. The primary cause of acidic (and alkalotic) states are differentiated medically between metabolic acidosis (diabetic ketosis is a prime example) and respiratory acidosis (those caused by respiratory abnormalities such as not breathing deeply enough to clear the CO2 from the lungs). (Written from memory from a physiology class of 30 years ago and experience as a (non-ICU) RN (retired)).

    I am not really qualified to judge the validity of the Robertson paper; however that won’t stop me from commenting that I would not be surprised if other physiological compensatory mechanisms could compensate for chronically high atmospheric CO2 levels (to a minor degree). It would be nice to hear an ICU attending MD weigh in on this.

  31. 131
    Hank Roberts says:

    Don Healy writes ” … it would appear …” and cites to co2science’s blog.

    Don, I’m sure you’re right that they make it appear so.
    That’s their business. They’re a PR site doing “advocacy science” spinning everything the way their funders need. You can’t rely on their interpretations.

    Look them up at the Nature blog:

    Look them up at climateaudit:
    Well, the actual posting has disappeared, but here’s a reference to it from the same thread. Dr. Judith Curry had just visited co2science for the first time and debunked it. This is a response quoting from that now-missing posting

    >> Re the CO2 site. I seem to have inadvertently
    >> stirred up a hornets nest on this one, apologies
    >> for previous flip posts but my “spin meter”
    >> on this particular topic is acutely
    >> sensitivity.
    >> The post on the CO2 site is “high class” spin,
    >> where factual info is presented without obvious
    >> errors and the motives of scientists aren’t
    >> attacked (this is in contrast to low class
    >> spin).
    >> …
    >> When i said i could refute the CO2 site, i was
    >> specifically referring to their faulty reasoning,
    >> not the data or anything else.

    Check it out.

  32. 132
    Hank Roberts says:

    Correction — when I started the above, full text search hadn’t turned up the original, for some reason, but I’d gone through the thread, find the original, and the quote above is from the source posting:

    The exchange began earlier in the thread:

    Also check Sourcewatch, of course.

  33. 133
    David B. Benson says:

    Arch Stanton (130) — From my brief explorations on acidosis, well done!

    I’m certainly not qualified to comment on the paper, but again from what little I have learned about respitory acidosis there does seem to be some sort of ‘buffering’ which lessens the symptoms.

    I, too, would very much like someone knowledgable to comment, but in the nonce what is a ‘ICU attending MD”? As opposed to an MD, that is?

  34. 134
    Don Healy says:

    Re: #131, Hank Roberts:

    Hank please disregard CO2 Science which was only in vehicle and tell what your beef might be with Dr. Bruce A. Kimball. Please check out his website at As an employee of the USDA with an extensive history in this area of expertise, perhaps his comments and research carry some considerable weight. Shooting the messenger before you evaluate the message appears a bit short-sighted.

    Thanks, Don

  35. 135

    KW writes:

    In the long run, I’m not afraid of a warming planet. It sounds unfrightening to me, really.

    One of the official slogans of George Orwell’s Oceania was “ignorance is bliss.”

    Global warming will mean more droughts in continental interiors. In the 1960s 20% of the planet’s agricultural areas were experiencing droughts at any one time. In the past few years, it has been more like 30%. Droughts cut agricultural production. Less food for more people is bad.

    Global warming will cause more violent weather along coastlines. Cat 4 and 5 hurricanes cause massive property damage, as with the recent Katrina. They kill people, too. Destruction of infrastructure and of human life is bad.

    Global warming will melt and sublime glaciers around the world. 100 million people in Asia depend solely on glaciers for their fresh water. People not having fresh water is bad.

    Global warming will raise sea level. Two degrees change in the mean global annual surface temperature is enough to raise sea level by six meters. That is enough to make San Francisco, Houston, Miami, New Orleans, New York, coastal cities around the world and most of Bangladesh and Florida uninhabitable. Massive loss of expensive infrastructure and having to deal with hundreds of millions of refugees is bad.

    A warmer Earth may not be bad in any cosmic sense. But our agriculture and economy are adapted to the unusually stable climate we’ve enjoyed for the past 10,000 years. Changing that climate hurts our agriculture and economy. That’s bad.

    Sounds frightening to me.

  36. 136

    RE: #84, Bob Carter

    Here is one example of Bob Carter’s misinformation:

    On 12 July 2007 he participated in a debate on Australian ABC TV following a showing of The Great Global Warming Swindle. He said that the hypothesis of the danger of human-caused global warming was disproved by the fact that “in the ice cores, the change in temperature precedes the change in carbon dioxide”.

    This is one of the classic denialist arguments, and it is embarrassing that a scientist would attempt to pass it off as carrying any weight.

    Would Prof Carter like to comment on exactly what logic leads him to think that the ice cores disprove the danger of AGW?

    You can listen to Prof Carter making the above argument by going to click on “The Debate” tab, then “The Debate – part 3″, and go in about 2m 45s. Rewind to 1m 30s to see the beginning of his comments.

  37. 137
    Biff Baffin says:

    There’s a certain kind of mindset that can readily recognize the social poses of authority better than the subtle signs of expertise. You have to wonder if environment can play a role in that, and then consider for a moment oil and the toxic environment that has given us at least one recent and notable mess abroad. What does Exxon-Mobile call its headquarters? The God Pond.

    Are geologists different? Well yes, of course. It’s a different kind of endeavor. I can’t connect the dots to denial, but I can for the sake of argument hypothesize. For starters the subject is so broad that they must be educated differently although just as rigorously as other scientists–even if the process takes a little longer. Attention must be paid, for instance, just to the extensive and arcane vocabulary required. Visualization skills need to be developed in conjunction with the analytic skills of other sciences. In practice the profession can be very demanding physically as well as intellectually. This is all because geology isn’t one science so much as an aggregate of sciences applied to the study of the earth, a good chunk of which takes place out in the field in difficult environments.

    Key to geo-culture is that early on, geologists get a strong dose of historical geology which turns out to be as much about the history of geology itself as it is about the earth. While the culture soon merges with other sciences, there is still that sweet, nostalgic whiff of curio cabinets and musty libraries that tends to linger. You can’t help but think that every now and then some poor, old geocritter falls out of bed in the morning after so many gallons of beer and chili, after years of freezing his cajones off and baking his brains and trying to make sense of p-chem/hysterisis loops/chaotic orogeny etc. — he falls out used and exhausted, rubs his eyeballs still throbbing from the dolomite chips his rock hammer shot off an outcrop and the headache he got banging his head on some overhang and says, “Screw it. Today I’m jumping down a Victorian rabbit hole.” Pfft! That’s it! He’s a goner.

  38. 138
    Jim Eaton says:

    Last night I received an email from a geologist friend who attended the International Geological Congress (IGC). He wrote that the program chairman of the IGC was David Gee who is “violently vociferous” against the IPCC and its conclusions. So he was not surprised that climate change sceptics were dominant.

    He also mentioned that the Geological Society of America has a group, the Concerned Issues Coalition, which is composed of geologists who are very concerned about the climate change issue. They are quite upset about the IGC bias on global warming.

  39. 139
    Hank Roberts says:

    Don Healy, reread what Dr. Curry wrote, please.

    CO2S uses the names of many good scientists and attributes things to their papers that fit their sponsors’ agenda. That’s how the PR business works. Being named there is no reflection on anyone.

    You could email the researcher and ask if he feels that he’s being represented accurately at CO2S or any other opinion site — but I’d recommend first that you read the researcher’s work in the original, read the footnotes, and then read the subsequent papers citing the research to see what later scientific work has found it interesting or reliable.

    If you want to do the homework of checking out what you’re reading. I recommend the latter approach. Having read the original and citing papers also will let you ask the researcher an intelligent question when you do make direct contact.

    Scientists are shocked and awed when ordinary readers like us actually bother to try to read their papers, understand some of the work, and ask intelligent questions. Recommended:

  40. 140
    Hank Roberts says:

    Oh, and, for Don Healy — this is definitely off topic, so I hope you’ll take it to another thread if you want to pursue your interest in CO2 and agriculture. It’s a great area of research, there’s lots to learn.

    But — you should actually read that USDA website you link to.

    They’re _hoping_ to find strains of C3 crops that will do well, by growing thousands of varieties in simulations of future climate conditions (high heat and high CO2), hoping they will find strains to use in crops. Not found yet!!!

    Read the latest paper on his Publications list:

    “… the productivity of C3 crops … the average yield stimulation observed to date is well below the potential theoretical gains. This suggests there is significant room for improving productivity. There are tens of thousands of lines of wheat, rice, soybean and other crops available, but only a fraction of these have been tested for CO2 responsiveness in a production environment. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment…..”

    ———-end excerpt—————-

    This is adaptation by artificial selection. It’s what ag spe-cial-ists do.

    Don’t mistake hope for success. The greatest barrier to accomplishing something is to believe it’s already been done.

  41. 141
    Don Healy says:

    Re: #139, Hank:

    Please disregard any reference to CO2 Science; I’m sorry I even mentioned it. It was only used as a vehicle to located scientist that had worked on FACE experiments. It turns out that one of the dominent figures in FACE experiments was Dr. Bruce Kimball, who by the way also works for the same organization, the USDA, that Elizabeth Ainsworth works for, whose work was cited by Gavin in an earlier post. In fact, you can access both Kimball’s and Ainsworths pulications on the same USDA website. Now, that being said, here is an abstract from one of Dr. Kimball’s recent papers, from:

    “Technical Abstract: The likely effects of future high levels of atmosperic CO2 on several agricultural crops were investiaged. Using literature reports from free-air CO2 enrichment (FACE) experiments, the relative responses of the crops were extracted, tabulated, and analyzed with regard to many plant and soil processes. Elevated CO2 increase photosyntheses and biomass production and yield substantially in C2 species, but little in C4; and it decreased stomatal conductance and transpiration in both C3 and C4 species and greatly improved water-use efficiency in all the crops. Growth stimulations were as large or larger under water-stress compared to well-watered conditions. Growth stimulations of non-legumes were reduced at low soil nitrogen. Root growth was generally stimulated more than that of shoots. Woody perennials had the largest growth responses to elevated CO2. Detection of statistically significant changes in soil organic carbon in any one study was impossible, yet by combining results from several sites and years, it appears that elevated comaprisons between the FACE-based data and those from reviews of prior chanber-based data were consistent, which gives confidence that conclusions drawn from both types of data are accurate. However, the more realistic FACE environment and the larger plot size enabled more extensive robust multidisciplinary data sets to be obtained under conditions representative of open felds in the future high-CO2 world. ” (I believe that the C@ in the text above is a typo and should be C3)

    The comment “it appears that elevated comparisons between the FACE-based data and those from reviews of prior chamber-based data were consistent, which gives confidence that conclusions drawn from both types of data are accurate.” is particularily telling in that it means that the very large body of research done earlier using “chamber-based” methods is valid.

    Are you unable to acknowledge that in light of the perponderance of evidence showing that while not uniform, CO2 enhancement is on average of benefit in numerous ways to the plant community? We are not discussing other factors that may influence life on earth in a warming world. Only the simple question: Are there some benefits to CO2 enhance to many members of the plant community? A simple yes or no will suffice.

    Thanks, Don

  42. 142
    Arch Stanton says:

    (141) Don wrote: “…Only the simple question: Are there some benefits to CO2 enhance to many members of the plant community? A simple yes or no will suffice.”

    No one denied that there were some therefore this question is superfluous (smoke). A yes/no does not do the topic justice. The relevant question should be: “Will all the benefits outweigh all the detriments?”

    (recaptcha: “nowhere false)

  43. 143
    Nick Gotts says:

    What Don Healy reports Kimball as saying is consistent with what Bob Watson (chief scientist at DEFRA, and certainly no denialist) said at a talk I attended a couple of months ago. As a result, the point at which crop yields decline will indeed be somewhat further off than if the effect on efficiency of water use is not taken into account. I can’t now remember the details, which were different for tropical and temperate regions – I’ll consult my notes on the talk next week.

  44. 144

    #136 Michael Ashley

    Thank you for pointing that out Professor Ashley. I’ve also put together a collection of the Swindled videos from YouTube here:

    On this page, Dr. Carter is in Video IV

    He may have made the same mistake I have made so many times in his assessment. That is to think i know what I’m talking about based on the information I have, rather than the information that is available. It is a common mistake and an easy trap to fall into as I have demonstrated over and over in my life, getting better though ;)

    I ‘try’ to operate on the premise that I know the tiniest fraction of what is knowable. From that basis, I try to examine the views, knowledge, understanding and facts and attempt to get a reasonable picture in my head.

    The scientific method of understanding is a superior method of understanding, but unfortunately not well understood or assimilated by the general public.

    Dr. Carter might want to consider the following:

    It is well known scientifically that in the natural cycle Co2 lags behind and then adds to the climate forcing as the Milankovitch forcing increases the climate effect of TSI which alters the bio diversity in the ecosystem which alters the atmospheric Co2 which adds to the forcing etc. Then when we head back into ice age, the system reverts to it’s normal ice age state, ice grows Co2 levels drop etc.

    The fact that atmospheric Co2 is now largely above natural levels as measured and we know that Co2 and other GHG’s including high GWP’s have an effect on heat trapping capacity in the climate system.

  45. 145
    Hank Roberts says:

    A reply to Don Healy may be in the spam bucket; shorter:
    This is off topic here, it’s a good area worth discussion and very important. Don quotes from a 2003 paper; I quoted from the current latest paper:
    Next generation of elevated [CO2] experiments with crops: A critical investment for feeding the future world – (Peer Reviewed Journal) – (27-May-08)

    That points out the need for the work to be done for the few varieties of species we use for food, to find variations that can handle increased heat and CO2 and incorporate them. This is “mass selection” and has been done since long before agriculture became a science. It’s very important; it’s very routine; and it’s always a challenge.

    Like all the other behaviors we’ve selected for — time of maturation, emphasis on food value at the expense of other strengths — adding selection pressure for higher temperatures and CO2 will no doubt find varieties that do better. Other factors will be tradeoffs. Getting the valued traits into widespread production is a race against time.

    Remember, we _need_ variety. Anyone else here old enough to remember the corn blight, when the USA’s seed companies sent the same strain to all the farmers? It set up a _very_ attractive field for the blight to spread.

    Same for varieties adapted to higher CO2 and higher temperatures (and more drought, and more extreme but short-term precipitation, and so forth). When those are found — and it hasn’t happened yet — they can’t simply be turned into huge volumes of seed. That sets up a monoculture and will lead to more blight years.

    Don, it’s not simple. It’s nowhere as simple as ‘yes or no’ and it’s well worth reading deeply on the subject.

    Pointer welcome to anywhere this is being discussed in a science forum — clearly it’s going off topic here in this thread.

    ReCaptcha: Gases clerks

  46. 146

    Dr. Bob Carter

    In addendum to my previous post. I think this wonderful article from Rasmus is very clear on the subject of modern Co2 concentrations added to the atmosphere vs. natural Co2:

    There is no doubt that the CO2 is from fossil sources, as isotope ratios show that the carbon has been less exposed to galactic cosmic rays (GCRs).

    When protons from GCRs collide with the nitrogen-14 (seven protons plus seven neutrons in the nucleus) in the air, carbon-14 is created (in addition to other isotopes such as beryllium-10) through a nuclear reaction:

    14N + p → 14C + n

    This means that carbon with a low isotope carbon-14 ratio must come from deep in the ground, out of reach of cosmic rays.

    Furthermore, the ratio of O2 to N2 has diminished. This is expected from the increased combustion of fossil fuels, in which O2 combines with C to form CO2. The oceans have also become more acidic, leading to an increase in CO2 levels in both the atmosphere and the oceans.

  47. 147
    Patrick 027 says:

    Re 144,146 – just a few technicalities here:

    TSI isn’t much changed by Milankovitch cycles, if I understood what is meant by TSI correctly: the solar power per unit area facing the sun, in space, at the distance of Earth. The big effect of Milankovitch cycles is to redistribute the incident solar energy seasonally and latitudinally (bigger tilt (obliquity) effect => more solar power incident at high latitudes, less at low latitudes, more extreme seasonal variation, same effect in both hemispheres). Precession effect=> seasonal variations more or less extreme, opposite effect in each hemisphere. Eccentricity effect -> modulates effect of precession).

    The mechanism causing the CO2 feedback that amplifies glacial-interglacial variations must have something to do with the way the ocean holds and distributes CO2, which is actually rather complicated. (The increased solubility of CO2 (as with gases in general) in water at lower temperatures can’t explain it by itself – but there are other possible factors.)

    The n and p are reversed in the nuclear reaction – it should be

    N-14 + n -> C-14 + p
    for the nuclei – for the whole atom, an electron is also lost.

    Re 141:
    “The comment “it appears that elevated comparisons between the FACE-based data and those from reviews of prior chamber-based data were consistent, which gives confidence that conclusions drawn from both types of data are accurate.” is particularily telling ”

    From only what you provided, I’m not clear whether that refers to the whole of the studies or just the organic carbon content of the soil.

  48. 148

    #147 Patrick

    My mistake, I worded that without decent context. My apologies for the oversimplification as well.

    As I understand it now, TSI does not change, at least the amount coming at us doesn’t change much beyond the natural Schwabe cycle variance and the very slow illuminance increase. I’m more curious about how much reaches us at any particular time in the cycles.

    I like the way you described it as redistribution, in how the Milankovitch cycles alter or affect the amount of forcing energy W/m2 that is absorbed or retained within the climate system. I was alluding more to how much of the TSI would be measured on the earth surface due to geometric effects.

    I am also assuming that the eccentricity cycle does actually alter the TSI to some degree outside our atmosphere as well, but that is only an assumption and it may be insignificant. I’d like to know if anyone knows if we lose a little TSI, or how much, when the eccentricity is elongated when averaged over a year.

    I also believe you are correct on the tilt, and not sure how significant the wobble variance is in total affect pertaining to forcings large enough to get us in and out of ice ages but I’m sure it plays it’s part at various times in the cycles.

    I’m not qualified to comment on the formula. has anyone graphed the Milankovitch cycles with forcing amounts imposed/indicated?

    Found some more links for FACE I saw some video footage somewhere, but don’t remember if it was online or a documentary?

  49. 149
    Ray Ladbury says:

    Don Healy, I am sure that the experimenters looking at the effect of CO2, being good experimenters, did not vary things like the amount of water available. Thus, their conclusions need to be understood with the caveat–ceteris paribus–all things being equal. Of course, Nature is under no such constraints, and we know for a fact that ceteris sure ain’t gonna be paribus. BTW, one plant that does extremely well in a high-CO2 environment is poison ivy. Don’t confuse fetid with fertile.

  50. 150
    Bob Raynolds says:


    I do not think geologists are “different” in the sense you propose. Some cling to outdated academic training, and indeed many are preoccupied in their endeavors and do not keep up with the literature.

    Geologists hold the rear view mirror. We see and understand the past in detail, often with surprising resolution in distant eras. The layered deep sea core data sets tie elegantly to the layered ice core data sets, that in turn merge neatly into the instrumental data sets; thus our discipline of stratigraphy amalgamates with modern measurements. Many of my colleagues see climate change as the Issue of our time, and the paradigm shift associated with the recognition of rapid climate change to be on a par with the recognition of plate tectonics or the appreciation of the great age of the Earth.

    Our realization that the tempo of the Pleistocene (seen so clearly in deep sea cores and ice cores) harmonizes with orbital variabilities has given us causal mechanisms for the ice ages. The growing realization that the pattern of the Pleistocene has been broken and that we are blithely conducting global experiments on the only planet we will ever inhabit has led to the concept that we live in the new geologic time termed Anthropocene.

    Our discipline harbors a wonderful spectrum of practitioners, some of whom assist the cottage industry of denialists, but I venture that most, like you, are watching with apprehension as each cubic kilometer of ice melts, as each fossil emerges from beneath the ice, and wonder what manner of Earth our children will inherit.

Switch to our mobile site