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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. -
Riccardo at 01:13 AM on 26 May 2010Greenland rising faster as ice loss accelerates
HumanityRules, yes, they were both going down and now are going up. -
Berényi Péter at 01:00 AM on 26 May 2010Robust warming of the global upper ocean
#41 Riccardo at 22:57 PM on 25 May, 2010 The jump in OHC you claim as an indication of XBT bias is between 2001 and 2003. The two do not match so it is easily discarted as an explanation of the jump Notice change in ARGO coverage please.
Current status:
#43 Ken Lambert at 00:31 AM on 26 May, 2010
BP is simply applying the first law ie. conservation of energy. etc., etc.
Thanks. This is exactly what I was trying to say.
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Riccardo at 00:59 AM on 26 May 2010Greenland rising faster as ice loss accelerates
Ron Crouch, ops, you're right. I myself wrote elsewhere that Iceland sits on the Mid-Atlantic Ridge. Thank you. -
Riccardo at 00:54 AM on 26 May 2010Robust warming of the global upper ocean
Ken Lambert, are you looking here for the answer on the missing heat when professional scientists couldn't yet? The difference between me and you (and BP) is that I do not try to solve the problem by so naively applying conservation of energy. I'm sure that any scientist knows about conservation of energy ... -
Ken Lambert at 00:31 AM on 26 May 2010Robust warming of the global upper ocean
BP#30. CoalGeologist #39, Riccardo #41 BP #30 came up with a jump of 6-8E22 Joules in OHC between 2000 and 2004, and I read Fig 2 as about 7E22 Joules 2001-2003. This translates to a TOA imbalance of about 2.1W/sq.m when model based estimates (Dr Trenberth) calculate 0.9W/sq.m over a similar period. Sharp jumps in short time periods which match the transition to Argo from a much smaller more fragmented XBT system can only be an offset error - an artefact of the transition. A similar jump occurred with the SORCE TIMS monitors which since 2005 read 4.5W/sq.m lower TSI that prior satellites. No-one is trying to splice TIMS to prior satellites or we would have a big drop in incoming solar radiation - a similar offset problem as XBT and Argo. BP is simply applying the first law ie. conservation of energy. If there is an imbalance at TOA then the energy must show up somewhere in the biosphere and the oceans have vastly greater capacity than the land or atmosphere (or ice melt)to store heat energy. The integral of the TOA energy flux imbalance WRT time should show up in the increase in OHC. Where else could it feasibly be absorbed in sufficient quantity? As far as six years of flat OHC data being insufficient to drawing conclusions on warming - then explain where the missing heat is stored in this period when CO2GHG theory requires a continuous and increasing TOA imbalance of about 0.9W/sq.m and rising. -
Ron Crouch at 00:16 AM on 26 May 2010Greenland rising faster as ice loss accelerates
Iceland sits half on the North American plate and half on the Eurasian plate Riccardo. No connection can be made between the volcanic activity in Iceland and the off-loading of ice in Greenland (at least not until any uncertainties can be resolved). The uplift and any lateral movements in the crust at the Greenland margin could have an effect at the plate boundary as I understand it and would be representative of the delayed viscoelastic response as opposed to the current observed uplift which only represents the immediate elastic response (local). If I'm wrong with this analysis could someone more knowledgeable enlighten me. -
HumanityRules at 23:35 PM on 25 May 2010Greenland rising faster as ice loss accelerates
35.Riccardo "Not worth to discuss any further." Okay I'll accept my ignorance on acceleration. So let's get down to basics. Is Fig 1 showing Iceland (and Greenland) subsiding between 1995 and 2000? -
HumanityRules at 23:25 PM on 25 May 2010Robust warming of the global upper ocean
39.CoalGeologist pielke snr in one of his posts suggests that 70% of the increase in OHC seen in this study is accounted for by just 3 years (1999, 2002 and 2003). You can draw a line from 1994 to 2009 and describe a trend the question might be what is the relevance of that. It's naive to suggest just AGW sceptics use the data to tell a particular story. Anybody have any general thoughts on how the very large interannual variability in OCH change impacts on our understanding of real world processes in the ocean? I have in my head that the oceans are a very stable environment. For example this diagram shows much of the volume of the ocean is homogenous, do we have to start thinking that the ocean is much more dynamic in it's transport of energy than we classically thought?
Volumetric temperature-salinity diagram of the world ocean. 75% of the ocean's water have a temperature and salinity within the green region, 99% have a temperature and salinity within the region coloured in cyan. The warm water outside the 75% region is confined to the upper 1000 m of the ocean.
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Riccardo at 23:14 PM on 25 May 2010Polar bear numbers are increasing
Eric, is it your speculation that the cause of the projected population reduction is hunting? In the link you provide there's nothing about it. -
Riccardo at 22:57 PM on 25 May 2010Robust warming of the global upper ocean
Berényi Péter, the heat budget as we know it does not close and no one knows why. I assume you don't know either. Logically, you cannot draw any conclusion from TOA imbalance and OHC, let alone using the OHC to calibrate TOA imbalance. The graph you keep posting shows a steady increase in the number of Argo profiles from 2001 to 2008. The jump in OHC you claim as an indication of XBT bias is between 2001 and 2003. The two do not match so it is easily discarted as an explanation of the jump. All the known sources of bias of the XBT data has been taken into account by Lyman et al. 2010. Definitely there might be more but no one has identified them yet. I assume you didn't either. What's left are just speculations and as such should be taken. -
Eric (skeptic) at 22:20 PM on 25 May 2010Polar bear numbers are increasing
The real current problem for polar bears http://www.bearskin-rugs.com/polar-bear-rugs-c-62.html is that they are worth $8000 dead. -
Eric (skeptic) at 22:14 PM on 25 May 2010Polar bear numbers are increasing
The Norwegian polar bear study group shows polar bear populations declining in 8 areas: http://pbsg.npolar.no/en/status/status-table.html but obfuscates the fact that they are declining because they are hunted. Also their estimates have been challenged by indigenous groups interested in hunting. (e.g. nunavut_government_reduces_baffin_bay_polar_bear_quota/) A more accurate phrasing would be "What the science says: polar bear populations are declining primarily due to overhunting. Their long term survival is at greater risk from declining sea ice."Moderator Response: [RH] Fixing links that are breaking page format. -
Berényi Péter at 20:52 PM on 25 May 2010Robust warming of the global upper ocean
#32 doug_bostrom at 07:26 AM on 25 May, 2010 Do you see a possibility that OHC has in fact increased during the period examined by Lyman et al, and if so do you have a reasonably complete mechanism in mind to explain how it may have completely failed in reliability after ~2003? I don't think it has failed after ~2003. That was the year when global coverage increased tremendously both in extent and density. The quality of instruments also improved a lot, even if some of the ARGO floats used to have problems. Therefore I think OHC data after mass deployment of ARGO floats is more reliable than before. You may consider checking the analysis provided at the Does ocean cooling prove etc. thread.
I don't have anything against the early part of the Lyman reconstruction either. However, the huge rise in their OHC history reconstruction between 2000 and 2004 is not supported by net radiation budget at TOA which was measured in this period indeed. Also, there is very little temporal overlap between XBT and ARGO measurements with small chance for proper intercalibration.
In fact the otherwise indeterminate offset of net radiation budget at TOA can be calibrated against the last 6 years of ARGO OHC data. OHC should be close to the temporal integral of the former signal with little delay because heat storage capacity of climate system is absolutely dominated by the oceans. If it is done, OHC increase during the last 15 years turns out to be much less than claimed by Lymann.
#35 michael sweet at 09:17 AM on 25 May, 2010
It strikes me that for amateurs to dismiss a paper by professionals
Please try to digest first what is said. Follow the links if necessary. Science is not about blind faith in professionals, nor it is about appeal to authority. It is about understanding.
If you find answers you do understand to questions I have raised here in papers published by professionals in the peer reviewed literature, you are most welcome should you decide to share it. The same applies to the case you happen to find valid answers on your own.
-
CoalGeologist at 19:22 PM on 25 May 2010Robust warming of the global upper ocean
Humanity Rules @36, Although I gather you were aiming at sarcasm, I believe you're approaching a reasonable explanation of what John was getting at in using the term "robust". Bearing in mind that climate is defined on the basis of long-term trends--variously defined at 20 or 30 years--shorter term oscillations of 4 to 6 years such as you describe, are not meaningful in quantifying the effects of climate change. Thus, although your description, "4 years of little to no warming, 6 years of intense warming and finally 6 years of no warming" might evoke some guffaws from those who question the validity of AGW, your usage of the term "warming" is different from its intended meaning with respect to climate change. Assuming the data have been measured and processed reasonably, the observed increase in temperature provides robust evidence of a warming climate on a multi-decadal scale. Given the uncertainty in the data, however, and the shortness of the measurement interval, we're still not sure of the longer term trend. I seem to detect an "inconsistency" in how temperature data are treated by AGW skeptics. On the one hand, some argue that the data are biased toward warming or are otherwise unreliable, er.... that is, until we hit a few years of (apparently!) declining temperature, at which point the previously worthless data suddenly provide clear evidence that warming has stopped! What's up with that?! The more valid question here, is whether the "offset" in the temperature data noted by Berényi Péter@ #6 is a relict of the measurement methodology. The difference in temperature from 2002 to 2004 appears to be statistically significant, yet we can't define meaningful trends on the basis of just 2 or 3 data points. Unfortunately, I'll have to defer to qualified experts to sort this out. In the meantime, given the importance of the answer, I will agree that it is indeed a travesty that we can't do better at present. -
James Wight at 18:52 PM on 25 May 2010It's not happening
Have you thought of adding to this list the decline in lizard populations, and the warming of Lake Tanganyika?Response: I hadn't but I have now :-) Thanks for the suggestion. I've also added both to the positives and negatives of global warming. -
Riccardo at 18:25 PM on 25 May 2010Greenland rising faster as ice loss accelerates
wanyden, it has been proposed (here the original paper, paywalled) that the lowering of the ice load may trigger more intense volcanism. The effect would be local, i.e. melting of glaciers in Iceland would trigger more volcanic activity there. Melting in Greenland has probably nothing to do with volcanic activity in Iceland, they are also on different tectonic plates. -
fydijkstra at 18:11 PM on 25 May 2010Greenland rising faster as ice loss accelerates
It’s all true, what you say in this post about accelerating ice loss from Greenland, but it’s not the whole truth. Let’s put the things in the right perspective. 1. The Greenland ice cap has a total mass of 2.85 million GT. The estimates of the present annual ice loss converge to 250-300 GT, let’s say 285 GT to get round figures. The annual ice loss is 0.01% of the ice cap. With the present melting rate it would require 10,000 years for the ice cap to melt completely. 2. The uncertainties in the estimates of the annual ice loss are high: the error bars are 20 to 50% of the values. The uncertainty in the slope of the line is much higher. You do not give an error bar, but I suspect that the error bar could cover any value between 0 and 100%. Any extrapolation of such data is highly speculative. 3. “If the acceleration continues, Greenland could soon become the largest contributor to global sea level rise.” Melting of the whole ice cap would cause a sea level rise of 7.2 meters. The present annual ice loss is good for 0.01% of that figure, i.e. 0.72 mm, which is one quarter of the sea level rise of 2.8 mm/year. If other factors remain constant, a tripling of the melting rate would make it the largest contributor. With the present estimate of the acceleration we have to wait 28 years. If other factors also increase, we have to wait much longer. It is a matter of taste whether you want to call this ‘soon’. 4. There is no reason to suppose, that the acceleration of the ice loss will continue for a long time. The process can be reversed as well. The temperature on Greenland has always fluctuated strongly. In 1930, 1947 and 1960 it was higher than today. Between 1920 and 1930 the temperature at the Greenland coast increased 2 degrees. In the Middle Ages it was much higher than today, as we all know form historical sources. Greenland’s temperature has only little to do with the average global temperature. Changes in persistent wind patters have much more influence. See for instance: X. Fettweis, E. Hanna, H. Gasllée, P. Huybrechts, M. Erpicum – Estimation of the Greenland ice sheet surface mass balance for the 20th and 21st centuries - The Cryosphere 2(2008), 117-129. 5. Melting of the Greenland ice sheet has little influence on the sea level in Britain and the Netherlands because Greenland is very near on a global scale. The gravitational effect of the ice cap causes a higher sea level in the North Atlantic Ocean and surrounding seas. The disappearance of this effect on melting of the ice cap compensates the sea level rise.Response: "There is no reason to suppose, that the acceleration of the ice loss will continue for a long time"
The evidence that Greenland is highly sensitive to sustained warmer temperatures comes from the past. In the last interglacial, around 125,000 years ago, sea levels were at least 6 metres higher than current with global temperatures around 1 to 2 degrees warmer. Ice melt from Greenland and Antarctica were the main contributors to this sea level rise.
The past can tell us a lot about our future. -
Riccardo at 18:05 PM on 25 May 2010Greenland rising faster as ice loss accelerates
HumanityRules, "When the thing reaches the top and stops it has no velocity or acceleration." Absolutely no. This very very basic kinematics. Not worth to discuss any further. -
HumanityRules at 17:53 PM on 25 May 2010Greenland rising faster as ice loss accelerates
32.wanyden I believe your theory has been suggested. -
HumanityRules at 17:52 PM on 25 May 2010Greenland rising faster as ice loss accelerates
Thanks again John but I'm still blocked. 31 Riccardo 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. I guess we're I'm going with this is that the title of the paper worries me. Instead of "Accelerating uplift in the North Atlantic region as an indicator of ice loss" More accurately it should be something like. "Change in displacement in the North Atlantic region as an indicator of ice loss and gain." Because there appears to be periods when mass is rising and when mass is falling. It's fair to say the last decade has seen mass falling at an accelerated rate but this was preceded by mass gains in the 1990's. Kely is an example of this in post 4 as well. Or is this me still mis-understanding acceleration. -
wanyden at 17:39 PM on 25 May 2010Greenland rising faster as ice loss accelerates
So, here's a question I was asked a few weeks ago in my capacity as volunteer guide at the Monterey Bay Aquarium: Could the eruption of the [Eyjafjallajökull] volcano in Iceland have been caused by some aspect of global warming? At the time I answered that it was highly unlikely. Could I have been wrong? Might the uplift of Greenland bedrock have caused a tectonic movement that stimulated the volcanic action under Iceland leading to the eruption? -
Riccardo at 17:13 PM on 25 May 2010Greenland rising faster as ice loss accelerates
HumanityRules, when you throw something straight up it slows down, stops and falls back. Acceleration is constant throuhout the path, velocity varies. And yes, it's a seasonal cycle. -
Riccardo at 17:09 PM on 25 May 2010Robust warming of the global upper ocean
HumanityRules, the main effort was on the bias corrections of the XBT data, considered the weak part of the OHC dataset. Then the full dataset allow the author (not me!) to come to more robust conclusions. Your claim that there has not been any attempt to close the energy budget is astonishing. Many scientists has worked on that for years and are still working. Anyways, keep in mind that the they are missing the closure for a few tenth of W/m^2; unacceptably large, ok, but still they're not completely missing the goal. Finally, the closure of the energy budget does not prove or disprove anything about climate change and AGW theory. It's just about the ability to measure the energy of our planet, about the understanding of how our climate works. -
HumanityRules at 17:08 PM on 25 May 2010Greenland rising faster as ice loss accelerates
Thanks John but I still need the whole truth to emerge for me. It's being blocked by yet more dumbness. "Iceland is subsiding. But this subsiding is slowing down, stopping, then rising. The acceleration rate is fairly constant through this whole period." I guess now I don't get how the acceleration can be constant through this whole period. If it's subsiding, stops, then rises it's essentially changed direction how can acceleration continue through that reversal? Surely the subsiding decelerated stopped and then rising started. This rising has accelerated since 2000. I can accept that much.Response: Just imagine if your car is slowly rolling down a hill. You start pushing it back upwards. The car starts to slow it's downhill descent. Let's say with your pushing, the car is slowing down at a rate of 1 metre per second per second. Eg - every second, the car's speed slows down by 1 metre per second.
The car stops rolling downhill. If you keep pushing, the car will then start to roll up the hill. If you push at the same rate, the car will then accelerate at a rate of 1 metre per second per second. So the car's "acceleration" is constant over the whole time - it's always going in the same direction (uphill).
Not sure if I'm explaining this right - someone else want to have a go? -
Riccardo at 16:46 PM on 25 May 2010Arctic sea ice has recovered
Eric, I didn't mean that PIOMAS is a perfect model, just that even a hypothetical perfect model would fail the forecast if the input data are not good enough.
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