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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 126351 to 126400:

  1. East Antarctica is now losing ice
    The measurement of ice loss is dependant on two halves of a sum. Firstly apparent mass loss is measured (e.g. by GRACE). This mumber is then adjusted to take into account movement (rise/fall) in the rock of the antarctic, my understanding is this is called Post Glacial Rebound or GIA. Two computer models have been popular for measuring this second part of the sum, they are called IJ05 or ICE-5G. In recent years GPS sites have been setup in the antarctic. Two studies have looked at the information coming from this GPS data Bevis, M., et al. (2009), Geodetic measurements of vertical crustal velocity in West Antarctica and the implications for ice mass balance, Geochem. Geophys. Geosyst and http://rses.anu.edu.au/geodynamics/tregoning/36.pdf Both these studies suggest that the measurements of GIA are wrong. In summary the assumption has always been that antarctic was rising due to loss of ice from the last ice age when in fact the actual GPS measurements suggest stasis. The first of the papers suggest the ice mass loss for part of West antarctic is over estimated by 33Gt/yr although states that really the sums have to be done again with this new information. There is no estimate of the error in the East Acrtic data. Would you be interested to see the GRACE data analysed with glacial rebound calculated on the basis of GPS data?
    Response: Chen 2009 takes GIA into account when calculating the mass loss from GRACE data. This is then independently confirmed by the InSAR satellite data which is not affected by GIA.
  2. What do the hacked CRU emails tell us?
    This is off topic, but may help address some of the questions that have been raised here. On Tuesday the IPCC released an update to the AR4 for Copenhagen. You can view and/or download the file at: http://www.copenhagendiagnosis.com/ Sorry for the intrusion.
    Response: I've posted a review of the Copenhagen Diagnosis in The Physical Realities of Global Warming.
  3. Record high temperatures versus record lows
    Steve L, I have made an exhaustive search though the literature and have found only one paper which explores relationship between lighting activity and soil moisture (my interest) in Mongolia. This is a very new field. I can track the paper down if you like. Regarding changes in the rainfall, the IPCC update which was released today includes a couple of references to large-scale trends in precip. in the 20th century (e.g.., Zhang et al., 2007, Nature). Check it out at: http://www.copenhagendiagnosis.com/ PS; Also try this one for lightning land use interactions. Kilinc and Beringer 2007, J. Climate (AMS) There are more on this topic (land use lightning).
    Moderator Response: [Daniel Bailey] An open-access copy of Zhang et al 2007 can be found here.
  4. What do the hacked CRU emails tell us?
    Thanks for the reference to Chris Colose's website. Much appreciated.
  5. East Antarctica is now losing ice
    Sorry if this is answered elsewhere, is there expected behavior for Antarctic ice? For example, are there estimates for ice loss as a function of time? Is the loss due to CO2 concentration increases expected to be greater than other causes of ice variation? The reason I ask is that I can just see a time in a couple of years when the ice is growing again and the whole controversy starts again. Head it off at the pass.
  6. What do the hacked CRU emails tell us?
    Thank you, Chris. I think I understand what you're saying about the broader certainty. Kind-of like the uncertainties over gradual evolution vs punctuated evolution against the broader background of the certainty of evolution itself. Right? I'll take a look at the links you provided for the radiative forcing explanation. Do you know if anyone has specifically address Lindzen's recent claim that satellite readings of LWIR data indicate a negative feedback rather than a positive one?
    Response:

    Lindzen's claims are addressed at Chris Colose's website (another topic for a future post).

  7. What do the hacked CRU emails tell us?
    Here's what the "decline" looks like: http://akwag.blogspot.com/2009/11/hiding-decline-what-that-really-looks.html
  8. What do the hacked CRU emails tell us?
    I meant to link to a pdf of the Trenberth/Fasullo?Kiehl article in Bull Am Met Soc 2009
  9. What do the hacked CRU emails tell us?
    re #70 billbrent, I think you're discussing a sort of sub-level of uncertainty that lies underlies a broader certainty of understanding. There are (at least) two examples of this in climate science: (i) sea levels. There's rather good evidence that sea levels are rising a bit over 3 mm per year at the moment (highish certainty [*]). This must be the result of some combination of heat accumulation (thermal expansion) and mass increase (polar ice sheet and mountain glacier melt), and the summation should match the observed sea level rise if the "energy budget" is properly "closed"). Each of the latter can be estimated independently; however each of the latter measurements has greater uncertainty than the more easily measured total sea level rise. So there is a sub-level of uncertainty in the precise partitioning of sea level rise within its (less easily measured) components. The greater uncertainty in the latter doesn't negate the lesser uncertainty in the former. (ii) Radiative forcing and it's precise partitioning. This is very similar to (i) but more complex. We have rather good evidence that the net forcing from raised CO2 is equivalent to a warming near 3 oC (plus/minus around 1 oC) per CO2 doubling. The forcing is the result of a radiative imbalance between incoming solar radiation and outgoing longwave IR emitted from the earth's surface. Partitioning this to the components (solar radiation reflected to space; solar radiation reflected by surface; solar radiation absorbed by clouds; surface emitted LWIR; surface LWIR reflected from the atmosphere...and so on)...is very complex (see Figure 1 here [**]). The nett top of the atmosphere radiative imbalance that we can estimate reasonably well from theoretical analysis combined with paleoproxy analysis (that allows us to estimate the expected equilibrium temperature response to doubling CO2), is a small number that results from the summation of many large numbers. So the uncertainty in this summation of many large numbers to give a net TOA forcing has a lot of uncertainty since tiny errors in the large numbers (solar radiation emitted from the earth surface; LWIR absorbed by the atmosphere etc; see Figure 1 [*]) result in large errors in the summed TOA radiative forcing (i.e. "closing the enrgy budget"). However that doesn't mean that we don't have quite a good handle on the estimate of the total radiative forcing from independent analysis. Trenberth's problem (if I am interpreting his email correctly), is that we need to understand the component forcings and their responses if we want to assess whether geoenginering approaches will have any chance of being successful. That makes sense since geoengineering approaches (blast sulphurous aerosols into the atmosphere) affect sub-components of the total radiative forcing (.e. they mostly reduce solar radiaiton reaching the surface, but we need to know by how much before we start pumping the stuff into the atmosphere). [*] http://www.skepticalscience.com/Are-sea-levels-rising.html and: http://www.skepticalscience.com/A-broader-view-of-sea-level-rise.html [**] Trenberth, K. E., J. Fasullo, and J.T. Kiehl, 2000: Earth's Global Energy Budget. Bull. Amer. Met. Soc.. 90, 3, 311-323.
  10. What do the hacked CRU emails tell us?
    I did not make a random selection.
    No, not you, the people who stole the e-mail have published a random selection, and we have no idea as to what's missing or not, or how cherry-picked the published e-mails are.
    I have not misrepresented Trenberth's work in any way.
    Well, Trenberth is on record as saying that the kind of conclusions you draw do misrepresent his work. I'll take his word on it, sorry.
  11. What do the hacked CRU emails tell us?
    Well, I just looked at the Briggs discussion of tree ring proxy reconstructions and, really, it's a cartoon description that really bears little resemblance to reality.
  12. What do the hacked CRU emails tell us?
    dhogaza #67 You wrote: "Can you explain why Trenberth disagrees with your assessment regarding policy to my (or anyone's) satisfaction if your reading of the tea leaves (sorry, "random selection" of purloined e-mail) reflects the level of uncertainty being discussed?" I did not make a random selection. I picked a discussion that reflects my deep concern about the policy implications stemming from climate science being passed off as "settled" when there are disagreements among leading AGW scientists about the physics. I have not misrepresented Trenberth's work in any way. And I don't like tea. As I said in my response to SNRatio (#78), Trenberth's question, "What are the physical processes?" doesn't seem to be "a relatively minor problem" easily explained by the "existing instrumentation isn't sufficient for researchers to close the earth's energy budget during La Niña." I'm not saying Trenberth's concerns mean that the underlying physics are "contradicted," I'm saying that he's indicating that the physics are not completely understood. And the exchange with the other scientists most definitely shows that the physics - the science - is certainly not "settled," which is my biggest concern. You will not find anywhere in what I've written that "maybe global warming doesn't exist."
  13. What do the hacked CRU emails tell us?
    Actually I was talking about the fact that his proxies don't work well for the last ~50 years.
    First of all the proxies aren't "his", he analyzes work by others. But what you're referring to is exactly the "diverenge problem", no secret, openly discussed in the literature, actively discussed in the literature. The problem is only with *some* tree ring proxies, not *all* tree ring proxies, much less non-tree ring proxies. John's going to do a post on it, I suggest postponing discussion until he does.
  14. What do the hacked CRU emails tell us?
    re #11 SNRatio, I agree with much of what you say. However, I’d like to comment on your post re: IPCC projections (you say they haven’t been conservative enough) and models (you suggest that they have been somewhat oversold). Since model output has been around for quite a while now we can compare model projections to real world outcomes. Likewise since the IPCC projections have been around since 1990 these can be compared with real world outcomes. (i) IPCC projections cf real world outcomes. A comparison of IPCC projections since 1990, with real world outcomes through 2006 allows us to assess their accuracy. If one looks at (i) CO2 levels [*] (ii) temperatures [*], (iii) sea level rise [*] (iv) arctic sea ice retreat [**], it’s pretty obvious that the IPCC projections have been conservative. CO2 emissions have followed IPCC projections since 1990 quite closely. Temperatures have risen at a rate that is right at the top end of the IPCC projections. Since this is a short comparison period this might just be the result of natural variation on top of a rising trend. Sea levels have risen much faster that the IPCC projections [*]. Arctic sea ice recession has occurred at a very much faster rate than the IPCC projection [**]. Obviously all of these metrics are for a rather short period (8-18 years). But if a comparison of the important metrics (atmospheric CO2, temperature, sea level, sea ice retreat) are occurring at the upper limits, or outside the upper limit of the IPCC projections, I don’t see how we can say that the IPCC projections aren’t conservative enough. Whether they’ll continue to be conservative into the future remains to be seen (very likely the IPCC sea level projections are conservative since they exclude any “non-linear” contributions from poorly predictable ice sheet dynamic responses). [*] S. Rahmstorf et al. (2007) Recent Climate Observations Compared to Projections Science 316, 709-710 [**] http://www.copenhagendiagnosis.org/download/Copenhagen_Diagnosis_LOW.pdf (ii) Comparison of models with real world outcomes This is more difficult to assess. There’s no question that models outputs have to be treated with caution. However we can compare model projections with real world outcomes. The earliest simulation (and one you comment on) is Hansens’s simulation set up around 1985 and projecting temperatures forward. This simulation has followed reality rather well (it is pretty much spot on through 2005; see Figure 2 here, a freely downloadable paper [***]). You comment that this particular model is parameterized according to a climate sensitivity of around 4 oC (4.2 oC). But this wasn’t so well-defined in the mid 1980’s nearly 25 years go. And the fact that the simulation parameterized according to a 4.2 oC climate sensitivity, matches the real world temperature progression, means that the real world temperature is rising at a rate that is consistent with a rather higher climate sensitivity than the mid range (3 oC). Of course it might not be (too soon to say); but I don’t see that we can say that model outputs are oversold when they match reality quite well… ..and that applies to the model predictions of polar temperature amplification…of water vapour feedback (before this was measured directly, Dr. Lindzen was asserting that tropospheric warming would result in a drying of the upper troposphere – he was shown to be wrong; the models were shown to be right)…of a temperature induced water vapour feedback yielding a close to constant relative humidity….the models predicted the magnitude and temporal response of temperature to the Pinatubo eruption…they predicted a fast Arctic and delayed Antarctic response to global warming…they predicted greater nighttime warming over daytime warming in a greenhouse-warmed world…they predicted a tropospheric warming that was, for about 15 years, asserted to be incompatible with the UAH satellite measure of tropospheric warming, until in 2005 it was shown that a series of systematic errors in the UAH analysis was responsible for the apparent incompatibility….the models were correct again… ..and so on.. ..it’s very easy to be sceptical of models (and we should be!), but they’ve been pretty successful so far. Whether they will continue to be successful into the future remains to be seen. [***] http://www.pnas.org/content/103/39/14288.abstract?sid=30711dcf-c67f-48ba-8983-f775d6a54d3f
  15. What do the hacked CRU emails tell us?
    re #55 sorry, mate...what people write or say in magazines, newsletters, newspapers, and so on is not necessarily scientifically sound nor even necessarily science. Ollier has published proper papers in the scientific literature. The stuff you refer to isn't. The whole point of publishing in the scientific literature is that it forces a degree of scientific rigour on the measurement, analysis and presentation of the data, and that it becomes part of the scientific record to be built upon, referred to, contradicted (or sink into oblivion). If Ollier discovers something worth publishing in the scientific literature, no doubt he'll do so. (Incidentally I made a small disservice to Ollier - his last paper wasn't 2007 - he published a paper in 2008 on Deccan duricrusts, which is nothing to do with sea levels of course. He hasn't published a scientific paper in 2009 so far.) Nope Morner's comments aren't relevant. They're from some interview on some web site. We know how sea level measures are made. There's dozens of papers on this. A recent update of the subject can be found on the links to pages on this site [*]. If Morner has some problem with this he should publish on it rather than sniping in interviews. It's not scientifically interesting since it seems not to accord with the science. [*] http://www.skepticalscience.com/Are-sea-levels-rising.html and: http://www.skepticalscience.com/A-broader-view-of-sea-level-rise.html Incidentally, I wonder if you would really be happy in the world that you seem to want to inhabit, neilperth? Where you decide what seems like an expedient course of action that suits a particular political point of view, and then propagandise for this for all your worth. You might be comfortable in a world where "science" was "decided" by propagandising bullies, but you might find that their agenda didn't always match yours! To my mind, we're extraordinarily fortunate that we live in a world where a degree of independent scientific rationality exists, so that we aren't at the whim of those that consider it expedient to pervert the science on the toxicity of tetraethyl lead (say), or the role of cigarette smoking in lung cancer, or the dangers of aspirin taking in children with respect to Reyes syndrome, or the effects of CFC's on stratospheric ozone...and so on (a long litany of anti-science propagandising on behalf of vested interests). The science has pretty much always been right on these things...not sure why you think the science of the greenhouse effect is any different. I expect we'll find that the scientific understanding that develops from careful and independent thinking, researching, measuring, interpreting, synthesizing and publishing in the scientific literature is still going to be a better route to understanding, than random assertions from website interviews or articles in newsletters.
  16. What do the hacked CRU emails tell us?
    SNRatio #57 You wrote, "Why don't you check the facts before jumping to conclusions? And with explanations easily available, your reference to and interpretation of the notorious "Mike's Nature trick" either shows an ignorance I would not expect from contributors to this site, or willfull misrepresentation." Why don't you read my post more carefully. I did not say one word about "Mike's Nature trick"! I don't have a problem with the term "trick" being used, especially without a better understanding of the context. I know mathematics and science are full of "tricks" to accomplish certain tasks. Plus, I'm not a "contributor" to the site - as in a professional scientist - I'm a commenter. I stated up front that I was a layman. When you finally did address my question, you take issue with my "sweeping statement" that there is a "very serious disagreement" about the physics. I'll grant your point that I don't know all the details and so perhaps shouldn't have used the modifiers "very serious." But there is an undeniable disagreement about the physics that doesn't seem to be easily explained with "it's more about the lack of data," or Trenberth's higher standards. Trenberth asks, "What are the physical processes? Where did the heat go?" These questions are not simply answered with more data, are they? Aren't they more about a fundamental physical understanding? I deeply appreciate that you are willing to state that "the models are not adequate, and they have to be improved." And that you are "concerned that the results may have been oversold." That is my concern as well. And I must say, this is not a small thing. In a world where the primary motivator in journalism is, "If it bleeds it leads," and the most sensational stories make the front pages, and those stories motivate policy makers to pass legislation that can constrict individual choices and freedom, I think honest scientists need to shout those concerns to the heavens. So, again, your honesty in this regard is deeply appreciated. You wrote, "The positive feedbacks, while still very significant, have been smaller than implied by the models, and now they are looking into why." Recently, Prof. Lindzen wrote that the satellite data is showing that the feedback is actually negative. Are you familiar with that argument? And can you argue for or against it? Also, there seems to be some thought that the large quantities of SO2 being pumped into the atmosphere in India and China is having a moderating effect on the greenhouse effect of CO2. Could that be the case? Thanks for addressing the issue of social engineering. You wrote, "even with zero positive feedback, "carbon liberalism" will get us into climate problems pretty soon." But with zero positive feedback, won't we get only 1 degree C rise in average global temperature with every doubling of CO2? And even with the accelerating CO2 emissions of India and China, won't that doubling take tens of years? And has there been adequate study of CO2 sequestration by additional plant growth to warrant the severe GHG restrictions currently being discussed?
  17. What do the hacked CRU emails tell us?
    dhogaza:The only proxy I imagine you might be talking about was the lake bed proxy from Finland which McIntyre et al trumpet "was used upside down!". Actually I was talking about the fact that his proxies don't work well for the last ~50 years. IAC, here is a pretty good overview of proxy reconstruction issues IMO: http://wmbriggs.com/blog/?p=1362#comments "Meanwhile - the CO2 science site is thoroughly unreliable as a source of objective information. My saying so probably won't convince you, but it needs saying." Well, perhaps, but it references dozens of peer-reviewed papers. Personally, my view is pretty much in line with Briggs above, so I don't put too much faith in any reconstruction. FYI, here is a reconstruction that differs from the mainstream ones. http://www.ncasi.org/publications/Detail.aspx?id=3025 My point here is that there is substantial difference in the reconstructions depending on how they are done(this makes confirmation bias a problem IMO no matter how you reconstruct temperatures). Cheers, :)
  18. The albedo effect
    So in what paper specifically will I get the answer to my question: If carbon dioxide traps infra red radiation from earth (keeping us warm) then it must follow that carbon dioxide also shields us from the sun (similar to ozone blocking UV and water vapor blocking IR). So what is the nett effect, especially at the relevant levels of carbon dioxide of 0.02% – 0.05%? If you think it is so easy to get an asnwer to my question, why not just give it to me? I have been searching for months, and I did not get it.
  19. The albedo effect
    Oh nice, "hidden in a published paper". It's called an oxymoron.
  20. What do the hacked CRU emails tell us?
    Models are still, for all their apparent sophistication, unable to include many known factors that influence climate..a fact that is acknowledged by the modellers...
    Please name the *known* factors which models are unable to include. I'd appreciate your using your own words. Thank you.
  21. What do the hacked CRU emails tell us?
    Yes, I've read a bit. It seems to me that people have logical seeming reasons for why they choose the proxies they do, whether they actually are good proxies is another question.
    Yes, of course, that's why a variety of proxies are compared and why paleoclimatologists don't hang their hat on a single one. Compare that with how, say, McIntyre works - "Yamal! Yamal! Yamal!" - as though chipping away (ignorantly, IMO) at one proxy will make them all disappear.
    Mann's proxies seemed logical to him until we found that they don't work under certain conditions.
    The only proxy I imagine you might be talking about was the lake bed proxy from Finland which McIntyre et al trumpet "was used upside down!". Here's an interesting fact: Mann's paper stated clearly and upfront that it was though there might be problems with that proxy. Therefore he checked for robustness of his multi-proxy reconstruction with and *without* the questionable proxy. And got virtually the same result. The denialist screams about "upside down proxies!" very cleverly for the most part fail to mention that Mann himself was the first to state potential problems with the proxy, and most especially tend to ignore the fact that he tested for robustness without the proxy in question. Yet this is the proxy that is claimed "breaks the hockey stick!" and "breaks Mannian science", etc.
    IAC, I admit to not being that up to date on the issue, perhaps you can help me resolve this question by pointing to some research where the proxies match reasonably well for both the long-term reconstruction and the current temps.
    About a month ago I found a really great overview paper (probably prepared as background material for a college course or seminar) by googling. Unfortunately, I've tried several times in the last couple of days to find it again, without success. I'll try to spend more time being clever in google to see if I can find it again, and if so, will post a reference. Meanwhile - the CO2 science site is thoroughly unreliable as a source of objective information. My saying so probably won't convince you, but it needs saying.
  22. What do the hacked CRU emails tell us?
    #73: No, we need to acertain what the risk is before embarking on 'corrective action' which could conceivably cause more harm than good. We do not know enough and do not yet have adequate models or computing power to do more than make rough assessments. Climate change will occur whether or not we modify our output of CO2, to what extent we still do not know with any exactitude that enables us to make 'proper' decisions. Models are still, for all their apparent sophistication, unable to include many known factors that influence climate..a fact that is acknowledged by the modellers...but unfortunately not by the politicos and eco-warriors. I readily accept much of the science underpinning AGW, but I do not accept the output of the models which include so many assumptions that IMO they are pretty worthless. ( I await the deluge ).
  23. The albedo effect
    Henry, those papers are not "hidden." They are published in journals. Publicly. That's the point of "publishing." That's what "published" means. That blurb about none of the articles being available on line is left over from when the list was first started. Now many of the articles are available on line, and some even for free. If you go to the trouble to actually click on the links that are the titles of the articles, you will be able to see for yourself whether the full articles are available on line. In fact, the very first one on the list (Toth et al. 2008) is in fact available on line for free--the full text, both in HTML and PDF. If the full article is not available for free on line, often you can still get it on line by spending just a little money. Or you can get any of those articles for free by getting out of your armchair and going to a library to look at the paper versions. If you don't have a university library nearby, your local public library can get copies of the articles for you.
  24. The albedo effect
    Tom, here is the quote from your "list" "This is a list of papers on laboratory measurements of the absorption properties of carbon dioxide. In the context of these paperlists this is a difficult subject because none of the papers seems to be freely available online, so we have to settle on abstracts only. However, I don’t think that matters that much because the main point of this list really is to show that the basic research on the subject exists. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative." Now go back to see what I wrote in 74: As Weart told me some time ago: you cannot see the evidence because the wise men have decided to hide it in papers that cannot be accessed. If it is so difficult to explain as to how the tests were done that proves that those 70 ppm's of CO2 added since 1960 are significant, how can we expect non-scientists to make the right decisions in Copenhagen? I am not interested in abstracts. I want to see the results and how the tests were done... how much heat retention is caused by 100, 200, 300, 400 ppm etc. and you will find that such results do not exist because you cannot measure anything relevant at those concentrations of CO2. To extraolate results from high concentrations back to lower concentrations is the wrong type of science. Properties change at different conc. levels. You must always measure at the relevant concentrations. In addition, no one seemed to have realised that CO2 causes cooling (reflection of sunlight) as well as trapping of earth's radiation. So you have to take that into account in your testing method as well.
  25. East Antarctica is now losing ice
    Just to add a bit of context... Antarctica is estimated to contain some 30 x 10E6 km3 of ice; about 10,000 years worth at current rate of melt. Antartic climate is subject to high inter-annual variabilty as indicated in Ferron et al 2004 which shows steep temp rises over very short time scales in the past. As with the Greenland ice sheet, melt/calving is mostly at the edges since inland air temps are far too low to allow melt. Equally, inland precipitation is generally low for the same reason. It seems logical to me that the increase in ice loss is due to changes in sea temperatures and circulation, with possible correlation to PDO and similar southern ocean cycles. Also intersting to note that the GRACE pic shows noticeable anomalies around 0 degrees.....??
  26. What do the hacked CRU emails tell us?
    People, how much time do you think we have to quabble about some academic infighting at one research outfit? The longer we argue about minutia, the longer we wait to act based on the broad body of supporting evidence from around the world, the more difficult it will be to mitigate the risk that climate change presents. And why are skeptics so quick to criticize some climate scientists for unethical behavior, yet they readily accept a few ideas or findings, often involving similar unethical practices, from the few dissenting scientists that remain? They are probably heavily biased themselves, due to a rigid belief system, financial motivations, or otherwise. We need to move forward with the more relevant discussion asking "To what degree should we mitigate the risk, using what methods, and how will we pay for it?" Anything else is just a waste of precious TIME.
  27. What do the hacked CRU emails tell us?
    dhogaza:"Have you read anything on how, for instance, tree ring chronologies are chosen for temperature proxy work? It's not based on "confirmation bias" based on recent warming, but rather on site characteristics and ring morphology that reflects known temperature signatures in tree ring tissue based on knowledge of tree physiology." Yes, I've read a bit. It seems to me that people have logical seeming reasons for why they choose the proxies they do, whether they actually are good proxies is another question. Mann's proxies seemed logical to him until we found that they don't work under certain conditions. CO2science.org lists quite a few different proxy studies(that I'm sure the authors believed were properly chosen). IAC, I admit to not being that up to date on the issue, perhaps you can help me resolve this question by pointing to some research where the proxies match reasonably well for both the long-term reconstruction and the current temps. Cheers, :)
  28. What do the hacked CRU emails tell us?
    5) CO2 in reality is coming from warming and de-pressurizing sea water, all year round, and from the deep sedimentary basins in the northern spring
    Hey, Peter, that's very interesting. But I'm wondering ... where is all the CO2 produced by our burning of fossil fuels going?
  29. What do the hacked CRU emails tell us?
    Just to make it clear: I do not defend their approach to the divergence problem in that case, in particular their presentation.
    Not "their", but one person, and in the case under discussion, one graph which appeared in one brochure put together by the WMO. In the published literature, the "divergence problem" is, of course, openly discussed (it is scientists in the field who coined the term in the first place), comparisons of reconstructions with and without the troublesome recent decades made, comparisons to the instrumental record made, etc etc. If the divergence problem were being "hidden", etc, denialists wouldn't know about it and wouldn't've been screaming about it for years. Denialists only know about it because it's a well-known issue in the field, not because they've recently read some stolen e-mail messages.
  30. What do the hacked CRU emails tell us?
    This isn't science, its arranging data to suit a pre- conceived agenda
    Yeah, the "preconceived agenda" which is ... hmmm ... let me think: The instrumental (thermometer) record is more reliable that tree ring proxies, and when they conflict, the direct measurement is preferable to the indirect proxy. Some agenda. Some conspiracy.
  31. What do the hacked CRU emails tell us?
    I'm sorry, but it is not true that the inaccuracy of the proxy data within about 0.5C of current temps has nothing to do with the MWP. Many points during the MWP had similar proxy values to the post 1961 values. (http://www.21st-century-citizen.com/Hockey_stick_chart_ipcc1.jpg) If the post 1961 proxy values can mean that temperatures are as high(or higher) than current ones, then obviously it is *possible* that MWP temps were also as high (or higher) than currently. Also, it bears mentioning that it does not follow necessarily that a warmer MWP means that feedback is higher, it is also possible that forcing was higher than our current estimates allow for. Cheers, :)
  32. What do the hacked CRU emails tell us?
    John, this is a very serious disagreement over the physics of planetary warming, or lack thereof over the last few years. It has the potential to profoundly impact policy-makers decisions. Can you explain the physics to Trenberth's satisfaction?
    Can you explain why Trenberth disagrees with your assessment regarding policy to my (or anyone's) satisfaction if your reading of the tea leaves (sorry, "random selection" of purloined e-mail) reflects the level of uncertainty being discussed? As Ternberth himself complains, his scientific work is being misrepresented by the denialist camp. A relatively minor problem - existing instrumentation isn't sufficient for researchers to close the earth's energy budget during La Niña (the cooling he's talking about) - is being misrepresented as somehow contradicting the underlying physics or the basic fact that the earth is experiencing a long-term statistically significant warming trend. "We don't precisely understand the physics of how La Niña shuffles energy around" does not translate into "maybe global warming doesn't exist", etc.
  33. What do the hacked CRU emails tell us?
    "Objectively" chosen or not, temperature reconstructions being what they are, it is virtually unavoidable to separate measurements into the ones that reflect a real temperature signal and those that do not. You have to make some assumptions one way or the other. If you already know what the "correct" answer is, it is human nature(at least IMO) to be more likely to reproduce that answer again.
    Have you read anything on how, for instance, tree ring chronologies are chosen for temperature proxy work? It's not based on "confirmation bias" based on recent warming, but rather on site characteristics and ring morphology that reflects known temperature signatures in tree ring tissue based on knowledge of tree physiology. The confirmation bias, I guess, would be the assumption that trees today grow very much like trees did a thousand or two years ago. The weakest assumption - acknowledged in the literature - is that the single most significant limitation on growth is likely to remain the same for long periods of time at a single site. The basis for this assumption, I imagine, is that the "long" timescales they're looking - one or two thousand years, say - are just a blink of an eye geologically. But that's not "confirmation bias" as you're speaking of it. Really, go read, don't speculate. I spent a day reading up on the dendro/temperature proxy stuff - reading intelligently (i.e. ignoring McIntyre, jeff Id, and the like in favor of scientific sources of information) - and was able to learn quite a bit. Enough to know you're just speculating.
  34. Record high temperatures versus record lows
    Albatross, thanks for the info. Do you recommend anywhere to look regarding background on lightning and land-atmosphere feedbacks?
  35. What do the hacked CRU emails tell us?
    To date, there has not been a single credible journal article that shows a natural cause for the modern day warming while also showing how record high greenhouse gas concentrations are not significant. NOT ONE. Do people really believe that the scientists at CRU are able to squelch every scientist on the planet who tried to publish this landmark anti-AGW paper? Is there no sense of the low probability and the large scale of this conspiracy for this to be true? If one throws out the HadCRU data and all papers by these folks, there is still a mountain of evidence for AGW. Do the rapidly melting ice sheets and glaciers have access to these emails and joined in on the conspiracy? Do the various climate models that show GHGs as the dominant forcing mechanism have access to these emails and joined in on the conspiracy? Do the GISS, UAH, RSS data have access to these emails and joined in on the conspiracy? Certainly Spencer and Christy would not align themselves with AGW and yet their satellite-derived measurements track reasonably with GISS, RSS, and HadCRU. Does the ocean read these emails and magically increase its heat content? Does the cooling stratosphere (even accounting for ozone loss) read the emails and join in on the hoax? Do the plants and animals read these emails and decide to die off and/or change their migratory habits so that they can support the conspiracy? I could go on ad infinitum. For quite a long time, we have known that a doubling of CO2 will warm the climate at least 1C and there is fairly good certainty that the resulting feedbacks will produce at least 2C additional warming with 3C more likely. We are also measuring CO2 increases of 2 ppm and climbing (except last year where there was a slight decrease due to the global recession) and we have levels that have not been seen in the past 15 million years. Are we to conclude that these emails deny all of this evidence? It is obvious that pre-Copenhagen, the tried and true method of “if one does not like the message then attack the messenger or redirect the conversation” practiced by Big Tobacco and now Big Oil and their front groups (Heartland Institute, George C. Marshall Institute, Competitive Enterprise Institute, etc.) is alive and well. Scott A. Mandia – Professor, Meteorologist, Concerned Citizen http://www2.sunysuffolk.edu/mandias/global_warming/
  36. Water vapor is the most powerful greenhouse gas
    For one: The reason "I don't know enough to argue in any specialized field" is quite simple due to the fact that next to the majority of what is to be read is not worth it. A lot of it is in my view often stating trivialities cloaked on science language. On the other hand by far too often statements are made that can't stand any initial logical evaluation. Let's take as an example for the latter the wikipedia article on water vapor you referred to. Now let's just take a look at the paragraph on Condensation. I will include my comments in lines starting by the usual comment sign known from programming # continued citation will be marked with an >. It states: Water vapor will only condense onto another surface when that surface is cooler than the dew point temperature, or when the water vapor equilibrium in air has been exceeded. When water vapor condenses onto a surface, a net warming occurs on that surface. # not necessary because that would depend on the ability of that surface to hold additional heat (energy). > The water molecule brings a parcel of heat with it. # why referring here at molecules when this amount is given in the properties section as 2.27 MJ/kg. I'm too lazy to look up what that would make in watts but I'm pretty sure we are talking about real energy here and not some negligible portion as indicated by the term parcel. >In turn, the temperature of the atmosphere drops slightly. # That is absolute nonsense it implies that the surface it condenses to absorbs more energy (heat) than is set free in the process. > In the atmosphere, condensation produces clouds, fog and precipitation (usually only when facilitated by cloud condensation nuclei). # Does that mean when taking place in the atmosphere no energy (heat) is released at all or maybe absorbed by the condensation nuclei? That would be a rather absurd notion and to my knowledge contradict the first law of thermodynamics. ># I canceled the rest of the paragraph. So far so well (or not so well). I hope this made a bit more clear what I mean when speaking of "not knowing enough". Now, this is what happens in my view: Given the right conditions water evaporates mainly near the earth surface. Due to it's density it then starts a path to higher altitudes. If then again the conditions are right it condenses and continues it's route until at last it comes down again as rain, snow or hail. In the process of evaporating the amount of 2.27 MJ/kg of energy is used. Logic dictates that the same amount has to be released at condensation. I hardly dare saying that it should be obvious that at the point where condensation occurs it's getting warmer. Now given the fact that on average water stays only 10 days in the atmosphere this is a real fast process. Now I'd like to know if you can find something wrong in this statement. Anyway it would prove a better starting point for a real discussion because it is more suitable to uncover differences in the understanding of the basic principles.
  37. The albedo effect
    Henry, I already answered your #75 in my comment #69. Extra water vapor "added by humans" includes water evaporating from human-created pools.
  38. The albedo effect
    Henry (#74), I answered your #68 question already in my #55. But apparently you stopped reading before you got to my last paragraph, where I pointed you to a list of scientific papers reporting on experiments that systematically varied the concentration of CO2, and other parameters, and measured the effects. Those empirical results, and others, have been built into a graphical computer program by David and Jeremy Archer, that you can run to see the effects of varying concentrations of CO2, water vapor, and other factors, in the transmission of radiation through the Earth's atmosphere.
  39. The albedo effect
    @Tom at 72 There is an important point that you forgot. As we have discussed much earlier in this subject, one of the reasons that the earth's albedo increased, is (probably) because of increased human activities concerning the creation of shallow waters (dams). This is water for human consumption and irrigation. This water heats up (easily, because it is shallow)), and water vapor is created. This traps the heat coming from earth. This is what is definitely not counted in AHF?
  40. What do the hacked CRU emails tell us?
    What worries me most is the science discussions suddenly turn into politicized discussions where pro- and contra- arguments fly across the table. There is no need for a contra AGW discussion, the CRU data hack didn't change the discussion at all, because man made global warming is widely accepted despite the fact that real data are added back in.
  41. What do the hacked CRU emails tell us?
    To neilperth I seem to agree with every word you say. No changes.
  42. What do the hacked CRU emails tell us?
    John, It is clear that skeptics are the badguys. But when they ask, "OK, so if CO2 is the culprit, what alternative do you propose? And what are the risks of these solutions?", all that you find on this website is the same churning about CO2, CO2, CO2. Where is the science that points to solutions and alternatives??? Whether global warming is manmade or not should have no relevance if the alternatives are so attractive and have no "risks". Please explain.
  43. What do the hacked CRU emails tell us?
    Regarding your response above, my reply is as follows : It is clear from some of the hacked Hadcrut emails that the climate research scientists agree that they do not understand why there is a lack of warming at present and that their computer models do not predict this lack of warming. There are also emails which state that when climate changes, it is often difficult to apportion the cause ( man-made, natural or some combination of the two. ) Your statment above : "there is a greater than 90% chance that humans are causing global warming" is not correct is it ? It should read : "there is a greater than 90% chance that humans are having some effect on global warming - but natural forcings still play an important part" In any event, given the many factors that go into any estimate of probability in this case, I would not take the scientists 90% chance claim seriously in terms of a statistiacl probability. I believe that in the IPCC reports this probability is expressed as more of a "gut feel" rather than a statistically calculated probability. If all the uncertainties are taken into account, each with its associated confidence interval, I would be amazed if the result would be a 90% probability. If this 90% chance was based on a statistical calculation, do you have the complete data sets used as I would like to see them? Many (most ?) skeptics ( including myself ) are not anti AGW or anti environment. I would say that most (?) of us would agree that the temperature is rising in general and would agree that trying to curb toxic emmissions is good. What I cannot abide is the fact that the way of doing this ( carbon tax, possible " world government", passing billions of dollars over to third world countries etc ) is the wrong way. It is clear that this scenario would be based on very shaky science and one would have to be naive not to realise that such a decision would be motivated by wider political considerations.
    Response: You're putting the horse before the cart. Carbon taxes and one world governments have nothing to do with climate science. The confusion and muddled thinking that occurs when politics are inserted into climate debates are the reason why this website is concerned with a single question - are we causing global warming? The answer to that question lies purely in the realm of science and empirical measurements. I would encourage you to clear your head of one world governments for the moment and consider what observed empirical data has to say about man's influence on climate.
  44. CO2 effect is saturated
    i thought venus's atmospheric pressure has a lot to do with its temperature?
  45. It's cooling
    i'm new to this and i'm a skeptic. however, i'll admit that the planet is still warming. using satellite data from UAH and RSS, if you look at the past decade or so including 1998, it shows a cooling trend. however, if you remove the 1998 el nino freak year, the planet is still warming at a similar rate to pre-1998.
  46. CO2 is not the only driver of climate
    commenting on IPCC radiative forcing diagram: gee...so many anthropogenic causes and just one natural variable? does that seem a little biased? has the IPCC really investigated all the variables, or did they decide that humans were the cause before the investigation?
  47. What do the hacked CRU emails tell us?
    For me, what comes out of the hacked Hadcrut emails is that there is much disagreement between scientists about many aspects of climate research, particularly in the area of interpretation of proxy data. That is tree-rings, ice cores, lake sediments etc. One email states that it is generally considered by scientists that the effect of the solar cycle cannot be identified in the temperature record. The same scientist then does some research and comes to the conclusion himself that effect of the solar cycle can be identified in the temperature record. My point is that the emails show that there are large uncertainties in the field of climate research. But it seems we have not been told this. We are instead told that the science is settled. It is not ! And now world governments want to spend hundreds of billions of dollars fighting this global warming (or is it climate change ? ) based on such shaky science.
    Response: Certain key questions are settled. The warming effect from CO2 is known with high understanding and directly observed by satellites and surface measurements. The planet's energy imbalance is directly measured from ocean heat and satellites. There are other areas with higher uncertainty such as the radiative effects from aerosols or the behaviour of clouds as climate warms. When all the uncertainties are considered, climate scientists conclude that there is a greater than 90% chance that humans are causing global warming (I believe this actually understates the certainty).

    If you were told there was a greater than 90% chance that a plane was going to crash, would you get on board with your family? And yet this is the risk skeptics are happy to take with the planet we're handing over to our children and grandchildren.
  48. What do the hacked CRU emails tell us?
    re: divergence problem I don't see why people seem to have such a hard time understanding this issue. There is a variety of proxy data available as well as the instrumental record. There is no problem with omitting proxy data that deviates from observed results. If I have 10 clocks in my house and I notice that one of them starts working: 1) I know that it is more likely that one clock is giving the wrong reading than the other 9 showing the same wrong reading. 2) It would be silly to criticize me for not using the errant clock when its clearly wrong. It is neither devious nor underhanded to avoid the bad clock. I have to admit that I thought the CRU leak was going to be a big deal. After reading through it and reading the explanations given I am surprised that so little of substance can be used to criticize the team. I do think as a PR issue they should make a statement which will clear the air and also serve as a scary science lessen for those that think AGW is a hoax.
  49. The albedo effect
    I note that nobody answered me directly on 68! Steve, nobody has shown to me in an experiment what the influence is of 70 ppm's of CO2 that were added to the atmosphere since 1960. The formiula's and the values for the forcings for CO2 concentrations just fall out of the air somewhere (no pun intended). 1.7 has been mentioned. Tom talks about 2.6. Riccardo even has a formula. I just don't know where those vales come from. I want to see experiments and meaurements, not proportional blame that the IPCC has decided upon/ based on comparisons to concentrations back to as far the year 1750. If it is so easy for you, why not just explain to me how the experiments were done? I asked you to comment on 68 and you did not. I am saying: whatever is causing global warming (if it still happens) my conclusion from whatever "evidence" I have seen so far is that it is not caused by CO2. As Weart told me some time ago: you cannot see the evidence because the wise men have decided to hide it in papers that cannot be accessed. If it is so difficult to explain as to how the tests were done that proves that those 70 ppm's of CO2 added are significant, how can we expect non-scientists to make the right decisions in Copenhagen?
  50. What do the hacked CRU emails tell us?
    @billbrent, 54 "John, this is a very serious disagreement over the physics of planetary warming, or lack thereof over the last few years. It has the potential to profoundly impact policy-makers decisions. Can you explain the physics to Trenberth's satisfaction? Or to the satisfaction of the average layman - like myself - who is concerned about the social engineering being proposed based on this very physics? " Why don't you check the facts before jumping to conclusions? And with explanations easily available, your reference to and interpretation of the notorious "Mike's Nature trick" either shows an ignorance I would not expect from contributors to this site, or willfull misrepresentation. Just to make it clear: I do not defend their approach to the divergence problem in that case, in particular their presentation. But it's not fraud to proceed as they do. And it's not about the benefit of doubt here, the wording uses "trick" as in my favorite definition of "method": "A method is a trick that you use twice." Any attempt at a fair interpretation would show up this. And no, it is NOT a fair interpretation to pick one that implies malpractice without checking alternatives first, even if that one comes easily to mind. Then, to "very serious disagreement over the physics of planetary warming". You did check all the details before you make such a sweeping statement, didn't you? Oh no, then you wouldn't used that wording. First, the "balancing of the energy budget" is according to Trenberth's standards, and they are higher than average, to say the least. Second, this is mostly not about lack of physical understanding, but lack of data. The observations show that the models are not adequate, and they have to be improved. Which is not shocking unless you have had very much faith in the present incarnations of the models - and that may be the case with some in the general public. I'm concerned that the results may have been oversold. But the focus on this blog is on the science, and there is really nothing new or very problematic in what Trenberth is talking about. To get us where he wants may very well imply some methodological revolutions, but almost surely none of physics. To put it simple: The positive feedbacks, while still very significant, have been smaller than implied by the models, and now they are looking into why. Your concern about "social engineering" is valid. But to me, it's a bit the other way around: Increasing the GHG emissions as we do is a gigantic, for a large part non-reversible, experiment, and THAT should not be allowed unless we know the consequences fairly exactly, and there is global agreement that they are acceptable. We know, both from theory and observations, that anthropogenic global warming occurs, the question is about the extent. And, contrary to what many "skeptics" maintain, that question is not that relevant to decide about regulations of GHG emissions. Why? First, even with zero positive feedback, "carbon liberalism" will get us into climate problems pretty soon. Second, even with small temperature changes, CO2 emissions will, sooner or later, lead to catstrophic acidification of the oceans. I might add a third: Sooner or later, we have to get off the fossile fuel hook anyway. And why not sooner, when we, basically, already have the technology? But that's not something we should focus on here, I think.

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