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Comments 122351 to 122400:

  1. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    Following up on Philippe's comment about the consensus being based on evidence rather than simple voting, here is a link to Naomi Oreskes's new talk, which addresses that topic right from the start. She even responds to skeptics who bring up Galileo as a counterpoint. Other commenters have pointed to this talk repeatedly, but some other commenters seem to not have bothered to watch it. It would be more productive if some of the commenters who deny the role of consensus in science, were to react specifically to Oreskes's points.
  2. Peter Hogarth at 04:20 AM on 14 March 2010
    CO2 levels during the late Ordovician
    One of the main points of this post is that our understanding of temperature and CO2 levels over the past few million years has evolved and become much more detailed over the past few years. As we look more closely at new higher resolution data we find that the linkage between temperature and CO2 is very tight, and it seems previous ideas about high temperatures concurrent with low CO2 levels were based on incorrect interpolations over huge geological time periods. We also find that some other higher estimates of ancient CO2 levels need to be revised. For example the 2010 paper by Breecker reports “Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100”. It appears that for paleosols, (fossil soils, one of the main proxy sources for estimating ancient CO2 levels) previously assumed soil CO2 concentrations during carbonate formation were far too high (by factors of around 2 or more). If this is taken into account it follows that ancient climates did not involve variations of 1,000s of ppmV of CO2, and past greenhouse climates were accompanied by concentrations similar to those currently projected for A.D. 2100. In addition the corrected paleosol record agrees more closely with other independent proxy paleo-evidence (such as that from fossil plant stomata) which adds confidence in both results. Obviously this gives some perspective on current rising levels of CO2 and temperature. Breeckers work has been commented on by Dana Royer in 2010, Fossil soils constrain ancient climate sensitivity . Here she follows up on estimates of CO2 sensitivity up on her earlier work summarized graphically (2009) in Climate Sensitivity during the Phanerozoic: Lessons for the Future . This shows that recent revisions of climate sensitivity (change of temperature due to doubling of CO2) derived from paleo records have been converging on values around 3 degrees C. Some have asked about CO2 rise preceding temperature rises in the past, and to add to what Ned at 02:18 AM on 13 March, 2010 has listed: “The Paleocene-Eocene Thermal Maximum (PETM) occurred approximately 55 million years ago, and is one of the most dramatic abrupt global warming events in the geological record. This warming was triggered by the sudden release of thousands of gigatons of carbon into the atmosphere and is widely perceived to be the best analogue for current anthropogenic climate change” This is quoted from Productivity feedback did not terminate the PETM Torfstein 2009. It has also been argued in Carbon dioxide forcing alone insufficient to explain PETM warming. (Zeebe 2009) that either current estimates of climate sensitivity are underestimates (as Breeckers work suggests), or that other positive feedbacks or causes are operating. In Ocean chemistry and atmospheric CO2 sensitivity to carbon perturbations throughout the Cenozoic (2010) Stuecker and Zeebe add that recent work indicates an increased sensitivity to carbon cycle perturbations and state “we expect much more severe effects in the near future than during the PETM because of the likely higher anthropogenic release rate (even at the same total carbon input)”. There is also earlier evidence (120 million years ago) of dramatic negative consequences of rapid increases in CO2 from Méhay 2009, “A volcanic CO2 pulse triggered the Cretaceous Oceanic Anoxic Event 1a and a biocalcification crisis”. We must also appreciate (as John pointed out) that the gradual increase in solar output over the past 4 billion years (which we can estimate from looking at similar stars at various stages in their evolution) is likely to lower the threshold of CO2 levels at which the transition between glacial (we still have ice caps on Greenland and Antarctica, as well as the Himalayas) and essentially ice free conditions will occur, as well as other temperature sensitive thresholds or tipping points. The link between glaciation (obviously related to temperature) and CO2 levels, and the effects of positive feedback, lags, etc are covered comprehensively in the scientific literature, but I list some recent work Flower 2009 , Langebroek 2009, (for middle Miocene, 13.9 million years ago) Tripati 2009 (covering the past 20 million years), Westerhold 2009 “the crossing of a critical pCO2 threshold may have led to the formation of the first ephemeral ice sheet on Antarctica as early as_50 Ma ago” None of this work precludes other drivers (lesser or greater) for global temperature and climate, and in geological history as well as now, other factors must be taken into account (such as insolation, plate tectonics, etc) but the weight of evidence for rising/falling CO2 levels being a significant cause as well as an effect of temperature rising/falling is overwhelming and increasing, and explanations for climate change which do not include CO2 have so far either been falsified or have been diminished in significance due to conflicting, ambivalent or updated evidence.
  3. Philippe Chantreau at 04:18 AM on 14 March 2010
    Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    There seems to be some misunderstanding as to what scientific consensus means. Nobody has polled the members of scientific associations and ranked their opinions to come up with a consensus. The consensus model of Earth climate slowly emerged from all the research being done. Study after study being reviewed and published. It is not a consensus of opinion but of research results. When considering these results as a big picture, a certain model can be defined, which is supported by an overwhelming preponderance of evidence, very much like in Ned's plate tectonics comparison. Within that model, some stuff will be settled, some will have a certain level of uncertainy or unresolved inconsistencies, some will be the subject of much debate and some will even be unknown. This applies to Quantum Theory as well as Evolution or Climatology. None of it is "proven true." Science does not provide truth. Truth is vocabulary appropriate in the law, theology, politics and so forth. In science, the word truth should be limited to the qualification of mathematical facts, really. Science attempts to understand reality. It does that by approximating with models, mind constructs. Since it is well known that these are approxiamtions, "truth" is out of the question. Scientific consensus is in fact a strong statement of validity. It means that a very large body of research points in a certain direction, not that a number of people in positions of influence agree to make a model the "chief" model. There is no choice as to what the model is: it is dictated by the evidence. There are numerous theories very much shakier than the consensus model of Earth climate. It would be very interesting to subject theories used in psychology, medicine, economics and many other fields to the same level of scrutiny applied to climate science and see how they hold up. I would also be interested to see how the experts in these fields would react when faced with media campaigns aimed at having their expertise challenged by amateurs, their work and reputation attacked, and throwing each and every word they write or say into endless spins of misquote and misinterpretation.
  4. CO2 levels during the late Ordovician
    Current deforestration is causing soils to wash away and exposing large areas of fresh rocks in the tropics to the atmosphere. This increaes the rate of rock weathering and therefore c02 is also being removed from the air at greater rates due to current deforestation. Never heard this mentioned from pro AGW advocates.
  5. Philippe Chantreau at 03:44 AM on 14 March 2010
    CO2 levels during the late Ordovician
    We should probably keep in mind that there is only so far that climates can be compared between vastly different geological eras. Our current glaciation/deglaciation cycles apply to continents and, more importantly, oceans as they are configured today. http://www.whoi.edu/oceanus/viewArticle.do?id=2508 Under different conditions, especially different oceanic circulations, tresholds for climatic regime changes would likely be different. So, really, what should preoccupy us is how different our current CO2 levels are from anything seen during the whole glaciation/deglaciation record of the past few hundred thousand years.
  6. CO2 levels during the late Ordovician
    Thanks for pointing out the reference to the lower Ordovician insolation. I chased up the reference to the Royer 2006 paper - sorry but I haven't yet mastered the hyperlinks. However, it says: ‘Global climate models calibrated to mid-Cenozoic conditions suggest a threshold of 560–1120 ppm (DeConto and Pollard, 2003; Pollard and DeConto, 2005), however during the Late Ordovician surface conditions were different, most notably in having an ~4% lower solar constant. A consequence of this decreased luminosity is that if all other thermal forcings were held constant, the CO2 threshold for initiating glaciations would be higher.’ I guess we are not that far away from 560 ppm, which could be a worry. However, how does this 4% lower insolation compare with insolation as per the Maunder Minimum? The thread ‘What would happen if the sun fell to Maunder Minimum levels?’ started on 19/02/10 argues inter alia for the very weak influence of solar forcing. The use of very different units - percentages as per Royer and Watts/M2 in the Maunder Minimum thread - makes it difficult to know how much weight to give the 4% insolation figure.
    Response: This is very rough figures, eyeballing the numbers from a Maunder Minimum graph and yes, I'm aware the eyeballing does not constitute scientific proof. But the difference in solar output from the Maunder Minimum (around 1364.7 W/m2) to the solar maximum in the late 20th Century (around 1366 W/m2)  is roughly 0.1%.
  7. CO2 levels during the late Ordovician
    Should have added.... the pervasive leaching that led to the bleached wall-rocks clearly took a very long time indeed.... in post-glacial times the lead-bearing lodes have had ~12,000 years worth of weathering but with only modest results.
  8. CO2 levels during the late Ordovician
    As offered last night - here are some notes about Tertiary-Recent weathering of lead-bearing lodes in Central Wales - a little O/T but it's interesting to see what weathering can do: There is compelling evidence for two separate phases of supergene alteration of galena in the metalliferous veins (upper Palaeozoic Pb-Pb ages) of Central Wales. Firstly, deep sub-tropical leaching in Tertiary times resulted in the formation of large quantities of oxidation products occurring as coarsely-crystalline masses with consistent, highly evolved parageneses (cerussite - PbCO3 - overgrowing uncorroded pyromorphite - Pb(PO4)3Cl) and indicative of a system which is relatively evolved and where there has been time to reach a point very close to chemical equilibrium. Strong bleaching of the normally dark grey late Ordovician to early Silurian turbidite wallrocks to pinkish or buff-yellowish colours is a frequent observation in association with this assemblage. Glacial erosion, that in some cases has left fresh sulphides (including minerals, such as marcasite, that are particularly unstable) today exposed at the surface along the sides of U-shaped valleys, must have physically removed the evolved supergene assemblage from many lodes, exposing new horizons at which supergene chemical processes once again began to operate. This scenario produced microcrystalline secondary minerals (this time without obvious wallrock bleaching), again in a well-defined paragenesis, but in this case reversed i.e. pyromorphite overgrows corroded cerussite in a system that is clearly some way from approaching equilibrium. The source of the phosphate in the coarse-grained assemblage is likely explained by the consistent spatial link between such mineralisation and severely-leached turbidite wallrocks. In these strata, phosphatic concretions and phosphate-rich hemipelagites are common. Although carbonate, both from dissolved CO2 in meteoric water and leached from the wallrocks and hypogene vein carbonates, would also have been readily available, in the presence of the enhanced phosphate concentrations in the fluids low down in the supergene zone, pyromorphite would appear first in the final paragenesis. The overgrowth, in the coarsely crystalline supergene assemblage, of pyromorphite by cerussite, presents an interesting problem. The underlying pyromorphite shows no signs of corrosion during this process, so there is no question of destabilisation of pyromorphite. Most likely, following the thorough leaching of the wallrocks, the available phosphate supply literally dried up, so that the supergene system defaulted back to a meteoric carbonate-dominated process causing cerussite to precipitate. In the close-to-surface, post-Quaternary microcrystalline assemblage, the carbonate activity in meteoric water is clearly sufficient for the first stage of alteration of galena to be to cerussite. Regular flushing with rainwater, which would have little time to leach phosphate from the surrounding rocks, but already be in equilibrium with CO2 in the atmosphere would ensure that galena altered to cerussite. Over time, however, in the presence of even small amounts of phosphate in solution pyromorphite would eventually replace cerussite simply due to the relative solubilities of the two minerals. In other words, if phosphate is available, the more stable pyromorphite will invariably form. Mason, J.S. 2004. The development and preservation of supergene lead mineralisation in Central Wales. UK Journal of Mines and Minerals, 24, 35-46.
  9. CO2 levels during the late Ordovician
    thingadonta writes: "Current deforestration is causing soils to wash away and exposing large areas of fresh rocks in the tropics to the atmosphere. This increaes the rate of rock weathering and therefore c02 is also being removed from the air at greater rates due to current deforestation. Never heard this mentioned from pro AGW advocates." That's because (a) the timescales are too short so far, and (b) it's counteracted by much faster releases of stored carbon into the atmosphere from fossil fuels and land use change. If you kept up our increased rate of weathering for the very long-term future, and eliminated our fossil-fuel and land use CO2 fluxes, then yes, the CO2 concentration in the atmosphere would begin to decline.
  10. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    gallopingcamel writes: Real science cannot be settled. Anyone who makes statements such as "the science is settled" or "unequivocal" betrays his lack of understanding of what science is about. Such people are anti-science. This is a problem of language (what does it mean to be "settled"?) The theory of AGW is very, very analogous to the theory of plate tectonics. Both of them are "settled" in the sense that they appear necessary to explain all the evidence of the world around us. Both of them are complex theories that can't be reduced to a couple of equations or simple statements, so they differ from (say) Maxwell's work on electromagnetism or Newton's laws. The details of our understanding of AGW and plate tectonics will continue to evolve over time (and yes, evolution itself is another example of a theory analogous to AGW). But neither AGW nor plate tectonics is likely to be overturned by new discoveries. That's what Trenberth means when he says "It is absolutely certain that carbon dioxide is a greenhouse gas and produces warming". I dislike the term "settled" because it suggests that there's nothing left to learn. (And has any scientist actually used the expression "the science is settled"? Pretty much every reference to it is from "skeptics"....)
  11. CO2 levels during the late Ordovician
    "Strontium is produced by rock weathering, the process that removes CO2 from the air. " Current deforestration is causing soils to wash away and exposing large areas of fresh rocks in the tropics to the atmosphere. This increaes the rate of rock weathering and therefore c02 is also being removed from the air at greater rates due to current deforestation. Never heard this mentioned from pro AGW advocates. "Consequently, the ratio of strontium isotopes can be used to determine how quickly rock weathering removed CO2 from the atmosphere in the past. " Unfortunately, Sr isotope ratios are also affected by amount/type of volcanism, so the correlation is not perfect. "Using strontium levels, Young determined that during the late Ordovician, rock weathering was at high levels while volcanic activity, which adds CO2 to the atmosphere, dropped." It is well known that a vast belt of subduction -related increase in volcanism occurred fromn the middle to late ordovician from the stratigraphic record, so the inference of reduced volcanism based on Sr ratios above is wrong. "This led to CO2 levels falling below 3000 parts per million which was low enough to initiate glaciation - the growing of ice sheets". This is an inferance based on chicken and egg arguments, c02 could have dropped because ocean temperatures dropped first, causing increased solubility of c02, not the other way around. This is why c02 rises and drops throughout geological hitory,it follows ocean temperatures (eg recent glacial/interglacials) rarely the other way around. "Young 2009 - CO2 levels dropped at the same time that sea surface temperatures dropped". As expected from the above, and consistent throughout the geological record and from simple chemistry. The resolution from Young 2009 is not sufficient to determine cause and effect, however the resolution from recent ice ages is, and they show c02 closely follows ocean temperatures. Your conclusion that c02 within the ordovocian is consisent with c02 as a strong dirver of climate is academic gymnastics. No such conclusion can be made from the data.
  12. CO2 levels during the late Ordovician
    I see Chris Canaris and others up-thread alluding to the average levels of CO2 in the Ordovician, which were much higher than today's. Even the new estimates (~3000 ppm) for the late Ordovician are, as Chris points out, about 8 times the current concentration. What's up? As John Cook mentions in the very first paragraph of this post, the sun has been getting brighter over time. While the largest variations in total solar irradiance in recent decades have been around 0.1%, over the lifetime of the Earth the Sun's brightness has increased something like 25-30%. So, with a Sun that was much, much dimmer than today, life (and liquid water) could only exist on Earth in the Paleozoic with much higher levels of CO2. Likewise, a drop in CO2 to levels that seem high today was enough to produce glaciation. See the "faint early Sun" paradox.
  13. CO2 levels during the late Ordovician
    gallopingcamel writes: Ned (#20), are you saying that CO2 in the atmosphere does not matter unless it is caused by humans? Sorry, if there is any illogical argument going on here it is not from Arkadiusz Semczysza. That's not even remotely what I said in that comment. How on earth did you take that message? Please go back and re-read my comment, more closely. Do you see the four papers I link to? Every one of them is about a time (or times) in the Earth's history when CO2 levels increased and the planet then warmed in response. It's mind-boggling that you could be so confused about what was written in fairly clear words. (If English isn't your first language, I apologize.)
  14. Every skeptic argument ever used
    I've just noticed that "We're coming out of the Little Ice Age" has now disappeared from the taxonomy list (but I can get to it from the numbered list). Where's it gone?
    Response: It disappeared into the ether of incorrectly categorised arguments - I've reached in and extracted the argument, putting it back where it belongs. Thanks for pointing out it's disappearance. :-)
  15. It's not happening
    A valuable resource! Thanks!
  16. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    Galileo is particularly famous in the skeptics quarters. I find it a bit superficial. The first thing that people usually overlook is that Galileo was not the first to think of an eliocentric solar system. What i mean is that new ideas do not come from nowhere, it's more like an ongoing cultural process which end up in a clear statement (theory) or new strong evidence. What Galileo did is a measurement with a new and powerful instrument he developed. The second is that Galileo is so beloved for having been harassed not by other scientist but by the Catholic Church, he confronted a religious belief. Although he put is life at risk, from a modern scientific point of view it was a relatively easy game. The third is that Arrhenius had a similar fate. After Angstrom criticism, a scientific one this time, his idea was dismissed for decades. In the long run, the scientific self-correcting method prevailed. This is indeed the very same fate any new idea "deserves" in the highly sceptical scientific community. Galileo Galilei is indeed one of the best minds in the whole history of humans. He deserves much more than the trivial and scientifically irrelevant fame for the dispute with the Church. He is often called "the Father of Modern Science" and Stephen Hawking once said that Galileo "perhaps more than any other single person, was responsible for the birth of modern science". He studied the great ellenistic scientists and revived and applied their scientific method. He was a giant and it's really depressing seeing his name so badly invoked. I need to apologize for this offtopic disgression but i hope that sooner or later we will see his name linked to his more important findings and contribution to science.
  17. CO2 levels during the late Ordovician
    Since 3000 parts per million CO2 (as compared to 389 parts per million today) apparently sufficed to initiate glaciation, what are projected CO2 levels over what time scale using a 'business as usual' scenario? In short, do we envisage an anthropogenic CO2 and other greenhouse gas 'hockey stick' as opposed to 'just' a temperature hockey stick? And what would be the time scale for such projections? I note the comment from John as quoted by Leo G @ 36 - do we know of any other negative feedback loops apart from acceleration of rock weathering? Incidentally, I recall reading about proposals for geosequestration of CO2. As matters stand, Ordovician CO2 levels were more than eight times higher than today's. I ask because people tend to resist making changes when not faced with immediate profits, costs, or like consequences. Moreover, we find it very difficult to consider consequences extending beyond our lifetimes (and perhaps our immediate offspring's'). Even so, I'm not totally pessimistic about our species' prospects for survival - our capacity for foresight (ie, respond to future consequences) is part of our remarkable adaptability. The problem lies in our inability to agree on future consequences.
  18. gallopingcamel at 17:56 PM on 13 March 2010
    CO2 levels during the late Ordovician
    Did John Cook omit some relevant papers from C.R Scotese, R.A. Berner, R. Lindzen and others? It appears that CO2 concentrations were very high in the Ordovician with comparatively little variation and yet the temperature swung from hot (no ice at either pole) to cold (extensive glaciation) and then back to hot again. Hardly a ringing endorsement for the canard that CO2 drives global temperatures. My understanding is that CO2 concentrations were in the range 4,000 to 6,000 ppm for the entire Ordovician period. Given that the radiation forcing due to CO2 follows a logarithmic relationship one would not expect variations in this range to have a significant effect on radiation capture. Once you have captured 95% of the outgoing energy in the 15-16 micron bands the remaining 5% won't make any noticeable difference. To claim that CO2 caused the wild temperature swings in the Ordovician fails the sanity test. Ned (#20), are you saying that CO2 in the atmosphere does not matter unless it is caused by humans? Sorry, if there is any illogical argument going on here it is not from Arkadiusz Semczysza.
  19. gallopingcamel at 16:56 PM on 13 March 2010
    Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    Ned (#69), it seems that I am not making myself clear. Let me try again. Counting the number of scientists (or even the number of published papers) is meaningless. In science, quality is more important than quantity. One Gallileo prevails over a multitude of Urban VIIIs. Real science cannot be settled. Anyone who makes statements such as "the science is settled" or "unequivocal" betrays his lack of understanding of what science is about. Such people are anti-science. When I hear such statements coming from Al Gore I don't get upset because Al does not pretend to be a scientist. Prominent "scientists" such as Watson and Trenberth should avoid publishing such exaggerated claims if they want to retain the respect of their peers or the general public. doug_bostrom (#65), I could have gone on at length about Trenberth's paper but it would not have been relevant to my point. The quote I chose demonstrates that Dr. Trenberth lacks objectivity in relation to "global warming" which he should realise is not scientific truth. It is a theory and a shaky one at that.
  20. CO2 levels during the late Ordovician
    HumanityRules - what is the source of your graphic? Hopefully you realize that the thrust of the two new papers is that earlier reconstructions don't have sufficient resolution to determine what happened during the timescales of actual glaciation. Showing a graph of low-resolutions won't rebut the newer papers. So, really, the provenance of the graph is crucial. Thus far, you've posted a random graph hosted by arstechnica (good enough at what they do, which is not science) without provenance, and saying "nya nya proves published papers wrong!" I could draw and post any graph I choose here and say the same. You don't refute published work by showing a cute graph with no provenance provided, sorry. Just doesn't work that way. Oh, and your green line is labeled "biodiversity", what does that have to do with geological weathering causing sequestration of CO2???????????????????????????????????????????????????????
  21. CO2 levels during the late Ordovician
    Mikemcc and Tenney Naumer Thank you both for responding. Mikemcc first, you said.... Ok Miekol, I'm assuming that your tongue is firmly in your cheek, but I'll bite anyway. What cost would you put on this mammoth re-building task? Is it likely to go ahead for the inhabitants of the Maldives, Seychelles, Bangladesh, Micronesia? What highlands do those people have. Each time Bangladesh floods 100s die, thousands suffer from epidemics from contaminated water and millions are made homeless. What happens when rainfall patterns are disrupted causing problems for food growers, or when plants are ready for pollination too early for the insects that traditionally pollinate them? ******************************************************** Yes Mikemcc you did read me correctly, i did have my tongue in cheek but only lightly not firmly :-) Firstly get use to idea that no matter what we do the climate is going to change. Its alway has and always will. Better we persue increasing the worlds wealth and more evenly share it, not condemn the 3rd world to permanent poverty and cause much of the 1st world to join them. Yes it can go ahead for the Maldives and others. All it needs is the will. The will to create greater wealth and to plan the necessary construction required. Google .... Globalism World of Plenty miekol@bigpond.com Cheers Michael Smith ******************************************************* Tenney Naumer , you said... Miekol conveniently forgets the increasing acidification of the ocean's and its consequent destruction of aquatic life. We can't survive with dead oceans. ******************************************************* Tenney, please supply me a link regarding the increasing acidification of the ocean's and its consequent destruction of aquatic life. I recall reading an article that the atmosphere has contained 10 times the current level of CO2 in the past, and aquatic life must have survived, its still with us. Google ... Globalism World of Plenty miekol@bigpond.com Cheers Michael Smith *******************************************************
  22. CO2 levels during the late Ordovician
    J.C. - {But unfortunately this process occurs over geological periods - over periods of thousands of years or greater. The process is way too small to offset our CO2 emissions (some hard numbers would be nice - can anyone help here?) So rock weathering is not a magic bullet that will save us from ourselves. However, there is research into accelerating rock weathering process as a way of sequestering CO2.} I like Prof. Dyson's idea about genetically engineering carbon eating trees!
  23. HumanityRules at 14:58 PM on 13 March 2010
    CO2 levels during the late Ordovician
    19.dhogaza at 02:16 AM on 13 March, 2010 Your wrong Young is far from clear when the whole of the ordovian period is analysed. Here is a graph showing SST My reading of Young is he is completely unable to explain the temp drop from 490-460 mya when CO2 levels remained high (above 5000ppm). To paraphrase you. This picture clearly can't explain the first half of the Ordovian?
  24. HumanityRules at 14:14 PM on 13 March 2010
    CO2 levels during the late Ordovician
    John you don't mention in the first paragraph what method (or a reference) for the 5600ppm CO2 in the Ordovician era. Could you give us a heads up on that? If you are to accept the new estimates it shouldn't just make us re-appraise the conditions in the Ordovician it should also make us re-appraise the methodology used to derive the 5600ppm estimate. What implication does this have for other theories based on this method? As Young says in his 2010 paper while his observations and theory may possibly explain the glaciation period they can't explain the initiation of cooling through the preceeding era's. Based on Young's theory CO2 levels are still too high to explain the initial phase of cooling. This means there are still major holes in this theory. Finally I'm not sure that your final statement is totally accurate. Even if Youngs research were correct what we now have are competing theories in what happened during the Ordovian era. As Young aknowledges in the intro to his papers there are even competing theories to explain how the process occured. The science of this period seems to still be under debate, the work of this group may add to our knowledge but doesn't seem to totally re-orientate the field. This leads me to my major worry with John's article. While being selective in his choice of time periods, Late Ordovian, ignoring the early and mid periods he is able to make such a strident statement in his last two lines. Finally the original estimate of 5600ppm is still out there in the literarture it will take time for the geology profession through further publications, conferences and debate to decide which becomes the accepted best estimates. I don't see this has happened. Simple publication of this paper does not overturn the science.
    Response: The 5600 ppm value comes from Royer 2006. In this paper, Royer discusses how the data for CO2 levels over this period is very coarse with poor time resolution. Therefore, there is no contradiction or competition between Young 2010 and Royer 2006 - Young 2010 is filling in the gaps.
  25. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    1077 writes: Ned (#69) gives an admirable defence of his teacher and probably mentor. No, I've never met Trenberth face to face as far as I know. We used his textbook in one or another of the climate modeling courses I took in graduate school. Prof. Trenberth seems to be sincere too. But what he says is that we just do not know enough. How does he jump from there to an affirmative belief if any kind is intellectually suspect. Anyone here who knows enough about Christopher Landsea who appears to have a scientific disagreement with Prof. Trenberth. Is Mr. Landsea dishonest by any chance? I'm sorry if I wasn't clear, though I tried hard to be clear in my comment. There's nothing wrong with disagreeing about the science; the problem is with claiming that someone secretly believes the opposite of what he clearly and adamantly says he believes.
  26. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    People who have taken a political stance on what is really a matter of scientific fact have often been wrong footed. How many ended up on the wrong side of reality after backing Lysenko or Sir Cyril Burt? Let honest science investigate the nature of the physical world and let politics address the allocation of resources.
  27. Does record snowfall disprove global warming?
    I want to thank Riccardo and doug_bostrom for their helpful comments. I think the temperature records are an excellent proof that the climate is warming. I didn’t really want to imply that the climate is not warming because there is much evidence that it is. If you look at the NCDC data set (ftp://ftp.ncdc.noaa.gov/pub/data/anomalies/annual.land_ocean.90S.90N.df_1901-2000mean.dat) it shows a 30 year period of stationary temperatures, then a 30 year period of a rapidly rising temperatures followed by a repeat of that cycle. While temperature highs and lows are good proof that the temperature is increasing since it includes the last peek of that cycle, the better evidence is the NCDC data set. Yes I know that there are some questions about that dataset that has come up lately, however I have read the skeptics arguments and don’t believe there will be any major change. Also I might note that the location where the warming is occurring could just be part of the NAO and PDO cycle we are in. You may have to go back 60 years to make that comparison. My big concern is this: We may be in one of those 30 year periods where the temperature will change little, however sometime in the late 2020’s the temperature will start to climb again and climb fast. The issue of what is caused by “Global Warming” and what isn’t is a side issue. What’s important is the issue of what percentage is natural verses man-made. Climategate seems to be drawing the debate into unhelpful areas and people seem to be using it at proof that all the Global Warming is natural. This is most certainly wrong. Anyhow that is what spurred me to make that reply.
  28. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    1077 said: “Thus the poll should yield an equal percentage of liberal and conservative sympathizers on both sides of the controversy.” Let’s suppose that such a poll would achieve these results. I am to infer that this would show that indeed it doesn’t matter which side of politics people sit, it would mean that belief climate change is apolitical? In principle it sounds great...but when you have results such as this: http://www.gallup.com/poll/126563/conservatives-doubts-global-warming-grow.aspx It highlights the danger of siding the science with political agenda, and destroys the neutrality that scientists generally are perceived as having in their work. Say political party X offers more funding for a particular science project (not even climate science related), or better, some more funding for hospitals, then I would expect a survey would show a spike in doctors that have a political preference that is higher for party X. The results would not be an inconvenience, but would be highly spurious. Maybe i’m lost with what you’re talking (perhaps you flatter my intelligence) but what exactly is a scientific poll, and what interesting answers are we to expect from it?
  29. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    Ned (#69) gives an admirable defence of his teacher and probably mentor. Prof. Trenberth seems to be sincere too. But what he says is that we just do not know enough. How does he jump from there to an affirmative belief if any kind is intellectually suspect. Anyone here who knows enough about Christopher Landsea who appears to have a scientific disagreement with Prof. Trenberth. Is Mr. Landsea dishonest by any chance? Just curious as a non-specialist beholding professional disagreement which, if it was only academic, it would be interesting and essentially none of my business. Given the stakes however, permit me to be very skeptical.
  30. CO2 levels during the late Ordovician
    While we are talking about the Snowball earth, I thought i'd post some paraphrased excerpts from the "Principles of Planetary Climate" the book John recommended to explain it a little better: The Snowball phenomenon is pregnant with Big Questions, the most obvious of which are: How do you get in? And how do you get out?... Most theories for the entry into a Snowball involve the drawdown of whatever greenhouse gas had previously been maintaining the planet’s warmth – usually CO2 and CH4 in some combination.... Assuming for the moment that the cooling process caused a Hard Snowball, the next question is how to deglaciate the planet...Based on rather simple reasoning of the sort that will be covered in the remainder of this book, Kirschvink proposed that once the Earth freezes over, the weathering of silicate to carbonate (which requires liquid water washing over weatherable rocks) ceases, so that CO2 outgassed from the Earth’s interior accumulates in the atmosphere until it reaches concentrations sufficient to cause a deglaciation. I highly recommend this book to fellow n00bs! RE#32 dghozza: yes please!
  31. Does record snowfall disprove global warming?
    I haven't put a lot of thought into this, but perhaps there should be some asymmetry in how we see record warm vs record cold days now. I don't take "record hot" days as proof of global warming (there's no need for that! the proof lies elsewhere). But I do take them as reminders or foretastes of what we're moving towards. In other words, the heat waves we experience this summer will be typical summer weather when my daughter is my age, or my parents' age. They're signs of what is to come. In contrast, I take cold weather as a reminder of what we're moving away from. Where I live there were fewer than normal cold days this winter. When I was a child, those days were more common. Half a century from now, what are now mild days will be considered cool, and the few "cold" days we still have will be even rarer. Snow is more complicated, as has been discussed repeatedly in this thread it's not linearly related to temperature.
  32. Rob Honeycutt at 08:50 AM on 13 March 2010
    Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    doug_bostrom... Good call. I think you're right. It's not just a matter of tabloid media ruling the day. It's also a function of basic human nature. Dan Miller does an interesting talk where he discusses natural human responses to danger. The instinctual responses that move people to action. It's purely an intellectualized fear that most people can't grasp. http://fora.tv/2009/08/18/A_REALLY_Inconvenient_Truth_Dan_Miller#fullprogram (click section 9)
  33. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    dhogaza 48. You gave another - very strong - anecdotal response! Thank you.
  34. Does record snowfall disprove global warming?
    Don at 07:57 AM on 13 March, 2010 Don, further to Riccardo's points, it helps to remember that the little of bit of warming we've seen is not equally distributed about the planet, tends to be greater in the "upper" part of the Northern Hemisphere. Blaming everything on global warming is a mistake as you say; there should be some line of evidence pointing that way as well as a clear understanding that each circumstance represents a statistical data point.
  35. Does record snowfall disprove global warming?
    Don, i'm sure that we all will not blame "everything we see on Global Warming". But record low temperature are becoming less frequent and record high more frequent. Record snow, instead, is a completely different process which does not match with record low temperatures. I also agree that it is hard to believe that "just" one degree or so may be responsibile of significant changes; but we all now that few degrees, maybe 5 °C, below current is called a glaciation. Really hard to believe, isn't it? Science way too often tells us stories hard to believe.
  36. Does record snowfall disprove global warming?
    Note: I’m not a scientist but I wanted to state my observations. It would be easier to accept that heavy snows doesn't disprove “Global Warming” if it weren't for the fact that I constantly hear that lack of snow is because of “Global Warming”. Certainly the heavy snow should disprove the idea that a lack of snow is the result of Global Warming. Over the last century the global temperature increased by .6 degree Celsius. I find it hard to believe that .6 degree increase can cause the large climate changes that it has been accused of. It seems clear to me that it takes a larger change in the climate than the .6 degree measured. This much larger change can only have come from natural cycles in the climate that results in hot spots and cold spots changing places (such as the PDO). Some such cycles last as long as 60 years and produce large climate changes between isolated areas. Perhaps if we quit blaming everything we see on “Global Warming” then it might be easier to get people to believe us and we wouldn’t have to explain that large snow storms won’t disprove “Global Warming”.
  37. It's not bad
    Vinny Burgoo at 07:35 AM on 13 March, 2010 "The whole field is less than scientifically kosher and large areas of it are politicised. " Mountains out of molehills, you illustrate my point nicely, thanks. What about dehydration is political, anyway? I don't understand that.
  38. It's not bad
    Robust counter-argument against what, doug_bostrom? It's certainly a good argument against political overreaction. Does it really not concern you that bogus claims are being made about the water supplies of one-sixth of the world's population? (Yes, I did read your lecture about seasonal flows etc. Meltwater from Kehrwald's 'TP' glaciers mostly coincides with the monsoon, when the glacial component is more like 2%, not 20%. So where is this one-sixth of the world's population? Not in the oases of Western China, which do rely to some extent in summer on glacial melt. That's most likely bad news for tens or scores of millions who live there but 100 million is not 1000 million. Exaggeration is neither scientific nor big nor clever. Also, your conflation of snow- and glacier-melt was... unhelpful.) Like many of your stripe, you are hung up on the denial of the theoretical basis for AGW. Things have moved on. Impacts are what matter and the science of predicting impacts is demonstrably weak and overstated. The whole field is less than scientifically kosher and large areas of it are politicised. It really shouldn't be up to ordinary 'hair-splitting' citizens to sort this out. It takes hours and days for a non-specialist to track back a single claim to its source and evaluate it. The IPCC is supposed to have done all that for us. It hasn't. I'm pissed off. Don't be surprised that a lot of other people are pissed off. And if you're not pissed off too, that isn't very flattering to you, especially when you're posting on a website called Skeptical Science. (Pre-emption: Yes, Kehrwald et al was published post-AR4. Will it be in AR5, though? Let's bloody hope not. Barnett too.)
  39. CO2 levels during the late Ordovician
    I can throw in a few ideas regarding deep weathering and the timescales involved - if people are interested
    Oh ... please! please! please! :)
  40. Climate's changed before
    If the forcing is transient then the temperature will return to its original equilibrium, yes. If the forcing persists for thousands of years (like CO2 in the atmosphere) then the planet's temperature will reach a new and higher equilibrium while that forcing persists.
  41. Climate's changed before
    The initial statement says Natural climate change in the past proves that climate is sensitive to an energy imbalance. If the planet accumulates heat, global temperatures will go up." This is false: If the planet accumulates heat then it will be hotter and hence will radiate more heat out until it returns to equilibrium per the gray body Stefan- Boltzmann Law. The planet goes from warming in the morning to cooling in the evening as the amount of absorbed energy increases and decreases. It passes through equilibrium temperature exactly twice every day. The concept that the planet could accumulate heat and be out of equilibrium for any extended length of time is just not possible. The computer model however assume this. They are wrong.
  42. CO2 levels during the late Ordovician
    paulgrace said: "@Arkadiusz Semczyszak,... if past warming events always preceeded CO2 increases, it wouldn't matter" The analogy I give skeptics is that just because a car accident usually precedes a broken car doesn't mean a broken car can't cause a car accident.
  43. Antarctica is gaining ice
    For a comprehensive analysis of Antarctica sea ice data, including the effect of the ozone hole see http://www.roperld.com/science/AntarcticSeaIce.htm . Dave Roper
  44. CO2 levels during the late Ordovician
    I've got another example of CO2 change fully preceding temperature change. The Azolla event. The relatively recent history of orbital cycles driving small warming/cooling trends that are amplified by CO2 (and thus giving the appearance of temperature leading CO2) might just be the exception, not the rule. It's all about what mechanisms are present.
  45. Watts Up With That's ignorance regarding Antarctic sea ice
    It should be pointed out that an increase in Antarctic sea ice was predicted in 1992 by climate modelers.
  46. CO2 levels during the late Ordovician
    I can throw in a few ideas regarding deep weathering and the timescales involved - if people are interested. I've researched & published on same over here in the UK. But right now, my tea's ready! It'll be UK-centric but I think I made some useful conclusions in my work. Be back later - likely in the morning UK time. Cheers - John
  47. CO2 levels during the late Ordovician
    "Is rock weathering factored in to CO2-rise predictions in the current models? " This happens on geological timescales, as I understand it. However, speeding the process artificially is one of the geoengineering ideas kicked around out there.
  48. CO2 levels during the late Ordovician
    "true enough. I only find the snowball earth case clearer because it has puzzled scientist for a long while. There's no other plausible way to come out from an almost fully glaciated state and there are no other concomitant effect to possibly invoke." Yes, the snowball earth case is great, I just found it ironic that Arkadiusz Semczyszak made his claim in response to a top post showing his claim to be false!
  49. CO2 levels during the late Ordovician
    @John Cook Is rock weathering factored in to CO2-rise predictions in the current models? As glacial retreat ends because the glaciers are gone, rock weathering will be at it's maximum. How similar in scale is this CO2 absorption compared to human output? (A century from now--[shudder])
    Response: That's a good question. Rock weathering is a negative feedback - as temperature gets hotter, rock weathering activity increases so more CO2 is removed from the atmosphere. In fact, this is one of nature's "control knobs" to ensure climate doesn't get too hot or cold - when it gets colder, there's less CO2 removal which leads to CO2 rising and warming the earth. When the Earth gets too hot, rock weathering removes more CO2 which has a cooling effect.

    But unfortunately this process occurs over geological periods - over periods of thousands of years or greater. The process is way too small to offset our CO2 emissions (some hard numbers would be nice - can anyone help here?) So rock weathering is not a magic bullet that will save us from ourselves. However, there is research into accelerating rock weathering process as a way of sequestering CO2.
  50. CO2 levels during the late Ordovician
    @Arkadiusz Semczyszak, Both are true: Temperature rise releases CO2 and CO2 increases temperature rise. This is known as a "positive feedback loop", and it's very unfortunate. But if past warming events always preceeded CO2 increases, it wouldn't matter (even though you are wrong, they don't). Today we are increasing CO2 levels, which will increase temperatures, which will further increase CO2 levels beyond which we are directly responsible for. Your argument is A) Wrong and B) Not relevant.

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