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Paul D at 07:09 AM on 25 May 2010Greenland rising faster as ice loss accelerates
J Bowers @ 24 I'm at the South End. It's the same situation in that the reason for it is ice. The fact the ice melted thousands of years ago, is why the rising and sinking here in the UK is small compared to Greenland. -
Doug Bostrom at 07:09 AM on 25 May 2010Greenland rising faster as ice loss accelerates
GFW that's an interesting idea. Probably could be modeled? With known rates of rebound exceeding 3cm/yr in some places I'm guessing it may already be included in projections. On a general note there's a pretty good article on rebound here on Wikipedia. It's rather an amazing phenomenon. -
Berényi Péter at 07:04 AM on 25 May 2010Robust warming of the global upper ocean
#26 Riccardo at 01:20 AM on 25 May, 2010 As for TOA imbalance, OHC trend and the like TOA imbalance is extremely important. Below is satellite measurement for the last ten years:
These measurements have low accuracy but reasonable precision. It means that the curves above have an arbitrary offset (within several Wm-2), but would show a marked level change whenever accumulation rate of thermal energy changes in the climate system. Nothing like that is seen between 2002-2004.
Therefore either satellite data are absolutely useless or the 6-8×1022 J heat accumulation in the oceans after 2000 followed by a more or less level plateau from 2004 on is an artifact due to transition to ARGO.
There is no other possibility. Net TOA radiative imbalance should be very nearly identical to the temporal derivative of OHC, because there is no heat storage capacity in the climate system comparable to the oceans and all energy exchange between Earth and its environment is mediated by electromagnetic radiation (any other forms of energy transfer, e.g. tidal breaking are many orders of magnitude smaller).
For scientists it is left as an open question, as it should.
The open question is not the "missing heat" but inconsistency between satellite and buoy measurements of energy budget and inconsistency between measurements and computational model predictions.
The often quoted more than 0.5 Wm-2 positive global energy imbalance is not measured in any reasonable sense. It is a model prediction, all but falsified by now.
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johnd at 06:30 AM on 25 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
chris at 04:46 AM, the abstract for the article gives the impression that "productivity" and "primary productivity" are somewhat more closely related rather than separate, and perhaps like both Reuters and The Straits Times they should have made it clearer also. Thats the trouble, all put their own spin on everything. Just to be precise, the study measured biogenic silica BSi, the production of which is controlled by the availability of silica and other nutrients amongst other factors, as the proxy for primary productivity. -
J Bowers at 05:43 AM on 25 May 2010Greenland rising faster as ice loss accelerates
@ 11 The Ville While the northern end of the British Isles is rising, the southern end is sinking, both ends at roughly the same rate. It's not the same situation as Greenland. -
GFW at 05:30 AM on 25 May 2010Greenland rising faster as ice loss accelerates
If the rebound of Greenland is in some places faster than the sea level rise, could that at least reduce the basal undermine/melt problem along the outlet glaciers? -
Jim Eager at 05:01 AM on 25 May 2010Greenland rising faster as ice loss accelerates
Based on the fact that Iceland sits astride the mid-atlantic ridge created by the spreading of the Eurasian and North American plates while Greenland sits entirely on the North American plate means that Greenland's glaciers are almost certainly not warming from the bottom due to volcanic activity. It's a shame that the AGW denial fanatics are so fixated on latching onto any and all possible and imagined causes other than AGW that they forget that grasping at straws does not hold up in the world of real science. -
chris at 04:46 AM on 25 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
johnd at 02:59 AM on 25 May, 2010 Two seperate issues are being conflated, johnd. 1. Primary productivity "Primary productivity" relates to the generation of biomass at the bottom of the foodchain largely by fixing of CO2. So in marine/lake environments this is normally measured as algal load or density. This is the measure that Tierney (and others) report on both as contemporary measures and as a proxy. So "primary productivity" has a particular and specific meaning. 2. Productivity in relation to fish yields. This is a different issue, and is the one that is subject to "other factors". This has got nothing to do with Tierney et al's proxy for primary productivity which is something else entirely (see 1.). As is very clear from the paper, the reduction in fish catch in recent decades may have some relation to the reduction in primary productivity (see 1.), but is more likely due to over-fishing: so Tierney et al. (2010) state:Specifically, from AD 1913 to 2000 the lower metalimnion (~110 m depth, just below the thermocline) of the lake warmed by 0.9 °C, the hypolimnion (below ~300 m depth) warmed by 0.2 °C and phytoplankton biomass between 1975 and 2000 decreased by 70% (ref. 2). The late-twentieth-century drop in primary production in Tanganyika may have contributed1 to declines in catch per unit effort during the late twentieth century (absolute catch increased between the 1950s and 1990s; refs 4,6), although most of this short-term change is probably the result of changing fishing intensity and technologies4.
This is quite clear from reading the paper. I don't think anyone is "admitting" anything. They're simply describing what the evidence indicates.... Incidentally, the Straits Times headline: "Lake Tanganyika's life is dying" is rather overwrought! And both the Straits Times and Reuters accounts fail to seperate the two meanings of "productivity" clearly. So they also give the impression that there is a causal chain from warming to reduced fish catch, whereas the causal chain as described in the paper is from warming to reduced primary productivity (fixing of carbon into biomass at the bottom of the food chain). This (loss of PP) may have impacted fish catch, but the main contribution in the short term is likely over-fishing. -
Doug Bostrom at 03:52 AM on 25 May 2010Robust warming of the global upper ocean
It'll be interesting to see what does come of the pressure sensor problem. I should take my own advice and go try to find out how many buoys are suspect, whether the manner in which the buoys are run can cause a measurement error in gross heat content as opposed to simply making it more difficult to obtain a depth/heat profile. I suppose that's already been done by the operators for that matter. Great website, Ari. A tremendous compendium of papers; well done! -
Ari Jokimäki at 03:43 AM on 25 May 2010Robust warming of the global upper ocean
Doug, remember that the world ocean database document is only for the data analysis in NODC. The "official" situation of Argo can be found from Argo website. The Argo information centre there is the interesting thing for the discussion here. There is an item in the news list saying "Advice on Pressure Biases in the Argo Data Set", it says: "A part of the global Argo data are subject to biases in reported pressures. These biases are usually less than 5db, but occasionally can be larger (> 20db). These bias errors are being steadily removed by the reprocessing of historical Argo data. We expect that by the end of 2010 these errors will be removed from the global Argo data set in both the delayed-mode and real-time data." So it seems that next year we will have a better idea of how much of less warming of post-2003 has been due to the pressure sensor problem. So far studies have just rejected the bad Argo floats from the analysis (this latest study included), so it will be interesting to see the end result, when the data has really been corrected. But I bet there's still something else biasing the Argo-data that we don't know about. -
Doug Bostrom at 03:41 AM on 25 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
I wonder what mechanism of error would produce Tierney's graph, what the coincidence of problems would be that would yield such an image that resembles others we've seen? Stuck at this point, it seems, until somebody extends the path of research. Thanks for the link, johnd. -
johnd at 02:59 AM on 25 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Subsequent to the study being published, Jessica Tierney did a telephone interview with Reuters which is reported here. http://www.straitstimes.com/BreakingNews/TechandScience/Story/STIStory_527551.html Interesting the final note from Reuters about how the paper apparently admits that other factors, like overfishing, may be doing more harm than any warming. If the study considers that "other" factors may be more significant in falling productivity than any warming, then logically the study must have had to quantify those other factors before being able to calibrate the proxy chosen for productivity, namely BSi, and the temperature data from the relevant instrumental records available. Does anyone have any information on the proportions allocated to the various factors to allow the calibration? 'INTENSE WARMING' MOST climate change studies have focused on the atmosphere, but increasingly scientists are studying the effects on the oceans, seas and lakes, which all absorb a huge amount of heat. The paper argues that recent rises in temperature are correlated with a loss of biological productivity in the lake, suggesting higher temperatures may be killing life. 'Lake Tanganyika has become warmer, increasingly stratified and less productive over the past 90 years,' the paper says. 'Unprecedented temperatures and a ... decrease in productivity can be attributed to (human) ... global warming.' The rise in temperature over the past 90 years was about 0.9 degrees Celsius and was accompanied by a drop in algae volumes. 'We're showing that the trend of warming that we've seen is also affecting these remote places in the tropics in a very severe way,' Tierney said by telephone from the United States. 'We've seen intense warming in recent times ... not down to natural variations in climate.' She said the lake life had been harmed because in a lake as deep as Tanganyika, the nutrients form at the bottom but the algae needed to make use of them live at the top. Higher surface temperatures mean less mixing of waters at the top and bottom.' That's why a warmer lake means less life.' But the paper admits that other factors, like overfishing, may be doing more harm than any warming. -- REUTERS -
Riccardo at 02:43 AM on 25 May 2010Greenland rising faster as ice loss accelerates
Thank you Jeff for elaborating on ice-quakes. I've been too lazy to do it myself and I sure have not your competence on this. :) -
Steve L at 02:18 AM on 25 May 2010Greenland rising faster as ice loss accelerates
Jeff @17: thanks. I was wondering how come more hadn't been said about this basal heating over the last couple of years subsequent to the preliminary finding. Now I have a some idea. -
Jeff Freymueller at 02:16 AM on 25 May 2010Greenland rising faster as ice loss accelerates
#13 Riccardo, actually there has been an increase in seismic activity in Greenland, but it is all in the form of low-frequency earthquakes that originate in the ice, not regular earthquakes in the rock. These events increased in rate at about the same time that the GPS says the ice load began to decrease and glaciologists observed that the outlet glaciers sped up. See Ekstrom et al. (2006) for details. It is yet another independent piece of evidence that there has been a fundamental change in the behavior of the ice sheet and its outlet glaciers. -
Doug Bostrom at 02:10 AM on 25 May 2010Greenland rising faster as ice loss accelerates
That's an excellent point, Jeff, and in fact it makes Jiang's result all the more striking since by extension it would appear the rebound spotted in his analysis has overwhelmed the prior adjustment process. -
Jeff Freymueller at 02:09 AM on 25 May 2010Greenland rising faster as ice loss accelerates
#9, #12. No, volcanoes under Greenland are not the cause of this. As pointed our already, Iceland is located on the Mid-Atlantic Ridge and Greenland is not, and Greenland is about as tectonically and volcanically active as the Canadian Maritimes (which is to say, not at all). I looked up the abstract for the meeting presentations that the news article cited in #12 was based on, and it is pretty vague. The URL to the abstract is about as long as the abstract, so here's the abstract: "Rapid ice flow in the northeast quadrant of the Greenland Ice Sheet is associated with unusually high heat flow. Heat flux can be greatly increased in deep valleys to promote basal melting with additional feedback due to locally increased friction. However, crustal thinning can also enhance heat flow because the relatively thermally conductive mantle is closer to the surface. In addition to incised topography, relatively shallow Moho also occurs beneath the northeast quadrant of the Greenland Ice Sheet. We made regional three-dimensional thermal models that include the effects of topographic and mantle relief. These effects can strongly enhance the heat flux at the base of the ice sheet. " The Moho is the seismic discontinuity between crust and mantle, so they are talking about a change in crustal thickness. Typical crustal thickness is 30-40 km, and if you cut that in half you would double geothermal heat flow, which would still be pretty small compared to the changes in heating from the top. I'd say the news article is overblown. In any case, even if geothermal heat flow in NE Greenland is higher than average and has an effect on the ice there, the heat flow would have been high for millions of years (so no change around 2002-2003), and all of the data in the paper came from SE and W Greenland, so this argument is just a big red herring. -
Doug Bostrom at 02:05 AM on 25 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Chris also takes the time to digest his findings and produce synopses with some useful remarks on relevance. Worth emulating, if you're claiming to have better insight than experts. -
michael sweet at 02:00 AM on 25 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
I hope that people appreciate the amount of time it takes people like -
Doug Bostrom at 02:00 AM on 25 May 2010Robust warming of the global upper ocean
Further to my earlier remark, for those wishing to dismiss the entire collective anomaly apparently revealed by OHC measurements you'd do well to begin by reading and comprehensively understanding the item pointed out by Ari, the WORLD OCEAN DATABASE 2009, then extend your effort to a point where you feel your expertise exceeds that of the authors of this study. At that point you'll be prepared to offer some useful critique. Short of that-- short of some miracle-- your offering will inevitably reside in the "I doubt it" arena in terms of utility with drawing conclusions. -
There's no empirical evidence
PaulK, Riccardo, I was attempting to address this comment from PaulK > "Quote Now suppose that prior to our starting time, climate forcing was constant and equal to zero, and temperature departure was constant and equal to zero. After time t0, climate forcing increased to 1 W/m^2 and stayed there. Then the solution turns out to be: Theta(t) = (1 – exp(-lamda*t/C))/lamda Endquote It is hopefully evident to you that Theta (t), the temperature change from the forcing, must asymptote mathematically from this expression to a constant 1/lamda at large values of t. So now ask yourself the question whether it is possible in terms of first law of thermodynamics to have an imbalance of TOA radiative energy for an infinite time which results in a finite (constant) change in planetary temperature. If you can truly answer yes to this question , then I think that I am going to sign off, since I am wasting my time here. " I'll admit I probably misunderstood what you were trying to say Paul. I don't see what is wrong with Tamino's solution for Θ(t) in his scenario. To repeat what you said in your recent post: "As the system heats up, it will increase its power output until the temperature restabilises at a new constant value." Isn't this exactly what Tamino was showing in his solution for temperature departure Θ(t) in his scenario? How does this violate the first law of thermodynamics? -
Jeff Freymueller at 01:56 AM on 25 May 2010Greenland rising faster as ice loss accelerates
#6, #8, about isostatic rebound. Greenland may have been subsiding just a bit because of isostatic rebound from the Laurentide ice sheet. When the ice sheet was at its maximum, Greenland was on or close to the forebulge that surrounds the central depression. Collapse of the forebulge after the ice was gone goes hand in hand with uplift of the depressed area. As I recall the signal was very small, which is consistent with the data prior to about 2002-2003. The earth is viscoelastic (think spring + shock absorber). When you remove a load from the surface, there is an immediate elastic response, and then a delayed viscoelastic response, which can last a very long time depending on the spatial scale of the load. Parts of Canada and Fennoscandia are still uplifting at about 1 cm per year due to the melting of ice sheets after Last Glacial Maximum. What we are seeing in Greenland now is almost entirely the immediate elastic response to removing the load. The reason for the change in trend in the GPS vertical measurements is because there has been a drastic increase in the rate of ice loss. -
Doug Bostrom at 01:50 AM on 25 May 2010Greenland rising faster as ice loss accelerates
Sheer speculation, picking any explanation other than what's shown by scrupulous measurement to the very best of our ability is not an argument that is even remotely persuasive. If a wild guess is extended and made concrete with a plausible hypothesis and subsequently observations that are sufficiently solid, it might become useful. Otherwise it falls in the large but vacuous category of "I doubt it." -
Riccardo at 01:33 AM on 25 May 2010Greenland rising faster as ice loss accelerates
Tony O, what is measurend is the fast elastic response which need to be discriminated from the annual cycle (yes, strange as it may appear, there's one) through carefull analisys. You can find some details in the supplementary informations. -
Steve L at 01:23 AM on 25 May 2010Greenland rising faster as ice loss accelerates
If sea level rises, but the Canadian archipelago doesn't, I wonder if sea ice will more easily float out of the Arctic. Probably I'm getting a little 'carried away'. #9 may not be as far adrift as I first thought. I did a brief search for magma and greenland and found this mention of a study indicating a hotspot in northeast Greenland. I couldn't find any update. -
Riccardo at 01:20 AM on 25 May 2010Robust warming of the global upper ocean
Actually I have some difficulty on the critics people are making here. The aim of the paper was exactly to address the well known problem of XBT vs Argo periods. The final result is the black curve in fig. 2 here. It shows a steady increase starting around 1998 (or earlier) and a smaller (not null) trend after 2003/04 for the next 5 years. The authors are, of course, well aware of the possible meaning: "The fact that this transition occurred at the same time as the flattening could be oincidental, but also raises the possibility of a yet-undiscovered bias in the observing system." Trenberth 2010 adds that substantial warming is found when considering the full depth data "indicating that substantial warming may be taking place below the upper 700 m". ((Some more details here). It's surprising how people can be so superficial to claim they know the answer by eyeballing the graph and without, apparently, any evidence but "coincidence". For scientists it is left as an open question, as it should. Neverthless, this dataset represents the best of our knowledge, given the joint effort to produce it. As for TOA imbalance, OHC trend and the like, never forget that we all know that it's a travesty we cannot track the flow of energy through the climate system in the short run. -
Paul D at 01:18 AM on 25 May 2010Greenland rising faster as ice loss accelerates
Tony O, @8: Here in the UK we have an isostatic rebound that equates to 1 or 2mm per year. Depends how much you are talking about. Clearly an inch in the UK will take a few years, but that is not thousands. -
Doug Bostrom at 00:37 AM on 25 May 2010Robust warming of the global upper ocean
I've not heard anybody yet be so bold as to dismiss the entire instrumental record- splices and other warts included- as "just nonsense." Is anybody expressing skepticism of this result prepared to explain how the OHC difference between the left and right ends of the graph is "just nonsense?" If so, can you explain exactly how so many years of data was collected and so much work expended in a meaningless effort? Can you do that in detail? -
Tony O at 00:03 AM on 25 May 2010Greenland rising faster as ice loss accelerates
I thought the isostatic rebound was supposed to take thousands of years. This is surprisingly quick, even for a doomsayer like me. Can we now expect volcanic activity in Greenland? How will Niels Axle Molnar spin this? -
Ken Lambert at 23:30 PM on 24 May 2010Robust warming of the global upper ocean
BP#6 has probably got the intepretation about right. Figure 2 shows a huge increase in OHC from roughly a 2 year period 2001 to 2003 in which the OHC rises from the zero axis to about 7E22 Joules or about 700E20 Joules. This is about 350E20 Joules/year heat gain. Dr Trenberth's 0.9W/sq.m TOA energy flux imbalance equalled 145E20 Joules/year. Therefore a rise of 350E20 Joules/year in OHC equals about 2.1W/sq.m TOA imbalance - a seemingly impossible number. Coinciding with the start of full deployment of the Argo buoys around 2003-04 this impossibly steep rise in 2001-03 looks like an offset calibration error. Similar would apply to Fig 3. In such case, fitting a linear curve from 1993-2009 and calling it a 'robust' 0.64W/sq.m is just nonsense. One might also note that the better the Argo coverage and analysis gets from about 2005 onward - the more the teams curves converge on a flattening trend - no OHC rise - no TOA imbalance. -
Arkadiusz Semczyszak at 21:34 PM on 24 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
I think that "threatening" Africa's alleged harmful effects of climate change - for the people (here fisheries), finished as those for malaria: "Climate change and malaria, the global recession" - Gething et al., 20.05.2010, Nature. (I hope separate comment JC on this) "First, widespread claims that rising mean temperatures have already led to increases in worldwide malaria morbidity and mortality are largely at odds with observed decreasing global trends in both its endemicity and geographic extent. Second, the proposed future effects of rising temperatures on endemicity are at least one order of magnitude smaller than changes observed since about 1900 and up to two orders of magnitude smaller than those that can be achieved by the effective scale-up of key control measures. Predictions of an intensification of malaria in a warmer world, based on extrapolated empirical relationships or biological mechanisms, must be set against a context of a century of warming that has seen marked global declines in the disease and a substantial weakening of the global correlation between malaria endemicity and climate." I hope that this ERROR WHO, WWF, UNEP and, the parts, IPCC (here, the fact in IV report presents the question, but ...) once again makes people think about the REAL effects - "impact on humanity" - of global warming ... -
Arkadiusz Semczyszak at 20:59 PM on 24 May 2010Greenland rising faster as ice loss accelerates
Such large differences for the same latitudes indicates that the decisive role played by atmospheric and oceanic circulation - their changes. Note that some glaciers Fennoscandia over the past two decades have increased their range and volume. Increasing range of THC to the north, particularly well explains the imbalance between NE and NW Greenland, Canada. It is true that the Gulf Stream has too little energy, but by changing the albedo of the Arctic Sea (melting sea ice) ... -
Marcel Bökstedt at 19:14 PM on 24 May 2010Robust warming of the global upper ocean
Bérenyi Péter> Yes, the behaviour of the bias uncertainty around 2006 should be reated to the shift to ARGO. The more curious thing is that the bias-related uncertainty goes up from 1996 to 2000, but maybe you solved that too, if the XBT system was deteriorating, this could introduce more uncertainty. I don't quite see how the increase in ocean heat content up to 2003 can be a measurement error due to change of instrumentation, it seems that the old XBT system was still in place (possibly on a lower level), so there was no big change of instruments there? The recent argo data seem to present a big problem. There are several things to explain simultaneously. Why did the upper level ocean heat content rise in 19993-2003, and then stop rising? Can we account for both the total energy content ("closing the energy budget") and the observed sea level rise? As long as we can't explain all of this, something is so missing. A mechanism to transfer heat down into the ocean would be one possible way to start resolving it. It might not work out of course. If the ocean is taking up less energy recently, this just leads to a new mystery: Why did the behaviour of the ocean suddenly change in 2003? From Peru> Figure 1 are the original curves as published by various authors. In Figure 2 the same curves have been recomputed with changes in the input data. That is, they use the same method of bias correction as the original authors, but with three types of homogenizations in the input data. The homogenizations used with a certain bias correspond to the three curves in fig 2 with the same color. So it is not so surprising that the curves in fig 2 are closer than those in fig 1, some (but not all) or the causes of difference has been eliminated. I believe that the reason for that the authors are doing this is to analyse the difference between published estimates of OHC. The idea is that the differences come from several independent differences in the approaches: The dataset, the bias correction method, and the choice of baseline climatology (I'm still not sure what the last means, but something like what period is considered as baseline). -
Riccardo at 19:06 PM on 24 May 2010Robust warming of the global upper ocean
A joint effort between groups (usually in competition) to improve the scientific understanding is a great thing. Congrats. From Peru, this is exactly what this new paper is addressing, the switch from XBT to Argo floats. -
chris1204 at 19:02 PM on 24 May 2010Greenland rising faster as ice loss accelerates
Greenland seems to be subsiding (or perhaps showing decelerating uplift) pre-2003 (as best as my rough eyeballing can make out). Canada seems to be on a slight decline or decelerating uplift (whether significant or not I've no idea). Iceland's see-saw might be the result of its unique tectonic location. But why would Greenland see-saw? -
Riccardo at 18:56 PM on 24 May 2010There's no empirical evidence
PaulK, indeed F(t) is not equal to I(t)−O(t). No one ever said it is, Tamino even wrote it explicitly. Let's see if you like a different wording more: I(t) = Ie+F(t) O(t) = Oe+λΔT(t) (to first order) I(t) − O(t) = Ie + F(t) − Oe − λΔT(t) = F(t) − λΔT(t) with Ie and Oe equilibrium values. Straightforward, I'd say. -
Jacob Bock Axelsen at 18:44 PM on 24 May 2010Are we too stupid?
embb, I have read all your references and answered all of your questions above. The trivial pretext of preventing 'carbon leakage' versus your question of taxing all products of defectors are two different issues. In general, taxes do not hurt the economy. They change the fluctuations from extreme values (catastrophic climate change, financial crashes) to something more benign, say, steady growth with finite moments. This is what everybody wants, and that is not even counting the benefit of investing the revenue in sustainability. The anti-'carbon leakage' customs tax is trivial because it would not hurt anyone undeservedly. The companies would still benefit from other advantages of unregulated locations, the temptation to move would just be smaller and the poor nations would have an excuse to start regulation. The US will not put a carbon tax on every product coming from countries that do not have a carbon tax by next year. The most urgent question would be which international treaty sets the standards? The US defected on Kyoto and they are not the cleanest producers per capita themselves, so which entire countries would they actually punish? In fact, with China and the EU leading the race they might face large reciprocal punishments. That is were the next treaty comes in. And never forget: everybody will benefit from preventing climate change in spite of the transient pain of moving to a sustainable economy - because it is cheaper in the long run. -
Arkadiusz Semczyszak at 17:16 PM on 24 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
@jtierney "Given this long paleoclimate contexte, the recent warming really does Appear To Be Atypical for the lake." Looking at the combined graphs of your works - papers in 2008, and 2010, even without the use of statistical calculation to smooth the data (eg average filter, or Fourier analysis), shows excellent activity cycle of the sun - circa 6000 years (Xapsos and Burke, 2009). What has to rely so that "recent warming really does appear to be atypical"? -
Doug Bostrom at 17:13 PM on 24 May 2010Greenland rising faster as ice loss accelerates
It's an odd thing that Nature does not charge for supplementary material. I just noticed this quirk recently. -
Doug Bostrom at 16:58 PM on 24 May 2010Greenland rising faster as ice loss accelerates
Extra-juicy supplementary material for article complete with depressingly curvaceous graphs freely available here.Response: Thanks for the link, Doug. The paper kept refering tantalisingly to the supplementary material but I assumed it was stuck behind a paywall and didn't bother looking. Here's a short excerpt:
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PaulK at 16:43 PM on 24 May 2010There's no empirical evidence
e, To expand a little on Riccardo's comment. The physics says that if one applies a positive impulse forcing to a system in steady state (input power equals output power), then the system will heat up. As the system heats up, it will increase its power output until the temperature restabilises at a new constant value. The small issue I have with Riccardo is definitional. If the input power is I(t) and the output power is O(t), then at time t0, in steady-state, we have I(t0)-O(t0) = 0. If one defines the net forcing over time, F(t), as the difference between input and output power, i.e. F(t) = I(t)-O(t), and one applies an impulse forcing F(t0) to the system, then to restore steady-state, F(t) must then decay to zero after a period of time as temperature restabilises. However, the expression used for F(t) in Riccardo's heat balance equation (C dΔT/dt = F−λΔT) is not a net forcing over time. Instead, it is equal to the difference between the input power at time t and the output power at time, t0. For this expression to make sense, mathematically, F(t) = I(t) - O(t0) - equivalent to a series of stacked impulse forcings applied to the input side of the power equation. -
David Horton at 16:40 PM on 24 May 2010Greenland rising faster as ice loss accelerates
Yes, Doug, I'm waiting for the first comment that says, well, of course, this is only Greenland! -
Doug Bostrom at 16:37 PM on 24 May 2010Greenland rising faster as ice loss accelerates
Convergence as David says, unless somebody can put together a detailed explanation of how all the relevant observations are wrong in a way that coincidentally resembles coherence. Remember that requirement when folks begin quibbling over accuracy of one set of observations or the other; hypothetical errors have to somehow converge. -
Doug Bostrom at 16:26 PM on 24 May 2010Robust warming of the global upper ocean
That's a really useful (and fascinating for instrument enthusiasts) compendium of information, Ari. Here's the relevant section on various errors which have cropped up as the ARGO system has gone through its "teething pains" and adolescent years: "In 2003, it was found that problems with the Druck Pressure Sensor were causing some floats to stay at the surface for prolonged periods and eventually to become surface drifters. The Druck Pressure Sensor is the successor to the Paine pressure sensor in Seabird CTDs. Even when not severe, the problem may have caused errors in the salinity measurement due to increased biofouling due to prolonged surface exposure. When the problem was found, the CTDs were recalled and the source of the problem was fixed, but this was not possible for floats already deployed. A large number of SOLO floats with FSI CTD packages deployed in the Atlantic Ocean between 2003 and 2006 were found to have a pressure offset problem due to a software error. This error caused pressures to be paired with the temperature measurements from the next lower level, creating the illusion of a cooling ocean. Once the problem was found, a list of such floats was compiled. An effort was made to correct the problem, successful in some floats, not in others. All data from all these problem floats are included in WOD09. For those data which could not be corrected, all float cycles are flagged. More recently, in early 2009, a problem with the Druck pressure sensor has been found (J. Willis and D. Roemmich, minutes of 10th meeting of International Argo Steering Team). This problem causes pressure sensor drift after deployment. Deployment of new floats was halted temporarily, until the pressure sensor design could be altered. Already deployed APEX floats are being monitored closely for sensor drift. The full extent of this problem is not yet apparent" -
David Horton at 16:19 PM on 24 May 2010Greenland rising faster as ice loss accelerates
And still, sadly, the totally independent lines of evidence all confirm each other. -
Ari Jokimäki at 15:54 PM on 24 May 2010Robust warming of the global upper ocean
NODC data seems to contain some cooling biases relating to Druck pressure sensors which have not been corrected. These problems start in 2003: WORLD OCEAN DATABASE 2009 (see chapter 6.6 for data problems) -
thefrogstar at 15:39 PM on 24 May 2010Unprecedented Warming in Lake Tanganyika and its impact on humanity
Albatross (#121), Doug Bostrom (#122), Phila (#123) [This topic has been plagued by remarks diverging entirely away from discussion of the Tierney paper. Thefrogstar's comment while very long did not actually refer to the paper under discussion even once. After editing out the irrelevancies, all that is left is this.] -
Doug Bostrom at 15:15 PM on 24 May 2010There's no empirical evidence
What, I'm supposed to take your word for it, PaulK? Sorry, not until you work it out w/Tamino directly. If he says you're correct then congratulations. But based on your waffling w/Riccardo I doubt you'll end up w/anything to celebrate. -
PaulK at 15:01 PM on 24 May 2010There's no empirical evidence
Doug_Bostrom, I have now discovered that "Tamino" is the blog pseudonym of the author of the site to which Riccardo referred me. You wrote: "I may be wrong but as far as I know Tamino has never been found wrong w/regard to posts he's made on his site." I am then especially honoured to have been the very very first to have done so. Thank you. Riccardo, You introduced the reference to Schwartz to counter my arguments about the difficulty of reconciling various assumptions to an observed increase in OLR. Can we now agree that one cannot derive an expression for OLR from the Schwartz model in the way you attempted and return to the main thrust of the conversation? This is a serious, not a provocative, question. The impatience I expressed in #68 was because I suspected that you already understood the implications of my comments on interpretation of the F term in Schwartz, but you did not wish to acknowledge this. However, this may not be true, and hence, my question. Do I need to expand further on this subject? Do you question my interpretation of the Schwartz model? Or can we agree and move on? -
Marcus at 14:20 PM on 24 May 2010Robust warming of the global upper ocean
What I see from that close up is a "wobble" between 10*10^22-13*10^22 Joules between 2004 & 2009. The peaks seem to correspond quite nicely to periods of higher & lower atmospheric temperature. Also, Berenyi, you mustn't forget that incoming solar radiation was also falling significantly over this time period, which might also explain an overall lack of growth in the Oceanic Heat Content.
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