tag:blogger.com,1999:blog-9959776.post3786318788918050760..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: More on SchmittnerJames Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger36125tag:blogger.com,1999:blog-9959776.post-78834418447233753722011-12-06T09:50:39.008+00:002011-12-06T09:50:39.008+00:00Thanks to James for the blog site, and to Steve fo...Thanks to James for the blog site, and to Steve for comments and questions<br /><br />Well, a range of climate sensitivity, however defined, complicates our situation in two ways. First, while true that we are in one climate state at present-day, all indications are that Earth can exist in multiple climate states. Second, the difference from one climate state to another may not lead to a simple linear relationship in terms of climate sensitivity. This would assume that various feedbacks are linear (or fortuitously add together in a linear function). The geological record does not support this. To cast another way: why should the climate sensitivity as Earth moves from the last Glacial to Holocene accompanied by internal changes in the partitioning of carbon so that pCO2 rose about 90 ppmv be the same as that for an interglacial world moving to future state X, Y, … with an external forcing of the carbon cycle so that pCO2 rises to Z. (Now, of course, many of my colleagues will say that certain potential biosphere and geosphere feedbacks are probably not important on the 100 year time frame, so we know the climate sensitivity much better on this short time scale, and it seems close to 3*C/doubling of CO2. This may correct but it is not a very satisfactory answer for understanding how Earth works over longer times, let alone to 3+ generations down the road).<br /><br />To be honest, I am not exactly sure where the work by Pagani stands with regards to climate sensitivity. For example, in Pagani et al. (Science, 2006 and several abstracts since), the writing begins by excluding certain mechanisms for carbon release across the PETM (e.g., seafloor methane) on reasons of mass balance (too little), climate sensitivity (too large), and triggering (invokes environmental change), and arrives in the end with other carbon release mechanisms (e.g., permafrost) that have much worse balance considerations, that conform to pre-conceived climate sensitivity, and are carbon cycle feedbacks. <br /><br />If you like the idea of a HUGE permafrost reservoir causing the carbon injections at the PETM and other early Paleogene hyperthermals, ask about the palm and baobob pollen found in the Arctic and around Antarctica during ETM-2, or how this works when surface ocean temperature is 9 to 14 °C around Antarctica, or how to make large amounts of permafrost without an ice sheet to provide wind-blown loess, or the true carbon masses that must be involved, or…? I think we are a ways off from understanding how carbon cycling in the Early Paleogene worked, although we know to first order what happened: we have a series of massive carbon injections into the ocean and atmosphere; somehow associated with these injections are major rises in Earth’s surface temperature and a whole range of other environmental changes.<br /><br />The shallowest clathrate in any ocean, present through past, is limited by bottom water temperature. If our interpretations for bottom water through time are correct, then the shallowest clathrate would have been around 800 m in the late Paleocene (pre-PETM), which is deeper than the shallowest occurrences today. This is one thing we do know, because it is set by constraints of physical chemistry. Now whether gas hydrates are important to climate change, and whether they are more or less sensitive to being a carbon cycle feedback in the Paleogene or the near future, I have to “pass” without making a really long post. With some irony, my answers would be far more detailed but far less certain circa 2011 than in 2006 than in 2001, now that we have really started studying and arguing about these very issues.J Dickenshttps://www.blogger.com/profile/03754339524691448875noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-1338520286097570762011-12-05T19:32:10.194+00:002011-12-05T19:32:10.194+00:00As J. Dickens will already know, Pagani's late...As J. Dickens will already know, Pagani's latest research points toward not only (Earth system) sensitivity being quite variable depending on the initial climate state (not sure how this complicates out situation since fortunately we just have the one climate state, unless it amounts to an argument for our ESS being higher), but toward Antarctic permafrost being the key factor in the PETM and subsequent Eocene hyperthermals (with, I would assume, clathrates still doing much of the heavy lifting). <br /><br />But I wonder: Could the Antartica of that time have been host to shallow clathrate deposits similar to what we see off Siberia today? (Do we know enough about the off-shore topography to say anything?) If so the past may have become a much better guide to the immediate future than I had been thinking.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-88831519051155812152011-12-05T19:30:05.488+00:002011-12-05T19:30:05.488+00:00"High warming is possible if we pump out enou..."High warming is possible if we pump out enough CO2, which may be augmented to some extent by carbon cycle feedbacks (relative to the no-feedback case which already soaks up a lot of CO2). We will have to keep doing this for a long time, all the while watching the temperature rising more and more rapidly, in order to get to 6C in a century."<br /><br />James, I have to say I feel less optimistic every time I see something like <a href="http://www.nytimes.com/2011/12/05/science/earth/record-jump-in-emissions-in-2010-study-finds.html?_r=1" rel="nofollow">this</a> or read the news from the latest COP. When exactly will we start correcting course?<br /><br />Part of the problem is that delay in the present increases the burden on the future people who will actually have to (try to) resolve things, such that they too will find it tempting to delay things yet more. Etc., until the really nasty stuff happens, at which point all possible outcomes are unpleasant.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-63752315707034159152011-12-03T19:12:30.323+00:002011-12-03T19:12:30.323+00:00I think we need to be a bit more open minded on th...I think we need to be a bit more open minded on the issue of climate sensitivity.<br />There is abundant data across the PETM. Earth’s surface almost assuredly warmed by at least 6°C; there is little to no terrestrial ice for a major ice-albedo effect; there are no data or arguments to support more than a doubling of atmospheric CO2 (other than the circular reasoning of climate sensitivity). <br />So, here we have the Schmittner et al. study framed on a glacial-interglacial transition with low absolute CO2 and no external carbon forcing and we derive low sensitivity. Then, we have a time in the Paleogene that spans a rapid warming with clear external carbon forcing, major carbon cycle feedbacks, or both, during a time of presumably high CO2 and we derive an extremely high sensitivity. (The graph by Mark Pagani et al., Science, 2006, nicely shows the problem, although without a solution).<br />In my opinion, the community needs to be very careful about defining sensitivity (Charney, equilibrium, earth system …), and that a range of responses are possible depending on time-scale of interest (100, 1000, 10000 years), the rate and timing of carbon addition, and the boundary conditions. It would be great to understand and explain this range as our future lacks any true geological analogs.J Dickenshttps://www.blogger.com/profile/03754339524691448875noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-40218441681453545062011-12-02T08:04:22.676+00:002011-12-02T08:04:22.676+00:00High warming is possible if we pump out enough CO2...High warming is possible if we pump out enough CO2, which may be augmented to some extent by carbon cycle feedbacks (relative to the no-feedback case which already soaks up a lot of CO2). We will have to keep doing this for a long time, all the while watching the temperature rising more and more rapidly, in order to get to 6C in a century. I don't think we will see methane fireballs in any case.<br /><br />I think quite a lot of people have been talking about the risks of high warming - Stern, IPCC, and many conferences <a href="http://www.eci.ox.ac.uk/4degrees/" rel="nofollow">eg</a> explicitly talk about warming of 4C or more.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-63948981642531473132011-12-01T19:53:38.367+00:002011-12-01T19:53:38.367+00:00Oops, double acronym entendre alert:
ESS as used ...Oops, double acronym entendre alert:<br /><br />ESS as used by me two comments up refers to the East Siberian Shelf, not Earth System Sensitivity.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-19260960099929971612011-12-01T19:50:29.809+00:002011-12-01T19:50:29.809+00:00"So given the risk involved, I don't unde..."So given the risk involved, I don't understand why scientists involved in climate prediction are so reticent about emphasising the risks involved with 5C type outcomes."<br /><br />They're not being paid to jump up and down and bang cymbals, are they? Actually I think they've been quite clear. The problem is on the paying attention end.<br /><br />On one level scientists have been the victims of their own success. Usually by the time a specific impact is identified it's been sufficiently anticipated that the thing itself no longer makes much news.<br /><br />Ocean acidification actually impacting sea life? Ho hum.<br /><br />Mountain pine beetles entering the eastern boreal forest? Ho hum.<br /><br />Major changes in ocean circulation observed, e.g. the Agulhas Current accelerating warming of the North Atlantic and Arctic? Ho hum.<br /><br />Tropics expanding, among other things *compressing the entire atmospheric circulation poleward*. Ho hum. <br /><br />Etc., etc., etc.<br /><br />Yep, talked all those to death before they actually started happening, so away goes the news value.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-20515567047219840092011-12-01T19:39:01.013+00:002011-12-01T19:39:01.013+00:00When we talk about such outcomes it seems to me mo...When we talk about such outcomes it seems to me most useful to switch over to discussing paleo-analogs. Of course that begs the question of how fast, which only the models (eventually) can tell us, but as the saying goes if we keep on in this direction we will eventually end up where we are headed, i.e. on a different planet.<br /><br />In other news, I see that the bulk of journalists were so exhausted by their efforts on Schmittner at al. that they were unable to give much attention to the far more important permafrost expert elicitation (confirming Shaefer et al.'s figure if I recall the latter correctly) just published in Nature. This is pathetic. It wouldn't be hard to come up with a long list of recent papers of much greater importance that got zip or nearly so for coverage. It's the "man bites dog" syndrome at work, I'm afraid. <br /><br />And we have yet to hear from that ESS expedition, although that should be soon enough. Let's hope that the methane release trend is small.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-85175790042625092382011-12-01T14:12:49.030+00:002011-12-01T14:12:49.030+00:00That is not actually what I am saying. And I am de...That is not actually what I am saying. And I am definitely not saying that 5C is probable. <br /><br />What I am saying is that if we take James' constrained upper end of Charney sensitivity and add in carbon cycle feedbacks then based on current emission trends 5C outcomes are not unlikely. <br /><br />If 5C plus is not an unlikely outcome, and given the impacts associated with 5C plus, it is a major risk. Pick up a copy of the Journal of Finance and you get academics urging that practitioners pay attention to risks an order of magnitude or two less than this in the financial field. <br /><br />It is easy to sneer at Mark Lynas' 'fireballs tearing across the sky', but at least he talks openly about 5C plus outcomes. OK so his impacts may be wrong (or at least suffering from a severe case of melodrama) but 5C isn't that difficult to get to. <br /><br />So given the risk involved, I don't understand why scientists involved in climate prediction are so reticent about emphasising the risks involved with 5C type outcomes.The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-11073686064273605622011-12-01T13:33:46.309+00:002011-12-01T13:33:46.309+00:00Re "it appears to me that we are up at 5C wit...Re "it appears to me that we are up at 5C without going down the tail of possible outcomes much at all. <br /><br />Given the impacts of such level of warming, it would appear to me that every climate prediction scientist should be stressing risk aggressively in their interactions with policy makers."<br /><br />Huh? I don't follow. <br /><br />Surely if 5C is probable, near unavoidable and action needed imminently to keep impacts avoidable without going into unlikely tails then I would expect scientists should be stressing that catastrophic 5C warming is ***probable*** (and incidentally there are, in addition, unlikely but even worse risks).<br /><br />Muted climate scientist expression of opinion could possibly indicate that it isn't really approaching unavoidable but there are political choices about how soon and how aggressively and in what ways to start reducing emissions. If this is the actual situation, then the level of risk should be being stressed.crandleshttps://www.blogger.com/profile/15181530527401007161noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-53970022785605519402011-12-01T11:08:54.748+00:002011-12-01T11:08:54.748+00:00And I seem to remember that your original paper (A...And I seem to remember that your original paper (Annan and Hargreaves 2006) had the top end constrained at 4.5% with a 95% confidence level. Have you come in from that? If not, it would seem incredibly easy to get to 5C plus without getting anywhere close to the tail of possible warming outcomes.The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-26509979426279948602011-12-01T10:41:53.232+00:002011-12-01T10:41:53.232+00:00James. I fully understand your view that high leve...James. I fully understand your view that high levels of Charney sensitivity are unrealistic. What I am not sure is where you stand on the likelihood of us experiencing high levels of warming overall (surely the bottom line for any climate prediction scientist). <br /><br />In your last post, you throw out a 3C number for Charney sensitivity at the higher end. I am not sure how close to the tail we are with that? Let's assume a 95% interval. You then add in 0.5C to give as a carbon cycle feedback inclusive climate sensitivity number of 3.5C. <br /><br />We can then turn to the likely emissions outcomes. I mentioned that the IEA sees us plateauing at 650 CO2-eq in their New Policies scenario. But the New Policies scenario requires the very active implementation of policies not yet agreed upon. For example, it would require COP17 in Durban to be a success.<br /><br />Given the current situation, I think we could make a best estimate that emissions will follow a path somewhat worse than the New Policies scenario but somewhat better than their Current Policies scenario. That would give us a plateau of 700-750 ppm-eq before adding in any carbon cycle feedbacks. <br /><br />So if we take your carbon cycle feedback inclusive sensitivity number and combine it will a near trebling of CO2-eq above preindustrial levels, it appears to me that we are up at 5C without going down the tail of possible outcomes much at all. <br /><br />Given the impacts of such level of warming, it would appear to me that every climate prediction scientist should be stressing risk aggressively in their interactions with policy makers. <br /><br />However, in the exchanges I read in your blog comments over the years, it appears that Mark Lynas type high end warming scenarios are the source of knowing smirks. From a risk perspective, I am not sure why.The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-89215078378227452652011-12-01T02:12:19.941+00:002011-12-01T02:12:19.941+00:00I think the analogy is a bit unfair, as the 450ppm...I think the analogy is a bit unfair, as the 450ppm is not an assumption, rather a (possible) target. We can choose it if we want, and a concentration target has the advantage that we have a stronger confidence in what it would mean for climate change, relative to if we set an emissions target of say 1GT per year (in whicih case the concentration could either increase indefinitely, or slowly decline over the next century). In terms of what actually has to be done in the next few decades to achieve the target, I doubt it matters much either way, and any policy is hardly going to last for 50y, so I don't really see that it's important.<br /><br />50-100ppm on top of 650 actually doesn't amount to very much climate change - only .7W extra, so roughly half a degree extra on a warming of more than 3.<br /><br />Any sort of stabilisation at all requires a radical change in the way we generate energy, and accounting for carbon cycle feedbacks (or not) doesn't alter that fundamental point.<br /><br />I think it's important to be aware of uncertainty, but also important to ensure that policy is reasonably robust and appropriate for the overwhelmingly probable case that some extremely unlikely event <i>doesn't</i> happen.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-45946200122350242011-11-30T21:26:02.428+00:002011-11-30T21:26:02.428+00:00Ah, it was wonderful to be present more or less at...Ah, it was wonderful to be present more or less at the naming of the "Efficient Climate Hypothesis." :)<br /><br />Re "bias in the amazon region," those two anomalous droughts and their pinning to North Atlantic SSTs is slightly scary, although I realize it must seem a trifle to those innured to tandeming through the very-nearly-radioactive mean streets of Kamakura nearly every day. The pink cameras are the least of the hazards... :)Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-28400784003697559112011-11-30T11:38:38.626+00:002011-11-30T11:38:38.626+00:00We are back to the neo classical economists' o...We are back to the neo classical economists' opening assumption of 'let us assume perfect competition', but in this case it is 'let us assume we plateau at 450 to 550 ppm'.<br /><br />The IEA's latest WEO has its central 'New Policies Scenario' stabilising CO2-eq at 650 and the 'Current Policies Scenario' at much higher levels. As things stand, the 450 Scenario is very much in the left hand tail of the distribution of emission outcomes. <br /><br />The WEO also notes a paper by Schaefer et al (2011) that suggests that the New Policies Scenario will give rise to an additional 58-116 ppm though carbon feedbacks on top of the 650. <br /><br />Moreover, if you take the UK situation, for example, all the pressure is on the government to come off the New Policies Scenario back to the Current Policies Scenario in the face of mounting economic austerity. George Osborne has already been preparing the ground for a retreat from the 2008 UK Climate Change Act by linking UK mitigation actions to emission reduction achievements made overseas. <br /><br />What will make policy makers tough out taking difficult mitigation paths is their perception of risk. And a large part of their perception of risk is formed by the concept of climate sensitivity. <br /><br />Now I am sure that the literature is very thin for the carbon cycle feedbacks, but this seems a very strange reason for focusing almost exclusively on Charney sensitivity. <br /><br />More broadly, I find it very puzzling why so few scientists are comfortable poking about in the tails of climate outcomes. In the financial community we spend an inordinate amount of time concentrating on the tails, even though the tails are where data and theory is thinnest. This is because it is the tail events they get you carted out the market feet first. <br /><br />In the risk committee meetings I have attended over the years, probably 75% of the time was spent on the probability tails. If anyone had piped up with the comment that spending so much time and resource on such low risk events was 'alarmist', they would have been regarded as, well, 'silly'.The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-3385742441445525112011-11-30T10:24:51.098+00:002011-11-30T10:24:51.098+00:00Well, how much it matters depends a bit on the pol...Well, how much it matters depends a bit on the policy background - while people are talking about 450ppm or 550ppm, the carbon cycle feedback is likely small and in any case all efforts to stabilise at those levels require a strong reduction in emissions - whether the permitted emissions (for a given stabilisation) is a small negative or small positive value in 2050 is hardly crucial.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-12593231789578575022011-11-30T09:29:22.295+00:002011-11-30T09:29:22.295+00:00And on reflection (and as an economist by training...And on reflection (and as an economist by training), the focus on Charney sensitivity is eerily reminiscent of the blind alley the economics profession went up in the 1970s.<br /><br />Robert Lucas got the Nobel prize in economics for in effect arguing that macroeconomic models AND policy-making could be built on microeconomic foundations. But the microeconomic foundations assumed economic actors could form rational expectations in turn based on perfect information and frictionless transactions. <br /><br />But back in the real world, expectations weren't always rational, information perfect and transactions frictionless. So policy makers were given a very 'tidy' tool kit for a world that didn't exist. <br /><br />I suspect that few policy makers understand the difference between a Charney sensitivity and one that incorporates changes in carbon cycle feedbacks, but it is the latter that they should be crafting policy against. <br /><br />For the economics profession, guiding policy makers to where the models and theory were most complete (but not a true representation of the world) proved an absolute disaster. I am curious as to whether you agree that the scientific community is following a similar tack?The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-36522243565453277742011-11-30T08:15:43.056+00:002011-11-30T08:15:43.056+00:00Crandles and James - thanks for tidying that up. ...Crandles and James - thanks for tidying that up. <br /><br />I would note, however, that 'the bottom line' is the climate sensitivity including carbon cycle feedbacks. Mitigation and adaption policies need to be built around this rather than the 'Charney sensitivity'. <br /><br />When the AR5 comes out, it would be good to see the two sensitivity concepts disentangled.The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-88413107940662327862011-11-30T02:36:50.785+00:002011-11-30T02:36:50.785+00:00Chris is right, I'm basically talking about th...Chris is right, I'm basically talking about the "Charney sensitivity". Once you add in carbon cycle feedback, things get fuzzier and I haven't formed such a clear opinion. The Hadley centre however is very much at the extreme end due to a well-known dry bias in the amazon region (which means the whole rainforest collapses at the slightest drying). Privately many acknowledge that this is unrealistic, but of course it's a useful hook for more funding and research...<br /><br />I happened to see Friedlingstein give a fairly low (but positive) estimate of carbon cycle feedback at WCRP, but I don't know if this is a new consensus or not...James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-72620153389083227902011-11-30T01:32:17.371+00:002011-11-30T01:32:17.371+00:00The 6C silliness is almost certainly referring to ...The 6C silliness is almost certainly referring to climate sensitivity of 6C.<br /><br />Carbon cycle feedbacks would affect observed temperatures increases but not the climate sensitivity.<br /><br />Probably many choices for 6C silliness among them:<br /><br />CPDN Stainforth et al - how not to write a press release<br />http://www.realclimate.org/index.php/archives/2006/04/how-not-to-write-a-press-release/<br />(maybe that is 11C silliness but at least paper did not claim it was a pdf)<br /><br />Or Hansens 3C short term sensitivity = 6C long term sensitivity (maybe that is more 'do we care' than silly)<br /><br />Or Frame et al uniform prior with high upper cut off to hype the risky end<br /><br />Or maybe take your pick of (9 out of) 10 studies in IPCC Fig 10.2<br />http://julesandjames.blogspot.com/2011/11/how-not-to-compare-models-to-data-again.html<br /><br />and quite possibly others.<br /><br />(If it is temperature rise rather than sensitivity then there are more possibilities: maybe Mark Lynas's book 6 degrees.)crandleshttps://www.blogger.com/profile/15181530527401007161noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-34293660973678268712011-11-29T22:59:56.185+00:002011-11-29T22:59:56.185+00:00James. A question. When you refer to the 6C sillin...James. A question. When you refer to the 6C silliness, is this purely in the context of the Charney definition with fixed boundary conditions (as RC was also noting today in connection with the Schmittner paper)? <br /><br />When Richard Betts and others start changing the carbon cycle feedbacks, they do produce 6C scenarios (or thereabouts). Do you also view these as unrealistic?The Rational Pessimisthttps://www.blogger.com/profile/15839671809950298150noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-6038840590650877852011-11-29T00:47:07.662+00:002011-11-29T00:47:07.662+00:00DC, yes as I've said I think they are clearly ...DC, yes as I've said I think they are clearly too optimistic in the headline result - Nathan Urban basically acknowledges as much in his interview.<br /><br />Tom, I agree the multimodality is odd, and suspicious. I can't think of a good physical explanation for it, as it seems to require substantial nonlinearity in the climate's response to changes in the sensitivity parameter (at least locally).James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-49350218449116569762011-11-28T19:01:16.061+00:002011-11-28T19:01:16.061+00:00It's weird that the response is so multimodal....It's weird that the response is so multimodal. From the SOM, it seems like the underlying cause of this is the use of an ensemble with only 25 members. That might mean that the real distribution is somewhat undersampled by this experiment. I wouldn't expect that to dramatically change the tails, but it might move the mean around a fair amount.Tom Fiddamanhttps://www.blogger.com/profile/00095645518031235272noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-64370009660325824602011-11-28T17:14:50.419+00:002011-11-28T17:14:50.419+00:00The land curve also seems to have a longer tail on...The land curve also seems to have a longer tail on the low end. So combining the land and ocean estimates differently would raise the l+o estimate median and overall range, but still leave the upper end more constrained (in terms of its shorter distance from the median estimate).<br /><br />So, James, do you think this study might overly constrain the upper end somehow, just as you've previously criticized other studies for the opposite problem? Or is this an irrelevant consideration (very possible)?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9959776.post-72350995827802205232011-11-28T10:35:39.433+00:002011-11-28T10:35:39.433+00:00Been waiting for that for years - it's the met...Been waiting for that for years - it's the methodology underlying their <a href="http://www.ukcip.org.uk/" rel="nofollow">UKCIP</a> outputs.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.com