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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 41351 to 41400:

  1. Why climate change contrarians owe us a (scientific) explanation

    (-snip-).

    Moderator Response:

    [DB] No new participation on other threads until you finish your interaction on this one here.

  2. Why climate change contrarians owe us a (scientific) explanation

    So when it comes to the philosophy of all this.  The burden of proof indeed lies with the claimant.  If the pro-AGW side says recent warming is caused by C02, they have to show a robust model which justifies their claim.  If the anti-AGW maks *ANY* claim, they have to provide justification of that claim.  The nutral position is 'we don't know', not 'natural variablity'.  

    Moreover, we expect justification to be sufficiently robust.  When someone asks, "What explains the formation of the solar system?"  It is not enough to say, "physics".   Similarly, it is not enough to say "nautral variability".  Either side will take the sum of the evidence provided (along with their own biases) and come to a conclusion if the evidence justifies the claim.  Most will say it doesn't. But as has been pointed out in this article, the anti-AGW side provides very little evidence to show that the current warming is due to 'natural variability'.  On the other side, the pro-AGW have gone out of their way to show it most certainly *is not* natural variability.  Could it be the sun? No. Could it be volcanos? No.  Could it be the oceans? No.  Could it be the clouds? No. etc. etc. etc.   Could it be any combonation of those? (First: how would you know?  Need a model!) No.  The other side has no model which justifies their belief.  This type of raw belief can be described as many things (e.g. a base axiom or faith) but it's not clear any of these are ever applied to the types of claims we are dealing with.

  3. Ocean In Critical State from Cumulative Impacts

    Link to "Fisheries: Hope or Despair?" should be changed to:

    http://www.stateoftheocean.org/pdfs/Pitcher-Cheung.pdf

    Moderator Response:

    [JH] Link fixed. Thank you for bringing this glitch to our attention.

  4. Why climate change contrarians owe us a (scientific) explanation

    Excellent article. I "face-off" against the deniers online all the time. To back up my claims, I'll post links to peer reviewed studies, to this website, and others like it. I am always respectful, and though I do admit to being a tad condescending at times, I never resort to name calling or ad hominem. The deniers on the other hand, almost every one of them, do use ad hominems, are insulting when proved wrong, and when they finally do cite their sources of information, said sources are almost always denier blogs which are supported by energy industry, or conservative think tanks, sometimes both. Of course on occasion they might post a study by a legitimate scientist that denies global warming, but I take thse with a grain of salt, knowing that the vast majority of studies prove GW/CC is happening, and caused by human actions. Last night I even had a denier use your website to support their argument. He linked to your websites trend calculator in an attempt to explain the current plateau, which caused a good laugh on my end. He even attempted to use  Schmidt/Ridgwell's study to refute ocean acidification, when a simple reading of the abstract states that CO2 is causing the acidification. LOL, sometimes I wonder why I even bother debating them, but on the plus side, I am learning more on the subject simply by doing the research to debunk their claims. 

  5. Ocean In Critical State from Cumulative Impacts

    The links for Bijima et al, and Ateberhwan et al lead to the wrong papers.  I have not checked the other links.

    Moderator Response:

    [JH] Links fixed. Thank you for bringing these glitches to our attention.

  6. Global warming – a world of extremes and biological hotspots

    TonyW,

    I disagree, however, with some other commenters, that it is never too late to take action.

    I didn't say it will never be too late to take action, and I don't think anyone else did either. What I warned against was saying "it's too late now".

    Presumably, positive climate feedbacks could potentially become forcings in their own right. At that point, nothing we could do would have the slightest difference longer term.

    That's precisely what I addressed when I said "It is possible that a tipping point will be reached at some point along that line but there's no point basing our actions on the idea that it's "2 C or bust". The overweight analogy would be like saying "Oh, well, I've eaten that eclair, I'll might now die of a heart attack in 30 years because of that, so I may as well not bother trying any more"."

    It is hypothetically possible that at some point we will pass a point of no return. It's highly likely that we won't know that point when it happens, it will only be apparent with a great deal of analysis and hindsight. If we pass that point and nothing we do from then on will make a difference, there's no point in assuming that we will. We assume that we won't pass such a point, and if we don't, we gain. If we are wrong and we do pass such a point, then at least our efforts will have delayed it.

    And there really is nothing we can do now that will make the slightest difference in the longer term, for a suitable definition of "longer". That doesn't mean that our efforts aren't worthwhile.

    We'd only have adaptation left as a strategy, if adaptation were at all possible at that point.

    Adaptation doesn't get easier if we allow the climate to get worse. It isn't better to say, for example, "Oh, well, we passed the 2 C threshold, let's give up on trying to mitigate and just adapt", because adapting to 2.5 C is easier than adapting to 3 C, and so on. The costs of climate change are a monotonically increasing function of the degree of climate change; it may be discontinuous at certain (unknown) points, where it suddenly jumps up a lot higher due to passing a tipping point, but it will always be more expensive and more difficult to adapt to if we allow it to get higher regardless of how high we have allowed it to get.

  7. Global warming – a world of extremes and biological hotspots

    James Hansen has frequently warned us, with his usual prescience, that a rise in 2°C above the pre-industrial is likely to be achieved by mid century and constitutes dangerous global warming producing an increased incidence of climate extremes. Hence his admonition on the need to keep average global surface temperature below +2°C.

    More recently (2012) he has shown that the Gaussian distribution of heat is shifting to the right and as explained by Dana Nuccitelli, the consequences for climate, humanity and other animals are not beneficial.

    Why do we continue to ignore the findings of science the advice scientists or find it surprising when oft repeated?

  8. Global warming – a world of extremes and biological hotspots

    I can’t help but be reminded of a post over at Tamino’s Site that concluded with:


    I’ll continue to do what I can, come hell or high water. Expect both.


    (http://tamino.wordpress.com/2011/05/07/hell-and-high-water/)

  9. Global warming – a world of extremes and biological hotspots

    Terranova - well the obvious action is reduce GHG emissions. The tricky bit is what methods do governments have to do this that are politically acceptable to their electorate. CO2 and black carbon are by far the most important emissions and furthermore they are more sustitutable for than say CH4. If you want to pursue this discussion however, perhaps it would be best to look for a more appropriate. I cant speak for Rob, but to me, the simple, direct and effective solution is ban on building more coal-fired power stations (unless they have full CO2 removal). Let the market work out the best alternative. Coal industry (except for steel) gets a 30 year sunset, better than asbestos got. Of course the right-winger would scream stuff about "freedom" and so many countries would have look at carbon tax or trading schemes instead which are a whole lot more complicated.

  10. Global warming – a world of extremes and biological hotspots
    It's more bad news. However, all projections are, in the end, estimates of the future, not hard predictions. That's why it isn't too late to take action to mitigate global warming. I disagree, however, with some other commenters, that it is never too late to take action. Presumably, positive climate feedbacks could potentially become forcings in their own right. At that point, nothing we could do would have the slightest difference longer term. We'd only have adaptation left as a strategy, if adaptation were at all possible at that point.
  11. Global warming – a world of extremes and biological hotspots

    Rob Nicholls @ 6

    I am interested in what "actions" should be taken and what effect they will have.  I assume you mean limiting GHG emissions (and I am glad you didn't focus on CO2 solely.)  

  12. Global warming – a world of extremes and biological hotspots

    Jason B, I couldn't agree more. We don't know exactly what the effects of 2 or 2.5 or 3 or 3.5 degrees C rise in temperature will be, but it seems very likely to me that the more we can slow down or limit the rise in temperature and ocean acidification, the more time we will give ecosystems, species and human societies to adapt. We urgently need to act now to prevent massive damage (and we should have acted decades ago), and every year of inaction probably condemns future generations to worse suffering, but I can't imagine a situation in the next 50-100 years in which action on global warming would be "too late" in the sense that it wouldn't do any good. Even if there is a several degree rise in temperature, accompanied by large increases in chronic hunger among humans and widespread extinction of many species, efforts to limit GHG emissions may still buy time to allow for adaptation to new climates and prevent a lot of further suffering and save many species from extinction.

  13. Global warming – a world of extremes and biological hotspots

    malamuddy @ 3,

    the frustration of knowing that we should have acted sooner and may be too late now

    Although I appreciate the sentiment, we should be careful not to say it's "too late now", because that feeds into another denialist meme (the final step along the path from "It's not happening" through "It's not us" then "It won't be bad" and "It's cheaper to adapt").

    A good analogy would be an overweight person eating a chocolate eclair and then cursing themself, saying "Oh, no, I couldn't resist the temptation, now I've eaten it and it's too late to go on a diet". Sure, having eaten that eclair they will now have to work harder to achieve their weight goals, or else they will forever be further from that goal than they would have been had they not eaten that eclair with all else being equal, but that doesn't mean there's no benefit in working on their weight problem from that point forward.

    Likewise, we may reach a point where it becomes impossible for us to limit warming to 2 C, say, but that's not an argument for inaction — it's still better to limit warming to 2.5 C than 3.0 C, or to 3.0 C than 3.5 C, and so on. It is possible that a tipping point will be reached at some point along that line but there's no point basing our actions on the idea that it's "2 C or bust". The overweight analogy would be like saying "Oh, well, I've eaten that eclair, I'll might now die of a heart attack in 30 years because of that, so I may as well not bother trying any more".

  14. A rough guide to the components of Earth's Climate System

    #26 - three hydrosphere arrows. The top one is pointing at some ocean :)

  15. Global warming – a world of extremes and biological hotspots

    I don't have access to the full text my comment on the results is just a best guess. So, looking at this article & the author's website, I deduce the average anual temperature data for RCP2.6 and RCP8.5 scenarios were calculated from a model run and the "cut-off" dates were shown when the model runs above historical variability until 2005.

    I think this presentation is somewhat incomplete because the clear cut-off cannot be determined reliably as a single model predictive power is small in short timescale.
     I would rather prefer to see an ensemble (such as CMIP5) run and the range (of say 1-sigma uncertainty) be shown as the possible cut-off date. Such presentation would give me better perspective, in adittion of being a better response to usual deniasts' trolls.

    However, (Anual Temp) is the only one aspect of climate change. Other aspects, like increased droughts & floods (that are predicted to affect my SYD neighbourhood) are not shown but they are more serious and delta Temp, IMO. For example, the news of a record hifgh 39 C for Sydney today, brought by tonyabalone@2 is not my biggest problem. The bigger problem is that SYD (in fact the entire East Coast of AUS) is experiencing serious drought (I don'r remember any rain for last 2-3 months) which makes the conditions for all species (including all my garden) so difficult. One day of 39 C wouldn't be that bad (it would go as weather variability) but the underlying drought is the reason most of NSW has been declared as "extreme" or even "catastrophic" fire danger by RFS.

  16. Global warming – a world of extremes and biological hotspots

    This, more than any study I have read about, brings home to me the precariousness of our global situation, the frustration of knowing that we should have acted sooner and may be too late now, and a burning resentment towards those who know what we face but, to further their own greed, continue to lie and obfuscate in order to convince our politicians not to act.

  17. Global warming – a world of extremes and biological hotspots

    While a one day weather event is not climate it is however worth noting that Sydney today is expecting a maximum temperature of 39 C. This will be the hottest day experienced in October and very very warm weather for mid Spring!  What does the summer hold for us?

  18. Global warming – a world of extremes and biological hotspots

    More significantly than the proximity of those dates is what they apparently represent — the year from which we will never again have a year "as good" as our worst year ever to date. In other words, recent extremes would be seen as a reprieve. By that point the world is already a pretty different place.

  19. SkS social experiment: using comment ratings to help moderation

    jdixon,

    I agree with the general thrust of what you have said, and agree that there are subtleties in defining the notion of truth, as well as variations in whether a line of reasoning fails at the level of fact or inference, but all that is still somewhat tangential to my original concern.

    As far as I am concerned, any contrarian post that works towards a conclusion that "AGW is not a problem" is going to fail somewhere along your line stretching from objective, checkable facts to inferences. I doubt I'll use the thumb system anyway, but if I did, I doubt that any contrarian posts would earn a positive thumb if I followed the current advice. (A contrarian might post neutrally, without supporting any position, but that is not what I am talking about; I am talking about posts that actually support a contrarian position) If their facts are wrong, I would thumb it down as obviously untrue; if the facts are correct, but cherry-picked and deliberately misleading, then I would thumb it down as leading to an untrue inferences. If their individual facts are true and they leave it to the reader to draw the false inference (a favoured tactic of some of the more sophisticated contrarians), I would also thumb it down. (If their facts are true and their reasoning is correct and they have not simply blown a minor problem out of proportion and this actually disproves AGW, then I guess 97% of scientists are wrong and we can all move on to to other pursuits.)

    When proponents of AGW post, on the other hand, I can see that there might be dissociation between correctness and support for the AGW position. Someone can get to the right answer by a faulty route, but can't get to a wrong answer by a correct route.

    For a contrarian, the same issue arises, but the situation is inverted.

  20. A rough guide to the components of Earth's Climate System

    Note that in the "components of the Earth Climate System" figure, there should also be an arrow pointing at the ocean.

  21. Latest myth from the Mail on Sunday on Arctic ice

    The Telegraph are playing hard to get when it comes to further "corrections". They've literally turned the World on its head in their more recent Arctic sea ice coverage! Here we berate their "Head of News" for that and other "inaccuracies" and "misrepresentations":

    http://GreatWhiteCon.info/2013/10/russias-northern-shores/

    There's even a video revealing a yacht happily sailing through David Rose's "unbroken ice sheet":

    Moderator Response:

    [DB] Reduced Video Player width to 450.

  22. SkS social experiment: using comment ratings to help moderation

    Leto @5 I do think there is a difference between statements that one should consider "inaccurate" and statements that do not support one's position.  If someone cites cherry-picked data, for instance, and leaves it to the reader to draw conclusions, their statement may arguably be misleading, but it is not false.  Under the current SkS system, I would probably give the comment a thumbs down, and the moderators would have to try to guess why.  Under the Helsingin Sanomat system I wouldn't say "I disagree," but I would say "Poorly argumented."  

    Sphaerica @15 I would add that scientific theories deal not only in "facts" (i.e., observations), but also inferences drawn from those facts.  Most of the time climate contrarians don't dispute actual facts, as that wouldn't get them very far as a principal approach, but inferences, like the inference that humans activity is the primary cause of the current warming trend.  To you and me this inference may "feel" like a fact because we understand it to be the only reasonable inference.  But I'm not sure that I would say that the cherry-picker was stating a falsehood even if he added the conclusion that "humans are not causing the warming" or "we don't know what is causing the warming."  I would still just say his argumentation was poor.  On the other hand, I might say he was stating a falsehood if he said something like "CO2 does not absorb longwave radiation," even though CO2 absorbing longwave radiation is technically an inference as well, although an exceedingly simple one based on the observation that every time we have shot longwave radiation at CO2, less longwave radiation comes out on the other side => "Duh."  

    So I guess it depends where you draw the line - on some level, we even infer that what our senses are telling us is true, because we could be hallucinating...  But I think almost everyone would draw the line between fact and inference somewhere between what we sense directly, and complicated, probabilistic logical conclusions drawn from what we sense.    

  23. SkS social experiment: using comment ratings to help moderation

    I tend to agree with Yves #10. In my experience, a "flag as abusive" button is more useful in moderation than thumbs up/down.

    No matter what criteria are expressed, these tend to end up meaning "I agree with this" or "I disagree with this," which is not particularly useful information to a moderator--lots of thumbs down simply means that the membership doesn't agree with the comment, not that the moderator needs to do something about it.

    Lots of flags, on the other hand, means that the membership finds the comment to be uncivil, and therfore worthy of a glance from the moderator.

  24. A rough guide to the components of Earth's Climate System

    re - #21, I am talking of all plantlife in bulk, not about regional factors.

  25. A rough guide to the components of Earth's Climate System

    Eric - I think the sun deserves a blog-post all on its own. Watch this space!

  26. 2013 SkS Weekly News Roundup #41A

    I came upon this comment, well written thus worth sharing, about natural gas prices in Australia:

    Industry's coal seam gas campaign is a con

    In a nutshell: gas was subsidised in Aus until now. Just like Saudis are subsidising petrol for their domestic market.

    When producers built LPG to be able to export gas, the politicians are telling us all sorts of nonsense about "looming gas crisis", etc. But they don't tell us when the export opens up without limits, the subsidies must collapse due to market mechanisms at work. Very simple and positive result from the point of view of anyone who cares about the environment - subsidies must go.

    But certainly things are not that simple for gas lobbist. Read their scare campain here if you're interested. If you know a little bit how market economy works you'd be laughing at it.

  27. SkS social experiment: using comment ratings to help moderation

    Thanks all, some good comments (which I thumbed up :-)

    Re the suggestion of hiding the final scores, on the plus side, this system would be just as useful whether the final scores are hidden or not. On the negative side, my sense is that would inhibit people actually using the ratings - feedback is a big part of the motivation for using it. So I'm inclined to keep the scores visible.

    Someone suggested providing the option of cancelling a vote and a way to seamlessly integrate this into the system wasn't immediately apparent to me. But WheelsOC's suggestion (now thumbed up by me) of reclicking a thumb to cancel an existing rating is actually quite elegant. Will discuss this with Sphaerica.

    DSL, I accept the comments that only providing up/down options is simplistic and we had discussed a more nuanced rating system (e.g., two dimensions of ratings). My concern is making it too complicated and have opted for the simplistic system to begin with. For now, I'm in the data collection stage - when enough data is collected (which will depend on the level of adoption by users), I'll see what the data is telling me.

  28. SkS social experiment: using comment ratings to help moderation

    I agree with Don9000, but I also recognize that it might be an interesting experiment to see how much new user traffic is generated and how much of that traffic is there solely to push thumbs.  Even with that research goal, I don't think it's worth it unless it's more sophisticated than thumbs up/down.  This is a site that's prided itself on complex, measured responses.  The thumbs thing sticks out like a . . .

  29. SkS social experiment: using comment ratings to help moderation

    Oh, and one more thing.The Ars system allows a user to re-click their vote to cancel it once it's been cast. If you accidentally thumbed a post down, you can click again to remove that vote. This isn't the most common feature of internet discussion voting systems, but it's extremely useful in my experience and I wish more places would implement it.

    I just upvoted my own post. I could thumb it down, or thumb it back up, but I couldn't cancel the vote.

  30. SkS social experiment: using comment ratings to help moderation

    Ars Technica introduced a similar thumbs up/down system about a year ago, except that part of the impact is that comments downvoted by a large enough margin are collapsed from view and have to be manually unhidden to read. Once that happens, they also can't be quoted directly.

    Their front-page articles about this system can be found here:

    http://arstechnica.com/staff/2012/10/introducing-comment-voting-on-news-articles-and-features/

    http://arstechnica.com/staff/2012/10/comment-voting-working-getting-expanded/

    http://arstechnica.com/staff/2012/10/comment-voting-now-shows-the-vote-split/

    They also have a phpBB forum for site feedback where some discussions about the voting system have gone on in individual threads. Seartching that forum for things liek "voting" or "rating" or "thumbs" might turn up some insightful discussions (or whiny flame-fests).

    It might be a good idea to contact the site's administrators and ask about their voting system, how well it seems to be working after a year in action, etc. etc.

    One of the weaknesses of a user voting system is that votes (up AND down) taper off as the pages of comments stack up. Even egregious trolling, if not reported to moderators, tends to go unchecked by 4 or so pages into the average thread. Fortunately, SKS threads rarely drag on long enough for that to be an issue. There are comment threads on Ars Technica's climate science articles that have run over a dozen pages.

  31. IPCC model global warming projections have done much better than you think

    Whatever knowledge we think we have accumulated in regard to inter-related chaotic systems is likely only "educated" guesswork.  We project outcomes, and when they are wrong, we look backards to see what we missed, and introduce that into our next "educated guestimate".  It. too, will almost certainly be "off the mark" as reality unfolds.

    We all know what is happenning.   The planet is warming and the  biosphere is dying.

  32. SkS social experiment: using comment ratings to help moderation

    John,

    Having worked hard to get my brain to ignore this kind of scoring system on other sites, since I view it as being intellectually shallow, I don't want to see it implemented here at SKS.

    The problem with simplistic pass-fail scoring methods like this one is that they inevitably, at some level, reduce even nuanced comments to simplistic yeas and nays. Showing my bias, I find the highly visible green and red symbols on this page particularly annoying. Their color makes them more immediately visible to my brain than the comments themselves. There is nothing subtle about them, whereas the points raised in the comments often are very subtle.

    Here's what I'd suggest you do if you really want to gather data: make the vote total invisible to any of us on this end. If people want to click on a thumb, let them. But don't tell us about it, and make the thumbs less obvious.

    Personally, I don't need a count of thumbs to help me interpret comments. I know the ones I agree with and why, and I know the ones I disagree with and why. I'd prefer it if you let us do our own assessments without providing this kind of thing.

  33. SkS social experiment: using comment ratings to help moderation

    silence - see John's comment at #12.   It doesnt change the order of comments at all.

  34. SkS social experiment: using comment ratings to help moderation

    There's one big problem I see: there isn't a good way to respond to another comment anymore.  It used to be that responses would be posted below, which made for a useful thread of discussion.  Now that the orders are determined by votes, there isn't any way for somebody other than the moderators to post a response to a comment in a way that looks like a conversation.

     

    If you're going to keep the ratings system, it would be really helpful to add some sort of thread tracking, so that it is possible to hold a conversation.

    Moderator Response:

    [Sph]  The votes don't affect to presentation sequence.

  35. Eric (skeptic) at 04:57 AM on 9 October 2013
    A rough guide to the components of Earth's Climate System

    I would add a short section on the sun: graph of solar radiation with an explanation of the relative magnitude shown in the graph.  I would also add a sentence or two to the atmosphere section explaining how weather creates fluctuations in heat lost to space in the short term across regions and even averaged across the planet.  That mainly results in short term albedo changes, e.g. short wave flux but also changes in latent heat loss.

  36. SkS social experiment: using comment ratings to help moderation

    Have the whole range of policy targets turned into buttons:

    > unsupported by evidence

    > sloganeering

    > repetition

    > sounds suspiciously like Doug Cotton

    > read the friggin' OP

    > funny, but doesn't add to the discussion

    > John Tyndall and millions of graduate students

    > No.  See Marcott et al. 2013

  37. Eric (skeptic) at 04:29 AM on 9 October 2013
    SkS social experiment: using comment ratings to help moderation

    I can see how the thumbs down might help the mods.  I can't really see a use for the thunbs up button here.  Most threads here one must read all the comments in order including the ones that meet with disapproval or just end up confused.

    Will viewers click and evaluate the references and then give a thumbs up?  Or will they just  make it a social status symbol like pop (non-science) forums?  Or vote very quickly like the "like" button in some forums which get placed on quippy or humorous replies?

  38. A rough guide to the components of Earth's Climate System

    I just want to confirm the correctness of an assumption I've been making about the Nuccitelli et al. graph - the change in heat content of each component is represented by the vertical thickness of its respective color band, not the the distance of one of its boundaries from the horizontal axis, right?  I'm 99% sure this interpretation is correct, because otherwise there would be no way to make sense of the late 60's portion of the light blue band that extends both above and below the horizontal axis.

    That said, there are a couple slightly confusing spots in the graph for me - one is right around 1980, where the dark blue band abruptly disappears, but I assume this doesn't actually mean that the deeper ocean heat content suddenly leveled off from its brief downward plummet, but rather that it would have looked strange to overlay the negative blue band on top of the red band there, giving the initial visual impression of a dip in land/ice/atmosphere heat content.  As for the late 60's, am I correct in assuming that the red is slightly positive and the dark blue slightly negative, so that the lower bound of the dark blue curve represents the sum of red + dark blue, explaining why the negative light blue band departs downwardly from there rather than from the top of the dark blue band?  

    Also, am I correct to interpret that the top ocean layer component changes sign right around '73-'74?  

    These questions are purely based on academic curiosity, because from about 1981 on none of the three components ever dips below its baseline again, and the graph is quite easy to interpret.  Were it not the case that all three components are positive for most of the time period represented in the graph, stacked bands might have been a poor choice, but then again, we probably wouldn't be having this conversation then either =P

  39. A rough guide to the components of Earth's Climate System

    Re: "the fastest carbon dioxide sink - plantlife - is also carbon-neutral; plants take it in but re-release it when they die and decompose, which is an effectively continual process, recycling a lot of carbon dioxide all the time."

    I respectfully disagree with this statement. Surely the Sahara desert does not sequester as much carbon as the Congo or the Amazon forest per unit area? Indeed, regenerating forests is the quickest way to sequester the excess carbon in the atmosphere and it is time that the scientific community wake up to it.

  40. A rough guide to the components of Earth's Climate System

    All well and good, WHT, but how the **** is a newcomer to climatology going to understand a single word of what you have just written?

    Bear that in mind, and consider that this post has fortuitously turned into an online workshop on effective climate change communication, where the best way of stating the facts is being crowd-sourced. Now, how to put that to a beginner?

    There were a number of errors/poor ways of stating things in the original post that I have attended to. Let's continue to explore that, because whilst much of the rest of the post is accurate, I'm always looking for new ways to explain stuff more clearly, and the best way of learning how to do that is to look for criticism.

  41. Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy

    BTW, to illustrate the perils of using short time periods, the HadCRUT4 trend for 2010-2012 is -1.242 ±1.964 °C/decade. Plotting the central trend on Fyfe et al's Figure 1 would put it far off the left of the chart. Would this prove that there was a problem with the models? Or that perhaps the time period is just too short to reach definitive conclusions?

  42. SkS social experiment: using comment ratings to help moderation

    The rational arguments being advanced here as to how users might apply a rating system belies the reality of how actual real-world users on un-moderated comment boards (cough-Yahoo-cough) use the ratings.  Highly motivated political ideologues on both sides, but especially among the ultra-right will vote down each and every post by anyone who disagrees with them.  Respectful, knoweldgable posts citing references are likely to get a disproportionalte share of thumbs down while arrogant, snarky and factually incorrect rants are enthusiastically up-rated.  The bottom line is that climate deniers are not interested in having an intelligent discussion of the issue any more than drunken soccer hooligans are interested in a cogent discussion of the weak points of their team.  We should probably just be thankful that they can't start fist fights in the parking lot.

  43. Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy

    I wrote:

    Contrast this with the SkS Trend Calculator (which uses the method of Foster and Rahmstorf 2011) that gives a 2σ trend of 0.177 ±0.108 °C/decade for the former and 0.080 ±0.161 °C/decade for the latter.

    Sorry, accidentally used GISS. The HadCRUT4 figures are 0.155 ±0.105 °C/decade and 0.052 ±0.155 °C/decade, respectively.

  44. SkS social experiment: using comment ratings to help moderation

    Personally, I don't think a mere up/down-voting can do any good (to quality, behaviour, "culture" of a discussion/web page). Beside typical problems of web based voting systems (gaming the system, something that may well get the moderation from a "tiresome chor" to a complete and enduring hell!), these systems may be well suited for opinion based forae or "taste" orientated ( ;-) ) sites, but far less for a site dedicated to the (let's call it) veracity of arguments.

    There are websites where working complex voting systems, based on deliberately chosen rules, generate a user moderation of comments (slashdot comes to mind) and which are doing a good job on that - at least on behalf of nature of those sites. But those sites are out to generate a general culture for that special place, something that often leads to the "hivemind" and should be avoided on scientific websites at all costs.

  45. Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy

    adeptus,

    I haven't read Fyfe et al but looking at their Figure 1 you presented it strikes me that (a) the error margins on the HadCRUT4 trends are very narrow and (b) both 1993-2012 and 1998-2012 HadCRUT4 trends seem to have the same width.

    Contrast this with the SkS Trend Calculator (which uses the method of Foster and Rahmstorf 2011) that gives a 2σ trend of 0.177 ±0.108 °C/decade for the former and 0.080 ±0.161 °C/decade for the latter. (And note that the trends calculated by the Trend Calculator do not take into account the fact that the start date is cherry picked, which 1998 almost certainly is.)

    If the red hatched area in Figure 1a went from 0.069 to 0.285 °C/decade then it would cover about half the model trends; likewise, a red hatched area of -0.081 to 0.241 °C/decade in Figure 1b would cover about 2/3 of the model trends.

    I think the reason for the differences in trend uncertainty is because Fyfe et al aren't trying to determine the true underlying long-term trend (which the SkS trend calculator is trying to determine) but rather they are assessing whether the models have accurately captured the short term variability with a view to seeing what is to "blame" (e.g. ENSO, aerosols, etc.).

    As mentioned by Albatross here, Box TS.3, Figure 1a from AR5 looks to be the same as Figure 1b above:

    Note that from 1984-1998 those same models underestimated the warming trend (1b). Yet from 1951-2012, they did a really good job indeed.

    Therefore we can conclude that over short periods of time the models don't necessarily predict the actual, observed trend very well, but over long periods of time they do exceedingly well — and since what we're worried about is the long term effect, and not what the temperature is going to be next year, this is important. Also note that if you calculate the uncertainty in that observed trend to see what the range of possible values are for the underlying, long-term trend, there is a great deal of overlap even in shorter periods.

  46. A rough guide to the components of Earth's Climate System
    The issue of residence time versus adjustment time is that permanent sequestration of CO2 is not a first-order uptake process which leads to a damped exponential response. Instead, it is a diffusional response which leads to fat-tails in time. Diffusional responses are very common in physical systems, including related climate domains as ocean heat uptake.The Bern model of CO2 sequestration models the fat-tail diffusional response by a linear combination of damped exponentials with a range of time constants.I think the real issue is that no one seems to want to call it a diffusional response, which leads to the endless confusion and why deniers still refer to the Segalstat misinformation. This as recounted by McInt:"Segalstat of Oslo University led off the afternoon with a general, and, as far as I can tell, uncontroversial exposition of the carbon cycle, but closed with the well-known cartoon showing the correlation between change in bathing suits from bloomers to thongs and global warming. At this point, Bert Bolin exploded at Segalstat (who apparently is a former student of Bolin’s) saying that he needed to read a text book. Bolin announced hat he was leaving the conference because it was such garbage. After some efforts to restore order, Bolin sat down for a few minutes and then left, still without paying his entrance fee."
  47. SkS social experiment: using comment ratings to help moderation

    Sorry to comment again: I've just seen your hover text - good idea. Can I suggest an alteration? Don't have it float with the mouse, just float it to the right of the arrows when you hover, but with a link saying something like "click here to read the factors we'd like you to consider before using the thumbs up/down arrows".

  48. SkS social experiment: using comment ratings to help moderation

    How are you proposing to keep posters in line with your list of factors? Will new registerees have to view a web-page telling them what factors to consider? Without making sure all new commenters are aware of them (and even then perhaps) people will just default to "thumbs up/down = I likey / I don't likey".

  49. A rough guide to the components of Earth's Climate System

    Thanks John, I much prefer the new wording re residency time.

  50. SkS social experiment: using comment ratings to help moderation

    Sphaerica,

    I agree 100% that, for most of science, truth is absolute (the exceptions are potentially interesting but not on-thread). In fact, I have less sympathy than most for a relativistic view of truth. I actually think that, for most of the contrarians coming here, they only have themselves to blame for being ignorant - I would even say that most contrarians exhibit extreme hubris when they claim to know better than the vast majority of climate scientists, often on the basis of reading anti-science blogs with way too little true skepticism...

    But if accuracy is to be a major criterion for clicking the up-thumb, then we would basically be clicking to indicate which camp we are in, and the thumb clicks would then carry very little information. (It almost sounds like single-click sloganeering, to me.) This is directly at odds with the instruction "The point is not to vote up comments that support your position and to vote down comments that support their position."

    We already know that comments will, for the most part, be pro-AGW (i.e "accurate") or anti-AGW (i.e. "inaccurate"), so the clicks could end up being a continuous poll of how well each camp is represented in the readership (or clickership, anyway). The clicks won't be able to register any sort of behavioural dimension or reward appropriate behaviour if they are busy performing this fairly facile polling function.

    If contrarians come here to engage in honest dialog, and find every one of their comments is heavily down-clicked no matter how well behaved they are, this could undermine the very outreach function the site is trying to achieve.

    And note that, by expressing this view, I am not at all suggesting that truth is relative, or that all opinions are equally valid, and no such implication was contained in my earlier post.

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