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Sea ice minimum forecasts

Filed under: — gavin @ 17 July 2009

One of the interesting things about being a scientist is seeing how unexpected observations can galvanize the community into looking at a problem in a different way than before. A good example of this is the unexpectedly low Arctic sea ice minimum in 2007 and the near-repeat in 2008. What was unexpected was not the long term decline of summer ice (this has long been a robust prediction), but the size of 2007 and 2008 decreases which were much larger than any model had hinted at. This model-data mismatch raises a number of obvious questions – were the data reliable? are the models missing some key physics? is the comparison being done appropriately? – and some less obvious ones – to what extent is the summer sea ice minimum even predictable? what is the role of pre-conditioning from the previous year vs. the stochastic nature of the weather patterns in any particular summer?

The concentration of polar expertise on the last couple of questions has increased enormously in the last couple of years, and the summer minimum of 2009 will be a good test of some of the ideas that are being discussed. The point is that whether 2009 is or is not a record-setting or near-record setting minimum, the science behind what happens is going to be a lot more interesting than the September headline.

In the wake of the 2007 minimum, a lot of energy went in to discussing what this meant for 2008. Had the Arctic moved into a different regime where such minima would become normal or was this an outlier caused by exceptional weather patterns? Actually this is a bit of false dichotomy since they aren’t exclusive. Exceptional patterns of winds are always going to be the proximate cause of any extreme ice extent, but the regime provides a background upon which those patterns act. For instance, in the paper by Nghiem et al, they showed the influence of wind patterns in moving a lot of thick ice out of the Arctic in early 2007, but also showed that similar patterns had not had the same impact in other years with higher background amounts of ice.

This ‘background’ influence implies that there might indeed be the possibility of forecasting the sea ice minimum a few months ahead of time. And anytime there is the potential to make and test predictions in seasonal forecasting, scientists usually jump at the chance. So it proved for 2008.

Some forecasting efforts were organised through the SEARCH group of polar researchers, and I am aware of at least two informal betting pools that were set up. Another group of forecasts can be found from the Arctic ice forecasting center at the University of Colorado. I personally don’t think that the intrinsic worth of a successful prediction of overall sea ice extent or area is that societally relevant – interest in open shipping lanes that might be commercially important need much more fine-grained information for instance – but I think the predictions are interesting for improving understanding of Arctic processes themselves (and hopefully that improved understanding will eventually feed into the models and provide better tests and targets for their simulations).

What was particularly interesting about last years forecasts was the vast range of forecasting strategies. Some were just expert guestimates, some people used linear regression on past data, some were simply based on persistence, or persistence of the trend. In more mature forecasting endeavours, the methods tend to be more clustered around one or two proven strategies, but in this case the background work is still underway.

Estimates made in June 2008 for the September minimum extent showed a wide range – from around 2.9 to 5.6 M km2. One of the lowest estimates assumed that the key criteria was the survivability of first year ice. If one took that to be a fixed percentage based on past behaviour, then because there was so much first year ice around in early 2008, the minimum would be very low (see also Drobot et al, 2008). This turned out not to be a great approach – much more first year ice survived than was predicted by this method. The key difference was the much greater amount of first year ice there was near the pole. Some of the higher values assumed a simple reversion to trend (i.e. extrapolation forward from the long-term trend to 2008).

Only a couple of the forecasts used physics-based models to make the prediction (for instance, Zhang et al, 2008). This is somewhat surprising until one realises how much work is needed to do this properly. You need real time data to initialise the models, you need to do multiple realisations to average over any sensitivity to the weather, and even then you might not get a range of values that was tight enough to provide useful information.

So how did people do? The actual 2008 September minimum was 4.7 M km2, which was close to the median of the June forecasts (4.4 M km2) – and remember that the 2007 minimum was 4.3 M km2. However, the spread was quite wide. The best estimates used both numerical models and statistical predictors (for instance the amount of ice thicker than 1m). But have these approaches matured this time around?

In this year’s June outlook, there is significantly more clustering around the median, and a smaller spread (3.2 to 5.0 M km2) than last year. As with last year, the lowest forecast is based on a low survivability criteria for first year ice and I expect that this (as with last year) will not pan out – things have changed too much for previous decades’ statistical fits on this metric to be applicable. However, the group with the low forecast have put in a ‘less aggressive’ forecast (4.7 M km2) which is right at the median. That would be equal to last year’s minimum, but not a new record. It would still be well below the sea ice trend expected by the IPCC AR4 models (Stroeve et al, 2008).

There is an obvious excitement related to how this will pan out, but it’s important that the thrill of getting a prediction right doesn’t translate into actually wanting the situation to get worse. Arctic ice cover is not just a number, but rather a metric of a profound and disruptive change in an important ecosystem and element of the climate. While it doesn’t look at all likely, the best outcome would be for all the estimates to be too low.

858 Responses to “Sea ice minimum forecasts”

  1. 801

    This RH discussion is silly, as average GT’s increase so will total water vapor content per cubic meter.

    “Evaporation increases with temperature, not because the holding capacity of the air changes, but because the more energetic molecules can evaporate more readily ”

    Air does not “hold” water….

    So I really like to hear from more sources on present ice conditions, and surely if a model suggests constant RH , it makes sense because of the higher energy state of the air molecules.

  2. 802
    PeterMartin says:

    I moments of pessimism, I might agree with your assesment that trying to control the climate in the future is all going to be too hard. Not enough will be done quickly enough. Disaster will result. If that happens you, and those of like mind, will have played your part but, unfortunately you won’t be around to face the wrath of your descendents.

    But you’ve shifted your ground. What you actually believe, and have written on RC, is:
    “the arrogance of thinking that puny man IS changing global climate is only exceeded by the stupidity of believing we can – and must – urgently do something to stop it.”
    I would challenge you deny that this declaration is completely irrational. Furthermore, I would suggest that anyone whose beliefs are other than rationally based should stay off scientifically oriented websites.

  3. 803
    Anne van der Bom says:

    13 August 2009 at 5:53 AM

    From this horror scenario have come proposals that the USA should stop building new coal-fired power plants in starting in 2010 and shut down half of all existing plants by 2050.

    Now, I have figured out what impact this astronomically costly upheaval of US power generation would have on global temperature, and it is around 0.05°C.

    ‘man’ ≠ ‘US coal plants’.

    What you have proven is that US coal based power generation can not change the climate (significantly). To prove that man can not change the climate, you must include the other 94% of fossil fuel related CO2 emissions. And the other greenhouse gas emissions. Oh, and land use change. And use a longer horizon than 2050, let’s say 2100.

    After that exercise, let’s re-examine your claim that man can not change the climate.

  4. 804

    Wayne @ 801:

    Okay, air doesn’t “hold” water.

    However, when trying to explain something to people who don’t know the difference between an assumption and a result, “air holds water” is about the correct grade level.

    And yes, a constant relative humidity SHOULD be the outcome. The rate of evaporation increases as relative humidity declines and temperature increases. Increases in relative humidity are limited by overnight low temperatures because d pH2O / dT is positive, as it it’s second derivative (it’s an exponential function — see Java on previous page). I do very short term weather forecasting assuming a fixed dew point. Works pretty good, in terms of calculating relative humidity, which is what I’m after (solar power output is more strongly dominated by RH than Tambi-ent.)

  5. 805


    The least expensive way to do this would be to replace the coal-fired capacity with new nuclear fission plants. Maybe by 2050 the “fast breeder” technology with thorium could be an alternate to minimize the spent fuel problem. Maybe there might even be commercial nuclear fusion by then. Who knows?

    Nuclear fuel isn’t renewable. Not only is there no enough to do what you’ve described, but to the extent that there is, increasing the rate at which we burn up Uranium means that there still isn’t.

    Saving energy and increasing efficiency, where possible, is a given, of course, as are the development of more efficient electrical cars, trucks, etc.

    Correct. For which we need a massive increase in electricity production. Since non-renewable sources aren’t … renewable … the only way to successfully do this is with renewable energy.

    Whether wind and solar sources will ever be able to overcome the fact that neither has a better on-line factor than around 30% is questionable, but bio-fuels may have some promise. Ethanol from sugar cane works well in Brazil (but the rain forests suffer if this is where the sugar cane will be grown); ethanol from corn has been a disaster in the USA, driving up food prices in the process.

    You’re factually incorrect on both wind and solar. Wind averages 30% of nameplate capacity, not 30% up-time. I’m going over an ERCOT white paper on “Wind Ramps” at the moment and will be sending them my version of “how to make wind work better”. And solar is far better both in terms of nameplate rating AND up-time.

    You need to learn not to make false claims on a board when there are people around who really are experts.

  6. 806
    CTG says:

    Re 800. Ah yes, the “Have you stopped beating your wife yet?” trap. Lame. Is that the best you can do?

    Go away and find out how mathematical models work, then come back if you have something useful to say.

    It’s pointless talking to you when you obviously don’t have the first clue about how models work.

  7. 807

    #799 manacker

    First, what is your statement based on? An incomplete potential scenario? And if you were right, then you are merely saying we are going to cook, which of course will destroy the entire economy of the planet. This party now pay later type attitude is wholly unacceptable. We must not act like freshman in college, we are, each of us, called to rise to the occasion and take responsibility as best we can.

    Second, you don’t understand what is going on enough to make an intelligent statement on the subject. That is clear.

    For fun, let’s just assume you are correct for a minute and consider that. If all the mitigation plans only gave us a net reduction of 0.05C, would it be worth it?

    Well, let’s compare to the BAU alternative, increased temperature and positive feedbacks increasing the temperature to say around 5.2C in 90 years. Solidly into the catastrophic scenario where most of the worlds governments either have already failed or are on the brink of failure; a global economy in tatters; resource scarcity on a scale so severe as to strain the survival capacity; et cetera.

    So this is the choice you would make?

    Now, let’s say ‘some’ of the experts are right and we get another maunder minimum? Who cares? If the TSI is at or near thermal equilibrium, hitting a maunder minimum is a significant event. But that is not where we are at. Just look at the numbers: IPCC indicates best mean estimation at 1.6 W/m2 above equilibrium. So who cares if we remove .2 or .3 W/m2? That would only bring us down to 1.3 or 1.4 W/m2 positive. I may not be a math guy, but I am pretty sure that positive is still positive, so we continue to warm.

    Personally, I would really appreciate a maunder minimum event right now as that would buy us at least a little time.

    The reason I said you are cherry picking your solutions is because it is clear to me that you are not aware of all the potential solutions and how much C we may be able to sequester in a meaningful manner? We, as a human race, have not yet risen to the occasion. You can remain despondent if you wish, and you can stand in the way of progress if you wish, but that is your choice. Be aware of your part in the play… If you are not part of the solution you are part of the problem.

    I will not lay out my plans for you due to circumstance, but for you to say we can only… so why should we try… would be to say through recent history that man can not fly, man can not go to the moon, man can not achieve therefore man should not achieve… how utterly un-American!

    Do you live in a cave, or a house? Are you scrounging for grubs to sustain your life, or shop in a grocery store? Do you walk everywhere with a spear in your hand, or drive a car to run your errands. How dazed the mind that can not see the forest through the trees…

    Innovation got us here, so innovation will have to get us out. The first step is imagination. Maybe you are not the imaginative type, but then don’t stand in the way either unless you have substance to your reason. From my seat, you don’t.

    Context gives you relevance.

  8. 808

    #804, Its great to read the language of maths in all this, quite compelling and hard to refute!
    Well done..

  9. 809
    manacker says:

    Peter Martin

    I believe we have discussed the topic of man’s ability to change our planet’s climate ad nauseam.

    If you can show specific proposals that could be implemented to do so, including estimated investment plus running costs and resulting change in our planet’s climate, I would like to see your thoughts on this.


    [Response: Easy. We could try burning all the carbon-rich fossil fuels at a rate millions of times faster than it was produced, thereby increasing the amount of greenhouse gases in the atmosphere leading to warming at roughly 3 deg C per doubling of CO2. It would cost trillions of dollars – mining infrastructure, building networks to transport the fuel, the distribution of ‘engines’ to almost every single family so they could use it, the infrastructure of ‘refuelling’ locations, subsidies to exploration companies etc. Even better we could start to design cities so that it becomes impossible to get around without using large amounts of these fuels and then make sure that any consequent damage from pollution wasn’t paid for by the generators of that pollution so as to avoid any incentive to make better decisions. I figure it would take about 100 years to really start having an impact. You with me? – gavin]

  10. 810
    PeterMartin says:


    “Nuclear fuel isn’t renewable.” In the strictist sense of the term nothing is renewable. Even the sun is losing mass!

    However, the amount of nuclear fuel available, even on Earth, is such that it can just about be considered to be ‘renewable’.

    One possible pathway to the future would be:
    Current Technology (Enriched Uranium 235 based) > Fast Breeder reactors (U238 based)> Thorium Reactors > Fusion Reactors

    Fusion being the “Holy Grail” which could be 100 or even 200 years away. FBs and/or Thorium Reactors may be considered possible interim solutions.

    [Response: Not every thread has to end in a discussion of nuclear power. This is OT. – gavin]

  11. 811
    manacker says:

    FurryCatHerder (804)

    I agree with your statement : “And yes, a constant relative humidity SHOULD be the outcome.”

    All other things being equal, you are 100% right.

    But why is it that the atmospheric water vapor content has decreased (based on the long-term NOAA record) while temperature has increased?

    Not only has the RH decreased over this long-term period, but the specific humidity (water vapor content) itself has also done so.

    Do you have an explanation for this?

    (Please don’t come with “the observed data must be wrong, since they do not agree with the theory”.)


    [Response: This isn’t ‘observed data’, it is a reanalysis. Of which there are many. And none of the others show this. And this conflicts with actual observations (see the papers I gave you which you still haven’t read.) – gavin]

  12. 812
  13. 813
    manacker says:


    The link is provided on the curve in my earlier post, but for convenience, you can get the long-term NOAA specific humidity data on:


    [Response: Not observed ‘data’. – gavin]

  14. 814
    manacker says:


    To the long-term NOAA data you wrote:

    “And this conflicts with actual observations (see the papers I gave you which you still haven’t read.) – gavin]”

    Yes, it does conflict.

    I have read and am continuing to do so. Interesting stuff. Will get back to you when I have digested it all.


  15. 815
    manacker says:


    Of the long-term NOAA record showing a reduction in water vapor content as the planet warmed you state: “This isn’t ‘observed data’, it is a reanalysis.”

    Not to get into a fine point in semantics, but here is what NOAA writes about their water vapor content reanalysis record:

    “PSD maintains a collection of reanalysis datasets for use in climate diagnostics and attribution. Reanalysis datasets are created by assimilating (“inputting”) climate observations using the same climate model throughout the entire reanalysis period in order to reduce the affects of modeling changes on climate statistics. Observations are from many different sources including ships, satellites, ground stations, RAOBS, and radar.”

    Note that the reanalysis datasets are “created by inputting climate observations.” So they are a reanalysis based on observed climate data.


    [Response: Yes. But trends in reanalysis products are a mix of trends in the real world, trends in observing systems and the model used to do the interpolation. The RH trends in the NCEP reanalysis are unique to that product (they do not appear in the more up-to-date ERA-40, JAXA or MERRA versions), and are almost certainly tied to radiosonde technology changes (as they have gotten more responsive, they report drier conditions lower in altitude) and not real world trends. This was discussed at length in Chen et al (2008). – gavin]

  16. 816


    Whether wind and solar sources will ever be able to overcome the fact that neither has a better on-line factor than around 30% is questionable

    Where did you get the idea that solar is only on-line 30% of the time? By storing excess peak heat in molten salts to run the turbines at night and in bad weather, existing solar thermal plants are getting nearly 24/7 operation, and are already as reliable as most coal-fired plants.

  17. 817
    manacker says:

    John P. Reisman

    Your long post #807 reveals that you apparently firmly believe in the premise that AGW is a serious problem, is largely caused by human CO2 emissions and will lead to horrible consequences (ex. “increased temperature and positive feedbacks increasing the temperature to [sic] say around 5.2C in 90 years”).

    I do not believe that the scientific evidence supports a temperature increase of 5.2C in 90 years from AGW.

    Our opinions differ, to be sure. They are both based on independent evaluations of all the scientific information available, yet we arrive at two different conclusions.

    Who is right? Who is wrong?


  18. 818
    simon abingdon says:

    #809 gavin “I figure it would take about 100 years to really start having an impact” and this after the huge concerted efforts that you describe. Realistically, how long do you figure it might take us to engineer a reversal?

    [Response: A complete reversal? Probably never. The issue is to stop it getting much worse – that might be forseeable after 50 years or so of effort. – gavin]

  19. 819
    manacker says:

    Gavin (copy: simon abingdon)

    You wrote: “The issue is to stop it getting much worse – that might be forseeable after 50 years or so of effort.”

    I would be very interested in the specific proposals you have seen to “stop it getting much worse” after “50 years or so of effort”.

    How much effort at what overall cost (investment plus running cost) will be required?

    How much total reduction in emitted CO2 (GtCO2) over how many years?

    What impact would this reduction have on atmospheric CO2 concentration (ppmv) after these years?

    What net theoretical reduction in GH warming (°C) will this reduction cause as compared to not undertaking this specific long-term effort (using IPCC estimate of a 2xCO2 climate sensitivity of 3.2°C on average).

    What is the unit cost per degree C avoided (total cost in $, cost in $ per capita of those bearing it, i.e. all citizens of the “developed” countries).

    Just some basic questions, to get a bit more specific.

    Thanks for any input you have,


  20. 820

    #819 manacker

    Gee, you’re so clever. Instead of haranguing Gavin with your inanity, how about you tell us how much it will cost if we do nothing? Then we can all marvel at how smart you are.

    Just some basic questions, to get a bit more specific.

    Thanks for any input you have,


  21. 821
    manacker says:


    Thanks for link to Chen at al. This does not in any way show that the long-range NOAA record (based on a reanalysis of observations) is incorrect. In fact, it says:

    “Based on the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) and the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40), a comprehensive atmospheric structure associated with the GW trend is given. Significant discrepancies exist between the two datasets, especially in the tightly coupled dynamics and water vapor fields. The dynamics fields based on NCEP–NCAR, which show a change in the Walker Circulation, are consistent with the GW change in the surface temperature field. However, intensification in the Hadley Circulation is associated with GW trend in ERA-40 instead.”

    To the NCEP/NCAR Reanalysis (1948-present) to which I referred, NOAA tells us:

    “This reanalysis was the first of it’s kind. NCEP used the same climate model that were initialized with a wide variety of weather observations: ships, planes, RAOBS, station data, satellite observations and many more. By using the same model, scientists can examine climate/weather statistics and dynamic processes without the complication that model changes can cause. The dataset is kept current using near real-time observations.”


    [Response: Look at their fig 4 and then come back and discuss whether the reanalysis trends in humidity are robust. Then read Bengtsson et al 2004 for a deeper understanding for why that might be. – gavin]

  22. 822
    manacker says:


    Thanks for response.

    As I have read it, Chen does not refute the NOAA record of humidity, based on reanalysis of observed data from several sources, the link to Bengtsson et al. 2004 doe not work, and other links show Bengtsson et al. re tropical cyclone activity but not water vapor content trends. Can you give me a valid link to the Bengtsson et al paper so I can chack it out?



    [Response: Try this Bengtsson et al, 2004. The point in linking to Chen was to point out how non-robust reanalysis trends are. Bengtsson tells you why. – gavin]

  23. 823
    Timothy says:

    @gavin [809]
    Shh! Don’t give the game away! You know, I can’t believe Arrhenius & co. managed to get that experimental proposal past the ethics committee!

    And I must credit Lindzen et al for stepping in and ensuring the experiment wasn’t terminated in the late 20th century. If they had failed, we may have lost the opportunity to discover how quickly the Himalayan and Antarctic glaciers will melt. Fortunately the experiment will provide some interesting data in the decades to come!

  24. 824
    manacker says:

    Anne van der Boom

    Thank you for your comment (803), and sorry for delay in responding.

    I agree that the specific proposals that have been made to reduce GH warming by stopping new coal fired plants and shutting down existing ones in the USA will have no impact. They would, however, be quite expensive to implement.

    Broad statements that stopping all human CO2 emissions would show a major climate impact by year 2100 are rather meaningless. One needs to be quite specific here, because only specific actions can be implemented after cost/benefit evaluation.

    I have asked gavin for his ideas on what specific efforts should be made, along with a cost/benefit analysis, and I hope to get his thoughts on this.


  25. 825

    #824 manacker

    And I’m still waiting for you to answer my question…

    Please tell us specifically how much it will cost if we do nothing?

    And do add your cost/benefit analysis.

    I hope to get your thoughts on these important subjects.


  26. 826

    The discussion on humidity has been a useful one for me, as it has led to much better understanding of some basic issues. (Maybe I should have written “. . .led to some basic understanding. . .”)

    Gettleman 2008 seems pretty strong, to my layman’s eye. On the other hand, Max’s figure comparing the Relative Humidity reanalysis to Global Temps looked suspect to me from the get-go because the higher-frequency trendlines matched so well, while the lower-frequency trend was completely opposite in sign. Not an impossible situation, I realize, but you have to suspect a third variable. (Such as the changing bias in radiosonde data Gavin refers to later.)

  27. 827
    manacker says:

    John P. Reisman

    You asked: “Please tell us specifically how much it will cost if we do nothing? And do add your cost/benefit analysis.”

    Who is “us”, John? I will tell you.

    It’s a no-brainer, John.

    It costs nothing to do nothing.

    Since the benefit is divided by the cost in a normal ROI analysis, when you divide by zero you get infinity, but since that can’t be right, there is no cost/benefit analysis for “doing nothing”.

    Do you have one?

    Please try to be specific (and spare me “Stern reports” and other such stuff, please).



    [Response: Business-as-usual is not ‘nothing’. – gavin]

  28. 828
    manacker says:

    Kevin McKinney (826)

    It’s not MY reanalysis of water vapor content, it is that of NOAA.

    And the temperature record is that of Hadley.

    So it may have “looked suspect to you from the get-go”, but take it up with NOAA and Hadley, not with me.


  29. 829
    Rod B says:

    The reference in (815) starts, “…The dominant interannual El Niño–Southern Oscillation (ENSO) phenomenon and the short length of climate observation records make it difficult to study long-term climate variations in the spatiotemporal domain…” Not a very propitious beginning. But I’ll see what follows…

  30. 830
    Anne van der Bom says:

    14 August 2009 at 9:25 AM

    I agree that the specific proposals that have been made to reduce GH warming by stopping new coal fired plants and shutting down existing ones in the USA will have no impact.

    Hey, wait a minute, you said:

    Now, I have figured out what impact this astronomically costly upheaval of US power generation would have on global temperature, and it is around 0.05°C.

    What is it, no impact or 0.05°C?

    0.05°C might seem small but US coal power plants are responsible for only 6% of global CO2 emissions. You seem to be falling into the ‘divide and discard’ trap. Divide all emissions in categories that are so small that the effect of each one can be discarded as ‘insignificant’. If you do a little, you achieve a little. That was why I was asking you about the other 94%.

    What I then find a bit ironic is that you forward the question I asked you to Gavin in 14 August 2009 at 6:27 AM. You’re asking him to back up your opinions with evidence.

    I still feel you might be able to answer the issue I raised about how your calculations into the effect of dismantling US coal power generation extrapolates into ‘man can not change the climate’.

  31. 831
    Anne van der Bom says:

    Oops, the second quote I referenced to should have been 14 August 2009 at 7:08 AM

    When are we going to get our preview back so I can check my links and tags before posting.

  32. 832
    Hank Roberts says:

    Oh, lordy, it’s manacker again. Won’t someone else clean up after him?
    All you have to do is plug what he says into Google to find out he’s spinning.

    Or pick the search terms a little better to get a clearer idea:

  33. 833

    #829 Rod, “The dominant interannual El Niño–Southern Oscillation (ENSO) phenomenon and the short length of climate observation records make it difficult to study long-term climate variations in the spatiotemporal domain”

    Not really, if ENSO’s are weighed. So lets do one example

    El-Nino summer 2009, is not as strong as El-Nino summer of 1997.. Yet July 1997 GT was: +0.16 and July 2009 GT is +0.68 C (3rd warmest in history) … I hope Manacker can make a mental calculation disproving is own insinuations. Its obviously warming worldwide. The “world is cooling” since 1997 movement is academically dead…. RIP…… My flowers and condolences….

    I do watch FOX or some say FAUX news, it helps understand the stupidity out there, the most virulent, how shall I put it, the most misinformed or uneducated (in real time facts) zealot in the world making $$$$$ millions for spouting out inanities, Hannity was bragging about the coldest summer in history for the midwest, although humble me and others have seen this El-Nino driven regional cooling coming months ago. The fact that it was the 3rd warmest July in history worldwide does not fit the needed propaganda.

    And Faux network will skip this fact and they await the next gem of apparent AGW contradictions. Hank…. Manacker is small potatoes… Our focus must be at the higher exposure medias spouting out nonsense almost hourly.

    Ice wise the extent gap with 2008 has narrowed, and it is still very warm up there…

  34. 834
    CTG says:

    Re 832.

    Yes, he is rather tedious, isn’t he? It’s the bone-headed refusal ever to accept he might be wrong that is so tiresome, in that it takes so much effort to stamp him down.

    And yet he is clearly fishing for his “Banned from RC” badge, so it would just be giving in to him to have him banned.

    But you never know. Maybe he will pick up a dictionary and learn the difference between “assumption” and “result” one day. He might even read some of the references he is pointed to, and learn something. Although I doubt he will.

  35. 835
    realist says:

    Rut row Mr. Jetson, Arctic sea ice melt seems to have slowed considerably. Live by the weather, die by the weather.

  36. 836
    manacker says:

    Anne van der Boom

    You ask (830): “I still feel you might be able to answer the issue I raised about how your calculations into the effect of dismantling US coal power generation extrapolates into ‘man can not change the climate’”

    A major upheaval of the US power network to arrive at a 0.05C temperature difference is a true case of “Much Ado about Nothing” (with apologies to the bard).

    It’s pretty obvious to me that a 0.05C change in temperature is not a “change of climate”. In fact, it is not even measurable.

    I made a rough calculation of the added investment cost to do both “Plan A” (no new coal plants after 2010) and “Plan B” (shut down half of all existing coal plants by 2050), and the total is around $ 1 trillion, so this is obviously a poor “return on investment”.

    I have not yet seen any specific proposals that will bring any meaningful “change in climate”, and this is what I am asking Gavin to provide, if he has seen such proposals.


    [Response: Why do you think this is mysterious? We discussed it a couple of months ago – the need for coordinated actions and the level of changes required to likely avoid a > 2 deg warming. – gavin]

  37. 837
    manacker says:


    Thanks for “hit the brakes hard” link. Let me look at it more closely to see if there are any specific actionable proposals with direct results and estimated costs to implement.


  38. 838

    #827 manacker

    So if you have house payment due, and you don’t pay it, what is the cost of doing nothing?

    You get a bunch of notices and then the bank takes your house.

    hmmm… the cost of doing nothing actually can have a cost! what a surprise.

    So, if you create too many derivative markets and keep oversight out of the legislation, what is the cost of doing nothing… apparently as President Bush showed us last October, hundreds of billions of dollars… and those bills just keep coming…

    hmmm…. the cost of doing nothing is hundreds of billions in this case.

    And Gavin is right, BAU is not nothing, it’s continuing to add GHG’s and I can tell you based on my economic analysis, there is a very high cost to this. It doesn’t take a rocket scientists to figure out the economic strains, it actually only requires common sense.

    So you got your economics education from???

  39. 839
  40. 840
    Anne van der Bom says:

    14 August 2009 at 4:17 PM

    and the total is around $ 1 trillion, so this is obviously a poor “return on investment”.

    Only a trillion dollars? This is roughly the same as the cost of the war in Iraq. What makes you think the US can not afford this cost over a period of 40 years? 1 trillion dollars over 40 years is 0.2% of GDP. So actually, it turns out it is very doable.

    And you keep sidestepping the real issue I have with your reasoning. The real issue is that you concluded that ‘man can not change climate’ based on your calculation regarding the elimination of only 6% of global CO2 emissions.

    The second problem I have is that you take only 2050 as the deciding point in time. What about 2100? 2150? If the US decides to spend that 1 trillion dollars, the difference in CO2 emissions as compared to the BAU scenario will keep on increasing after 2050. In the do-nothing-scenario, those coal plants will still be there in 2050, increasing the CO2 level ever more, year after year. Can you please extend your calculation to 2100 and 2150?

  41. 841
    dhogaza says:

    Rut row Mr. Jetson, Arctic sea ice melt seems to have slowed considerably. Live by the weather, die by the weather.

    Cool, since it’s picked up again and is tracking 2008 very nicely.

    We have no way of knowing where it will end up, but it’s fun to watch.

  42. 842
    Hank Roberts says:

    > coal plants … dollars
    > around $ 1 trillion, so this is obviously a poor “return on investment”.

    Are you using the Acceptable Risk calculator?

    —- excerpt —

    Dow Acceptable Risk™ … For the first time ever, you will know beforehand what you can and can’t allow to occur. Will project X be just another skeleton in the closet–something your company comes to regret? Or will it be a golden skeleton–will it have harsh, but acceptable costs?

    To help you determine this, the AR Calculator™ accesses an immense knowledge base of over half a million risk events from every country on earth (reflecting the global risk breakdown). These cases are normalized according to location, time, casualties, financial outcome, litigation costs, and other parameters. 26 ancillary databases on products, laws, climate, income levels, etc. further clarify what any given case will mean in bottom-line terms.

    At the highest level, event data have been divided into four core types.

    Unproven Harm / Diffused Risk (UHDR)

    The most common type are those cases where harm shows up late, if at all, and investments are amortized through wide distribution.

    Beginning in 1972, for example, alarmists began linking casualties to one of our pesticides, Dursban, whose main ingredient came from German nerve agent research in WWII. Studies on student volunteers as late as 1998 showed no unexpected results, but Dursban lost out and was banned in the US. Its usefulness continues, fortunately, in places with more rational approaches to risk.

    Had we had Acceptable Risk™ back in 1972, we would have known that Dursban’s global potential, combined with low chances of major risk “blossoming,” would mean that if Dursban was going to be a skeleton in the closet, it would be a golden one–which it is.

    Mitigated Causality / Indirect Ownership (MCIO)

    A type of risk especially familiar to bankers is when the company involved is the agent of another entity who is primarily responsible.

    Close to home for Dow in this category are some products that helped cause wide and sometimes illegal devastation in wartime Vietnam. We got a lot of flak in the media for these products, but it never got worse for that, mostly because the ultimate culprit was the US military. Today, napalm and Agent Orange are definitely “skeletons in the closet” for us. But even in 1970, AR™ would have shown us that despite some mottling around the tibia, these skeletons would likely be golden.

    A more complex case is IBM’s sale of technology to WWII Germany for use in identifying Jews.This was bad. But IBM’s early management could have seen that the risks here would be mitigated by (a) uncertainty about what the technology would be used for; and (b) the likely distance in history from which judgment would happen, if it ever did.

    Some people would say that IBM’s decisions in this matter were lucky, others would say they were shrewd. But no one can deny they were profitable, and although this issue remains a skeleton in the closet, in retrospect it is quite clearly golden.

    Marginal Target / Unclear Impact (MTUI)

    Suppose Bill wants to set up a factory to produce a new pesticide. He logs on to the AR Calculator™ and plugs in the various chemicals, how much he wants to produce, and so on. The database finds roughly analogous cases, adjusts for geography and changes in law and income, and tells Bill that the risk of setting up in the US might well involve over $2 billion in liability from potential area lawsuits. After comparing that with profit projections, it’s very clear that taking this route will make Bill an unhappy camper.

    But the database proposes alternatives. The harm risk in India, for example, translates into potential losses of less than $400 million, based on previous liability settlements. Meanwhile, profit margins actually increase thanks to cheaper manufacturing, less draconian inspection requirements, etc. It is clear already that the skeletons here will be golden.

    As it happens, this case is typical of the type where risk acceptability varies depending on cultural and societal conditions. We would of course never wish to imply that an Indian life is worth any more or less than any other. I myself believe in the sanctity of life. But the market has its own logic, and if we’re going to live with it, we must make the most of its choices.
    —-end excerpt—–

  43. 843
    Paul K in Seattle says:

    Cost of replacing coal plants… There seems to be some confusion between capital cost to construct new generating plants and the actual increased cost of electricity. The ITC credit in the stimulus plan last fall would be sufficient to make a lot of renewable energy projects feasible. Unfortunately there is very little tax equity financing available due to the financial collapse of banks and financial institutions last year (banks traditionally have the largest need for tax reduction strategies). In any case, the 30% ITC instead of the general business 10% ITC provides roughly 3 cents per kwh. Contrast this with the average cost of electricity in the US at about 9 cents, which includes low cost legacy plants and hydroelectric generators.

    The US electricity consumption is around 3.8T kwh annually, with coal plants currently providing about half the supply. By multiplying 3.8 x 0.03 x 0.50 we find that if coal was replaced with renewable generators, the approximate increase in electricity costs would be about $60B annually. Of course, this doesn’t include the other environmental and health benefits of reducing coal fired emissions and mining impacts, or positive feedbacks from the large new renewable power generating equipment industry.

    It also doesn’t address US energy security issues. If this path takes us to a course where PHEVs take over on the country’s roads, US petroleum demand will drop. By comparison, the $60B annually contrasts with the over $200 to 300B in annual total loaded cost of the Iraq war.

    Also we should consider that the ramp to replace coal fired plants will take some time, so the annual cost will be much less than calculated over that ramping period.

    This looks like a no-brainer to me.

  44. 844
    manacker says:

    Hank Roberts (842)

    To my statement that $1 trillion investment for 0.05°C theoretical warming averted is a poor return on investment you asked:
    “Are you using the Acceptable Risk calculator?”

    No, Hank, Just common sense.


  45. 845
    PeterMartin says:


    If “just common sense” were enough we wouldn’t need science! I could give you plenty of examples to illustrate this point, but it would be better if we set you some homework and you had to think of one or two of your own.

  46. 846
    PeterMartin says:


    Further to my previous point I’ve just looked up World GDP. It is approximately $55 trillion per annum. Taking your figure of $1 trillion dollars to achieve a 0.05degC cooling would imply that, globally, we would need to spend $4 trillion per decade to offset 0.2deg of AGW.

    That works out at 0.7% of world GDP.

    Doesn’t sound too bad a deal to me.

  47. 847
    manacker says:

    John P. Reisman

    This has gotten hungup in the “spam” filter, so will try sending in three pieces, in order to locate the problem

    Part 1:

    Your examples (838) are weak.

    Not paying your house payment is not “doing nothing”. It is defaulting on a contractual obligation, which will, of course, have its repercussions.

    Part 2 to follow.


  48. 848
    manacker says:

    John P. Reisman

    Part 2:

    The derivatives mess started a long time ago and the U.S. sub-prime crisis started back with Fannie Mae and Freddy Mac (backed by U.S. Congress) promoting “easy money” for everyone (so everyone could afford a house) and greedy agents closing deals with people who had no chance of paying. This all has nothing to do with “doing nothing”. These problems were caused by a lot of people (politicians, bureaucrats, bankers, brokers, etc.) “doing something wrong”.

    Part 3 to follow.


  49. 849
    manacker says:

    John P. Reisman

    Part 3

    (Found the “spam” word and eliminated it):

    The lack of oversight by the SEC, etc. was also not “doing nothing”. It was gross negligence of duty by government officials who were payed by the US taxpayer to avoid the excesses that occurred. They were certainly “doing something” during all this time. They just weren’t “doing their job”.

    Now back to global warming: you say, “significant meaningful action is required”.

    Lay out a specific actionable proposal, John, rather than hypothesizing about what “doing nothing” means and costs.


  50. 850
    manacker says:

    Hi Gavin,

    Have finally checked out all the links you gave me plus a few others that popped up.

    All in all, the reports you cited indicated an agreement between model results and physical observations on water vapor, although some did not mention this at all and others were not too conclusive in this regard.

    Soden, B.J., et al., 2005: The radiative signature of upper tropospheric
    moistening. Science, 310(5749), 841–844.
    I could only get access to the abstract which tells me:
    “Climate models predict that the concentration of water vapor in the upper troposphere could double by the end of the century as a result of increases in greenhouse gases. Such moistening plays a key role in amplifying the rate at which the climate warms in response to anthropogenic activities, but has been difficult to detect because of deficiencies in conventional observing systems. We use satellite measurements to highlight a distinct radiative signature of upper tropospheric moistening over the period 1982 to 2004. The observed moistening is accurately captured by climate model simulations and lends further credence to model projections of future global warming.”

    Sounds good, but without the rest of the data this is simply a statement. Do you have access to the full report?

    Forster, P.M. de F., and M. Collins, 2004: Quantifying the water vapour
    feedback associated with post-Pinatubo cooling. Clim. Dyn., 23, 207–214.
    I could not get access to this study but here is a quote from a later study by Cordero and Forster.

    “For many years there has been controversy over apparent differences in modeled
    and observed temperature trends in the free troposphere, comparing trends from ra20
    diosondes, satellites and models (e.g., NRC, 2004). The recent CCSP report (Karl et
    al., 2006) and the papers it cites (e.g., Fu et al., 2004) resolve many of these issues.
    Our findings also tend to support the conclusions of this report, that models and observed
    trends appear in agreement, within their respective uncertainties. However, the CCSP report also notes that in the tropics “while almost all model simulations show greater warming aloft, most observations show greater warming at the surface”. Our results also support this conclusion. In particular they point to a real difference in the
    upper tropical troposphere. Since 1979 there seems to have been a real cooling trend in the radiosonde observations down to altitudes around 200 hPa, whereas in models it is almost impossible to get a cooling below 100 hPa”.
    This sounds like there is still some discrepancy between physical radiosonde observations and models although the report tends to support the conclusion “that models and observed trends appear in agreement, within their respective uncertainties”.

    Allan, R.P., M.A. Ringer, and A. Slingo, 2003: Evaluation of moisture
    in the Hadley Centre Climate Model using simulations of HIRS water
    vapour channel radiances. Q. J. R. Meteorol. Soc., 129, 3371–3389.
    “It is important to establish that climate models can accurately simulate the observed present-day fluctuations of water vapour. In particular, water-vapour and cloud-radiative feedbacks are intrinsically linked to processes governing relative-humidity distribution and variability. To explore these issues, clear-sky radiances, sensitive to upper-tropospheric relative humidity, are simulated within the Hadley Centre atmospheric climate model, version HadAM3, allowing direct comparison with High Resolution Infrared Sounder (HIRS) observations. The model is forced by observed sea surface temperatures and sea-ice fields over the period 1979-98. Evaluation of the simulated distribution and variability of water vapour is undertaken utilizing the HIRS 6.7 m brightness temperature (T6.7) and satellite measurements of column-integrated water vapour and clear-sky outgoing long-wave radiation (OLR). Modifications are made to the clear-sky OLR and T6.7 HadAM3 diagnostics to reduce sampling inconsistencies with the observed products. Simulated T6.7 over subtropical dry zones are higher than T6.7from observations, particularly in the southern hemisphere, and is symptomatic of an overactive circulation. The observed spatial signature of the T6.7 interannual variability is dominated by El Niño and is captured well by HadAM3. Interannual variability of the tropical ocean meanT6.7 is consistent between HadAM3 and the HIRS observations, suggesting that the small simulated decadal changes in relative humidity are realistic.”

    This shows a fit, even if it is hardly a robust link between physical observations and model out puts supporting a constant RH with warming. Does reducing “sampling inconsistencies with the observed products” imply that are physical observations are corrected to match the model outputs? I hope this is not what was meant.

    Dessler, A.E., and S.C. Sherwood, 2000: Simulations of tropical upper
    tropospheric humidity. J. Geophys. Res., 105, 20155–20163.
    “Our model of upper tropospheric humidity (UTH) of the tropics simulates well the measurements of tropical UTH at 216 and 146 hPa.”
    “Based on this analysis and previous analyses in the midtroposphere, we suggest that three-dimensional general circulation models of climate should be able to simulate the water vapor distribution well, as long as they can correctly simulate the large-scale circulation and temperature structure and can attain suitably moist conditions in convective situations.”

    This is not a confirmation that empirical physical observations support the model result of constant RH with warming. Taken together with the later report by Minschwaner and Dessler, also in the tropics, which showed that physical observations support an increase of water vapor with warming, but at only a fraction of the amount required to maintain constant RH, this does not provide empirical support for constant RH with warming.

    The best link to support your premise actually came from another blogger (it was published after IPCC AR4, however):
    Gettelman and Fu (2008)
    “Results indicate that the upper troposphere maintains nearly constant relative humidity for observed perturbations to ocean surface temperatures over the observed period, with increases in temperature _1.5 times the changes at the surface and corresponding increases in water vapor (specific humidity) of 10%–25% °C_1. Increases in water vapor are largest at pressures below 400 hPa, but they have a double peak structure. Simulations reproduce these changes quantitatively and qualitatively. Agreement is best when the model is sorted for satellite sampling thresholds. This indicates that the model reproduces the moistening associated with the observed upper tropospheric water vapor feedback. The results are not qualitatively sensitive to model resolution or model physics.”

    And then I ran across another quite recent related study:
    Colman and Power (2009)
    “The time evolution of the transient (or ‘secular’) feedbacks is first examined. It is found that both the global strength and the latitudinal distributions of these feedbacks are established within the first two or three decades of warming, and thereafter change relatively little out to 100 years. They also closely approximate those found under equilibrium warming from a ‘mixed layer’ ocean version of the same model forced by a doubling of CO2. These secular feedbacks are then compared with those operating under unforced (interannual) variability. For water vapour, the interannual feedback is only around two-thirds the strength of the secular feedback. The pattern reveals widespread regions of negative feedback in the interannual case, in turn resulting from patterns of circulation change and regions of decreasing as well as increasing surface temperature. Considering the vertical structure of the two, it is found that although positive net mid to upper tropospheric contributions dominate both, they are weaker (and occur lower) under interannual variability than under secular change and are more narrowly confined to the tropics.”

    So I will accept that there is some empirical evidence for water vapor increase with temperature to maintain near-constant RH, and there is also some empirical evidence to support the premise that RH decreases with warming, plus there is a long-range NOAA record that shows that even specific humidity has decreased over the years at the same time as globally and annually averaged land and sea surface temperatures (as well as tropospheric temperatures during the latter part of the record) have increased. The numbers of published reports (I have been able to see) favor the near constant RH, if numbers of reports are any indication

    Let’s not beat this dog anymore, Gavin.