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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 55751 to 55800:

  1. IPCC is alarmist
    'Don't expect SkS readers to fossick around in that mess. Cite one portion from WG1 that is based on 'grey literature.' ' I already cited on Rob http://www.newscientist.com/article/dn21940-climate-panel-adopts-controversial-grey-evidence.html
    Moderator Response:

    [DB] Do you understand the distinctions between WG1, WG2 and WG3? Your link (essentially a newspaper article/blog post) deals with WG2, not WG1.

    Again, you asserted that the whole IPCC report, which includes WG1, was based on grey literature.

    Try again.

  2. IPCC is alarmist
    'Rob, I think it would fairer to suggest the krisbaum is reading frothing-at-mouth denialist sites and prefers to believe what he is told there.' I think its a little unfair you can write such things about me - I havent been nasty to anybody here.
    Moderator Response:

    [DB] "I havent been nasty to anybody here"

    Actually, your very first comment in this forum contained sufficient vitriol towards a regular member of this forum that the entire comment necessitated immediate deletion. Nevertheless, can all participants exercise more discretion in their comment formulations, please?

  3. IPCC is alarmist
    Rob, I think it would fairer to suggest the krisbaum is reading frothing-at-mouth denialist sites and prefers to believe what he is told there. krisbaum, you are implying lead authors have "vested interests" in results. What is the basis of this belief? By the way, I would be perfectly happy for Exxon staff to be reviewing and writing what they would so long as they are Exxon's scientists. I am oil man. By your interpretation of the world, I should be a rabid anti-AGW activist because AGW threatens my current position. In fact, I mostly find widespread acceptance of the IPCC conclusions among my colleagues and client's scientists.
  4. IPCC is alarmist
    Don't expect SkS readers to fossick around in that mess. Cite one portion from WG1 that is based on 'grey literature.' If you're familiar with the details it won't take long. We're waiting.............
  5. IPCC is alarmist
    How about showing us a portion in WG1 (the scientific basis) that is based on 'grey literature.' Failure to do so will lead to the inescapable conclusion you simply made that up.
  6. IPCC is alarmist
    DB - i cant furnish your request unless I know what your interpretation of 'reputable' is ????
    Moderator Response: [DB] Either something like a commentary paper in a peer-reviewed journal or showing directly which section of WG1 was based on which specific piece of grey literature. It was your statement; it is incumbent upon you to be able to furnish documentation supporting it...or to withdraw the assertion.
  7. Watts' New Paper - Analysis and Critique
    Just saw this little gem over at WUWT: Ric Werme says: August 3, 2012 at 1:58 pm ........... It might be interesting to take pre and post homogenized data and see how that displays and analyzes. Is there anyone here who can help this poor guy out? ;)
  8. IPCC is alarmist
    'To suggest that government should not be involved is absurd. ' Thats correct, the government should not be involved in generating the report. Like I mentioned before, do you have the police judging their own court cases? Do you have the government enforcing their own laws? We have separate entities for a reason. 'what like the scientists of the world? That was the idea in drawing up the IPCC. Who do you propose should do this audit? the uninformed?' Its pretty easy to find people that have no vested interests in the IPCC's conclusions. You dont need to audit what the auditors write - you just need a cross-check from another external party. Over a 3rd of their sources are grey like i mentioned, yet Pachauri declares all sources 'peer reviewed literature'. So he says one thing and does another. Let it be clear the shortfallings of the report, or enforce your standards. Grey literature is used throughout the whole IPCC report. The fact you admit there was grey literature is enlightening. Dont you therefore see it a problem Pachauri tells everybody that its peer reviewed when its not?
    Moderator Response:

    [DB] "Grey literature is used throughout the whole IPCC report."

    Please provide a link to a reputable source that documents the usage of such literature in WG1, or, failing that, provide a link to that portion of WG1 in question and to the grey literature on which it was based. Note that fake-skeptic blogs are not reputable.

    Failure to provide such a link will result in further moderation of your comments here.

  9. IPCC is alarmist
    krisbaum at 10:23 AM on 4 August, 2012 Actually, you have made my day. Thanks. I think these news broke here at SkS too but I somehow missed it. And ok, you realize the police/judge/offender juxtaposition was a bit too much. Thank you again for being this open minded. So your main criticism is that the process does not garantee the quality of the information. You even imply that it has vested interests, and is therefore biased (correct me if I read too much from your comment). I will set aside for a moment the fact that it is painfully and repeatedly reviewed by thousands of scientists from all over the world before publication - including countries that make great efforts afterwards to ignore it in pratice. After 22 years, we have had time to check some of the main projections, and they are basically right. Even too conservative sometimes (sea level rise). Where would you say the report missed the point and got carried away by its "bias"? (it's bedtime here in Brazil, so see you tomorrow)
  10. IPCC is alarmist
    "You have countless IPCC staff who are inexperienced scientists and not experts. They determine what to include and what to not include from the science - and that doesnt just mean peer reviewed". The IPCC doesnt have countless staff - it has next to none. The review decision is by lead authors who are not IPCC staff and are chosen as the experts in their field.
  11. IPCC is alarmist
    Krisbaum - governments govern. That's what they do. They do it will if their policy is well-informed. To suggest that government should not be involved is absurd. They requested the report. Yes, the editors make their decisions but every decision is transparent. Which one do you agree with. You want audit by others with no vested interests - what like the scientists of the world? That was the idea in drawing up the IPCC. Who do you propose should do this audit? the uninformed? And whose choses the auditors? And would you then demand audit of the auditors if you still didnt like the answer. Note that "grey literature" was only used by WG2 in the absence of any other. However, you are challenging WG1 but so far I dont see a basis for that.
  12. IPCC is alarmist
    *if it wasnt for these people we'd have polluted water, rivers and probably be dead by now.
  13. IPCC is alarmist
    DSL; There is no error in my analysis - the problem is much wider than 'a few erros and loose practices'. You have countless IPCC staff who are inexperienced scientists and not experts. They determine what to include and what to not include from the science - and that doesnt just mean peer reviewed, they also include other grey literature. Something like 1/3 of the references in the last report are grey literature - WWF reports, Greenpeace, news, un-peer reviewed.. etc.. If you believe this kind of working practice is acceptable then fair enough, I on the other hand think its not. The world needs people who believe and are passionate. I have no problem with activists, climate activists or environmentalists - on the contrary - if it wasnt for some of these people, but - you have to consider people's vested interests and take precautions to make sure those interests dont get in the way. It would be like the IPCC obtained funding and had 1/3 of its staff filled with Exxon employees. What would you think then?
    Moderator Response:

    [DB] "You have countless IPCC staff who are inexperienced scientists and not experts."

    Participants here are not allowed to simply make things up as they please. You will need to furnish source citations for extravagant claims such as this. Else moderators will intervene.

  14. IPCC is alarmist
    krisbaum: "My suggestion is that, considering the report produced by the IPCC is being used to decide one of the most critical fates of humanity - spending trillions on alternative energy in effect - there could be an external policing of their processes." This represents a fundamental error in analysis on your part, krisbaum. The IPCC ARs gather the existing science and integrate it into a readable summary. If the IPCC did not exist, the science would still be there saying the same thing, and the probable outcomes would be just the same (or arguably worse). You imply the IPCC is a bad idea and subject to corruption. I say not having the IPCC is a worse idea. I can imagine a version of the IPCC that is worse than nothing at all, but the current form is far, far from that. I agree that the process can improve, but I fail to see how a few errors and loose practices (recognized and in correction) are justification for condemning the whole process. You also seem to assume that all of the regular SkS posters bow before the IPCC and are oblivious to its problems. No. In fact, they are so aware, from having to explain it daily, that they know where practice is sound and where it needs work. It is a large project with many aspects. It does inform the world, and it does a much better job than individuals trying to piece together the science and then explain it and the implications to the world.
  15. IPCC is alarmist
    Michael Sweet; ' In fact, the governments of oil producing countries, with help from the USA, diluted the conclusions of the scientists in the SPM. Your suggestion that the IPCC is alarmist is backwards, it reduces the conclusions to make AGW seem less of a problem' Well, this alarms me just as much as the opposite. No government should have their hands in diluting or concentrating such a report. Its my point exactly. At least we agree that politics is getting in the way ;).
  16. IPCC is alarmist
    Alexandre, It is here in Australia - the IPCC is quoted as the definitive place to go to for climate change science/recommendations. It was pivotal in the stern report brought out in the UK, and without it there wouldnt be a Carbon Tax in Australia. I think the police analogy came across wrong. What I mean is, they produce a report but there is no external auditor or group of people that have no vested interests, scrutinising the report and how its generated. So Alexandre - ther's your meaningful example - the Carbon Tax in Australia.
  17. IPCC is alarmist
    krisbaum at 10:08 AM on 4 August, 2012 Actually, 1)it's not really being used in practice 2) and governments struggle to ignore it, instead of convinceing themselves, let alone anyone else but that's beside the point. They gather information from openly available sources. Certainly not the offender, or judge, or police officer of the world. "Ignored scientific comittee" would be closer to the mark, I guess. If you disagree, could you please make my day and point to any meaningful measure to cut down emissions that has actually been taken? With or without the IPCC's report help?
  18. IPCC is alarmist
    Oh and this New Scientist article talks a little bit about the use of grey references (reference to un-peer reviewed sources and other grey literature). http://www.newscientist.com/article/dn21940-climate-panel-adopts-controversial-grey-evidence.html
  19. IPCC is alarmist
    Alexandre; They produce the report used by governments to convince the world about global warming & the science behind what we know at present. It has to be one of the most important documents on the planet at present. It is used to decide the fate of trillions of dollars of investment through carbon taxes or emissions trading schemes.
  20. IPCC is alarmist
    sorry guys i'd love to communicate more, but the moderator keeps 'snipping' my views
    Moderator Response:

    [DB] Comments constructed to comply with the Comments Policy never need moderation. Comments in violation of it, such as yours, invite moderation. As do complaints about moderation.

    This is a moderated forum in which the science of climate research and climate change is discussed. The no-holds-barred, anything-goes discussions commonplace on fake-skeptic blogs have no place here. FYI.

    Moderation complaints struck out.

  21. IPCC is alarmist
    krisbaum at 09:49 AM on 4 August, 2012 Man... you imply the IPCC is doubling as police force and judge?! For a crime they commited?! What kind of power do you think the IPCC has, besides gathering scientific papers and putting them together in a report?
  22. IPCC is alarmist
    Michael; And to reply to your final part. My suggestion is that, considering the report produced by the IPCC is being used to decide one of the most critical fates of humanity - spending trillions on alternative energy in effect - there could be an external policing of their processes. I'm sure you can work out for yourself how this could work in the future - the rest of the world seem to be capable of such ideas - take law enforcement and the state for example. Do you see judges doubling as policemen and appearing on their own jury for a crime they've been accused of?
  23. IPCC is alarmist
    'The SPM is reviewed word by word by representatives of all the countries. It is released in advance so that anyone interested can read it and develop their arguments (the draft of the scientific report is already on line for review when the SPM is written). Are you suggesting that the Bush Administration did not look out for oil interests and keep in mind the deniers arguments in this word by word review? ' Micheal Sweet; The point is; they hold a plenary with politicians and together create the SPM for release into the world before the main report has been released!!! How can the summary be validated against the main report or scrutinised correctly by external scientists? (-Snip-) (-Snip-).
    Moderator Response: [DB] All-caps usage (forbidden) converted to bold; moderation complaints and sloganeering snipped.
  24. IPCC is alarmist
    Tom Curtis; Greenland aerosol measurements tell you nothing, it is fairly common knowledge that aerosols do not travel far from their source typically 10km or so. You need localised measurements to get any kind of global pattern. Michael Sweet; 'The entire IPCC report is put online for comments before the final review. ' Yes it is, but the final version is the responsibility of authors, and they declare what changes will be incorporated into the final version and which wont. Sure here's an example of appointing non-experts; http://www.pik-potsdam.de/members/richardk/ Richard Klein .. An IPCC Lead Author at the age of 25 - back in 1994 after completing a geology degree 2 years prior. at 28 he was promoted to the most senior role - Coordinating Lead Author..
  25. The Independence of Global Warming on Residence Time of CO2
    Falkenherz: 1) The mass balance argument is an inductive, not a deductive argument. That is, its premises can be correct and its conclusion false. 2) The same is true of the other nine arguments I presented leading to the same conclusion. This is true both separately and conjointly. 3) The same is also true for the various arguments that the Sun rather than the Earth is at the center of the Solar System, that Relativistic, not Aristotelian, mechanics govern the behaviour of bodies, and indeed, that the Earth is not flat. 4) The question of interest is not whether the truism that scientific evidence is not deductive is true, but whether an alternative explanation to anthropogenic emissions as the dominant cause of the increase in atmospheric CO2 can be found. Any such explanation must be more elegant than the anthropogenic explanation otherwise it is a worse explanation and should be rejected. The alternative explanation should also make novel falsifiable predictions, and not resort to magical thinking (such as relying on physical sorting mechanisms that can distinguish between CO2 molecules which are physically identical, but have a different origin). No such alternative explanation has ever been proposed. Deniers have not even come close to proposing one. The nearest they have come is to propose an alternative that explains just one aspect of the evidence and rigorously ignores all other evidence and which makes no novel empirical predictions. Every proposed denier explanation I have seen has been contradicted by known facts, and makes fewer empirical predictions than does the theory of the anthropogenic cause of the increase in CO2 concentration. Frankly, I have seen more coherent and better worked out theories of geocentrism than any theory of natural increase in CO2 proposed by deniers.
  26. The Independence of Global Warming on Residence Time of CO2
    Falkenherz, ok yes a 'magical CO2 sink that absorbs 100% of human CO2 emissions and 0% of natural emissions' could 'disprove' the mass balance argument. However, even if it weren't inherently impossible... it would be contradicted by half a dozen other lines of evidence. That is, if a magical human CO2 sink existed then the strong correlation between human CO2 emissions and atmospheric accumulations (both in timing and rate) would be anomalous. Likewise, the C12/C13/C14 ratio changes indicate that fossil fuels are the source of the atmospheric increase... which would be odd if a magical sink were removing all the fossil fuel carbon. Et cetera. So even if we allow for one 'leprechaun' to invalidate the mass balance argument we'd still need to throw in a pixie, a couple of unicorns, and a bandersnatch in order for it to hold up in the face of the other evidence. 'It is not technically impossible'... well, no... but you'd have to be crazy to think otherwise.
  27. Surface Temperature Measurements: Time of observation bias and its correction
    Thank you Bob. You are right, it is a short 4-page letter. I have corrected this on my blog and also made the doi link more user friendly. I hope an admin can do the same here.
    Moderator Response: [DB] Updated post accordingly.
  28. The Independence of Global Warming on Residence Time of CO2
    Falkenherz: A sink that only reacts to fossil, not natural CO2 is not speculation - it's fantasy. When the the CO2 from this "natural" source has the exact same characteristics (isotope ratios, O2 reduction, etc., which are required as a result of the other evidence) as the fossil source, how is the natural sink supposed to know to suck up the fossil CO2 and not the natural source? "Not very probable" is in the rhealm of "when monkeys fly out of my butt".
  29. The Independence of Global Warming on Residence Time of CO2
    Ah, sorry, maybe I should have mentioned that I continue that same discussion from under a different article ("human fingerprint"), where a comment relayed me to this article here.
  30. Surface Temperature Measurements: Time of observation bias and its correction
    Minor correction: the last reference should be Geophysical Research Letters, not Journal of Geophysical Research. It's wrong on the original web page. Volume number, etc. are OK, and DOI leads to the correct spot (if it's an exact copy of the original web page).
  31. The Independence of Global Warming on Residence Time of CO2
    John thanks for the nice link, it always good to talk in pictures. KR, CBDunkerson, the flexible sink would react only to fossil, not to natural CO2 input. That is where I would map the analogy. E.g. because of a yet unknown mechanism, sinks are taking up fossil sources faster than from natural sources, and in place of fossil CO2, the increase in atmosphere really comes from some more arbitrary methane belching. This is of course speculation, as there is no knowledge about something like this, and I only do this in order to understand sceptics like Julian. It is sort of an "maybe we don´t know everything about it" point, which you can never ever totally deny. Your response here is, well, we do know a lot and nothing makes this kind of speculation very probable. E.g. the mechanism of oceans' uptake could be not so selective that it would priority-process the fossil CO2; the increase is proportional to increased fossil output so that breaking that obvious connection would require more than just abstract speculation; etc. That´s why I agree, it is indeed about LGM or Leprechauns. But who knows, maybe they are real, anyways... ;)
  32. Ivar Giaever - Nobel Winning Physicist and Climate Pseudoscientist
    Ah, this is a pity... I had to suffer through the whole video and argue with sceptics about his ridiculous claims all by myself, because I did not find this website in time... For me this shows that either Nobelpreis can sometimes be given to the wrong persons, or Nobelpreis really says nothing about the winner's personal scientific integrity.
  33. Ivar Giaever - Nobel Winning Physicist and Climate Pseudoscientist
    With tongue firmly in cheek, and full credit to Saturday Morning Breakfast Cereal and to "Jeremy" on Realclimate for pointing this out: The Life Cycle of Physicists
  34. Surface Temperature Measurements: Time of observation bias and its correction
    Good to see this post by Victor given additional visibility by reposting it here ...
  35. BEST Results Consistent with Human-Caused Global Warming
    C02 at near 400ppm is totally not acceptable- and we are near that now- though the effects of this are 25 years away- what we are seeing now is C02 just past 350ppm. The weather extremes in years to come will become worse- far worse. How society is able to hold up to an increasing erratic climate is an unknown. But it is likely to be chaotic. Over the long haul we we are likely to see C02 near 650ppm- perhaps higher and at least 3.5 degrees C in warming over the PI era- we will not see 350ppm again for at least a thousand years- perhaps longer.
  36. Is Greenland close to a climate tipping point?
    Falkenherz, no I didn't mean to imply that no portion of Greenland other than the summit melted in 1889 (or whichever year it was). Rather, the study with the '150 year' (on average) melt events was looking only at melting near the highest point... and thus doesn't tell us anything about the rest of the ice sheet. Each of previous occurrences could have been extremely localized, covered a significant portion of Greenland including the summit (most likely), or have been similar 'nearly all of Greenland' events. Basically, we know that the summit melted every 150 years on average. We don't know how often the entire ice sheet has melted. JohnB, the 'melting could stop' paper seems to me to sail right past the fact that the previous 'melting stop' they base their conclusions on happened during a cooling period before the main effects of global warming had kicked in. The ice sheet didn't just magically stop declining... it was due to climate factors which are no longer possible.
  37. Philippe Chantreau at 03:50 AM on 4 August 2012
    IPCC is alarmist
    Tom Curtis addressed the claims in post 25 above, I thought I'd add that, historically, the serious study of atmospheric aerosols dates back to the time when atmospheric sciences started being a field of their own and separated from geology, inthe late 1800s. Seminal work on the subject was published by Aitken in 1888, 1891, 1894, 1895. As of today, aerosols are the focus of intense work, and several scientific journals are exclusively dedicated to the subject.
  38. Daniel Bailey at 03:38 AM on 4 August 2012
    Is Greenland close to a climate tipping point?
    Without knowing which specific glaciers & portions thereof the aerial recon imagery covered, and having not read the study itself but just the abstract, I would caution against overly broad interpretations of the study. It covers a specific sub-region of a region of the world, the NW portion of the GIS. There is no mention of ground-truth comparisons of the dted's, a must-have to ensure accuracy (from personal experience working with such models). Also, differing topographies and differing season with differing deposition rates produce dynamically different responses in flow rates of the ice. Given that, I fail to see how anyone can derive anything scientifically useful out of the abstract alone, as there simply is not enough context for meaningful interpretations of the results vs the area of coverage itself, let alone the rest of the GIS. Therefore, the newspaper article is nothing but disinformationist overhype. Wait for the assessments of real glaciologists for proper understandings.
  39. It's not us
    Falkenherz, the problem is that your example assumes we only know one variable... the total atmospheric accumulations (the end result of each of your calcualtions). That is incorrect. We know accumulations and human emissions. The mass balance argument only works when using both of those values. Thus, your counter argument is 'correct' only if we ignore some of the data we have.
  40. The Independence of Global Warming on Residence Time of CO2
    Falkenherz wrote: "Again, this thought experiment is just to point out that mass balance is not an argument for itself that rising CO2-levels in the atmosphere automatically attribute to man made CO2." No. The mass balance argument is sufficient, in and of itself, to show that rising atmospheric CO2 levels have been caused by humans. For each of the past ~50 years we know the amount of CO2 released by human fossil fuel burning and the amount of CO2 increase in the atmosphere. In all of those years the amount we released has been greater than the amount which accumulated. Thus, the various 'analogy possibilities' you raised are not not possibilities. The only way that human emissions exceed atmospheric accumulation each and every year is if the net of other (i.e. natural) factors is taking some of the carbon out each year. It doesn't matter if the various components increase, decrease, or do the lambada... so long as we emit more than accumulates we are unquestionably responsible for 100% of the accumulation.
  41. Is Greenland close to a climate tipping point?
    JohnB @18 There's some comment on the same paper at CarbonBrief that is perhaps a little more balanced than TheRegister post you link to. The paper in question Kjær et al 2012 examined aerial photos to obtain local melt data back to 1985 giving 27 years rather than the 10 years of satellite data. Their findings is suggesting to them that rising Grennland temperatures, rather than resulting in a new regime of ice-loss, may result in a melt event lasting a few years followed by a new regime with less extreme ice loss, or 'stabalisation'. They suggest recent data from the likes of GRACE is too short a record and may only be seeing the melt events, not the longer term stabalisation. The language used by the lead author appears designed to attract attention. "It is too early to proclaim the 'ice sheet's future doom'..." is one of the quotes CarbonBrief got from him.
  42. BEST Results Consistent with Human-Caused Global Warming
    Micheal and Dana, What is safe? and over what time period? Crux questions I suppose. Maybe safe is the amount that means that we can adapt enough to prevent civilization chaos. 2C above pre-industrial seems the highest limit of safety for me due to complex interactions of everything, e.g. Bangladesh has ~100 million people, they will have go somewhere as sea level rises, deluge flooding increases and glacial melt flooding, make it irrational to stay, and so the knock effects go on. Not because of the possibility of inducing tipping points, they are wild cards that become more likely over 2C, but sudden 2C transition isn't looking that pretty in itself if 0.8C can induce these weather extremes being experienced, and we have been that hot for long (what will a natural 1:200 year event amplified by this warming be like?) Lots of ill-health and deaths occur after the acute flood and are rarely recorded, people from Pakistan are still not in permenant shelter after the floods, even here in the UK after the 2010 floods people are still displaced. And then of course there is all the costs of clear up, all the additional white goods to be made (positive feedback on CO2 emissions due to embodied energy and waste disposal), and the huge insurance costs, all picking away at fincancial security which isn't exactly that secure at present. And then there is the lack of water security after a flood, loss of crops, etc, etc... Is safe a level where food and water security can be maintained to a level that doesn't induce civilizations breakdown generally, although that is already in some areas. 350ppm however doesn't seem conservative safe to me, it seems at the edge of the safety, and still below the 95% safe that any medical practioner would accept as acceptably safe for the treatment of a patient. Why? Well as the Pliocene had CO2 about 350ppm, and was 3-5C hotter, all things being equal that is were we will end up with 350ppm, and although that will 1000years or so, about 60-80% is meant to occur in 100years, which seems reasonable as any heating event has a linear rise followed an expotential decay. Therefore 350ppm by 2100 induces 1.8C to 3C warming in a 100years, if GHG CS and Ice melt CS included. Although the carbon sinks are keeping at present as just reported in Nature, most feel this won't continue much longer and several sink areas are looking dodgey, like the Canadian Boreal forest seems to be source at present due fires and Pine beetle problems, and ofcourse there is the general fact that CO2 increases naturally by ~14-20ppm per 1C of warming and permaforst and permaice on the Arctic ice shelf are melting. 450ppm for me is really not safe in anyway, that is CO2 levels not seen for 20-40million years and means >2C for definant eventually and 2C by 2100 very likely indeed and >1.8C a certainity and 100ppm is a lot of CO2 to remove as 350ppm looks more appealign as events continue to occur. And it is all about the rate of change for eco-systems and crop growing potential, faster we go the less chance things can adapt or move and when looking at the fishery changes for PDO and Nina changes, eco-systems acutely react poorly to sudden changes in the prevailing regime. The desert regions will shift and are already, wet areas will become drier and so on. Then weather extremes which have a far deeper effect than just the acute event as highlighted above. How frequent to 1:100 events need to become for them to impinge on safety all round? Presuming the potential extreme events (flooding, heat waves, droughts) track the shift in temperature mean, a shift of another 0.8C, may be very significant indeed. How many SD from the mean is a 0.8C shift and what will that mean for severe events? Very hard to say as for the last 2000 years the mean has been shifting up and down, from the MWE, the Roman period and the LIA. But we are currently hotter than all these, indeed Hansen says hotter than the Holocene Thermal maximum, and the general noise arround the shifting mean for the last 2000yeas is about ~+/- 0.4C 95% range. So taking the 1900-2000 as a mean we have shifted from, we have shifted ~1.5-2 SD's...USA has only just shifted in the last 10 years due to the 1930-40's heat periods an dwhy the droughts are just becoming as severe as then now (Texas 2011, now 2012). So another 0.8C is lots of SD above, ~4 to 5, and intuitively doesn't that mean that 100 year heating events will basically be cold events and 1:1000, events occur every 10 years or so, and those sort of extremes do directly impinge of water and food security everywhere. Shift the mean by 2SD and doesn't that mean that the previous mean is now a cold extreme at the 95% range and the previous 95% hot limit is the new mean and thus the new 95% range (1:20 year events) include events that were basically 4SD from the mean previously or 1:500 events and 1:100 events become very extreme compared to now? Look at the mega droughts of Medeival Warm Event in the western USA, can these return as we warm, or were they due to more persistent La Nina periodicals due to increased equatorial solar irradation at the time? How will the changing Arctic sea ice effect weather events? Sudden out pourings of cold in winter and heat in summer due to blocking events seem to be already occuring more often and the irregularity of this is not helping, very warm March UK, cold wet April with frost, and the fruit tree crop was impacted severely. The American crop this year must be hard to predict at least, with the drought and the storms, the recent Austrailian drought and 2011 floods must have impacted things. What is safe? Well impossible to say for sure, but we are about to find out? The El-Nino is building, sunspots are rising, sulphur emissions are just about starting fall globally, and Arctic sea ice loss is racing away, all meaning the this next twleve months - 24 months should be hot? I don't really feel that safe at the 390ppm of now to be honest, these weather events are clearly extreme, and it is quite hard to break an extreme in a long record and gets harder with every year and there is clearly more heating to come, suggestive that these extremes will become more severe and more frequent. And what about all the heat of the last 30years that has been subducted to the middle depths of Atlantic in the last 30 years, when does that find its way to Antartica peninsula, the bottom warm water on the Antartic shelf is already heating significantly, if that heat returns to surface how sensitive will the CS be then? It takes ~30years for the Argus current heat to reach the North Atlantic so by push and shove thinking (push it in one end at a certian rate and it has flow somewhere else the North Atlantic sea level would rise and it has out of the other at a similiar rate), what is the transit for the heat accumulation of heat in the THC from the Indian Ocean, Southern Atlantic, Tropcial Atlantic and North Atlantic back to the Southern ocean upwelling? Would heat returning to the surface would turn the heating up rate or just get lost in the latent heat of undermelting the WAIS under Pine Island? What is safe? Not a lot for as Dana says 550ppm is looking almost inevitable unless things change, and no one can let go of our addiction to power despite the carbon costs of all power generation even wind turbines have a large carbon cost when you have a budget as tight as that needed to actually get to 350ppm. Could go on and on about what is safe, however for me it is wha tis safe for everyone, and therefore 350ppm is not really that safe but the best we even dream about.
  43. The Independence of Global Warming on Residence Time of CO2
    The bathtub analogy is illustrated and explained quite nicely in The Carbon Bathtub posted on the National Geographic website.
  44. The Independence of Global Warming on Residence Time of CO2
    Falkenherz - (paraphrase) "...and what if a leprechaun jumped into the tub?" Explanation by analogy is very useful. But reasoning from an analogy back to a system under investigation is only plausible if that portion of the analogy holds - it's much better to work matters out directly in the system of interest. In this case expansion and contraction of the bathtub is something you have not mapped to the carbon cycle. I would note, in addition, that mass balance/CO2 discussions are more relevant in the How do human CO2 emissions compare to natural CO2 emissions or possibly the Murry Salby CO2 source threads. This discussion is on CO2 rise rates and interactions with atmospheric residence time...
  45. The Independence of Global Warming on Residence Time of CO2
    Sceptical Wombat at 11:56 AM on 1 March, 2012, and Michael Hauber: I find the bathtub analogy very intruiging. I am not sure whether the mass balance argument really is prove alone for man-made atmospheric increase. To continue the bath tub: What if the sink can widen or narrow, according how far you open the hot water tap only, but the cold water tap opens, too? This is a reactive system and the mass balance seems not to apply so front-up as explained here. So we could have the situation that cold water increases its flow, you also add some droplets of hot water, and the sink expands to flush an amount equivalent to the additional hot water, but not to the arbitrary additional cold water. Water level would rise. If you stopped the hot water, the sink would narrow back to normal, but the water level would still rise because of the arbitrary additional amounts of cold water. Right? Wrong? Again, this thought experiment is just to point out that mass balance is not an argument for itself that rising CO2-levels in the atmosphere automatically attribute to man made CO2. Which means we need more linked evidence to that.
  46. It's not us
    Thanks, I will be commenting over there.
  47. BEST Results Consistent with Human-Caused Global Warming
    pauls @17 - yes, the nights warming faster than days is one of those 'fingerprints' that is consistent with AGW, but not necessarily indicative only of AGW. There are a number of those 'fingerprints' that could hypothetically be explained by other effects, but when you consider them all together, the fact that they're all consistent with what we expect to see from AGW is what's really convincing. Tony @ 18 - most of the studies illustrated in Figure 5 are model-based. So they generally perform model runs to try and match the observed temperature increase, and then determine how much of the modeled increase is due to each factor. But the models don't perfectly match the observations, so for example if they show 10% less warming than observed, the numbers will add up to ~90%. The graphics show what percentage of the observed warming was attributed to each factor. If it showed how much modeled warming was attributed, then they would add up to 100%, but I think that would be less informative.
  48. BEST Results Consistent with Human-Caused Global Warming
    Lots of good comments here. ranly @16 - I agree that 3°C sensitivity is middle of the road. I tried to be careful to call it "relatively" high, that being relative to the climate contrarian claims of climate sensitivity < 1°C. I didn't want to say "not low", though middle of the road may have been a better choice of words. As for what CO2 concentration is safe, we can't really answer that question. For one thing it depends on your definition of "safe", i.e. how much damage are you willing to accept. I'd say 350 ppm is a good conservatively safe value, but I'd be reasonably happy with 450 ppm, since I think that's the best we could possibly achieve at this point. As to where we'll most likely peak, my guess is somewhere around 550 ppm, but it could easily be much higher. A lot depends on how long the natural carbon sinks can continue to keep up with our rising emissions. So far they've been up to the task, but we can't expect that to continue forever.
  49. michael sweet at 00:57 AM on 4 August 2012
    BEST Results Consistent with Human-Caused Global Warming
    Ranyl, You ask what a "safe" maximum ppm of CO2 is. Safe for who? I live at 70 feet above sea level. I would be safe at a much higher level than millions of people in Bangladesh. Many of them have already been forced from their homes by sea level rise. Ask the farmers in Oklahoma what level of drought and heat they can stand. Can you define what you mean by "safe"? Or do you mean "less than a catastrophe for the USA"?
  50. BEST Results Consistent with Human-Caused Global Warming
    George Marshall (of the British Climate Outreach and Information Network, not of George C. Marshall Inst.) identifies in his Irresistible Story of Richard Muller post that Dr. Muller's change of heart is a cultural transformation, not a scientific one, dispite what Dr. Muller writes.

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