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Dikran Marsupial at 01:09 AM on 11 May 2010Estimating climate sensitivity from 3 million years ago
Tobyjoyce The thing that worried me about the article on Spencer's blog was the bit that said "I’ve been slicing and dicing the data different ways", which sounds to me a recipe for (unintentional) cherry picking. Also, the bit that said: "these feedbacks can not be estimated through simple linear regression on satellite data, which will almost always result in an underestimate of the net feedback, and thus an overestimate of climate sensitivity." isn't it the net feedback that the model is aiming to estimate, if so how can you know it is an underestimate? It will be interesting to read the full paper when it is available (and reading the discussion by those who understand the science rather better than I do! ;o) -
tobyjoyce at 00:34 AM on 11 May 2010Climate Change and the Integrity of Science: a letter to Science
@Arkadiusz Semczyszak #189 Jeez, seems to me you are arguing that climate scientists should throw up their hands in case the bean-counters get their sums wrong. Not for nothing is economics called the "dismal science". Paul Krugman (Economics Nobel Laureate 2008) wrote a lengthy article on a "Green Economy" in the NYT. Paul Krugman: Climate Change - Green Economy My rudimentary understanding is that all forms of pollution are a "negative externality" on a business, or on society as a whole. The classic study is by British economist Arthur Pigou in the 1920s. Pigou used an example of lettuce growers and rabbit breeders. The lettuce growers regard the rabbits as a negative externality because they have to incur extra costs in defending their crops. Clearly such a society of rabbit breeders and lettuce growers is not at its optimum economically because the growers cannot expand their business or employ more people. The answer is a "Pigovian tax" imposed on the breeders to induce them to pay their fair share in reducing the destruction caused by rabbits. Incidentally, many radicals opposed Pigovian taxes on polluters since they said taxing something made it morally acceptable. At least we have gone past that, and such taxes are accepted as the free market solution. Commentators who are against taxes have not come up with a viable solution to rival Pigou's. Now carbon is turning out to be a massive negative externality on the globe as a whole. The costs incurred in the massive dislocations that may take place must be balanced somewhere. This makes sense even if such dislocations are "only a risk". The energy sources which compete with carbon-based fuels are not at the level where they can compete with oil e.g. prices of electric cars. The solution is "Pigovian txes" on oil and coal to help countries wean off dirty energy and transfer that money into developing alternative energy sources. Hence cap-and-trade, regulation etc. Krugman's bottom line: "Its the nonnegligible probability of utter disaster that should dominate our policy analysis. And that argues for aggressive moves to curb emissions, soon". -
JMurphy at 00:02 AM on 11 May 2010Kung-fu Climate
One final thing about that list, which is rather telling and demonstrative of the D-K effect. Within the 'debunking 9/11 myths' section on his website, Poptech is very clear about dismissing opinions from those with no skill or real knowledge of things like architecture, structural design or engineering (in fact, he holds such types in contempt and highlights the troofers' lack of such qualifications), and refers to his own training in architecture to bolster his own opinions on the topic. And yet, with regard to his 'skeptical of some part of the global warming alarmism' papers, he includes non-experts and claims to know for himself that skepticism is involved in those papers, even if the authors themselves disagree. And he is not an expert on this subject himself ! Priceless. -
CBDunkerson at 22:09 PM on 10 May 2010Estimating climate sensitivity from 3 million years ago
I'm surprised at the concern some cite about these long term effects. Doesn't it seem very likely that, given "hundreds to thousands of years", humans will be able to adapt to or even prevent these effects? It has always seemed clear to me that there were further 'long term' warming impacts to be expected... for instance the expected decline of Greenland and Antarctic ice for centuries to come would perforce indicate changing albedo and more warming. This new Lunt paper seems the most robust quantification of those eventual impacts I've seen thus far... but is it really a concern? I mean, if we get through the ~2 C temperature rise expected just this century then why should a subsequent ~1.5 C rise over the course of 1000+ years be cause for concern? Whatever changes we make to avoid the looming crisis should also help to mitigate the long term impacts... and we've got centuries more to work on that. -
J Bowers at 21:37 PM on 10 May 2010Kung-fu Climate
An excellent article and I fully agree about how straightforward graphics can explain a lot to the layman. For my own sanity, a couple of months ago I decided to stack all of the graphs I could find above each other and align them over time, just to be able to eyeball different aspects of climate for an overall context. It's a simple montage taken from various sources, but the end plan is to take the source data and plot my own graphs at higher resolution, with an eye to also creating an animation. The conceptual montage is HERE if anyone is interested. Red dots are the volcanic eruptions I could find for now. If anyone can point me to reconstructions of insolation / sunspots, and a decent list of volcanic eruptions since 700 AD it would be greatly appreciated. The absence of red dots, so far, during the MWP was a bit of a bit of an "Oh, I really get it now" moment. Personally, I thnk the MWP should be renamed the MACP: Medieval Absence of Cooling Period. -
Spencer Weart at 21:28 PM on 10 May 2010Estimating climate sensitivity from 3 million years ago
John, instead of "This means climate is more sensitive to carbon dioxide than previously thought," you should say, "This means climate MAY BE more sensitive to carbon dioxide than previously thought." Let's not fall into the fallacy so common among deniers of leaping on a just-published paper that contradicts something and declaring that THIS is at last the truth! All papers should be taken with a spoonful of salt until a couple of years of checking have passed. Other paleo studies of other geological eras have tended to cluster (with large variations) around the 3-degree sensitivity mark, so let's wait and see. I must say this study looks really good, but we can hope it turns out to have some flaw. If Hansen et al. are right we are in very serious trouble indeed.Response: Fair call, thanks for the suggestion. -
Arkadiusz Semczyszak at 21:19 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
"Much more can be, and has been, said by the world's scientific societies, national academies, and individuals, but these conclusions should be enough to indicate why scientists are concerned about what future generations will face from BUSINESS-as-usual practices." "Integrity of Science" - of course, the economics ? I'm curious, how many economists are signed in this? UNEP: "Cost-benefit analyses (CBA) should be used as decision criterion only if there is nothing of moral importance at stake (Randall 2002). Therefore CBA should not be decisive in climate change issues. It should be used as a piece of information among many. The idea of calculating an economically optimal (‘efficient’) climate path is misleading. There is no single utility function for mankind over centuries. Moreover, many value-laden problems are implicitly entailed in economic modelling (value of a statistical life, damage function, rate of discount, distribution of benefits and disadvantages, etc.). These variables must rest on ethical judgments and cannot be derived from empirical facts alone. Cost-benefit analyses and other economic evaluations often rely upon discounting. Discounting implies the possibility of severe accounting errors in long-term environmental problems (see contributions in Hampicke & Ott 2003). For ethical reasons, it remains highly doubtful whether global climate change falls within the scope in which ‘normal’ discounting should be applied. The debate about the so-called Stern-Report has been a debate about the very low discount rate (0.1%) being used in the report. Such discount rates can only be defended on ETHICAL GROUNDS." Mine, and V. Klaus for example, quoted by him, Schmidt’s (unless a Nobel laureate?), in the above text, and: "Climate Change and the Integrity of Science"; raises concerns: perspective - range = up to 100 years - !!! - "Future generations "?!; and over of ideology - "ethical grounds" - used to identify the "business-as-usual practices. " -
BC at 21:19 PM on 10 May 2010University of Queensland talk wrap-up
Mike, Thanks for the two links. I see where they got the 1C rise since 1950 in the BOM site. The 'State of the Climate' read is a bit worrying for Australia. No different to most of the rest of the world though. -
CBDunkerson at 21:04 PM on 10 May 2010University of Queensland talk wrap-up
cdion #11, once the Sun goes down the Earth begins losing heat fast. The greenhouse effect slows down the rate of heat loss. Thus, a more pronounced greenhouse effect means that nights stay closer to daytime temperatures longer. This 'heat loss' anomaly is greater than the increased daytime temperature anomaly from the enhanced greenhouse effect and the source of the bit about nights warming faster than days. Basically, if GHGs make the average daytime temp 1 C hotter they might make the average night temp 2 C hotter... because the temperature doesn't drop as fast as it used to. barry #14, no the slide really is meant to be human (industrial) emissions. There is a separate slide right after that for atmospheric levels. The intent is to show that atmospheric levels have grown as our emissions have. The emissions charts I've seen are generally calculated estimates based on fuel sources used, population, and industry. Nichol #13, as you surmised the H20 impact is off the left side of that chart... as is most of the CO2 impact. My recollection is that the study didn't show that section because they were unable to differentiate between the two.Response: "My recollection is that the study didn't show that section because they were unable to differentiate between the two."
Actually, the chart doesn't go further into the CO2 band because the uncertainty of the data gets too large - they had to cut it off when the uncertainty range got large. That particular graph shows the change in outgoing energy with the humidity effects removed. The point of that graph is to isolate the effect of trace gases. -
Riccardo at 20:55 PM on 10 May 2010Estimating climate sensitivity from 3 million years ago
Arkadiusz Semczyszak, it would be nice and usefull to all of us if you could focus your expertise and knowledge of the litterature on the topic at hand. Your generic rants bring nothing to the discussion and they might dangerously be confused with propaganda. -
johnd at 20:52 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
tobyjoyce at 23:17 PM, perhaps reading this might offer some insight into the uncertainities that exist as mentioned in the first section. http://www.ipcc.ch/ipccreports/tar/wg1/022.htm -
Riccardo at 20:40 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
I'd like to add to tobyjoyce's comment that looking specifically at physics, often, though not always, a new theory "simply" highlights the limits of the current theory more than contradicting it. As for climate science, AGW has been the new rejected paradigm for decades untill relatively recently. It certainly has its limits, some of them we are already aware of. It should come as no surprise when someone will come out with a different theory on the behaviour of a part of the climate system. It might change the final outcome somewhat but a complete dismissal of the AGW theory is not at hand. This is how science normally works. Does it have anything to do with this post? Yes, I think. When you see hundreds of top scientists write a letter so strongly worded it must mean something. I believe that they feel that the standard scientific process is under attack, something from outside (politics? vested interests?) is trying to undermine the pillars that hold the whole building. This fear is shared by others, for example see the recent Position Statement of the University of Virginia Faculty Senate Executive Council on Cuccinelli's investigation of Michael Mann. The Statement ends with these words: "The Attorney General’s use of his power to issue a CID under the provisions of Virginia’s FATA is an inappropriate way to engage with the process of scientific inquiry. His action and the potential threat of legal prosecution of scientific endeavor that has satisfied peer-review standards send a chilling message to scientists engaged in basic research involving Earth’s climate and indeed to scholars in any discipline. Such actions directly threaten academic freedom and, thus, our ability to generate the knowledge upon which informed public policy relies." Others used even stronger words. Ken Caldeira (comment #12) says: "There is a historical example where politicians went after scientists because the politicians didn’t like scientific results. The example is Lysenkoism. The country was the Soviet Union. Are American politicians following in the footsteps of Stalin?" Hopefully this is just an isolated extremist political move, but still it's the air scientists breath every day. Should this fear turn out to be real, we're sailing really dangerous waters. There are several examples from the past, some even from a not that distant past. None of them I'd like to recall. -
Jacob Bock Axelsen at 20:37 PM on 10 May 2010Are we too stupid?
embb You honestly see no difference between banning a chemical and deliberately making the countrie's industry uncompetitive?? What gives you the idea that reducing CO2 emissions makes a country's industry uncompetitive? I have proof of the contrary: Spain, China, Denmark and Germany. How do you explain that most experts agree that a proposed reform to phase-out fossil fuels by 2050 in Denmark is not only necessary, but realistic, at a time when the economy is down and the danish oil production is in permanent decline? Samsø is completely self-sufficient in renewable energy, without any subsidies whatsoever. How do you explain all that? OPEC? Non-proliferation? OPEC is an excellent example of how powerful a coalition using reciprocity can be. Thank you. However, they were opposed by other coalitions so they did not eliminate 'defectors'- luckily. Non-proliferation more or less worked - otherwise you would have nuclear weapons all over in the Nash-equilibirum. In fact, it seems to be working even better these days. Nobody wants the tragedy-of-the-commons of a nuclear war, as I mentioned in the post above. you think that decreasing the amount of CO2 in a neighborhood increases the quality of life in that neighborhood? Neither I nor the EPA ever postulated that. Whatever gave you that idea? I think you mix up weather with climate. As we get to here at every cold spell the weather is NOT the climate. As I have recently studied the classic one-dimensional calculation of the Earth's boundary layer involving solving the Heat-diffusion equation for latitude bands using a Green's function, then surely such a mistake on my part can be ruled out. Did you ever read my post here on chaos? You just dismiss that "The Lancet and University College London's Institute for Global Health issued a major report concluding that climate change is the "biggest global health threat of the 21st century."? What is your source to the contrary? Jacob:Do you think voters favor cash in return for a destroyed planet? Yes. If they didn't you would not be thinking about game theory. The dilemma is that they want the planet to be safe and receive the temptation at the same time. You cannot see that? do you support geo-engineering? If no, why not? Do you think geo-engineering is more or less risky than switching to sustainable energy? If you argue for geo-engineering you will be contradicting your own concerns with the economic impact of reducing carbon. Why play around with huge risks when we are looking to reduce risks? If defection is so tempting there is one way of making this work, which is a global police force (...) it is a world police state. There is no police force in the case of the fig tree/fig wasp, is there? It is highly relevant because natural selection, which is mostly a Nash-equilibrium, can favor reciprocity and enhance symbiosis. We can undoubtedly learn from that. Interestingly, you put blind trust into economists' warning of trade wars in spite of the fact that the recent economic downturn was not correctly anticipated by economists and and no policies to properly mitigate the crises were proposed either. How come? The fact that Nobel prize winners themselves readily discard all current economic theory is not something you would take seriously? Look at CFCs. Here is what I said: A growing cluster of countries can eliminate defectors using science based coercive strategies and that is exactly what happened. Rather striking really. -
Arkadiusz Semczyszak at 19:39 PM on 10 May 2010Estimating climate sensitivity from 3 million years ago
"... radiative forcing and associated feedbacks—is estimated at 1.5–4.5 °C..." It is also worth a look to: Comment on "Aerosol radiative forcing and climate sensitivity deduced from the Last Glacial Maximum to Holocene transition", by P. Chylek and U. Lohmann, Geophys. Res. Res. Lett., 2008. Authors: Hargreaves JC and JD Annan; said: "The sensitivity of the climate system to external forcing has long been a subject of much research, the bulk of which has concluded that the climate sensitivity to a doubling of CO 2 is likely to lie in the range 2–4.5 deg. C (IPCC 2007: Summary C (IPCC 2007: for Policymakers, Solomon et al. 2007; Knutti and Hegerl 2008.). Chylek and Lohmann (2008) (hereafter CL08) claim to have found evidence that the true value is much lower, AROUND 1.8 deg. C ...[...] (commentary by the authors: is a mistake Chylek and Lohmann)"; ... and for discussion: http://www.clim-past.net/5/143/2009/cp-5-143-2009.html In addition, skeptics still notify the three basic concerns: 1. Signs of ancient CO2 concentrations may be subject to substantial error, excessive smoothing - low resolution, etc. 2. This temperature rise is always first, then the concentration of CO2. So once the CO2 could only possibly enhance the warming. There are, however, periods of significant decrease in temperature. Despite the lack of decrease in the concentration of CO2. Why? - Is a topic for another discussion. 3. "It turns out that UNCERTAINTIES IN THE ENERGETIC RESPONSES of Earth climate systems are more than 10 times LARGER than the entire energetic effect of increased CO2." - (The claim that anthropogenic CO2 is responsible for the current warming of Earth climate is scientifically insupportable because climate models are unreliable; Frank p., 2009 - using, among others: Prof. Carl Wunsch, Prof. Paul Switzer, Prof. Ross McKitrick, Prof. Christopher Essex, Prof. Sebastian Doniach ...). -
chris at 19:35 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
No problem John. If you want to remove this post and the one directly above [chris at 18:14 PM on 10 May, 2010], please do so. I think this site really benefits from the strict moderation you've used - it makes it so much better as a resource than other sites. It's tedious to have to moderate, but I wonder whether you might ease the situation by having an occasional "open thread", where lots of the stuff that isn't relevant to a particular thread can be discussed. You could even have "themed" open threads (e.g. "questions and answers" for those that want to ask specific questions about aspects of the science; "contentious publications" for those that want to talk about papers that support opposing viewpoints etc.....). -
sylas at 19:30 PM on 10 May 2010Where is global warming going?
The formal rebuttal to Gerlich and Tscheuschner has now been published, along with their reply. The two papers appear in IJMP(B), Vol 24, Iss 10, Apr 20, 2010. The references are: [1] Comment On "Falsification Of The Atmospheric Co2 Greenhouse Effects Within The Frame Of Physics", by Joshua B. Halpern, Christopher M. Colose, Chris Ho-Stuart, Joel D. Shore, Arthur P. Smith and Jörg Zimmermann, pp 1309-1332, doi:10.1142/S021797921005555X [2] Reply To "Comment On 'Falsification Of The Atmospheric Co2 Greenhouse Effects Within The Frame Of Physics' By Joshua B. Halpern, Christopher M. Colose, Chris Ho-Stuart, Joel D. Shore, Arthur P. Smith, Jörg Zimmermann", by Gerhard Gerlich and Ralf D. Tscheuschner, pp 1333-1359, doi:10.1142/S0217979210055573 I am collecting blog and journal links at Duae Quartunciae: Published rebuttal to Gerlich and Tscheuschner 2009 and will keep extending the list. I am also hosting discussion of the rebuttal and reply at a new bulletin board: Climate Physics Forums, which I have recently established to host substantive and courteous discussion of matters relating to the practice of climate science. I am a co-author of the rebuttal; my own name is Chris Ho-Stuart. In my opinion, an elementary familiarity with basic physics and thermodynamics is more than sufficient to see that Gerlich and Tscheuschner's paper and reply are without any scientific merit at all. However, it has an lot of technical material which can make it appear more credible than it really is, and daunting to many readers. Their hypothesis represents an extreme view which has no prospect whatsoever of having any genuine scientific impact. In fact, I believe our rebuttal paper will be their first proper citation for the original paper! I note that Steve McIntyre is mentioned here; Steve has more than sufficient basic understanding to appreciate why Gerlich and Tscheuschner's work is a dead end. The speculation that Steve feels out of his depth is quite implausible. Neither Gerlich nor Tscheuscher have any standing in this field either; they are writing well outside their normal areas of professional competence. The whole episode has been extremely silly. However, I am hopeful that discussion of the paper might help people who do feel out of depth, and I will be ensuring that any discussion at the new board is maintained at the highest levels of personal courtesy. Ideas are fair game, but I will strive to keep all members, of any persuasion background or level of ability, safe from personal ridicule or abuse. -
chris at 18:14 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
Tom Dayton at 06:40 AM on 10 May, 2010 Tom, you're probably right. However I was responding to a direct question by johnd about the new paper by Spencer. Since I am the slightly priviliged position of having seen both an earlier version and the in press version, I was able to answer the question directly, and illustrate my response with some direct excepts from the paper. And that paper and my post bears pretty directly on the subject of the "Integrity of Science" (e.g. the manner in which efforts are made to introduce analyses into the scientific literature that are more widely used to pursue agendas with a less than scientific basis; the question of the dissemination of science to the general public and the extent to which a balanced representation of the science finds its way into outlets that influence public perception....) So I find it slightly odd that my post was removed (or moved? how can one tell??), and yet this thread (and especially the "Kung Fu" one) have been allowed to be usurped by tedious bouts of trolling.... ...oh well...Response: I've reinstated that old comment - we're playing around with moving comments around but still need to work a few things out. -
tobyjoyce at 17:43 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
@Steven Sullivan, Of course, there are times where the accepted scientific consensus is overthrown. One good example is the theory put forward in 1985 by Marshall and Warren that bacteria caused gastric ulcers. It took 20 years for them to move from scorned outsiders to the Nobel Prize. The best philosophical description of this is Thomas Kuhn's book "The Structure of Scientific Revolutions". His view is that science works for long periods in "normal" mode in accepted "paradigms" (Kuhn invented the word, which he later regretted!). A paradigm is not rejected if it does not explain all the data - science is inherently conservative, and scientists will "save the theory" by tweaking the accepted paradigm to account for new data. For example, when it was found Newton's Theory of Gravity did not explain the orbit of Mercury, the theory was not rejected, because it worked so well elsewhere. However, if the old paradigm fails to account for the new data, & more holes appear, science enters a period of what Kuhn called "revolutionary science", like physics after the negative result of the Michaelson-Morley experiment, or Photoelectric Effect. You could say that gastrology entered a period of "revolutionary science" when Marshall and Warren first advanced their theory. The more it was shown to account for the data, the more adherents it gathered. Max Planck said a new paradigm triumphs because the adherents of the old one just die off! Is climate science in a period of "revolutionary science"? I think not. I do not see an alternative paradigm to AGW, nor is CO2-driven AGW failing to account for the data. Perhaps out there, a Michaelson-Morley experiment is happening that will turn everything on its head, but that has not happened so far. And, incidentally, new paradigms usually come from science and scientists, not the media. -
Argus at 17:41 PM on 10 May 2010Flowers blooming earlier now than any time in last 250 years
Juergen, The discussion in this thread seems to have died out, but you and I can continue if we like it, anyway. My point with examples of two shorter periods of 50 and 70 years respectively, was that you can get all kinds of results when examining this kind of graph, depending on which period you select. Now, 50 years may seem short, climatewise, yet almost all alarming reports now, that we can follow in threads on this site, are based on observations during (the last) 10, 20, or 30 years. 250 years is a long period, but to me it is incomprehensible that so much can be inferred from a tiny difference of three days between the start and the end of a graph - considering that in between there are maxima and minima that differ more than 10 days from each other! And this is even after taking averages of 25 years at a time. If you look at yearly averages (the red curve), flowering varies between day 120 and day 170. Quite a span. Another example: if we compare the average from around 1980 with the beginning of the curve, a headline 30 years ago could have read: 'Flowers now blooming 5 days later than 220 years ago'. So actually, all this report is saying, is that we see a change in the last 20-30 years towards a few days' earlier blooming. Thus, we are back to making grand projections about earth's climate for the coming millennium, based on small variations observed during the last couple of decades. -
tobyjoyce at 17:23 PM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
@johnd, I am sure you will agree that some contributors to this site do get a bit science done between watching episodes of their favourite soap operas. Perhaps you will now return to addressing the sudstantive points of #165. -
Riccardo at 17:06 PM on 10 May 2010Estimating climate sensitivity from 3 million years ago
johnd, you can calculate the forcing F (in W/m2) for an increase in CO2 concentration from C1 to C2 by the aproximate forumula: F=5.35 ln(C2/C1) -
Ari Jokimäki at 16:26 PM on 10 May 2010Estimating climate sensitivity from 3 million years ago
Hansen et al. (2008) also got similar result, but their numbers were little different. They got climate sensitivity of 3K with fast feedbacks and 6K with slow feedbacks included. It seems that this new study might have considered more effects than Hansen et al. so perhaps this new estimate is better. However, Hansen et al. studied the whole of last 65 million years while this new study only considers "one event". By the way, here's full text link to Lunt et al. (2010): http://www.leif.org/EOS/ngeo706.pdfResponse: Lunt 2010 does look at how other papers have found different slow feedback sensitivities greater than their estimate. They suggest that other analyses looking at periods such as the Last Glacial Maximum obtain higher sensitivities because transitions at that time involve large changes in the Laurentide and Eurasian ice sheets. These result in large albedo changes that aren't relevant for climates warmer than present. -
johnd at 11:19 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
If radiative forcing from CO2 is accepted as being 3.7W/m2 for a doubling of CO2, what does that equate to for the annual increase of CO2, about 2ppm? I have read that it amounts to 0.0075W/m2 per year. Is that correct if not what is the accepted rate? -
thingadonta at 11:12 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
"(there is still uncertainty over the timescales involved, from hundreds to thousands of years). " Where do you get these numbers? I think it's more like tens of thousands to hundreds of thousands. Do you have any references for these numbers?.Response: I was quoting Lunt 2010. -
Jim Eager at 10:35 AM on 10 May 2010Water vapor is the most powerful greenhouse gas
Ned wrote: "As a thought experiment, imagine that you could somehow remove all the water vapor from the atmosphere, and prevent any more water from evaporating into the atmosphere (but you keep CO2 constant)." But that's the rub, you could not prevent water from evaporating, at least not unless you also get rid of the ocean -- nay, all liquid and frozen surface water. Ned: "Now, alternatively, imagine that you removed all the CO2 from the atmosphere, but kept water vapor constant." A far more interesting thought experiment. If you instantaneously removed CO2 you could not keep water vapour constant because removing CO2 would reduce the temperature of the atmosphere, thereby reducing the amount of water vapour the atmosphere could hold, causing a portion to condense and precipitate out. This would in turn cause a further drop in temperature, and so on in an amplifying feedback loop. Temperature would eventually stabilize with substantially more ocean surface being frozen over, possibly even a global snow or slush ball earth state, greatly reducing albedo and cutting off a substantial portion of evaporation such that there would be relatively little water vapour in the atmosphere. In other words, CO2, which does not condense out of earth's atmosphere, makes it possible for there to be appreciable water vapour in the atmosphere, thus CO2 is, in the words of Richard Alley, the 'control knob' of the greenhouse effect. -
HumanityRules at 10:27 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
13.GFW That seems like a fairly static understanding of the processes. Surely anything in a process in transition can act as a driver for other aspects of the system. It's about cause and effect. At the moment we see CO2 being pumped into the system by us and ask what secondary affects is this having. If other things are changing under their own control these can then be generating their own feedbacks. For example the evolution of life and later green plants and their spread across the planet had a huge affect on atmospheric chemistry and all the subsequent effects that had on climate. In this case bacteria, plants and animals are the driver of change, generating their own feedbacks and CO2 becomes a feedback at this moment. So specifically in the Pliocene why shouldn't the geological changes be driving changes in climate directly. Certainly the joining of N and S America seems to have had massive repercussions on ocean circulation it's impossible to imagine this didn't have an affect on climate which would resolve itself over many timescales 11.Marcel Bökstedt I don't doubt all these processes resolved themselves over a much longer periods but it does seem that the Pliocene is often described as a mountain building epoch. We seem to accept that mountain building and tectonics could have a significant affect on CO2 why not other aspects of climate. This is a dominant process of the epoch. I've still not read anything here that rules out this as a driver of aspects of climate, I'm happy to find the big hole in my understanding. Again as an example the continued rise of the Himalayas must have had huge affects on the hydrological system of the regional and all the subsequent affects on vegetation, rivers, erosion and the like. Another description of Pliocene here http://www.enotes.com/earth-science/pliocene-epoch -
Tom Dayton at 09:48 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
If anyone else wants to reply to skepticstudent's comments about water vapor as a forcing, will you please do it over at Water vapor is the most powerful greenhouse gas? skepticstudent already has been pointed in that direction, so he should be reading that thread. If you want to get his attention on this thread, how about posting a short comment telling him your substantive comment is over there? -
Rob Honeycutt at 09:47 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
@Steven Sullivan... Your reference is really interesting but I would suggest that we're likely charting very new territory here on this issue. Can you think of a time when the media had as much influence on driving opinions that are counter to the mainstream science? Maybe with Darwin? There have been times when science was coming to conclusions that were not politically convenient and have come up against the establishment, so nothing new there. I think there are some ways to consider what is going on now that is both similar and very different from the past, that could potentially be very helpful to addressing the looming problem. What concerns me most is what I see happening in terms of potential damage to the whole scientific process. -
yocta at 09:47 AM on 10 May 2010Over 31,000 scientists signed the OISM Petition Project
As the Policy on Comments and Replies states: ...Both Comments and Replies will be refereed to ensure that the Comment addresses significant aspects of the original paper without becoming essentially a new paper... Notice how the word "comment" is in the title? You have to be careful with your language when using words such as 'refute' and 'challenged in the peer-review literature' when informing the readers on SkepticalScience as it is highly speculative language. If a new survey and hence a new paper was performed with results contrasting Doran and Zimmerman then you could say 'challenged in the peer-review literature'. At the moment all you can say is their are two published criticisms of the paper, and that the author replied to these. With your actual concerns over the survey, that the two critics made, the EOS is behind a pay wall so it would be difficult to discuss the actual contents and author's reply further unless somebody with a subscription can access the content. Also where do you get the number from Doran 2009 that 567 Scientists Surveyed do not believe man is causing climate change? -
Marcus at 09:37 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
Ah, SS, you're falling for the oldest trap in the book. It's true that water vapor accounts for around 60% of the planet's *natural* greenhouse effect (i.e the roughly 33 degrees C between the planet's average temperature of +15 degrees C & the -18 degrees C it would be without *any* greenhouse gases), whilst CO2 "only" accounts for 20%. However, water vapor accounts for between 1%-3% of the atmosphere. By contrast CO2 accounts for about .04% of the atmosphere-which of course makes CO2 a significantly stronger greenhouse gas-on a ppmv basis than water vapor. 2nd is the fact that individual water vapor molecules have a significantly shorter residence period in the atmosphere than CO2 (days to weeks compared to years to decades). 3rd is that water vapor contributes to both greenhouse effect & albedo wheras-to the best of my knowledge-CO2 contributes nothing to albedo-only to greenhouse effect. Thus its easy to see why CO2 is a driver, but water vapor is only a feedback. -
Steven Sullivan at 09:26 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
lost in edit: "where the view of a single or few 'eminences' over-influenced the mainstream view" -
Steven Sullivan at 09:25 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
omnilogos, I can cite easily cite examples from the history of science where the 'mainstream' view was later overturned, or where the view of a single or few 'eminences' the mainstream view. (There's a fine example in the early history of malaria research, for example, where the mistaken claim of an eminent parasitologist misguided the course of research for decades.) Now all you need to do is establish that this is what's going on in year 2010 climate science, which is not exactly in its infancy, is not controlled by the view of one or a few scientists, as has vocal 'skeptics' publishing peer--reviewed work (e.g, Pielke Sr., Lindzen, Christy). -
Rob Honeycutt at 09:22 AM on 10 May 2010Kung-fu Climate
I have to agree with JMurphy saying that it's probably not worth engaging Poptech on this site. What I see going on is, he plays my his own rules except when they are used to counter his position, then there are another set of rules. I think it's really bringing down the quality of the discussions here on John's site. -
Rob Honeycutt at 08:26 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
@skepticalstudent... I'd also highly suggest that you take one issue at a time and edit your posts for brevity. -
Rob Honeycutt at 08:25 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
@skepticalstudent... Maybe you should consider a different approach to presenting what you have to say. Many times frustration comes not from what someone says but how they say it. I can definitely see the frustration from those engaging you in this conversation. You seem to assert positions and cite little to back it up. Most of the people here are working scientists. Teachers. If a student turns in a paper making a lot of statements (like "it's the coldest since 1775") without backing it up somehow, that student would get a failing grade. If you are indeed a "skeptical student" rather than a "student of skepticism" then I would suggest you slow down with the rants and listed to criticism of your statements. Do what a student does. Learn. -
Marcel Bökstedt at 08:18 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
frogstar> It seems that they base the analysis on preliminary work on pliocene vegetation like: Salzmann,U. , Haywood, A.M.,Lunt, D.J.,Valdes, P.J.,and Hill, D.J.(2008).A new global biome reconstruction for the Middle Pliocene. Global Ecology and Biogeography, 17, 432–447. In that paper, the main result seems to be that they partition the Earth of that period into 27 vegetation zones like "desert" or "open conifer woodland" etc. I don't believe that they speculate on how evolution might have adapted plants to higher CO2 levels. -
Jim Eager at 08:00 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
skepticstudent is indeed 'just sayin'. Rather than 'just sayin' skepticstudent needs to do some actual studying. If he were to do so he would learn all the reasons why he doesn't have a clue what he's 'just sayin' about. Such as the very reason that CH4, N2O, O3, CFCs and the other purely man-made less common greenhouse gases are more potent than CO2 is precisely due to 1) their being so much less common: doubling them requires adding so much less of them to the atmosphere, times 2) their life in the atmosphere. Such as although those gases are more potent than CO2, meaning they have a much higher potential for influencing earth's radiative balance, the 38% and growing increase in CO2 dwarfs their combined increase by sheer volume. Such as the fact that water vapour, the one greenhouse gas in greater supply than CO2, by a factor of 10, can only act as a feedback to some initial change in temperature of the atmosphere, what ever the cause or sign of that change, while CO2 can act as either a feedback to an initial change in temperature, OR as an initial forcing when added to the atmosphere independent of an initial change in temperature. Such as the fact that the 'water' is currently a net absorber of CO2, which is why ocean surface pH is falling as CO2 increases in the atmosphere. -
batsvensson at 07:47 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
skepticstudent at 05:47 AM on 10 May, 2010 "how could co2 be a "driver" and the others which are far more powerful be mere feedback" It has to do with 1. the life time, 2. the concentration and 3. the scattering frequencies of these gases in the atmosphere. The three most common gases in the atmosphere Oxygen, Nitrogen and Argon, if I recall right now, do not absorb outgoing long wave radiation, but do scatters radiation in the incoming spectra (hence creating a blue sky by means of incoming scattered short wave radiation). All other gases are traces gases but the most abundant of them is CO2. CO2 – simply put, once there it stays there (I am deliberately ignoring the carbon cycle here). Methane, another trace gas, is broken down to CO2 and water vapor after a while and thus contribute to more CO2. Methane concentration is also significant lower than CO2 concentration, by a factor 200 about. Methane I believe is about 20 to 30 times more potent as greenhouse gas but far less abundant and not very long lived, therefore its effect fades compare to CO2. Methane can have a strong short term effect if pumped out in massive amounts but due to it short life time its effect will go away within a decade or so and be replaced with a long term effect from CO2. Water vapor, perhaps the most potent greenhouse gas, has its own life and its concentration varies by god know what and how many factors and it tends to crystallize and fall out now and then. Water and its vapor is an important substance when it comes to transport heat around, in seas as in air, and its vapor has an great effect on the greenhouse effect – when it pleases to be present that is - but its behavior is erratic and the understanding of water vapors life cycle and it effect on global warming is poor at best. For the rest of the trace gases they do simply not contribute significantly to the energy balance. Does this motivation make sense for you? -
thefrogstar at 07:46 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
How are the effects of flora modeled in these paleo-climate reconstructions? As a reult of the impact of growth and death on CO2 and methane levels, I would expect the effects to be significant. The increase (and decrease) of living agents is (by definition, I would argue) exponential in nature. And this is without factoring-in any Darwinian selection processes such as, say, selection for flora that are better able to compete at higher concentrations of CO2. Do paleo-climate reconstructions have the kinetic-resolution to adequately describe such changes? I whould hazard a guess that small photo-synthetic organisms do not leave leave much of a trace in the fossil record irrespective of their genome. -
johnd at 07:30 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
tobyjoyce at 23:25 PM, the use of the word "you" was not directed at you personally, perhaps it would have been better I had used the word "one" instead. The use of the word is no indication of my demeanour, merely how is is generally used amongst my peers. Political correctness often catches us out and I apologise to those who are sensitive to such gaffs. Obviously in the first paragraph, and in the last sentence, the you does refer to, well, you. -
tobyjoyce at 07:29 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
@Tom Dayton, Thanks, that's given me some good reading From tamino's blog. Very helpful. -
tobyjoyce at 07:25 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
@scepticstudent #172, A friend of mine once told he saw a drunken man bang his head repeatedly against a stone wall "to show what a brave man could do". I hope you agree that there are different types of courage, and sometimes faintness of heart is a Darwinian advantage. On the substantive point, or points (I lost count),I am going to kick for touch, and refer you to another part of this blog, where you can comment as you wish: Broken Hockey Stick -
kdkd at 07:20 AM on 10 May 2010Kung-fu Climate
Poptech #216Computer models can be useful in engineering and design.
You appear to be implying that this is the only situation that computer models are useful in, although you haven't answered all of my question. That perception is rather far from the scientific consensus on modeling of stochastic and complex systems. I'm afraid that as you have implied that modeling is not useful in any situations, then you are suggesting that a large proportion of the modern sciences in biology, psychology, meteorology, medicine, and elsewhere is not valid. As much of the infrastructure of civilisation is based on this "soft" modeling, your position appears to be little related to the reality of the situation. -
Philippe Chantreau at 07:07 AM on 10 May 2010Kung-fu Climate
Well, looks like I'm going to recant on my promise about Bond events but, to my defense, I'll say that it is because the connection between Bond events and Loehle's reconstruction deserves some attention, would it be only because Poptech advocates for both. This poses a problem, since, from cursory inspection, their respective realities do not match very well. The most recent Bond event has been dated approximately 1400 years BP, possibly from 450 to 900 AD (Bond 1997) but with a peak at about 600 AD, where Loehle shows a postitive anomaly of 0.3C, among the highest in the entire graph. -
Tom Dayton at 07:01 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
Skepticstudent, go to the Search field at the top left of the page. Type "water vapor feedback" and hit the Go button. In the resulting list, click "Water vapor is the most powerful greenhouse gas." If after reading that post and the comments you still have questions, ask on that thread, not this one. -
Riccardo at 06:51 AM on 10 May 2010Climate sensitivity is low
The problem is that Spencer keeps repeating the same wrong conclusions in his blog ("These results suggest that the sensitivity of the real climate system is less than that exhibited by ANY of the IPCC climate models. ") so that they're still usefull for the skeptic community. I prefer not to comment on this attitude that he has in common with other (luckly few) skeptic scientists. -
Tom Dayton at 06:40 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
Chris and Riccardo,may I gently suggest that you copy your comments about Spencer to a thread about sensitivity? Then perhaps our host can remove those comments from this thread and delete all subsequent comments by anybody on sensitivity from this thread? -
Marcel Bökstedt at 06:19 AM on 10 May 2010Estimating climate sensitivity from 3 million years ago
skepticstudent Please refrain from off topic comments, they clutter the thread. -
scepticmike at 05:57 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
Perhaps if you ignore "scepticstudent" he will go away. He seem to me to not adding anything useful to the discussion. -
chris at 05:54 AM on 10 May 2010Climate Change and the Integrity of Science: a letter to Science
johnd at 19:27 PM on 9 May, 2010 I suspect that Spencer's paper was allowed through once he removed any suggestion that his model and analysis has any particular relationship to the climate sensitivity as it is commonly understood (i.e. the change in the Earths equilibrium surface temperature in response to a radiative forcing equivalent to a doubling of atmospheric [CO2]). So for example Spencer and Braswell have qualified their description to point out that their analysis doesn't necessarily have much to say about climate sensitivity [***]. Particularly in the physical sciences, papers can be published that pursue a particular analysis in line with simplified physical models, even if these don't have any necessary relationship to the real world. I think this is one of these. No doubt it will take its chances and sink or swim according to its ultimate usefullness/validity (which on past experience is likely to be low). Of course we can be sure it will be trumpeted all over the blogosphere as (another!) "proof" that science has got it all wrong on atmospheric physics, the greenhouse effect and climate change. Plus ca change... ----------------------------------- [***]e.g. Spencer and Braswell conclude:"Although these feedback parameter estimates are all similar in magnitude, even if they do represent feedback operating on intraseasonal to interannual time scales it is not obvious how they relate to long-term climate sensitivity." and "Since feedback is traditionally referenced to surface temperature, extra caution must therefore be taken in the physical interpretation of any regression relationships that TOA radiative fluxes have to surface temperature variations."
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