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Global warming and ocean heat content

Filed under: — gavin @ 3 October 2011

The connection between global warming and the changes in ocean heat content has long been a subject of discussion in climate science. This was explicitly discussed in Hansen et al, 1997 where they predicted that over the last few decades of the 20th Century, there should have been a significant increase in ocean heat content (OHC). Note that at the time, there had not been any observational estimate of that change (the first was in 2000 (Levitus et al, 2000)), giving yet another example of a successful climate model prediction. At RC, we have tracked the issue multiple times e.g. 2005, 2008 and 2010. Over the last few months, though, there have been a number of new papers on this connection that provide some interesting perspective on the issue which will certainly continue as the CMIP5 models start to get analysed.

The most recent paper was a new study from NCAR out last week that looked into what happens to OHC in models when there are occasional 10 year periods with no trends in global surface temperatures (Meehl et al, 2011).

It is well-known (or at least it should be) that simulations for late 20th C and early 21st Century do not produce monotonically increasing temperatures at the annual or decadal time-scale. For the models used in AR4, the decadal trends expected under estimates of present day forcings are roughly N(0.2,0.14) (i.e. a Gaussian distribution centered on 0.2 ºC/decade with a standard deviation of ~0.14ºC/decade. This implies that one would expect an 8% probability of getting surface temperature trends less than zero in any one decade.

The Meehl et al study looked at the changes in ocean heat content during these occasional decades and compared that to the changes seen in other decades with positive surface trends. What they found was that decades with cooling surface temperatures consistently had higher-than-average increases in ocean heat content. This makes perfect sense if there is internal decadal variability in the fluxes that connect the deeper ocean to the surface ocean (which of course there is). An anomalous downward heat flux reduces the ocean surface temperature (and hence global surface temperature), which generates an anomalous heat flux into the ocean from the atmosphere (because the flux into the ocean is related to the difference between atmospheric and ocean temperature). And this of course increases total OHC.

A related study from the UK Met. Office looked at the relationship between the ocean heat content changes in the top 700m and the total ocean heat content change in models (Palmer et al, 2011). They found that (unsurprisingly) there is more variability in the top 700m than in the whole ocean. This is important to quantify because we have better estimates of the upper ocean OHC change than we do of changes in the whole ocean. Observational studies indicate that the below-700m increases are not negligible – but they are poorly characterised (von Schuckmann et al, 2009). The Palmer study indicates that the uncertainty on the decadal total OHC change is about 0.15 W/m2 if one only knows the OHC change for the top 700m.

So what can we infer about the real world from these tests? First, we can conclude that we are looking at the right quantities. Total OHC changes are a good measure of the overall radiative imbalance. Second, there is likely to be a systematic issue if we only look at the 0-700m change – this is a noisy estimate of the total OHC change. Third, if the forcings are close to what we expect, we should anticipate that the deeper ocean (below 700m) is taking up some of the slack. There are of course shorter term sources of variability that also impact these measures (OHC changes associated with ENSO, solar irradiance variability over the solar cycle) which complicate the situation.

Two further points have come in comment threads recently that are related to this. The first is whether the changes in deep ocean heat content have any direct impact other than damping the surface response to the ongoing radiative imbalance. The deep ocean is really massive and even for the large changes in OHC we are discussing the impact on the deep temperature is small (I would guess less than 0.1 deg C or so). This is unlikely to have much of a direct impact on the deep biosphere. Neither is this heat going to come back out from the deep ocean any time soon (the notion that this heat is the warming that is ‘in the pipeline’ is erroneous). Rather, these measures are important for what they tell us about the TOA radiative imbalance and it is that which is important for future warming.

The second point is related to a posting by Roger Pielke Sr last week, who claimed that the Meehl et al paper ‘torpedoed’ the use of the surface temperature anomaly as a useful metric of global warming. This is odd in a number of respects. First, the surface temperature records are the longest climate records we have from direct measurements and have been independently replicated by multiple independent groups. I’m not aware of anyone who has ever thought that surface temperatures tell us everything there is to know about climate change, but nonetheless in practical terms global warming has for years been defined as the rise in this metric. It is certainly useful to look at the total heat content anomaly (as best as it can be estimated), but the difficulties in assembling such a metric and extending it back in time more than a few decades preclude it from supplanting the surface temperatures in this respect.

Overall, I think these studies show how we can use climate models to their best advantage. By looking at relationships between key quantities – those that can be observed in the real world and those that are important for predictions – we can use the models to interpret what we are measuring in the real world. For these cases the inferences are not particularly surprising, but it is important that they be quantified. Note that the assumption here is akin to acknowledging that since the real world is more complicated than the (imperfect) models, inferences in the real world should at least be shown to work in the models before you confidently apply them to reality.

However, it is the case that none of these studies prove that these effects are happening in the real world – they are merely suggestive of what we might strongly expect.


References

  1. S. Levitus, "Warming of the World Ocean", Science, vol. 287, pp. 2225-2229, 2000. http://dx.doi.org/10.1126/science.287.5461.2225
  2. G.A. Meehl, J.M. Arblaster, J.T. Fasullo, A. Hu, and K.E. Trenberth, "Model-based evidence of deep-ocean heat uptake during surface-temperature hiatus periods", Nature Climate change, vol. 1, pp. 360-364, 2011. http://dx.doi.org/10.1038/nclimate1229
  3. M.D. Palmer, D.J. McNeall, and N.J. Dunstone, "Importance of the deep ocean for estimating decadal changes in Earth's radiation balance", Geophysical Research Letters, vol. 38, pp. n/a-n/a, 2011. http://dx.doi.org/10.1029/2011GL047835
  4. K. von Schuckmann, F. Gaillard, and P. Le Traon, "Global hydrographic variability patterns during 2003–2008", J. Geophys. Res., vol. 114, 2009. http://dx.doi.org/10.1029/2008JC005237

283 Responses to “Global warming and ocean heat content”

  1. 251
    Bob Loblaw says:

    Re: 250

    Yes, it’s like the apple bobbing down the river, ending up in the faster part of the flow. But for this to affect ocean heat content calculations – or, more specifically, changes in ocean heat content – you’d have to show how this tendency imparts a drift in the calculated value over time. If the bias is constant, it doesn’t impart a trend. If Y=mX + b is the correct model, and you always measure something that is Y=mX + b + e, you’ll still see the correct value of m.

  2. 252
    ldavidcooke says:

    Re: 251

    Hey Bob,

    In your estimation how often would a probe happen to rise into a “fast” current? It would seem more likely that most bouys would be restricted to slower currents which would suggest warmer conditions, at least in the lower latitudes.

    (Note: The bobbing apple is not a good example as it is constrained within the banks of the river. In open water it would be more subject to wind, as unlike a probe more of its surface is above water then under…)

    It was always difficult to sample atmospherics in the vacinity of a thunderstorm or squall line as the radiosonde would be pushed out in front and the opposite direction unless you could release within the wind field/updraft. (It is pretty difficult to manage a balloon in a 40knot down burst… Though we did experiment with kites…, brass key, leynden jar, the works…)

    Cheers!
    Dave Cooke

  3. 253
    Bob Loblaw says:

    Re: Dave Cook.

    I have no idea how often an Argo probe gets drawn into a fast current. From looking at the Argo web site, the probes spend most of their time (about 9 days out of 10-11) at depth, but it’s quite possible that most of their horizontal movement is related to the shorter time at the surface. Sounds like the sort of conjecture that is best resolved by actually looking at the data, rather than speculating.

    The apples analogy is just an easy visual.

    …but back to the bias question – do you think that there is a change in the bias over time, and (if so) why?

  4. 254
    ldavidcooke says:

    Hey Bob,

    As to bias change, I would have to go with observable evidence. The percent of the surface area through 700 meters where we see rapid currents in the Atlantic are low compared to the doldrums in the center of the gyre and encumbrences/bottoming near the shores.

    For the bouys to be universally distributed rather then concentrated would seem to suggest they would not be subject to localized conditions. Yet, knowing the basic topography of the coastal plains I wonder at how devices in shallow waters would be able to report T/S at depth.

    This would appear to point to areas where there is greater depth and faster moving currents would be where we get a full profile and a high optical depth. Suggesting that at best they can represent changes in conditions upstream.

    At the slower edge/centers we can not get a full profile and likely are caught in slow moving currents, suggesting higher temperatures/salinity at the edges or at the center, the submerged buoys are shaded by natural surface flora and though we get a full profile it may not be represenative of “high optical depth”.

    As a random sample, if we limit the data set to the surface readings we should get the least amount of bias. It is when we rely on non-directed or a lack of spacial definition (X,Y,Z) of the sample set, and unknown optical conditions we lose sample integrity, IMHO.

    I am sure the experts have solutions, I just had not seen them discussed. (BTW, I am a big fan of ARGO and would like to see generation improvements as we go through the replacement cycles.)

    Cheers!
    Dave Cooke

  5. 255
    Ken Lambert says:

    Bob Loblaw @251 & 253

    ‘…but back to the bias question – do you think that there is a change in the bias over time, and (if so) why?’

    Very good point. If the Argo buoys do not degrade significantly over time and the distribution stays roughly similar, any bias should also repeat and as differences are what we are looking for in OHC – then these should be accurate.

    Bunching of buoys in currents might significantly change the distribution, and looking at Google Earth there are few buoys above and below 60 deg N,S – and vast areas of the Indian, South Atlantic and Southern Oceans un-monitored.

  6. 256
    SirCharge says:

    The PDO was strongly negative during the period of 1946 to 1976, which is also the exact time period where global temperatures were stable. We also have experienced a more negative PDO since 2001 which also has coincided with a stable global temperature.

    I would suggest that if your deep ocean warming theory were correct it would have to be directly linked to the change in the PDO. The PDO’s negative cycle correlates too well with these multidecade temperature stabilizations for it to not be considered the probable primary driver. The mechanism by which it works may be heat sequestering or it may be changes in cloudiness, but whatever the mechanism, it’s the PDO.

    Unfortunately, if you admit that the PDO changes have that great of an effect on the climate you’re probably going to need to make some inconvenient alterations to the AGW beliefs and predictions.

    The temperature increase of the last 100 years could be more accurately described as linear rather than exponential as what we were seeing in the last 40 years wasn’t a drastic increase in temperatures but a normal multidecadal increase. Further, this would mean that models and predictions of future warming need to be revised as they do not include the notion of temperatures as cyclically increasing and then stabilizing over decades.

    [Response: You are confusing statistics with physics, and response with forcing. The PDO is not a ‘driver’ of anything. It is a statistical description of obverted temperature changes over the North Pacific, and as such, inherently has a ‘global warming’ signal in it. This is not to say that there aren’t possible oceanographic changes that have contributed to of recent decadal global temperature changes. However, the relationship of the PDO index with the global temperature series does not provide a means by which to examine this.–eric]

  7. 257
    SirCharge says:

    “The PDO is not a ‘driver’ of anything. It is a statistical description of obverted temperature changes over the North Pacific, and as such, inherently has a ‘global warming’ signal in it.”

    To believe that the PDO is not a driver you must contend that there was some other cause for the static temperature trend that occurred between 1946 and 1976. Don’t tell me you really side with the IPCC, that a mysterious cloud of aerosols suddenly appeared, stuck around for 30 years and just as suddenly disappeared without leaving any evidence or having any discernable reason for existing. You might as well believe that pixie dust and fairies kept the planet cool.

    In order to defend the notion that the PDO isn’t the cause of that cooling trend you need to come up with a more likely scenario. The PDO is not just statistics, it’s a representation of the movement of currents within an ocean that covers 46% of the planet. Of course it could be a driver of temperature whether by sequestration of heat, changes in cloudiness or some other methodology. I find it hard to believe that there is any more likely suspect for the 1946-76 trend than the PDO.

    “However, the relationship of the PDO index with the global temperature series does not provide a means by which to examine this.–eric]”

    Let me get this straight. You folks can search for missing heat for no better reason than because you’re convinced it must be there regardless of the evidence. You can then prove the existence of this missing heat using little more evidence then a couple of computer programs. Yet you can’t be bothered to attempt to understand what actual evidence shows appears to be a very close correlation between rate of temperature change and the PDO. It doesn’t seem that you’re trying to understand the world, it seems you’re just attempting to defend a theory.

  8. 258
    ldavidcooke says:

    RE: 257

    Hey Sir,

    So do you want the 50cent answer or the 5dollar…? Lets try 50 cent one to start with.

    For your position of PDO as a forcing agent, it is a symptom not a illness. As to a correlation between the PDO or PDO Index/NAO Index, it may not be circumstancial; however, it represents where weather patterns have changed. (Which is the point regarding AGW, a 1 dollar answer might be… Human activities have changed the influences of natural variation just enough that the normal distribution or variance has been skewed.)

    Secondly, a portion of the old emitted aerosols (pre-1970s) can be seen on the surface of Arctic Ice. As to their reduction, the international efforts to remove visible soot and smoke from exhaust systems post 1969 has been very sucessful. Now rather then being emitted as visable pollution, the carbon has been more thourghly combusted and instead contributes to the growing CO2 in the atmosphere.

    As for missing heat, that is an on going investigation, though it is likely the indications science has uncovered so far are where the insolation/re-emission imbalance is most like to be harbored.

    Cheers!
    Dave Cooke

  9. 259
    dhogaza says:

    Looks like sircharge is another galileo who has overturned all of climate science with a simple blog post …

  10. 260
    Hank Roberts says:

    > pixie dust and fairies

    We know they bought and burned the coal and oil.
    We have the invoices to prove it!

    You can find more recent numbers; here is an early paper covering the time span for which you’re expressing incomprehension or disbelief:

    http://fredbaes.com/dad/co2paper.html
    Carbon Dioxide and Climate: The Uncontrolled Experiment

    Possibly severe consequences of growing CO2 releases from fossil fuels require a much better understanding of the carbon cycle, climate change, and the resulting impacts on the atmosphere

    C. F. Baes, Jr., H. E. Goeller, J. S. Olson, and R. M. Rotty

    http://fredbaes.com/images/amscifig1.jpg
    Figure 1. The annual world production of CO2 from fossil fuels (plus a small amount from cement manufacture) is plotted since the beginning of the industrial revolution. Except for the brief interruptions during the two world wars and the great depression, the release of fossil carbon has increased at a rate of 4.3% per year. (1860-1949 data from Keeling 1973a; later data from Rotty 1976.)
    ——-
    This paper was originally published in
    American Scientist 65(3):310-320.Copyright © 1977 by Sigma Xi

  11. 261
    Hank Roberts says:

    Oh, and anticipating ‘Sirch’, now that he understands the aerosols were there, saying he can’t comprehend how they could have ‘disappeared’ while fossil fuel use was increasing: Sirch, the way coal was burned changed in the USA first, then across Europe, starting in the 1970s, to reduce acid rain. (China produced a lot of coal sulfate aerosols in the 1990s but has begun reducing their sulfate pollution since then)

    http://www.google.com/imgres?q=“clean+air+act”+aerosols
    http://adamant.typepad.com/photos/uncategorized/clip_image002.jpg

    (hat tip to Russell Seitz, who spins this in his own inimitable way by attacking the Clean Air Act of 1970, one of Richard Nixon’s better ideas)

    “… Clean Air Act advocates literally could not conceive that inventing the EPA could have a negative environmental impact, let alone that sulfur burned to no good effect could instead furnish shade sufficient to slow the melting of polar ice . Yet they are hoist on their own petard – it is now clear that curbing sulfur emissions exacerbated the rise due to CO2….”

  12. 262
    Hank Roberts says:

    http://sos.noaa.gov/datasets/Atmosphere/aerosols.html illustrates sulfate and black carbon in the atmosphere (links to datasets); one of many available at
    http://sos.noaa.gov/datasets/added.html

  13. 263
    Just Aidee says:

    Recently Counterpunch had an article which questioned the role of nuclear power to offeset carbon emissions. An interesting factoid within the article was that although electrical power was being generated (example of ~50GW per day for Japan), twice as much heat (100 GW per day) is being released into the oceans as “thermal discharge” from cooling systems. Although this appears as a significant amount on a daily basis (and only for one country), i’m wondering whether this is indeed significant and to what degree should such sources (indeed all heat sources) be also be considered as indirectly contributing to the warming of the planet.

    With the removal of significant nuclear capacity within Japan, would one expect to see changes in ocean surface temperatures?

    The article in question is at this link:
    http://www.counterpunch.org/2011/10/19/is-nuclear-power-really-a-trump-card-against-global-warming/

    [Response: Just think about the size of the oceans and the depth of the mixed layer, and the heat capacity of the water (~4000 J/kg/C). The waste heat is negligible on a regional scale (let alone global), though if it was restricted to a small bay, it would have a bigger impact. But waste heat is not restricted to nuclear power in any case… – gavin]

  14. 264
    SirCharge says:

    Silliness. Someone finding a smudge in Antartica does not prove that aerosols caused a temperature decrease between 46-76.

    Bear with me here and take a breath to think about what I’m saying before retorting by regurgitating climatology doctrine.

    Here is that lovely modern era temperature graph that I’m sure we’ve all seen a billion times. http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.gif

    Note the sudden directional changes that occur in 1946, 1976 and the early part of the last decade. These are not slow and gradual shifts, they are sudden alterations in directions.

    Here is a link to an article that discusses aerosols: http://earthobservatory.nasa.gov/Features/GISSTemperature/giss_temperature4.php

    Note the second graph. This is what a change in aerosols would look like in the real world because aerosols would slowly increase and decrease as people’s behaviors changed from country to country and as aerosols dissapated from the atmosphere. The above temperature graph does not show the same gradual change.

    My second bit of evidence is that the aerosol levels would have to be massive to cause that large of a change in the temperature trend. The aerosols released by Mount Pinatubo, for example, were enough that it took 4 years for temperatures to return to the pre-eruption level. Using a completely inaccurate guesstimate it would take a mount Pinatubo eruption worth of aerosols being released 7 times to keep temperatures from increasing for the 30 year time period. Do you honestly believe that people started releasing that much aerosol suddenly, and just as suddenly stopped? Human behavior does not change that quickly.

    Now, take a second to realize that all that you folks understand regarding aerosol levels during this time period comes from theories. It has very little to do with actual evidence. We do, however, have actual evidence of a change in currents of the largest ocean on the planet that occurred simultaneous to the temperature shifts. But even though every meteorologist on the planet knows that currents effect the weather, for some reason climatologists believe it is impossible for them to effect climate. Here’s the deal, currents effect clouds and clouds effect forcings. You can tell me repeatedly that it is impossible for PDO to be a driver, but you’ll just be repeating something that is completely nonsensical. Of course it can.

    Now, as requested, take a breath to think…

    Now feel free to regurgitate climatological dogma.

  15. 265
    Hank Roberts says:

    Sirch, people see things in graphs and other visual sources and assume there’s something in reality behind what they see; we’re built that way. There’s a word for it: https://www.google.com/search?q=define%3Aapophenia

    You haven’t taken Statistics 101. Basic statistics does change how you look at graphs like that.

    No dogma, not a matter of faith. Math.

    What’s pictured in that chart — and what isn’t — is not obvious from the picture: you need 20-30 years to define a climate trend.

    You’re arguing a notion you came up with on your own or found somewhere — fine, but use real information–you won’t convince anyone who understands the statistics by misreading a trend line as you’re doing above.

    You can learn this.
    https://www.google.com/search?q=“misleading+yourself+with+graphs” may help.

  16. 266
    Hank Roberts says:

    These may also help:
    http://hot-topic.co.nz/keep-out-of-the-kitchen/
    “an interactive graphic that shows how changing the length of the period you select for trend calculations affects the trends you see …”

    http://www.woodfortrees.org/notes.php#trends
    “After many requests, I finally added trend-lines (linear least-squares regression) to the graph generator. I hope this is useful, but I would also like to point out that it can be fairly dangerous….”

    http://atmoz.org/blog/2008/01/29/on-the-insignificance-of-a-5-year-temperature-trend/

  17. 267
    ldavidcooke says:

    RE: 264

    Hey Sir…,

    This has been thought over for many years by many people. As to quick changes in temperatures, to put into perspective; A large, what a VE III, volcano in the Sub-Tropics emitted the equivalent of roughly 5km^3 of aerosols with a size of 10-25 times the diameter of smoke or soot. Between 1990 and 1993 human activity raised an equivalent amount globally.

    The reason you would not see the same effect is three fold, the height of release, the time period of the release, and the distribution. At a lower altitude the large diameter aerosol residence is generally days to weeks, the finer aerosols weeks to months. Generally by the time new emissions are registered the former have been washed out of the air. Rather then being a concentrated plume they are dispersed, (except for fixed power generation and social centers).

    So to recap to have a dramatic effect the emission would have to be borne to the tropopause heights and be emitted within a one month period, and from a centralized location to have a similar effect to Mt. Pinatubo. Does the lack of these basic processes mean aerosols are insignifcant, in no way.

    The evidence in the polar regions of an apparent increase high altitude super cooled water droplettes demonstrates that: One the level of wv reaching high into atmosphere, beyond the normal adiabatic wet/dry transition height is a major change in the atmosphere. Two, the lack of change in the average humidity in the upper troposphere and yet a high presence of water droplettes suggests that there has to be a process happening which allows water to condensate and yet not freeze.

    If you add in the layering of dark aerosols in polar ice floes, it is clear that aerosol concentration and size have changed over the last 60 years. Matter of fact, between 1972 and 2000 the global man made fossil fueled aerosol production dropped by nearly 80%. At the same time the population doubled and dirtier fuels and less efficient combustion for home heating, and mass transportation delivery systems increased with them. When we consider the tell tale effects of these changes along with increases in either “slash and burn” farming or forest fires related to extended dry periods that seem to be on the increase, along with a significant drop in both soil carbon and moisture, it becomes clear that aerosols are on the increase and can effect both percipitation and hence weather.

    However, as the aerosol residence time is short and seasonal the effects should be likewise, they are not. Yes, there is seasonality in aerosols as well as CO2; but, the forcing on the natural variation in the weather is much broader then the seasonality in the emission patterns. This points to one possibility, the variation in the natural pattern has to be driven by a process where the effect exceeds the residence life aerosols can have. Is it possible for Spring releases of aerosols to balance out the natural CO2 release from dying vegetation in the Fall, yes.

    It can be restated that there are natural cycles of ebb and flow in most cycles, whether it be aerosols or CO2. The point is when something pushes these cycles into either greater intensity or duration, the patterns of the weather will change. These changes will be manifest in ways we are only now discovering. We know of one way we are pushing natural variation, the Glory satellite with the APS microfine Lidar system would have helped define how much aerosols play into changes in the weather patterns. Sad to say that input to the equation will have to wait for a long time….

    Cheers!
    Dave Cooke

  18. 268
    Steven Franzen says:

    @264 SirCharge:
    “Now feel free to regurgitate climatological dogma.” Poisoning the well now? Are you interested in advancing your/our understanding of nature, or only in defending your personal hypotheses? Your tone of writing, in any case, seems more suggestive of the latter, at least to me.

    Keep in mind that most aerosols (including sulfur-based ones) have very short lifetimes in the troposphere, on the order of several days, although they are longer in the stratosphere due to its reduced water content. The short lifetime and low altitude emission by humans (excepting aircraft) makes these emissions and their effects inherently much more local than e.g. CO2. Hence, the sulfur found in Greenland ice cores is more indicative of emission patterns from Canada and the US than of the global average aerosol concentrations, as is also explained in the Earth Observatory source you provide. It also means that, unlike CO2, even local aerosol emission reductions can show their effect very quickly, especially those done closer to Greenland and hence more likely to end up in its ice sheet. “Human behavior does not change that quickly” does not do much for me in explaining anything and, indeed, sounds rather like a dogmatic just-so story.

    Volcanic eruptions instead CAN propel their gases and small aerosols all the way into the stratosphere; the Pinatubo eruptions reached up to 24 km. Like this: http://hvo.wr.usgs.gov/volcanowatch/2007/images/Pinatubo_dust_layer.jpg. Up there they can have a much greater and longer-lasting effect, especially if released around the equator where the insolation is highest.

  19. 269

    #264–

    “It has very little to do with actual evidence.”

    Especially when you rationalize away the evidence that you are pointed to. . .

    But you could try looking at some of these studies, many (most?) of which have observational components:

    http://scholar.google.com/scholar?hl=en&q=aerosol+observations+climate&as_sdt=0%2C11&as_ylo=2006&as_vis=0

    There’s 17,000 citations to choose from. And that’s just since 2006.

  20. 270

    More on aerosols–this looks like a useful summary of the state of the art as of 2002. There’s several good citations on aerosol measurement, including remote and in situ techniques. (Thank goodness for review articles!)

    Should really have been filtered out, since I found it in that post-2006 search linked above, but the Google Scholar filtering tends to be a little porous. (I suppose it’s better than the reverse problem.)

    http://satelite.cptec.inpe.br/pesquisa/BIBLIO/AEROSSOL/Satellite-AER-Climate_Kaufmanetal_INSIGHT2002.pdf

  21. 271
    Hank Roberts says:

    Not for David Cooke:
    If anyone can cite the numbers posted above for “a VE II volcano” and human aerosol output 1990-93, I’d appreciate help identifying sources.

    For David Cooke:
    the request is _not_ for you. I understand you post vague recollections from a phenomenal memory. No worries, it’s your style, it gets by here.

    I like citations the way others collect stamps or beetles. It’s a hobby.
    I ask others for help, as I know others can find this stuff.

    [Response: Human: ~150 Mt SO2 (from here), Pinatubo was 20 Mt SO2, and smaller eruptions, much less. The outsize impact for Pinatubo is because it got into the stratosphere. – gavin]

  22. 272
    ldavidcooke says:

    Hey Hank,

    Thanks! I appreciate your understanding…

    As to aerosols the inclusion of dust/ash should also be considered as we are not only discussing albedo; but, are attempting to consider full spectrum optical depth, in addition to density of species/size of CCNs… The combination of which should change weather patterns.

    There were 2 papers that had addressed this, if I recall correctly. One was related to a aerosol modeling with the cooporation of NCAR and a Professor Thomas Choularton. The extent of which I believe touched on the Mt. Pinatubo event, (I think it was used as a modeling test case). The other I think was a review or AGU Poster of changes in LW/SW downwelling by a arm.gov supported NSF/DOE research team…, it may have been related to the UCAR COSMIC Lidar experimental series…?

    I believe there should also be a CCN study that should have support in a paper out of Washington State University about 2000, wrt the measurement of CCN/turbulance on droplet formation. The follow ups should have occured with a series of AGU CCN papers wrt saturated/super cooled cloud formations in the 2004 time frame.

    Sorry I can’t be more help, much of my old bookmarks, research data went the way of MS NT and (2) major systems crashes since then… Thats the price of being a hobbist rather then a professional…

    Cheers!
    Dave Cooke

  23. 273
    ldavidcooke says:

    Hey Hank,

    To also remedy my grevious error the VEI should have been a VI, I had suggested a III in error.

    (Though looking at a 2004 suggestion of between 3.8-4.3 km^3 of tempra would suggest a lower rating… I wonder if I made my mistake in est. based on trying to est. based on the I-II scale difference being based on log100 vs all other on the log10 scale. I’ll never know (or should it be, tell…)) Anyways thanks again.

    Cheers!
    Dave Cooke

  24. 274
    SirCharge says:

    A tremendous thanks to Kevin for linking every single paper that uses the word aerosol. Here’s a link for you:

    http://scholar.google.com/scholar?hl=en&q=unhelpful&as_sdt=0%2C11&as_ylo=2006&as_vis=0

    If you have an article that displays actual concrete evidence that total aerosols became extraordinarily high in the 1940s and dropped precipitously in 1976 please link it.

    The other links were stimulating but for the most part were very speculative or unrelated to the 1946-76 mystery cloud.

    Here’s an interesting tidbit from Mr. Cooke:

    “Matter of fact, between 1972 and 2000 the global man made fossil fueled aerosol production dropped by nearly 80%.”

    Once again, we’re talking about a slow change in behavior, not the sudden transformation that is evidenced by the temperature data.

    Again from Cooke:
    “This points to one possibility, the variation in the natural pattern has to be driven by a process where the effect exceeds the residence life aerosols can have.”

    I suppose if you believe that climate is only influenced by anthropogenic causes your mind will be forced to make all sorts of logical jumps to understand ‘unexpected’ variation in temperatures. Of course, if you considered the possibility that temperatures are influenced by other factors you might not have to sound like you’re insane when you explain the climate.

    Finally, Hank:
    “You haven’t taken Statistics 101. Basic statistics does change how you look at graphs like that.”

    Ok, let’s hypothetically consider the possibility that this mega cloud of aerosols existed. So, starting in 1970 state governments began mandating emission decreases. This began slowly, at first, in states like California and New York and then spread to the other states before adoption by the EPA. Next, the same restrictions were made more stringent over time. European states continued this behavior, although I’m sure communist countries merely flipped the bird at the suggestion of regulating emissions. Now, there’s another lag at each step in this transformation as individual corporations follow the regulations at their own pace and as equipment is replaced.

    So, I will conservatively say that this massive change in human behavior would take place over 10 years. Ok, Mr. Statistics 101, what is the probability that a change of temperature caused by aerosol reduction that took place over 10 years would, due to error and variability in data, actually appear to take place over a 1 year time period on gistemp? Pretty unlikely. Maybe it would be slower or faster, but it is extremely unlikely that it would be that much in error. Now, what is the probability that this same random occurrence of such an error would be repeated in all three temperature data sets? Mr Statistics 101? Would you guess it would be close to zero? Now, consider the fact that the opposite sudden change occurs in all data sets around 1946. I think it is a pretty safe conclusion to say that there was a sudden change in temperature as opposed to the long slow laborious process that would indicate aerosols.

    Just to remind everyone: We are currently experiencing a lull in temperature increases reminiscent of the one that occurred in 1946 and this time we know that aerosols were not a factor because we can see that they haven’t increased. I contend that it is quite likely that the two events have the same cause. The PDO

  25. 275
    Ken Lambert says:

    Sircharge@274

    “Just to remind everyone: We are currently experiencing a lull in temperature increases reminiscent of the one that occurred in 1946 and this time we know that aerosols were not a factor because we can see that they haven’t increased. I contend that it is quite likely that the two events have the same cause. The PDO”

    Well Sircharge, Jim Hansen would disagree with you because his latest paper suggests that Asian aerosols are a major cause of the stasis in temperatures and reduced warming imbalance to about 0.6W/M2 for the 2005-11 period. Dr Hansen also talks about a ‘delayed Pinitibo rebound effect’ which seems rather unlikely if not bizarre.

    Kevin Trenberth does not believe in the Asian aerosol cause of the stasis in temperatures and prefers to keep looking for the missing heat (about 0.3W/M2 equivalent) in the oceans.

    I must say that the IPCC charts on aerosol cooling with the wide error bars gives little confidence of the understanding of this effect.

  26. 276
    Bob Irvine says:

    Here is a quote from the “Atmospheric Aerosol Properties & Climate Impacts Report” by the US governments Climate Change Science Program, 2009.

    “ ES 3.1 Calculated change of surface temperature due to forcing by anthropogenic greenhouse gases and aerosols was reported in IPCC AR4 based on results from more than 20 participating global climate modelling groups. Despite a wide range of climate sensitivity (ie the amount of surface temperature increase due to a change in radiative forcing, such as an increase of CO2) exhibited by the models, they all yield a global average temperature change very similar to that observed over the last century. This agreement across models appears to be a consequence of the use of very different aerosol forcing values, which compensates for the range of climate sensivity. For example, the direct cooling effect of sulphate aerosol varied by a factor of six (6 ) among the models. An even greater disparity was seen in the model treatment of black carbon and organic carbon. Some models ignored aerosol indirect effects whereas others included large indirect effects. In addition, for those models that included the indirect effect, the aerosol effect on cloud brightness (reflectivity) varied by a factor of nine (9). Therefore, the fact that models have reproduced the global temperature change in the past does not imply that their future forecasts are accurate. This state of affairs will remain until a firmer estimate of radiation forcing by aerosols, as well as climate sensitivity, is available.”

  27. 277
    Hank Roberts says:

    > aerosol, particulates, sulfates, SirCharge generally
    Response posted in the open thread, as it’s unrelated to this topic

  28. 278

    #274–“A tremendous thanks to Kevin for linking every single paper that uses the word aerosol. . .”

    That’s not what I did, as you can plainly see from the link, which was searching “aerosols+observations+climate.” The point was to show that there is indeed a plethora of observations of aerosol abundance, contrary to your (unsupported) assertion that there is “little actual evidence” regarding aerosols.

    Sorry that didn’t answer your concerns, but if you spent less time on sarcasm and more on attempting to write clearly, it might have been easier to tell what “evidence” you were actually inquiring after–from your comment at #274, it appears that you specifically want evidence of aerosol abundance from 1946-1976, which of course are mostly pre-satellite measurement.

    But you still give little reason to think that you really want that evidence–you haven’t cited anything from the literature. And the last three paragraphs of #274 are classic “hand-waving”–you discuss at length what “must” have happened with no apparent attempt to look at the work of those who may have studied it then or since.

    There’s also a strange logical issue: previously in the comment you complain about those who (supposedly) “believe that climate is only influenced by anthropogenic causes,” yet your whole argument is based on the idea that aerosols and the PDO are exclusive possibilities. (For the record, I would speculate that the temperature record of 1946-76 is very likely the product of more than one ‘driver.’)

  29. 279

    #274, #277–Well, since I’ve found that taking ideas seriously regardless of whether I think them particularly well-motivated or well-founded can be quite educative, I took an hour or two to look for answers to Sircharge’s question about papers on aerosol and climate.

    A seminal paper, which is a good source for then-extent data (as of 1976) is RA Bryson & GJ Dittberner (1976), A Non-Equilibrium Model Of Hemispheric Mean Temperature–pdf here:

    http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281976%29033%3C2094%3AANEMOH%3E2.0.CO%3B2

    The hemispheric decline in optical transmissivity is well-supported and striking.

    A relatively more recent paper is Hegerl et al (1997), Multi-fingerprint detection and attribution analysis of greenhouse gas, greenhouse gas-plus-aerosol and solar forced climate change.

    As the title indicates, it’s primarily a modeling study, but has this to say about the aerosol data:

    The sulphate aerosol data were kindly made available by the Meteorological Institute of the Stockholm University and were calculated using the MOGUNTIA sulphur model (Langner and Rohde 1991) from historical SO2 emissions, based essentially on Mylona (1993) and Gschwandtner et al. (1986), and from projected future emissions from the IPCC 1992 scenario A (Pepper et al. 1992).

    The scenario forcing fields are similar to those shown in Mitchell et al. (1995a, b), except that the pattern of the aerosol forcing was not spatially fixed before 1990, but was allowed to respond to the spatially changing patterns of sulfur emissions (see Mitchell and Johns 1997). The forcing fields are shown in Cubasch et al. (1996).

    The impact of the computed aerosol concentrations was represented in the CGCM as an increased effective surface albedo. The global mean of the radiative forcing at the top of the atmosphere due to the aerosols is approximately !0.7 W/m2 in 1980. Indirect effects of aerosols on the formation and radiative properties of clouds were not considered. These are generally estimated to be of comparable magnitude to the direct effects, and may produce different climate change patterns (Jones et al. 1994; Boucher and Lohmann 1995). Our computations of the aerosol climate impact must therefore be regarded as only qualitative.

    (Quote reformatted for on-screen readability–thanks, Preview!)

    PDF here:

    http://www.geos.ed.ac.uk/geography/homes/ghegerl/hegerletal97.pdf

    So I do think the contention that the aerosol idea is based on “very little evidence” is adequately refuted. True, the evidence is not as complete or as unequivocal as one might wish (see Ken Lambert’s comment at #275.) And true, too, that the whole topic of aerosols is incredible complex. But the mainstream ideas about the possible role(s) of aerosols in the evolution of the temperature record are clearly well-supported by large amounts of solid observational data. Sircharge’s dismissal of those ideas in favor of “it must be the PDO”–without any evidentiary support whatever!–is somewhere between “wrong” and “not even wrong.”

    (BTW, I think Hank’s idea of migrating this discussion to the Open Thread is good; should I make any future contributions to the discussion, I’ll probably make them there.)

  30. 280
    Hank Roberts says:

    On-topic for ocean heat content:

    Would someone who has a subscription and can read the full article let us know what’s in this one?

    GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L20602, 1 PP., 2011
    doi:10.1029/2011GL049834
    Correction to “Tracing the upper ocean’s ‘missing heat’”
    C. A. Katsman
    G. J. van Oldenborgh

  31. 281
    JCH says:

    Hank, you’re the one who taught me to use Google Scholar:

    Tracing the upper ocean’s ‘missing heat’

  32. 282
    Rob Painting says:

    Hank @ 280 – See comment @ 71 by one of the co-authors Geert Jan van Oldenborgh.

  33. 283
    Hank Roberts says:

    Thanks JCH and Rob and my apology to Geert, who as Rob points out had in this thread mentioned an upcoming correction to a minor calculation error, along with providing the link for the full text of the paper as published.

    Consistent with the conclusions of that paper, “La Niña appears to have staged a comeback similar to 2008, and consistent with expectations formulated right here one year ago ….” — http://www.esrl.noaa.gov/psd/enso/mei/#discussion


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