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Climate Hustle

Tracking the energy from global warming

Posted on 18 April 2010 by John Cook

The most striking feature of Climategate is how readily people assumed dark, sinister conspiracies from isolated email quotes without trying to understand the actual science being discussed. This is apparent in the "hide the decline" quote which many took (and continue to take) to mean a nefarious hiding of a decline in temperature. What it actually refered to was a decline in tree-ring growth that has been openly discussed in the peer-reviewed literature since 1995. Similarly, Trenberth's "travesty that we can't account for the lack of warming" was an issue openly discussed in the peer-reviewed literature (Trenberth 2009). The issue of Trenberth's missing heat is now further discussed in a new Science perspective by Trenberth and John Fasullo, "Tracking Earth's Energy".

The article examines the planet's energy imbalance. This can be measured by satellites which measure both the incoming sunlight and outgoing radiation. The absolute energy imbalance is too small to be measured directly. However, the satellite measurements are sufficiently stable from one year to the next so it's possible to track changes in the net radiation. What has been observed is an increasing energy imbalance.

Another way to calculate the energy imbalance is to add up all the heat accumulating in the various parts of our climate. This includes all the heat building in the oceans, warming of the land and atmosphere, melting of the Arctic sea ice, Greenland and Antarctic ice sheets and glaciers. There is fairly good agreement between the satellite imbalance and total heat content leading up to 2005. However after 2005, there is a discrepancy between the two metrics. A divergence problem, if you will.

Figure 1: Estimated rates of change of global energy. The curves are heavily smoothed. From 1992 to 2003, the decadal ocean heat content changes (blue), along with the contributions from melting glaciers, ice sheets, and sea ice and small contributions from land and atmosphere warming, suggest a total warming (red) for the planet of 0.6 ± 0.2 W/m2 (95% error bars). After 2000, observations from the top of the atmosphere ( 9) (black, referenced to the 2000 values) increasingly diverge from the observed total warming (red).

Figure 1 has many interesting features. The blue area shows the rate of ocean warming. Note that when it falls after 2005, this doesn't mean the ocean is cooling but that the rate of warming slows. The red line is the total amount of net energy change. This means that all the energy going into the melting of sea ice, ice sheets and glaciers plus the warming of land and atmosphere is the tiny gap between the blue area and the red line. However, the most interesting feature of this graph is the divergence after 2005. From this point, the satellite data (black line) continues to show a growing energy imbalance. But the ocean seems to be accumulating less heat.

Why the discrepancy? Some of the heat seems to be going into melting the ice sheets in Greenland and Antarctica which are losing ice mass at an accelerating rate. However, this doesn't add up to anywhere near the measured energy difference. There are two possibilities. Either the satellite observations are incorrect or the heat is penetrating into regions that are not adequately measured. The satellite observations also agree with model results that expect a growing energy imbalance as CO2 levels increase. These model results have had quantitative confirmation in independent satellite measurements of outgoing infrared spectrum (Harries 2001, Griggs 2004, Chen 2007).

This would indicate the missing heat is the more likely option. If so, where has the missing heat gone? Is the ocean sequestering heat deep below where the ARGO buoys measure water temperature? I had my own Dunning-Kruger moment after reading this paper. My theory was we already had observational proof that the heat must be sequestered in the deep ocean waters. While measurements of ocean heat going down to 700 metres have showed declining heat accumulation, von Schuckmann 2009 shows that measurements of ocean heat going down to 2000 metres find the oceans have been steadily accumulating heat at 0.77 W/m2 from 2003 to 2008.

Figure 2: Time series of global mean heat storage (0–2000 m), measured in 108 Joules per square metre.

I emailed Kevin Trenberth, asking if von Schuckmann's result was evidence that the missing heat was being sequestered in deeper waters. Trenberth replied promptly (the guy is a class act), informing me that von Schuckmann's energy imbalance of 0.77 W/m2 was for the ocean only and when you average it out over the whole globe, it gives a net energy imbalance of 0.54 W/m2. This is still insufficient to meet up with the satellite data and there are unresolved issues with how von Schuckmann handles the deep water heating.

In fact, after reading Roger Pielke's blow-by-blow with Trenberth, I have to credit Trenberth for his patience - I wonder how many bloggers contact him each day, saying "Hey Kevin, you heard of this paper?!" or "Hey Kevin, did it ever occur to you that the heat is in the deep ocean?!" Hopefully, Trenberth won't get bothered too much by nagging bloggers such as myself and he can get on with the important work of better tracking the flow of energy through our climate.

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Comments 1 to 50 out of 141:

  1. Here is a PDF of the article.

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  2. Hi.
    Are there any estimates of the amount of energy that goes into warming of the ice (not only melting)? To what depth does the ice warm in what time frame?

    And what about a potential redistribution of heat (cold!) in the ice? An obvious example would be when melt water enters the interior of glaciers via moulins.

    /Martin Hedberg
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  3. An accurate measurement of ocean heat content would seem to be difficult as measurements would need to be made at various depths and estimates of volume(mass) at each of those depths would be needed to determine total heat content.
    What about the altimetry data on sea level from the Jason I,II satellites (and earlier TOPEX/Poseidon). The mean sea level continues to increase, a good portion of which must be due to thermal expansion. (Perhaps the contribution from ice melt can be estimated). If thermal expansion continues, the oceans must be accumulating heat and not losing it as it appears post-2005 in your figure.
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  4. There is a huge problem with the Schuckmann graph. Between December 2006 & February 2007 it does something entirely unphysical.

    However, if ice temperature on 2010-Apr-18 11:00 at N 84°07' W 40°30' can actually get as high as +15.2 °C, the missing heat is found.
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  5. BP at number 4:
    Since the preceding temperature in the series you referenced is -15.2 and the next measurement is -15.3 it is safe to presume that the 15.2 measurement is a typo. Why do you waste my time following up your link for such a trivial error in unfitered data?
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  6. Hey John, glad you found the time to do this post! Dealing with aged parents the last 4 months, so sorry for not being able to lend a hand.

    From my perspective, in my field of hot water heating, one of the observations that I have noted over the years is that as the outside temps go up, the heated water returning to the boiler has a lower DT. As the temps go down outside, the DT can get into the 30*F range. Now this is just pure speculation, but if the globe is cooling as of right now, from who nows from what factor, I would not be at all surprised with the satellite readings we have been getting for T the last few months. If my idle speculation happened to be true, do you think that the outgoing radiation may be overwhelming to the sats sensors? Sort of like if at night time someone shines a light in your eyes, your sight system is overwhelmed and can no longer function nromaly. i.e., you're for all intents and purposes blinded.

    As for the antartic, I think this week there will be very little if any continental ice melt -,106.87000275

    Check out some of the wind chill forecasts!

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  7. I'm not sure I understand your post Leo G. If I recall right, satellites use mostly microwave sensors for temperature.
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  8. Philippe, sorry, not very clear was I?

    Just a simple coorelation to what I do in my "real" life.

    If I say that the climate is cooling right now (the outside temps are dropping) then I would expect the oceans to be releasing very large amounts of energy to the "cooler" atmosphere (higher Delta T). So if the sats are not calibrated to pick up this huge increase in outgoing radiation, could they perhaps be missing it?
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  9. It seems there are two possibilities. Instrumentation issues - inaccuracy, lack of coverage etc - or a real phenomena.

    In either case, why such a sudden transition. If it is instrumentation, what changed in 2005?

    If it is physical, did some unexplained phenomenon 'turn on' in 2005? If this was simply a change in the rate of existing phenomena, wouldn't the divergence be slower?

    Simplistic observation - if the surface ocean has been warming faster than the deep ocean for decades, doesn't that change the temperature gradient down through the water column? Could a threshold gradient have been reached that is triggering new circulation patterns down below?

    On the Net Radiation side, how much of this is measurement vs measurement and estimation from theory?
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  10. Do the sats detect which way the energy is travelling? IE from/to space?

    If Drs. Spencer and Christy are right, clouds being a negative, would the satellites "see" the SWR going the other way or would they just pick it up and add it to the downward travel of the original SWR? Even Dr. Trenberth mentioned that clouds might be playing a part of the extra energy data.
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  11. So where is the energy?
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  12. A minor nitpicking point on Fig 1: rates (dQuantity / dTime) always have unit of reciprocal time: eg: Wm-2year-1.
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  13. I also found this paper on deep water heating which is in press. Can anybody to the mathes to see if this makes up the difference?

    Funnily I had also followed the Trenberth/Piekle email exchange and thought it was genuinely interesting. I don't know why you suggest Trenberth needs patience, Piekles seems a reasonably polite individual and it seems a genuine exchenge between two people who wish to get to the bottom of a problem. It's science. Anyway I also weighed in by sending this reference to Piekle, I guess we've both choosen our sides ;)
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    Response: I was refering more to my bonehead questions - seeing Trenberth and Pielke discuss von Schuckmann in detail made me realise of course Trenberth had looked at von Schuckmann from the front, from the back, sideways and upside down. A Dunning Kruger moment on my part.

    Funny you should mention that paper on bottom water heating - I was just talking to one of the authors, an Australian scientist Susan Wijffels (emailing her more of my bonehead blogger questions).
  14. 9.Glenn Tamblyn at 08:18 AM on 19 April, 2010

    Is there a third possibility.

    This issue, like most others in climate science, is subject to assumptions, data processing, modelling and theorizing. The best test for all these is how things develop going forward. What we are seeing is that some aspects are poorly understood to the point that the expected and observed data diverge. When this happened with solar irradiance and temperature we were all ready to kill off a theory. Shouldn't we be loading the syringe with Nembutal again?
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    Response: The comparison with sun/climate is not quite right. In that case, we're looking at a cause of climate change - if the sun is cooling while climate is warming, it's hard to see the sun is causing the warming.

    In this case, we're looking at two different ways of measuring the same thing - the planet's energy imbalance. So if the two metrics diverge, we need to examine both metrics. As there is independent confirmation of the veracity of the satellite data, the more likely problem is with the accounting for heat content. And as our observation systems don't currently observe all of our climate, the natural next step is to look to extending our observations to cover more of our climate. A good first step would be to measure the deep ocean more comprehensively.
  15. RE: "Hopefully, Trenberth won't get bothered too much by nagging bloggers such as myself and he can get on with the important work of better tracking the flow of energy through our climate."

    Don't discount the importance of communicating the subtleties of the work. This is just the kind of data that would be taken out of context by deniers. It's good for lay individuals to be able to refute it right away. After all, researchers can't solve the problem and communication is a key part of the resolution.
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  16. John, I would hope that Trenberth knows of your site here and appreciates the valuable and gallant job you're doing to help people understand the complex science going on with climate change. (I imagine that's why you got such a prompt response from him.)
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  17. Great posting John.

    I remember reading this posting by NASA on Balancing the Sea Level Budget in which Willis identified problems with the latest Argo floats which led to underestimating ocean warming.

    I am interested in what comes about from your correspondence with Susan Wijffels as she is quoted there saying "What we found was that ocean heating was larger than scientists previously thought, and so the contribution of thermal expansion to sea level rise was actually 50 percent larger than previous estimates.”

    Here is my DK moment but since Trenberth has used Argo data in his assessment of ocean heat content, could that not account for some of the divergence? My hunch is it is more likely an instrumentation problem than anything else.
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  18. Another important question is why did the energy budget balance for the first decade of figure 1?

    If we are looking for a nett transfer of energy to the deep oceans from 2005 onwards we have to assume that this wasn't happening before 2005 when things would have to have been in equilibrium. We need a machanism for the transfer and one that shows a fair amount of variation over time. Do we have anything like this? And evidence it went through some sort of phase switch in 2005?
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  19. Response #14
    I thought there is an independent confirmation of energy in the ocean and that is sea level rise. Extra energy in the ocean would cause it to expand making the sea level rise.
    Sea level rises via two mechanisms thermal expansion and extra volume (from melting land ice). The most recent measurements of sea level, I think from 2003 onwards, suggest that sea level rise has slowed. And that nearly all that sea level rise has come from melting ice. This would suggest there is little thermal expansion, suggesting little extra energy in the ocean. We should measure temp in the deep ocean but sea level rise suggests it probably isn't there.
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  20. Very curious - that's quite a divergence, rather unprecedented from the previous data. I would certainly trust the sat. data; radiation measures are pretty straightforward compared with ocean temp. accounting.

    My own DK idea would be to posit a change in deep vs. shallow water circulation - a new(ish) vertical cycling of the water providing a new heat sink. But then, I would be suggesting a WAG, not even a SWAG (scientific wild a** guess). Are there any suggestions of changes in circulation that might be consistent with this theory?

    I look forward to better suggestions from people who actually know what they're doing on this topic.
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  21. the following statement in the trenberth paper says "Increasing concentrations of carbon dioxide (CO2) (see the figure) and other greenhouse gases have led to a post-2000 imbalance at the top of the atmosphere of 0.9 ± 0.5 W m–2 ( 5);"

    going to reference (5), i looked at that paper and couldn't find that in it. can someone point me in the right directions and let me know what i missed?

    and i apologize if the link doesn't show as embedded. i followed the style as listed on this website but for some reason it didn't show right in the preview. i'll keep working on that.....
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  22. RE#21 garythompon. I think you may be looking at the wrong paper.

    The paper you have linked is titled "Global warming due to increasing absorbed solar radiation"
    K.E. Trenberth, J.T. Fasullo. Geophys. Res. Lett, 2009

    Reference 5 in the paper discussed above is titled Earth's Global Energy Budget
    K. E. Trenberth, J. T. Fasullo, J. Kiehl, Bull. Am. Meteorol.
    Soc. 90, 311 (2009)
    which can be found here
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  23. This seems to be quite a mystery. I wonder if it could have anything to do with the Pacific Decadal Oscillation (which appears to have switched to a "cool" phase).
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  24. Humanity Rules> The argument about sea level rise is nice, but has to be analysed a bit. The expansion of water under heating is not constant, it depends on the temperature you start with. The minimal volume and highest density is reached at 3.98 C. I understand that the temperature of the deep ocean is close to that minimum, so that its thermal expansion coefficient is close to zero, which means we cannot use sea level to restrain the temperature of the deep ocean. I think.
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  25. #24 Marcel Bökstedt at 16:28 PM on 19 April, 2010
    the temperature of the deep ocean is close to that minimum, so that its thermal expansion coefficient is close to zero

    A common misconception. Equation of state for sea water is rather tricky. At high pressure volumetric thermal expansion coefficient is positive even at 3 °C.
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  26. Berenyi Peter> That is a good point, maybe we can start quantifying? It seems you know this stuff, so perhaps you can offer an estimate on the sea level rise which would be caused if the "missing energy" was hiding in the deep sea?
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  27. Berenyi Peter> It seems that Trenberth does exactly this calculation, and gets that if the "missing energy" (0.9 W/m^ 3) were deposited in the ocean below 700 meters, it would rise the sea level by 1.3 mm/y. An imperative for climate change planning: tracking Earth's global energy .
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  28. There is insufficient heat transfer between the atmosphere, land and oceans on annual and interannual time scales for net radiation measurements and calculated heat contents to be in agreement, even if the calculated heat contents are correct.

    This means there will be a time lag between the two, which becomes most apparent after an inflexion in either trend. If the rate of warming has indeed slowed, and there is no 'missing heat' in the deep oceans, net radiation is lagging the decreased rate of warming and the two lines in Figure 1 diverge, and are correct as they stand. They should eventually re-align.

    Also, note that global heat transfer is weakest and slowest between the deepest oceans and everything else, so it is even more unlikely that this 'missing heat' is going into the deep oceans in the short time scales involved (ie years to several years).

    If this explanation is correct, it also contradicts at least some of the standard assumptions about climate sensitivity to greenhouse gases. Neither declining rates of warming, nor the divergence in satellite measurements of net radiation and modelled earth heat content should be happening if greenhouse gases are physically doing what the IPCC says they should be doing.
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  29. thingadonta> I think that we don't really know the amount of heat transfer between the top of the sea (say the top 700 meters) and the rest of it. I'm not saying that there must be a significant transfer, but I can't see how we can rule it out - how do you know that "global heat transfer is weakest and slowest between the deepest oceans and everything else"?
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  30. 27.Marcel Bökstedt at 18:37 PM on 19 April, 2010
    Berenyi Peter> It seems that Trenberth does exactly this calculation, and gets that if the "missing energy" (0.9 W/m^ 3) were deposited in the ocean below 700 meters, it would rise the sea level by 1.3 mm/y.


    May this be an explanation why we have had a continuing sea level rise in spite of very little surface temp increase 2000-2010, and only a fraction being explainable by ice caps/glaciers melting.
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  31. SNRatio> Yes, it seems that the expansion of water per added unit of heat is about twice at big at the surface as in the deep ocean, so if we (A) believe figure 1, (B) believe that all that missing energy went into the deep ocean, we would conclude from looking at figure 1, taking into account that the upper ocean is warming at a slower rate now, that the rise of sea level should have been approximately constant since 2005. This ignores the additional effect of melting glaciers.
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  32. The blog appears to faithfully reproduce the published article, but I think I'm missing something here.

    "....satellites which measure both the incoming sunlight and outgoing radiation. The absolute energy imbalance is too small to be measured directly."

    -So the simple calculation of Energy 'Out' subtracted from Energy 'In' can't be done because the errors of measuring the two are large, relative to the difference between them?

    "However, the satellite measurements are sufficiently stable from one year to the next so it's possible to track changes in the net radiation".

    -Isn't this the exact same calculation: "Net Radiation" is the difference between radiative energy 'In' and 'Out'? If the measurements are "stable" how does this make them better?

    ....Or are they just collecting data over a longer time period to get a better statistical grasp on the data?
    If this is the case, won't the signal-to-noise ratio only increase as the square-root of the time period?

    Separately, a third expanation:
    Might "a divergence problem, if you will" be due to a model which is incomplete, if you will?
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  33. #19
    "How you know global heat transfer is weakest and slowest between the deepest oceans and everything else"?

    Ever dived into a deep lake in the middle of summer?, it gets significantly colder as you go down because the surface warms much faster; warm water also rises and cold water sinks-creating long term stratification that isn't easily budged by further input of heat at surface. In fact with time the T divergence between the surface and deeper water can increase, until a point is reached whereby heat transfer can overcome this gravity-related stratification. The important factor is the time involved. The stratified water column resists heat transfer, and the time scales involved since 2005 are too short for the missing heat to be 'going into' deep oceans. Upwelling and downwelling currents are also much too slow to be transferring additional heat from surface to ocean depths in the matter of years.

    I suspect the explanation of the divergence in Figure 1 lies in some sort of time lag between net radiation and heat transfer,and that the figures are mostly accurate, and that net radiation might start to decline, as it does at the very end of the graph.
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  34. I never understood the explanation for why the Earth's inner mantle is so hot. Supposedly, all that pressure due simply to gravity makes for heat, but pressure in-and-of itself does no produce energy. Pressure on the increase in a fluid does, but if the pressure is static, it is not clear to me how this produces heat.

    I bring this up in the context of global warming as volcanic energy is assumed to not form a significant part of the radiate model as so far explained at this website, but in terms of something that could change over time, it seems suspect, perhaps accounting for "missing energy".

    With erupting volcanoes and earthquakes currently going on around the world, it seems this heat varies over time and is not constant.

    The fact that the Earth is a giant metal ball spinning in the magnetic field of the Sun should tell you something. A situation that should theoretically lead to electrical currents that in turn produce heat. And given that the Sun magnetic field changes with time, perhaps all this could explain the fluctuations we observe.
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  35. I have read some of the Willis and von Schukmann papers and it is not easy to understand their exact methodologies for correcting the temperature data from their 'tiling' the oceans and then measuring the heat content of each tile. A tile might be eg. 200m deep x 5nm x 5nm (nautical mile) or some such volume – but have made the point before that unless an instantaneous snapshot at Time1 was compared with a snapshot at Time2 of the whole volume of the oceans (all the tiles) then it would seem hard to measure an accurate difference between the OHC increase or decrease between Time1 and Time2.

    eg. for major currents like the Gulf Stream – running at 4-5 knots could move heat from one tile to another in minutes to hours.

    I would think that the Argo buoys would have to measure all at the same instant – eg. 12.00 noon GMT at Time1 and then at Time2 and a buoy would have to be in each 'tile' at the two reference points in time for that data to be useful.

    Since the Argo buoys are not tethered to a particular spot in the ocean, and move with the currents, would they tend to coagulate in warmer or cooler currents than calmer waters? and what happens to the data from a 'tile' location reporting temperatures at Time1 when it has no buoy in it to report at Time2?
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  36. Here's a couple of reviews from Trenberth and Cazenave which focus on sea level rise. Trenberth remains skeptical about the most recent data while Cazenave seems to have a more faith in the numbers. I think Cazenave makes a plausible case for the numbers in Table 1 of her review (page 7).

    Marcel Bökstedt point about deep ocean expansion is raised by Trenberth but isn't quite the issue Marcel suggests it might be and can't explain away the lost energy. Trenberth still has to come back to faulty ocean data even though several lines of approach confirm the lack of thermal expansion in the most recent data.

    Just on the question of lag raised by thingadonta. I think this is only an issue when you are measuring either atmosperic or ocean parameters alone. If your measuring both simultaneously it doesn't really matter where energy is building up or whether there are shifts in the rate of transfer between the two systems. It has to be observable somewhere and at the moment it isn't. Piekle makes a good point that total energy is a better parameter for understanding whats going on compared to global mean temperature for this very reason.

    There still remains one way to balance the energy budget and that is to accept the observed red line in figure 1 is also the actual energy budget. But I guess that raises too many uncomfortable questions!
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  37. The Pielke/Trenberth exchange continues here
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  38. #36: "There still remains one way to balance the energy budget and that is to accept the observed red line in figure 1 is also the actual energy budget. But I guess that raises too many uncomfortable questions!"

    How is that "balancing the energy budget"? The red line represents a cumulative estimate of where all the incoming goes... If you choose to ignore the satellite data on incoming and outgoing radiation, how do you estimate the incoming energy to balance against it?
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  39. RSVP, the amount of heat leaking to the surface from the Earth's interior is not merely an assumption. It is known to be very small relative to the heating from greenhouse gases. See the references I linked in my comment of 9:28 a.m. and the following one, on the thread Volcanoes emit more CO2 than humans.
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  40. Well, net radiation balance at TOA (Top of Atmosphere) as measured by ERBE & CERES satellites is 2 ± 5 W m-2, that much we know. Unfortunately this outrageously inaccurate value is quite useless for checking OHC history reconstructions.

    Toward Optimal Closure of the Earth's Top-of-Atmosphere Radiation Budget
    Journal of Climate, Feb 1, 2009
    by Loeb, Norman G, Wielicki, Bruce A, Doelling, David R, Smith, G Louis, Keyes, Dennis F, Kato, Seiji, Manalo-Smith, Natividad, Wong, Takmeng

    OHC measurements, at least for the upper 700 m are more accurate during the last couple of years. ARGO only accomplished its 3000 floats target in 2007, but coverage is reasonably good since 2005.

    So. The discrepancy is not between net radiation balance at TOA as measured by CERES and OHC as measured by ARGO, but between OHC measurements and computational model predictions.

    In cases like this the standard pre-postnormal science procedure is to abandon model and stick to measurement.
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  41. The case for a change in circulation patterns might be getting stronger. Changes in salinity distributions are being found, and since it is a thermohaline cycle...

    Here is a summary of a paper by Durack and Wijffels.

    Regarding #34 and #39, also, if the warming were being caused by from-within, electromagnetic interactions between the sun and the earth, I'd expect that this would be detectable by measurements of deep mine temperatures. To my knowledge, there are several rather deep mines in the world, but I've never heard of a warming trend over time with them. Warming trend with depth; yes, but not over time.

    @ #32, Sorry, but I'm going to guess that what you are missing is an understanding of how statistics can be used to distinguish between sampling differences that are simply a result of random noise and those that are noisy, but are some measurable probability of being caused by real differences in the data sets. I took stable to mean that the standard deviation did not vary much over time; if that is right, then more sample data will lead to less probability that observed mean differences are merely noise, not greater.

    Yes, technically, any model which can not make 100% accurate predictions can be said to be incomplete. I don't know of any model, even most of the basic physics ones, that can do this. (For instance, we've all been taught in beginning science courses that projectiles follow the path of a parabola; that is a fundamentally flawed model, but it's still useful.) That does not mean that models are without use. The whole point of this discussion is a question of how might this model be better completed.
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  42. Ken, I'm not sure why you'd need to get a instantly simultaneous reading from Argo buoys in order to derive a trend in total OHC from their collective data. If for instance you obtain a reading from each buoy over the course of 36 hours, wait for 6 months and then repeat the collection process, the 36 hour collection period should essentially vanishe from the OHC signal.

    There's a nice near-realtime map of Argo buoy distribution available: Current Argo distribution map
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  43. The discrepancy is not between net radiation balance at TOA as measured by CERES and OHC as measured by ARGO, but between OHC measurements and computational model predictions.

    In cases like this the standard pre-postnormal science procedure is to abandon model and stick to measurement.

    Yeah, well, Christy and Spencer said the same thing when their early satellite temperature reconstructions showed cooling rather than warming.

    Turns out the models (and surface temp measurements) were right, and Christy and Spencer were simply error-prone (several times over) and had made a seriously flawed analysis.

    What's the relevance to OHC vs. TOA vs. models?


    We are well aware that there are well over a dozen estimates of ocean heat content and they are all different yet based on the same data. There are clearly problems in the analysis phase and I don’t believe any are correct. There is a nice analysis of ocean heat content down to 2000 m by von Schuckmann, K., F. Gaillard, and P.-Y. Le Traon 2009: Global hydrographic variability patterns during 2003–2008, /J. Geophys. Res.,/*114*, C09007, doi:10.1029/2008JC005237. but even those estimates are likely conservative. The deep ocean is not well monitored and nor is the Arctic below sea ice. That said, there is a paper in press (embargoed) that performs an error analysis of ocean heat content.

    Our article highlights the discrepancies that should be resolved with better data and analysis, and improved observations must play a key role.

    Shorter form: current observational data and reconstructions of OHC built on said data pretty much suck at this point. This, BTW, is totally in line with his "travesty" e-mail touted by denialists as showing the Trenberth doesn't think there's been warming. Talk about misunderstanding the point ...

    Now, Josh Willis:

    I think that it is still premature to make claims about the Earth’s energy imbalance based on satellite observations and ocean heat content data over ANY period. As with the satellite observations, the ocean heat content data continue to undergo refinement and removal of systematic errors. Since the satellite data are insensitive to the absolute value of the imbalance, they rely on ocean heat content data to estimate it. However, I personally belive that there is not a long enough common period between the satellite observations and the RELIABLE ocean heat content record to make any strong claims about the energy budget. Many people are working on both data sets, however, and I hope that a more reliable comparison will become available soon.

    You yourself said:

    "Well, net radiation balance at TOA (Top of Atmosphere) as measured by ERBE & CERES satellites is 2 ± 5 W m-2, that much we know. Unfortunately this outrageously inaccurate value is quite useless for checking OHC history reconstructions."

    Apparently you're unaware that there's something circular in the notion of using TOA satellite reconstructions to check OHC reconstructions (since Willis points out that the former depends on the latter ...)?

    Anyway, two experts in the field suggest that your faith in the observations is, at this point, misplaced, and that the quality of observational data available to date isn't good enough to warrant "throwing out the models".

    Just as the quality of Christy and Spencer's early satellite temperature reconstructions weren't of good enough quality to warrant "throwing out the models".
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  44. RSVP the Earth's heat derives from energy conserved during the accretion of material forming the globe as well as by isotope decay, principally potassium-40, uranium-235 & 238, thorium-232.
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  45. RSVP @34. Although the earth's core was initially so hot due to the energy of gravitational infall as the earth accreted, it is believed that the source of the majority of the heat keeping it so hot is simply radioactive decay.
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  46. Chemware @12. Presumably everyone ignored this because it was wrong. Watts are already energy/time. 1W = 1J/s.
    So Wm-2 is an energy flux, and the area under any curve segment in figure one would represent energy (per square meter) accumulated during that time.
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  47. And, RSVP, the Earth's core continues to cool despite the contributions of radioactive decay. This topic is addressed by a Scientific American article, Why Is The Earth's Core So Hot?.
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  48. #22 vocta - thanks for pointing me to the right paper!

    so i read that one and it appears that the 0.9W/m2 net TOA imbalance comes from models. the actual measurements were 6.4 W/m2 which is way "outside the realm of current estimates of global imbalances" as Trenberth states. the authors further go on to state that "the TOA energy imbalance can probably be most accurately determined from climate models...."

    so am i understanding this correctly? every time we rely solely on measured data we get a TOA imbalance that is impracticle so instead we use model results. Pardon my ignorance but this seems very troubling to me why the scientist can't reconcile this and bring models and measurements into agreement. to me, TOA imbalance seems like the perfect tool to use to validate and/or monitor AGW. The fact that there is so much uncertainty in this is troubling.

    as a somewhat unreltated question - it seems to me that most satellite measurements of OLR are over bodies of water/ice. do we have any over land?
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  49. Berenyi Peter> I'm inclined to agree with you, this seems to be a point where the model does not agree with the data. The situation is unclear though, so its probably best to wait for better observations both from satelites and from the deep ocean.

    Humanity rules> I agree, whatever the answer is, it has to explain the observed rise in sea level, and this is also a restriction on the warming of the deep ocean.

    I'm not sure I understand the relevance of the satelite data as they exist today, Trenberth seems to claim that they do tell us something, but I'm not sure what. If someone has got this point, please explain!
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    Response: The point with the satellite data is it's not able to determine the absolute energy imbalance with great accuracy. However, as Trenberth puts it, "satellite measurements are sufficiently stable from one year to the next, so that by measuring incoming solar radiation and outgoing infrared radiation, it is possible to track changes in the net radiation".

    So satellite measurements are useful to determine whether the energy imbalance is rising or falling. And what we're finding is the satellites are measuring an increase in the energy imbalance while ocean heat measurements find a decrease in energy imbalance. As both these metrics are measuring essentially the same thing, this discrepancy needs resolving.
  50. Marcel @ 49 - Thought you might like this reply to Dr. Trenberth from Dr. Willis, on Pielke Snr.'s blog

    "....You should also note that Karina’s paper suffered from errors in the altimeter data that were still not corrected at the time of her paper. These errors tended to make the altimeter time series show too much global sea level rise, and after correcting them the trend in globally averaged sea level since 2004 or 2005 is significanly lower.

    Finally, I do not think that any of the techniques used by various groups should be supressing the global warming signal in the data over the period from 2005 to the present. As I mentioned above, the Argo data coverage during this period is such that any reasonable interpolation technique should do. Capturing the trend over 50 years, however, is another story.


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