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Riccardo at 00:18 AM on 27 May 2010Has the greenhouse effect been falsified?
Berényi Péter, could you please tell to which of the many figures posted in you comments you're referring to? Also, could you elaborate on the concept of the radiation temperature at the CO2 wavelength being "as cold as it can get"? -
Ken Lambert at 23:46 PM on 26 May 2010Robust warming of the global upper ocean
HR #57 #58, kdkd #59 If Josh Willis' 0.1W/sq.m sequestered in the deep oceans (below 1000m) is correct, and the upper levels (down to 900m)are showing flat OHC from Argo post 2004, then Dr Trenberth's 0.9W/sq.m TOA imbalance is *nine* times the increase in OHC. Both cannot be right when there is no other feasible heat storage than the oceans. The 0.1 W/sq.m is small enough to be from other sources like undersea volcanoes or geothermal (warm bottom) sources. The mechanism of heat transfer to the oceans from the atmosphere has always been unconvincing. Try heating your bath with a radiant heater held above the surface or from warm air in a room. SW penetrates about 300m into water and LW a few millimeters. An immersion heater is a different story. Undersea volcanoes or geothermal heating would be much more efficient in heat transfer terms. Or the other 8/9ths of Dr Trenberth's heat could simply be lost to space where the heat sink is at -273 degC. The above 60 posts show that warming of the upper oceans is not 'Robust' at all. BP has got it pretty right in his application of the first law, and the conclusion that the large OHC increases prior to 2004 are offset errors in the XBT-Argo transition is much more 'Robust' I would suggest. -
Berényi Péter at 23:06 PM on 26 May 2010Has the greenhouse effect been falsified?
Sylas, it is easy to see that radiation temperature in CO2 stopband (between 14 and 16 μm) is about as cold as it can get. It means that photosphere (the region from where photons have a reasonable chance to escape to space) in this frequency band is above the troposphere. Below that line atmosphere is opaque (optically thick) in stopband. Now. In that region (lower stratosphere) temperature does not decrease with height anymore. If you put more carbon dioxide into air, photosphere will ascend, but its temperature may even increase slightly. Therefore OLR (Outgoing Longwave Radiation) should not diminish in this range with increasing CO2. If you want to explain "greenhouse effect" anomaly due to changing carbon dioxide levels, you should provide some more details. Thanks.
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michael sweet at 22:48 PM on 26 May 2010Greenland rising faster as ice loss accelerates
Humanity rules: Can you provide evidence that Nature and Science are alarmist beyond your desire for them to be incorrect? These are two of the top journals in science today. They are well known for their unbiased publishing of a very wide variety of material. Why should they be biased in this one subject? Maybe they print this "alarmist" data because that is what all the data look like. If we have no evidence that they are biased the default hypothesis is that the data is really this bad. Sceptics are welcome to submit papers to Science if they have good data. -
kdkd at 22:28 PM on 26 May 2010Robust warming of the global upper ocean
HumanityRules #57 There's certainly something wrong somewhere. Your final comments are a mis-statement of the scientific process. If someone can find strong evidence that the missing heat doesn't actually exist then that will make their career. Meanwhile the surface observations are what are used to make the (to date rather conservative) IPCC & co predictions, and the heat imbalance model is a bit of a side show to the main game. Much as some people would like it to be central. However the uncertainties relative to the other things that are measured better, and easier to measure are so high this won't happen for a while. What's the uncertainty on the 0.1 W/m2 term by the way, i.e. ± how much? -
HumanityRules at 21:40 PM on 26 May 2010Robust warming of the global upper ocean
From the Pielke Snr website this was Josh Willis assessment of Johnson most recent paper on deep ocean warming "They looked at the prospect of deep warming on decadal time scales using the sparse, but highly accurate repeat hydrographic sections and found that below 3000 m in the global oceans, and below 1000 m in the southern ocean, the ocean is taking up an energy equivalent of about a 0.1 W/m^2 energy imbalance at the top of the atmosphere. So while this is significant, it suggests to me at least that the deep ocean is probably not taking up a bunch of heat really rapidly and the traditional idea that most of the action is in the upper several hundred meters is probably going to hold up." -
HumanityRules at 21:38 PM on 26 May 2010Robust warming of the global upper ocean
54.kdkd "it seems extremely likely that large scale observations of warming are also due to the same CO2 parameter." I guess it's the 10 of the 16years of OHC showing no large scale observations of warming that makes me question this. It's the reduced uncertainty in the measurement system for the most recent period of no warming that further backs up my cautious approach. This isn't even necessarily a question of if AGW is occuring but could just be the magnitude. Everybody seems fixed on finding the missing heat rather than considering whether we should reduce our overall estimate of the build up of energy in the system based on these observations. Given the singularity of this approach there's likely only one possible outcome somebody, somehow will find the missing heat. -
Ned at 21:06 PM on 26 May 2010Collective Intelligence and climate change
Putting aside Doug's car for a moment, I like the idea of this "Deliberatorium" experiment, but the implementation is not so great. It's an awkward and confusing user interface, there's a shortage of explanations and instructions, the text of the arguments is full of typos and grammatical errors, and if you want to be thorough about it, wading through the whole thing to rate all the arguments takes ... forever. If that's intended as a real research project, rather than just somebody's toy, they should pull the plug, invest much more time in the user interface, and then re-launch. -
Riccardo at 19:56 PM on 26 May 2010The significance of the CO2 lag
batsvenson, if common sense doesn't help, if chris's numerical example above doesn't help either, try the math yourself or see here. -
Riccardo at 19:18 PM on 26 May 2010There's no empirical evidence
PaulK, "Clearly, the structural forms are very different." They are not. Indeed they're identical apart from the term Q(0) which comes from working with T instead of ΔT and the use of C/λ which is τ. It's just simple math. @Doug sorry to disappoint you. It was not much fun, just trivial math. :) -
kdkd at 18:59 PM on 26 May 2010Robust warming of the global upper ocean
Riccardo #55 Absolutely. The measurement model as it stands is indadequate to assess these heat budgets with a reasonable degree of certainty over a sufficiently long timescale. Until we have enough good quality data over a long enough timescale, this global heat balance stuff will not be good enough to make a substantial contribution to the state of the scientific consensus. -
batsvensson at 18:50 PM on 26 May 2010The significance of the CO2 lag
@chris, Ned, et al. RSVP claim is that "A causes more of B cause more of A is a runaway solution". This claim is valid. The straw man attack on RSVP claim is to claim RSVP stated "A causes B cause A", which he never did. -
Riccardo at 18:48 PM on 26 May 2010Robust warming of the global upper ocean
I know I'm going to be a bit boring by repeating the same thing, but I cannot resist to quote from the paper linked by Doug (thanks Doug, by the way): "The data from these repeat sections suggest that abyssal variations may contribute significantly to global heat, and hence sea level, budgets. To close ocean heat, sea level, and likely freshwater budgets on interannual time scales, the ocean below 2000 m must be much better sampled in space and time than it has been, or is likely to be, relying on repeat hydrography alone." Different paper, different people, similar conclusions, it's a travesty we cannot track the flow of energy through the climate system. -
batsvensson at 18:39 PM on 26 May 2010The significance of the CO2 lag
@Ogemaniac at 10:47 AM on 19 May, 2010 "few seem to understand that not all positive feedbacks are "runaway". " True if the control system use a discrete time sampling model. (Which climate models do but, as far as we know, mother nature doesnt.) -
johnd at 17:54 PM on 26 May 2010Collective Intelligence and climate change
doug_bostrom at 10:36 AM, you think you have problems with your fuel gauge. My car has a readout that tells me how much further I can travel on the remaining fuel. Trouble is that distance really does decrease faster than the distance on the odometer increases. If ever two pieces of data should correlate, these are those two. The manufacturer solves the problem by the remaining distance readout going blank once it goes below 50 km. I'm wondering if there is some other form of data that I could input, such as tyre pressures as they should increase due to heat buildup the further the vehicle travels, but I don't know whether it can be correctly calibrated given I drive on both gravel and paved roads, or if it's even relevant. :-( -
HumanityRules at 17:12 PM on 26 May 2010Collective Intelligence and climate change
4.doug_bostrom ditto your gas gauge. You thought about selling that pile of junk? ;) -
HumanityRules at 17:02 PM on 26 May 2010Collective Intelligence and climate change
3.doug_bostrom I got no problem with you driving your car based on your dodgy pressure measurements. It when you demand the complete re-organisation of the transport system based on them that I think it's necessary to take a closer look at your notebook. -
kdkd at 16:59 PM on 26 May 2010Robust warming of the global upper ocean
HumanityRules #52 Given that we can't model the observed 20th and 21st century warming without using CO2 as a parameter, it seems extremely likely that large scale observations of warming are also due to the same CO2 parameter. This is not mathematics, we can't provide logical proof - inductive proof is just how science works, and the global warming story is remarkably consistent for such a large poorly measured complex system. Just because some things are uncertain in the measurement system, it doesn't follow that everything is uncertain, which appears to me to be your argument. More generally I'm most unimpressed with the way that short term problems with the measurement model of ocean heat content are used by so called climate sceptics to try to draw strong conclusions about longer term climate implications, discarding much prior work on the topic in the process. -
Doug Bostrom at 16:38 PM on 26 May 2010Robust warming of the global upper ocean
HR, no problem and I realized I sounded defensive as soon as I hit the "Submit" button. I'm trying to retrain myself to avoid signaling unfounded conclusions so was trying to be clear on that. OT but speaking of "Submit", I wonder what is the subconscious effect of that common term used on web interfaces, at sites sometimes featuring contention? Reminds me of the old New Yorker cartoon depicting a heavily ribboned and brassed military man at the wheel of his automobile, approaching a "Yield" sign and barking out "Never!" -
HumanityRules at 16:13 PM on 26 May 2010Robust warming of the global upper ocean
51.doug_bostrom I wasn't accusing you of assigning casuality more this publication and the general assumption this is a AGW signal. It maybe but there seems a lot more to measure and explain before we say it is. -
Doug Bostrom at 15:58 PM on 26 May 2010There's no empirical evidence
Holy Cow, this is fun to watch. -
Doug Bostrom at 15:07 PM on 26 May 2010Robust warming of the global upper ocean
HR, I'm not assigning any causality or even forming conclusions, instead looking at what's available in the way of hints in publications such as those I cited. Recent Bottom Water Warming in the Pacific Ocean (pdf, full text) has a pretty good discussion of general factors controlling transfer of heat in the ocean, definitely worth a careful read. Be sure not to become beguiled or transfixed by the sentence "Abyssal cooling of about 0.02°C has been reported in the southwest Pacific Ocean...", heh! Ok, I lie, I'll allow myself one conclusion, namely that the classical understanding of vertical heat transfer in the ocean is appropriately conservative in the face of limited understanding of what's actually "going on down there" but needs and indeed is receiving some freshening (pun!). It'll be absolutely fabulous to see some instruments drifting around in the bottom half. Can we hold our breaths that long? I doubt it! -
HumanityRules at 14:03 PM on 26 May 2010Robust warming of the global upper ocean
48.doug_bostrom "Seeing that the upper ocean is not effectively isolated from the lower approximately 1/2 of the ocean" I had it in my head that the deep and upper ocean are effectively isolated in our classical understanding. The known mechanisms tranfer relatively small amounts of energy to the deep on a year to year basis. Look at the difference in heat accumulation in 2003 and 2004. Given that the ocean is just sitting there absorbing the suns energy then those large differences need to be accounted for before you can start asigning causality. -
Pat Moffitt at 14:01 PM on 26 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
johnd at 08:53 AM on 26 May, 2010--If we are looking at the total amount of nutrients within the entire lake water column- then harvest will have a minimal effect on the total nutrient store. (The residence times are enormous). Internal recycling is critical to this lake however the production of biomass is complex and terrestrial sources do have a role. I don't really see the loss of nutrients to the fish catch as a vital link here. Overfishing may have deleterious and multiple effects that can cascade through the system but I don't think it is related to the loss of nutrients within the harvested fish. Langenberg's thesis posits that the changes in fish production catch data are the result of fishing practices not climate. In fact he showed that increasing temperatures that lead to a shallower mixed layer does not necessarily result in decreased production. However the ability to blame climate may perversely lead to a collapse in the fishery by undermining the need of he involved parties to create and enforce a workable fishery management plan. -
HumanityRules at 13:56 PM on 26 May 2010Robust warming of the global upper ocean
47.CoalGeologist i'm not so concerned about the accuracy of the data. It's the best we've got and have to accept that. What I'm concerned about is taking highly variable data, drawing a straight line through it and saying look it's AGW. This is not an objective process like writing down readings from an instrument. For every argument that says this is a valid approach there is one which will question the validity. -
actually thoughtful at 13:45 PM on 26 May 2010Collective Intelligence and climate change
The deliberatorium needs an expand all. And more sophisticated arguments, with sources. It kind of, sort of, needs to be more like skeptical science! -
HumanityRules at 12:45 PM on 26 May 2010Greenland rising faster as ice loss accelerates
47.Jeff Freymueller Your post sort of contradicts the general idea that the earth as a whole has been losing ice for 200-300years (with some reversal periods). Hopefully your not suggesting that ice loss is only a 21st century phenomenon. Here's a longer term estimate of Greenland mass balance.
(It came from here which looks to be an endless sourse of climate change imagery. Try Greenland in teh search for example)
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jimmck at 12:30 PM on 26 May 2010Human CO2 is a tiny % of CO2 emissions
I am please to find this site as I have been working on building up a Balance Sheet and "C" Flow for the period 2000 to 2010 and you have filled in some gaps. It seems to me that ocean temperatures must be rising. If they were static then the oceans would absorb any amount of CO2 due to equalisation of partial pressures given thay there is 50 times as much CO2 in the oceans as in the air. How much has the average ocean temperature changed from 2000 to 2010. -
PaulK at 12:28 PM on 26 May 2010There's no empirical evidence
Riccardo, The solution I proposed for OLR in posts #52 and #55 is mathematically exact, and makes very few assumptions. The solution is based directly on a flux response function which varies as a function of time, and therefore represents a generalized solution to a wide variety of energy balance models. Because it makes very few assumptions, the conclusions about the shape of the OLR response are mathematically robust but have low information content. I would prefer to use this model directly as a basis to discuss observed OLR response, rather than a more informative model, but with questionable assumptions. However, in response to the points I made about the geometry of the OLR response, you referred me to the Schwartz paper and you attempted to abstract a solution for OLR from that model (your posts #56 and #60). I did the same thing, initially mistakenly assuming that F was a net forcing in time (Q(t) – E(t)), since Schwartz rather loosely describes F as a Delta(Q-E). When I reexamined the solution form, however, it was apparent that F has to be an impulse forcing in Schwartz, as more conventionally applied. So I again recalculated OLR and found that I had a solution that was different from (both your original and) your corrected OLR solution. I concluded, since we had been talking originally about net flux response functions, that you were misunderstanding the F term in Schwartz. It is apparent from your last post that this is not the case. Therefore, I now believe that it is either your maths or mine which are wanting. For the case F=bt, I obtain the following result for OLR, using the Schwartz model and Schwartz nomenclature:- C * d(Deltat)/dt = CdT/dt = dH/dt =Q(t) – E(t) = net flux in time For constant input Q(t) = Q(0) for all t. We “transfer” the forcing to the output side as follows: Net flux in time = Q(0) –(E(t)-F(t)) = Q(0) – OLR(t) = C*d(Deltat)/dt Hence OLR(t) = Q(0) - C* d(Deltat)/dt But Deltat = b((t-tau) + tau*exp(-t/tau))/lamda and Therefore d(deltat/dt) = b(1-exp(-t/tau))/lamda Substituting into the solution for OLR we obtain : OLR(t) = Q(0) – Cb(1-exp(-t/tau))/lamda Note that at time t=0, we obtain OLR(0) = Q(0), and for t>>tau, OLR tends to a constant = Q(0)-Cb/lamda = Q(0) –b*tau. If we note that b can be written as F(tau)/tau, then this asymptote is equal to Q(0) – F(tau). All of this seems reasonable to me within the context of the assumptions made. The above solution may be compared with your corrected solution (post#60) : OLR(t) = β *((t-τ)+τ*exp(-t/τ))-β*t Clearly, the structural forms are very different. I emphasise that I am not wedded to the Schwartz model, but I believe that we need to get this out of the way if there is any hope of having a sensible conversation on the subject of whether an observed rise in OLR can be rendered compatible with common assumptions. -
HumanityRules at 12:18 PM on 26 May 2010Greenland rising faster as ice loss accelerates
46.Jeff Freymueller That's the problem I did biology and chemistry at High school. 43.llewelly Thanks I think I've got that it's to do with vectors etc. still not sure that in Riccardo's example the outside force of gravity is not having an effect to change the rate of acceleration but let's move on. If this study shows that for almost half the time of the study period Greenland and Iceland were accumulating mass rather than losing it I'm still concerned with teh emphasis on ice loss here. There is variability in ice accumulation so what. It seems like Nature and Science are competing to produce reports that can generate the most alarmist press releases, news reports or politicians oneliners. Irrespective of what the full data set tells us. This is worrying. -
Eric (skeptic) at 12:09 PM on 26 May 2010Polar bear numbers are increasing
Riccardo, the Norwegian group doesn't use the word hunting, only the word "removal" which is an obfuscation. The Baffin Bay population with 2000 bears has a hunting quota of about 100, but in fact about 200 have been hunted each year. But the indigenous groups maintain that the population is both underestimated and replenished by polar bears migrating from neighboring areas. -
Jeff Freymueller at 12:09 PM on 26 May 2010Greenland rising faster as ice loss accelerates
#36 fydijkstra, the key point you seem to be leaving out is that Greenland was not losing much mass (maybe not any) in the late 20th Century, and then over a short period of time it switched over to shedding mass like crazy. The changes in uplift rate observed here are far bigger than the uplift or subsidence rates observed over most of the planet. This is a big change, and it is a big deal. -
Jeff Freymueller at 12:04 PM on 26 May 2010Greenland rising faster as ice loss accelerates
#44 johnd, HumanityRules was mixing up velocity and acceleration, and getting very confused. The ball in the air example is a basic high school physics problem, so it seemed a logical one to me. Especially given that the acceleration is due to gravity, and we all (should) know that gravity is always pulling objects back to the ground. I like your block of ice on a kitchen scale analogy quite a bit. Especially if you think about the sort of kitchen scale that visibly depresses when you put a weight on it. As the block of ice melts and the water drips away, the weight reading on the scale will get smaller, and the scale will rise up as the ice melts. What's missing from the scale analogy is that this movement is superimposed on a general subsidence or uplift, so what you see most clearly is a change in the trend of height over time. -
Johnny Vector at 12:03 PM on 26 May 2010Collective Intelligence and climate change
So I went to the Deliberatorium, and ugh. Most of the arguments, in both directions, I gave low marks to, mainly because hey, [citation needed]. For me, an argument is only convincing if there's real data behind it. Also, it was clunky to navigate, ugly as sin, and the content was terribly uneven in quality and style. But I did get an error from the LISP interpreter when I was done, so that was a nice blast from the past. Ah MIT, how you do love the LISP. I like the organization here a lot better. Plus the content and citations are 2-3 orders of magnitude better. -
dhogaza at 10:56 AM on 26 May 2010Greenland rising faster as ice loss accelerates
In Riccardo's example, the thrown object is stopped only for a moment. It is only a prolonged stop which requires a lack of acceleration. A momentary stop
An infinitely momentary stop ... a point on the curve describing its arc, HumanityRules. -
Doug Bostrom at 10:36 AM on 26 May 2010Collective Intelligence and climate change
Further to my last remark, I suppose it's just as well I can't drive my car because of the gas gauge problem. I -see- my gas gauge sinking steadily but it varies a little bit from moment to moment as I check it, apparently due to natural variations mostly I hypothesize down to various accelerations as well as tiny changes in instrument supply voltage, the influence of sunlight causing the gasoline to expand, other things I may not even be able to identify at all. It's really a serious problem with the instrumentation since due to these variations I see it's impossible to draw any conclusions from the gas gauge. Annoying, but I can't be certain about my observation of which way the gas gauge is headed; at any moment a temporary excursion upward might lead to a full tank. Who's to know? So to be on the safe side I do nothing; my doubt about the gas situation means inaction is the best course. But again, it's beneficial to my carbon footprint. -
PaulK at 10:31 AM on 26 May 2010There's no empirical evidence
e, You are the only person here who is NOT confused. There is nothing wrong with Tamino's solution for Θ(t) given his assumptions and approximations. My question was directed at Riccardo, who I believed had a conceptual misunderstanding of the F-term in Schwartz, based on his attempts to derive an expression for OLR from this model. (See my post #65 for context.) I'll address the reason for why I believed this in a separate post for Riccardo. -
Doug Bostrom at 10:20 AM on 26 May 2010Collective Intelligence and climate change
Johnd I hear you but the trouble is, when I take my daily 100 measurements of my tire pressure I see that even though I consistently get readings roughly centered on 200kPa I find each reading is +/- ~6kPa from any other. This means I cannot drive the car because I cannot draw any conclusions due to the noise in my measurements. On the other hand, this paralyzing uncertainty is a good way of reducing my carbon footprint. -
johnd at 09:37 AM on 26 May 2010Greenland rising faster as ice loss accelerates
Trying to use an object thrown into the air or a car on a slope seems convoluted analogies to draw upon. Would imagining a block of ice or a dripping bucket of water sitting an a kitchen scale make it any easier? At least with a bucket of water varying both the rates of water dripping in and water dripping out the effects of all combinations of relevant forces could be imagined. -
llewelly at 09:09 AM on 26 May 2010Greenland rising faster as ice loss accelerates
HumanityRules at 17:52 PM on 25 May, 2010 :When the thing reaches the top and stops it has no velocity or acceleration. So if acceleration is constant in your example it's because there is no acceleration through the whole process. But that seems wrong.
In Riccardo's example, the thrown object is stopped only for a moment. It is only a prolonged stop which requires a lack of acceleration. A momentary stop, on the other hand, is a result of acceleration which continues through the stop. The acceleration is why the object does not remain stopped; if acceleration vanished when the object stopped, it would stay stopped. -
johnd at 08:53 AM on 26 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Pat Moffitt at 08:20 AM, I concur mostly with what you are saying, and feel that this is at last focusing on what I took to be the primary objective of the study. As you noted, within the the media the focus has been drawn to other factors which then snowballs as it drags in others whose perception is programmed by the headlines they read. With regards to nutrient recharge from run off, looking at it from the Primary ProductION perspective, whilst it is a very large body of water, any foodstuffs that are harvested from the water permanently strip nutrients out that ultimately must be replaced. Run off would replace some of these nutrients directly into the immediate zone where they can be recycled rather than taking them into storage at lower levels, but that is only one side of the equation. -
Pat Moffitt at 08:20 AM on 26 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
johnd at 05:47 AM on 26 May, 2010 My comments were with respect to primary productivity. To simplify what is being said by Tierney--Most of the nutrients required to grow the food that the fish eat (directly or indirectly) are recycled from the deeper portions of the lake. (95% internal lake recycling cited) The amount of nutrients entering the lake from runoff etc is not significant. The fish population fluctuates with the amount of food that is produced. Water has different densities at different temperatures. The larger the difference in densities the more stable the water column becomes. A stable or stratified water column makes it difficult to mix the water which brings the nutrient rich lower water mass to the surface. The mixing is provided by the wind and the more stable the water column the more wind energy that is required. Increasing temperatures tend to make water columns more stable and thus theoretically could diminish lake mixing and thus primary productivity. A reduction in primary productivity may lead to a reduction in the catchable fish supply. Tierney assumes by using the charcoal that the lake was less productive than in periods when the lake was arid, and cooler and as such it is temperature that is controlling the primary productivity of the lake. (The BSI or biogenic silica index measures the amounts of biological derived silica in the sediment. Diatoms, which have a high silica content, can be used as a n estimate of primary productivity when the dominant fraction of primary producers are diatoms.) But we need to know much more information than just the temperature differential. We need wind speed, sheer, depth of mixing etc to understand if the temperature gradient problem from surface heating is significant. The Lake Tanganyika Regional Fisheries Programme (TREFIP) ENVIRONMENTAL IMPACT ASSESSMENT REPORT -GCP/INT/648/NOR and its modeling of wind and lake mixing found that temperature was only of secondary importance. So temperature alone cannot tell us the amount of mixing and nutrient recycling. My previous comment makes note that diatoms and thus BSI may not be a good proxy for Lake Tanganyika as at times it sees most of its primary production coming from cyanobacteria- not diatoms. A presentation by Hecky and Verburg http://www.espp.msu.edu/climatechange/…/Physical%20and%20Ecological%20Responses%20of%20the%20Great%20 showed the switch from cyanobacteria in the wet season (warm) to diatoms in the dry season (cool) on an annual basis. The cyanobacteria do not appear as biogenic silica in the cores and as such will not be measured as productivity. Tierney’s correlation of BSI with LST may be nothing more than diatoms being relatively more plentiful in periods of lake upwelling (aridity and low T) and cyanobacteria during periods of low upwelling (wet, high T and stable stratification). Tierney’s BSI as a result may say nothing about the overall changes in productivity of the lake. (The BSI simply reflecting the Lake’s primary productivity mode switching between cyanobacteria and diatoms.) Without a reliable proxy for total productivity the assumed correlations to temperature and fishery catch becomes less grounded. Another marker for primary production is chlorophylla. Langenberg’s 2008 thesis on the Lake cites evidence that chlorophylla analysis shows no decline in productivity in the period of the 1970 to 1990s. Nor have secchi measurements shown any increase I lake clarity. Tierney has acknowledged a “potentially” large role for overfishing in her Nature paper- however the media interviews have tended to diminish the relative threat of overfishing. TREFIP has demonstrated the reality of overfishing. There have been over two decades work trying to get the multiple interests and nations involved in the Lake fishery to agree to an enforceable/workable fishery harvest plan. Pointing a finger of blame at global warming may very well undo these vital efforts. Tierney cautions that increasing temperature may imperil the percentage of the food supply derived from fish. One can gain no understanding on the relative risk to food security in this region until one presents the information in the context of overall food production and risks -which is not given. She acknowledges t increasing temperatures have been accompanied by increased rainfall. She states that as many as 1million people are “employed” in the fishery however 2/3rds of the surrounding population survive by eking out a subsistence agriculture existence. I don’t have the answer yet (but am checking) but it seems answering the impact of increased rainfall on agricultural productivity may be an even more important question. -
johnd at 08:10 AM on 26 May 2010Collective Intelligence and climate change
doug_bostrom at 07:18 AM, your confidence may in some way be further restored instead by double checking tyre pressure against ambient temperature. If it doesn't restore confidence in the ability of some to correlating relevant data, it should at least restore it in the steering and braking performance of your push bike. ;-) -
Paul D at 07:42 AM on 26 May 2010Ocean acidification isn't serious
John Abraham has dissected Moncktons presentation on climate science here: http://www.stthomas.edu/engineering/jpabraham/ It's well worth listening from beginning to end! -
Doug Bostrom at 07:18 AM on 26 May 2010Collective Intelligence and climate change
How did I miss the Master List of Mutual Exclusion?? How about a corollary list of Convenient Untruths, showing all the observations, measurements and models that are coincidentally incorrect, the product of conspiracies, etc.? In other words, any measurement, calculation or plotted trend that may happen to lend confirmation to anthropogenic warming no matter how distantly related to the actual central issue? So far we've learned that thermometers don't work or at least work differently depending what they show, the GPS system is hopelessly flawed in certain cases but not in others, tide gauges are subject to a plethora of flaws making them unable to accurately record sea level increases but leaving them otherwise reliable, noise overwhelms plotted trends no matter the resolution of the y-axis or length of the x-axis. The list is large, and growing. My confidence is so shattered that I've taken to double-checking my tire pressure versus ambient barometric pressure of late because otherwise there's no way of determining if my tires are completely flat or dangerously overinflated. I also swing my compass daily before I try to drive in any of the cardinal directions. Maybe I should shut up and get to work... -
johnd at 05:47 AM on 26 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Pat Moffitt at 11:29 AM, given the definitions that Chris has applied above, can you clarify whether it is productivity or primary productivity that you note as BSi being a proxy for. The abstract for the Nature article states "We conclude that these unprecedented temperatures and a corresponding decrease in productivity can be attributed to anthropogenic global warming, with potentially important implications for the Lake Tanganyika fishery." Unless they are confusing the terminology, the inferred direct link between productivity and AGW is at odds with the definitions above. One other point I would like to pick up on from the study before this thread, like Lake Tanganyika, dies, is the assumed relationship between humidity and charcoal levels, the assumption being that low humidity leads to drought which corresponds with more bushfires, and more bushfires means higher charcoal levels. Given that the correlation between charcoal levels and productivity was weak, that infers that at times higher charcoal levels instead of correlating with low productivity, correlated with higher productivity. I feel that this is perhaps the more correct assumption to make. Whilst fires are needed to produce the charcoal that is then washed into the lake to settle in the sediments, fuel for the fires is required first, and it is a well established fact that fuel loads increase most with the prolific growth resulting from wetter, not drier conditions. In addition, the majority of charcoal that results from fires anywhere in the catchment areas will require heavy runoff in order to be washed into the lake, either from the areas surrounding the lakes or via any of the rivers that feed into the lake during periods of high flow rates. Therefore higher charcoal levels may not necessarily indicate more fires, but quite likely higher fuel loads, and if higher charcoal levels correlate with periods of higher productivity, then the proposition of "Higher rates of precipitation may increase primary productivity" may well be a factor that has to be included rather than being dismissed as it was. -
Doug Bostrom at 05:15 AM on 26 May 2010Robust warming of the global upper ocean
Thanks for the reply, Berényi. In sum I guess most folks agree that Lyman's graph shows an increase in heat content of the upper ocean, leaving a couple of open issues. --Poor confidence in the marriage of XBT data w/ARGO observations leading to what may be interpreted as an artificial discontinuous jump in OHC during the transition period. My problem with that is the same as with my ability to describe what I think -may- be a countervailing argument. As ARGO has superseded XBT and simultaneously has been refined in accuracy, if indeed there had been an artificial discontinuity introduced its seems plausible we should have seen an overt seeming -decrease- in OHC as the discontinuity was revealed as artificial in subsequent years of improved measurement conclusions. We do not see a decrease of that kind, certainly not w/statistical significance. So perhaps either the discontinuity was simply an extra large case of variability or subsequent addition of heat has overwhelmed the effect of discontinuity as an artifact. Maybe; as I say it's a problem because I don't have the intimate knowledge of the measurement acquisition and processing system to form a useful conclusion. Unfortunately I don't think any of us here do. --If indeed total OHC has been increasing despite what seems to be a recent slackening of upper ocean heat content increase, where's it going? Seeing that the upper ocean is not effectively isolated from the lower approximately 1/2 of the ocean, a reasonable intuition would be that the missing heat is finding its way into the portion of the ocean where we don't have dense instrumentation and in fact measurements are quite spotty. In fact there are some strong hints to the effect that the lower ocean is warming on a broad scale: Recent western South Atlantic bottom water warming Geophysical Research Letters 33 (2006) Johnson, Gregory C.; Doney, Scott C. Abstract: Potential temperature differences are computed from hydrographic sections transiting the western basins of the South Atlantic Ocean from 60°S to the equator in 2005/2003 and 1989/1995. While warming is observed throughout much of the water column, the most statistically significant warming is about +0.04°C in the bottom 1500 dbar of the Brazil Basin, with similar (but less statistically significant) warming signals in the abyssal Argentine Basin and Scotia Sea. These abyssal waters of Antarctic origin spread northward in the South Atlantic. The observed abyssal Argentine Basin warming is of a similar magnitude to that previously reported between 1980 and 1989. The Brazil Basin abyssal warming is similar in size to and consistent in timing with previously reported changes in abyssal southern inflow and northern outflow. The temperature changes reported here, if they were to hold throughout the abyssal world ocean, would contribute substantially to global ocean heat budgets. Warming and Freshening in the Abyssal Southeastern Indian Ocean J. Clim. 21, 5351–5363 (2008). GREGORY C. JOHNSON, SARAH G. PURKEY, JOHN L. BULLISTER ABSTRACT Warming and freshening of abyssal waters in the eastern Indian Ocean between 1994/95 and 2007 are quantified using data from two closely sampled high-quality occupations of a hydrographic section extendingfrom Antarctica northward to the equator. These changes are limited to abyssal waters in the Princess Elizabeth Trough and the Australian–Antarctic Basin, with little abyssal change evident north of the Southeast Indian Ridge. As in previous studies, significant cooling and freshening is observed in the bottom potential temperature–salinity relations in these two southern basins. In addition, analysis on pressure surfaces shows abyssal warming of about 0.05°C and freshening of about 0.01 Practical Salinity Scale 1978 (PSS-78) in the Princess Elizabeth Trough, and warming of 0.1°C with freshening of about 0.005 in the abyssal Australian–Antarctic Basin. These 12-yr differences are statistically significant from zero at 95% confidence intervals over the bottom few to several hundred decibars of the water column in both deep basins. Both warming and freshening reduce the density of seawater, contributing to the vertical expansion of the water column. The changes below 3000 dbar in these basins suggest local contributions approaching 1 and 4 cm of sea level rise, respectively. Transient tracer data from the 2007 occupation qualitatively suggest that the abyssal waters in the two southern basins exhibiting changes have significant components that have been exposed to the ocean surface within the last few decades, whereas north of the Southeast Indian Ridge, where changes are not found, the component of abyssal waters that have undergone such ventilation is much reduced. Recent Bottom Water Warming in the Pacific Ocean GREGORY C. JOHNSON, SABINE MECKING, BERNADETTE M. SLOYAN AND SUSAN E. WIJFFELS J. Clim. 20, 5365–5375 (2007). ABSTRACT Decadal changes of abyssal temperature in the Pacific Ocean are analyzed using high-quality, full-depth hydrographic sections, each occupied at least twice between 1984 and 2006. The deep warming found over this time period agrees with previous analyses. The analysis presented here suggests it may have occurred after 1991, at least in the North Pacific. Mean temperature changes for the three zonal and three meridional hydrographic sections analyzed here exhibit abyssal warming often significantly different from zero at 95% confidence limits for this time period. Warming rates are generally larger to the south, and smaller to the north. This pattern is consistent with changes being attenuated with distance from the source of bottom water for the Pacific Ocean, which enters the main deep basins of this ocean southeast of New Zealand. Rough estimates of the change in ocean heat content suggest that the abyssal warming may amount to a significant fraction of upper World Ocean heat gain over the past few decades. Rumor has it that the instrumentation situation in the deep ocean is going to be improved so while revisitations of the kind Johnson et al are doing are currently our best way of gathering data on deep OHC, we can expect to have a more comprehensive picture of the situation in a few years. -
CoalGeologist at 04:34 AM on 26 May 2010Robust warming of the global upper ocean
Humanity Rules (@42): The relevance of a trend line, as in Figure 3 (above), depends entirely on the accuracy of the data. If the data are accurate, so is the trend; but our argument becomes circular at this point, and I don't think we can take it much further until the data are further corroborated. I will only add that poor Kevin Trenberth is already anguishing over his missing heat, and apparently (?) Pielke Sr. wants to take away another 70%?! If he's correct, we'll need a stronger word than "travesty". Unfortunately, Dr. Trenberth has left us little linguistic ground, other than by adding a few choice expletives in front! I don't think I'm being naive. Dr. Pielke Sr. has persistently raised skeptical questions regarding the accuracy of the surface temperature data, and thus plays an important (even if occasionally nettlesome) role in the scientific method. For every Pielke Sr., however, there are countless AGW Denialists who cherry pick or otherwise distort the data to serve their desired conclusion. Finally, in the spirit of multiple working hypotheses, I will suggest that the once tranquil water column in the ocean has been stirred up by fishing trawlers trying to fulfill humanity's (Yes, That means you!) appetite for Omega-3 oils. It's not easy feeding 6.7 gigapeople. (BTW... I'm kidding.) -
Doug Bostrom at 03:02 AM on 26 May 2010Greenland rising faster as ice loss accelerates
fydijkstra I've noticed your point #1 being highlighted elsewhere. It's an odd thing to worry about; nobody in the relevant fields is making any such predictions. Be careful about wasting your time on distractions. Regarding your point #4, there is excellent reason to suppose that Greenland's ice problem will -not- vanish within the next few hundred years; hypothesizing about some process that -may- arrest the loss of ice is not really very useful in the context of our own known modifications of the climate. For folks in Miami or similar locales point #5 seems rather pointless. :-) -
Riccardo at 01:19 AM on 26 May 2010Robust warming of the global upper ocean
Berényi Péter, big changes up to almost now while the OHC short term trend slowed down, good confirmation. But we knew that already from the discussion in the other post, we're repeating ourselves.
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