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Arctic Sea Ice Volume: PIOMAS, Prediction, and the Perils of Extrapolation

Filed under: — group @ 11 April 2012

Guest Commentary by Axel Schweiger, Ron Lindsay, and Cecilia Bitz

We have just passed the annual maximum in Arctic sea ice extent which always occurs sometime in March. Within a month we will reach the annual maximum in Arctic sea ice volume. After that, the sea ice will begin its course towards its annual minimum of both extent and volume in mid-September. This marks the beginning of the ritual of the annual sea ice watch that includes predictions of the extent and rank of this year’s sea ice minimum, as well as discussion about the timing of its eventual demise. One of the inputs into that discussion is the “PIOMAS” ice-ocean model output of ice volume – and in particular, some high-profile extrapolations. This is worth looking at in some detail.

Prediction methods for the sea ice minima range from ad-hoc guesses to model predictions, from statistical analyses to water-cooler speculation in the blogosphere. Many of these predictions are compiled in the SEARCH-sponsored “sea ice outlook“.

This year’s discussions however will be without the input of the father of modern sea ice physics, Norbert Untersteiner, who recently died at the age of 86. Much of the physics in PIOMAS and global climate models can be traced to Norbert’s influence. Norbert was sober-minded and skeptical about the prospects of skillful short-term sea ice predictions, but even he couldn’t help but be drawn into the dubious excitement around the precipitous decline of arctic sea ice and regularly added his own guestimate to the sea ice outlook. Norbert’s legacy challenges those of us who engage in predictions to prove our skill and to understand and explain the limitations of our techniques so they are not used erroneously to misinform the public or to influence policy…more about that later and here.


PIOMAS is the Panarctic Ice Ocean Modeling and Assimilation System. It belongs to the class of ice-ocean models that have components for the sea ice and the ocean, but no interactive atmosphere. There is an active community (AOMIP) engaged in applying and improving these types of models for Arctic problems. Without an atmosphere, inputs that represent the atmospheric forcing (near surface winds, temperature, humidity, and downwelling short and longwave radiation) need to be provided. Typically those inputs are derived from global atmospheric reanalysis projects. The advantage of such partially-coupled models is that they can be driven by past atmospheric conditions and the simulations match well the observed sea ice variability, which is strongly forced by the atmosphere.

This is in contrast to fully-coupled models, such as those used in the IPCC projections, which make their own version of the weather and can only be expected to approximate the mean and general patterns of variability and the long-term trajectory of the sea ice evolution. Another advantage of ice-ocean models is that they don’t have to deal with the complexities of a fully-coupled system. For example, fully-coupled models have biases in the mean wind field over the Arctic which may drive the sea ice into the wrong places, yielding unrealistic patterns of sea ice thickness. This has been a common problem with global climate models but the recent generation of models clearly shows improvement. Because sea ice is strongly driven by the atmosphere, model predictions depend on the quality of the future atmospheric conditions. Therefore an ice-ocean model, like PIOMAS, is much more accurate at hindcasts, when the atmospheric conditions are simply reconstructed from observations, than for forecasts, when atmospheric conditions must be estimated. That is not to say that PIOMAS can’t be used for predictions, it can (Zhang et al. 2008, Lindsay et al. 2008 , Zhang et al. 2010) but it is important to recognize that performance at hindcasts does not necessarily say much about performance at forecasts. This point often gets confused.

Figure 1: PIOMAS mean monthly arctic sea ice volume for April and September. Dashed lines parallel to linear fits represent one and two standard deviations from the trend. Error bars are estimated based on comparison with thickness observations and model sensitivity studies (Schweiger et al. 2011)

PIOMAS was developed and is operated by Jinlun Zhang at the University of Washington. It is the regional version of the global ice-ocean model of Zhang and Rothrock (2003). The sea ice component represents sea ice in multiple categories of thickness and accounts for changes in thickness due to growth and melt as well as mechanical deformation of ice (Thorndike et al. 1975, Hibler 1980).
It has evolved with continual improvements, including the addition of data assimilation capabilities (Zhang et al. 2003, Lindsay et al. 2006) and the development of sister models for new applications (BIOMAS for biology) or specific regions (BESTMAS for the Bering Sea and GIOMAS for the entire globe) (publications). As a modeler working among observationalists from a variety of disciplines, Jinlun has never been short of tire-kickers who probe, push, and challenge his model from all sorts of different angles and identify warts and beauty spots. This is one of the reasons why PIOMAS has evolved into one of the premier ice-ocean models (Johnson et al. 2012), particularly when it comes to the representation of the sea-ice cover.

PIOMAS has been used in a wide range of applications but arguably the most popular product has been the time series of total Arctic sea ice volume which we have been putting out since March 2010 (see also Fig 1). The motivation for this time series is to visualize the fact that the long term Arctic-wide loss of sea ice is not only happening in extent, which is well measured by satellites, but also in thickness, which isn’t. Ice volume, the product of sea ice area and thickness, is a measure for the total loss in sea ice and the total amount of energy involved in melting the ice. Though this is a very small part of the change of global energy content, it is regionally important and investigations into the cause of sea ice need to pin down the sources of this energy.

But why use PIOMAS to show the decline in ice volume when our group of researchers has been involved in measuring, rescuing, and collecting sea ice thickness data from in-situ observations for 30-some years? The answer is that even though wide-spread thickness losses from observations alone have been apparent for some areas or time periods, Arctic-wide thickness losses are more difficult to document because of the sparse sampling in time and space. The problem can be visualized by constructing a “naïve” sea ice thickness time series from in-situ observations:

Figure 2 Naïve sea ice thickness time series. Sea ice thickness observations from the sea ice thickness climate data record (small grey dots), averages for all observations in a given year (large grey dots), and 5-year running mean through those observations. The same calculation for the corresponding PIOMAS simulations at the location and time of observation is shown by the big red dots and line.

Before those claiming that global warming stopped in 1998 have a field day with this figure, they should appreciate that our total volume time series and the naïve thickness time series are entirely consistent. The sampling issues arise from the fact that sea ice is highly dynamic with lots of spatial and seasonal variability so that measurements from individual moorings, submarine sonar tracks, and aircraft flights can only construct an incomplete picture of the evolution of the total Arctic sea ice volume. Progress towards establishing ice thickness records from satellite (ICESat, Envisat, and CryoSat-2) will change this over time, but these sources won’t yield a record before these measurements began and satellite retrievals of ice thickness have their own issues.

PIOMAS is not normally run as a freely-evolving model, but rather it assimilates observations. Ice concentration and sea surface temperature are currently assimilated and we have experimented with the assimilation of ice motion (Zhang et al. 2003, Lindsay et al. 2006). Assimilation helps constrain the ice extent to observations and helps improve the simulation of sea ice thickness. Ice thickness observations are not assimilated into the model. Instead, ice thickness and buoy drift data are used for model calibration and evaluation. So using a model constrained by observations is quite possibly the best we can do to establish a long-term ice volume record.

Model calibration is of course necessary. We need to determine parameters that are not well known, deal with inadequately modeled physics, and address significant biases in the forcing fields. Parameters changed in PIOMAS calibration are typically the surface albedo and roughness, and the ice strength. Once calibrated, the model can be run and evaluated against observations not included in the calibration process. Evaluation does not only mean showing that PIOMAS says something useful but also establishes the error bars on the estimated ice thickness. To establish this uncertainty in the ice-volume record (Schweiger et al. 2011), we spent a significant effort drawing on most types of available observations of ice thickness thanks to a convenient compilation of ice thickness data (Lindsay, 2010). We have also compared PIOMAS estimates with measurements from ICESat and conducted a number of model sensitivity studies. As a result of this evaluation our conservative estimates of the uncertainty of the linear ice volume trend from 1979-present is about 30%. While there is lots to do in improving both measurements and models to reduce the uncertainty in modeled ice volume, we can also say with great confidence that the decline in observed ice thickness is not just an effect of measurement sampling and that the total sea ice volume has been declining over the past 32 years at astonishing rates (for instance a 75% reduction in September volume from 1979 to 2011).


The seasonal prediction issue and the prediction of the long-term trajectory are fundamentally different problems. Seasonal prediction, say predicting September ice extent in March, is what is called an initial value problem and the September ice extent depends both on the weather, which is mostly unpredictable beyond 10 days or so, and the state of the ocean and sea ice in March. Improving observations to better characterize that state, and improving models to carry this information forward in time is our best hope to improve seasonal predictability. The prediction of the long-term trajectory, depends on the climate forcing (greenhouse gases, aerosols, solar variability) and how the model responds to those forcings via feedbacks. A recent model study showed that the crossover between initial-value and climate-forced predictability for sea ice occurs at about 3 years (Blanchard-Wrigglesworth et al. 2011). In other words, a model forgets the initial sea ice state after a few years at which point the main driver of any predictable signal is the climate forcing. In fact, coupled model simulations have shown that even removing all the sea ice in a particular July has little lasting impact on the trajectory of the ice after a few years (Tietsche et al. 2011).

PIOMAS has been run in a forward mode (and hence without data assimilation) to yield seasonal predictions for the sea ice outlook (Zhang et al. 2008) and has also provided input to statistical forecasts (Lindsay et al. 2008) and fully-coupled models. We have also done experiments with PIOMAS in a climate projection mode by scaling atmospheric forcing data from a reanalysis to 2xC02 projections from the CMIP3 models (Zhang et al. 2010). This setup provides more realistic wind fields and spatial thickness distribution but cannot account for important atmosphere-ocean feedbacks.

Global climate model projections (in CMIP3 at least) appear to underestimate sea ice extent losses with respect to observations, though this is not universally true for all models and some of them actually have ensemble spreads that are compatible with PIOMAS ice volume estimates and satellite observations of sea ice extent. With error bars provided, we can use the PIOMAS ice volume time series as a proxy record for reality and compare it against sea-ice simulations in global climate models. This provides another tool in addition to more directly observed properties for the improvement and evaluation of these models and is in our view the best use of PIOMAS in the context of predicting the long-term trajectory of sea ice.

Predictions of a seasonally ice-free Arctic Ocean

The eventual demise of the summer sea ice is a common feature of nearly every climate model projection (the exceptions are models with very inappropriate initial conditions). But the question of when the Arctic will be ‘ice-free’ is imprecise and calls for a clear definition of what ice-free means. Does it mean completely ice-free, or is there a minimum threshold implied? Does it mean the first time the summer sea ice goes beneath this threshold or does it imply a probability of encountering low-ice conditions over a period of time? (e.g. high likelihood of Septembers with less than 106 km2 of ice in a 10-year period). Regardless of whether the concept is actually useful for any practical purpose (say for planning shipping across the Arctic), it is nevertheless a powerful image in communicating the dramatic changes that are under way in the Arctic.

Once defined, predictions of when an ice-free Arctic will occur seem justified. In the published literature there are several papers specifically targeting such predictions (Zhang and Walsh, 2006, Wang and Overland, 2009, Boe et al. 2009, Zhang et. al. 2010) while others include discussion about the timing of ice-free summers (e.g. Holland et al. 2006). Some address the fact that the CMIP3/IPCC AR4 simulations show sea ice declines less rapid than the observations and attempt to correct for it. Published projections, though with varying definitions of what constitutes ice-free, all project an ice-free Arctic ocean somewhere between 2037 (Wang and Overland, 2009) and the end of the century. Predictions of earlier ice-free dates so-far seem to be confined to conference presentations, media-coverage, the blogosphere, and testimony before to the UK parliament.


A different class of predictions are based on simple extrapolation using historical sea ice extent, concentration, or volume. An example is included in the materials presented by the so-called ‘Arctic Methane Emergency Group’ who show extrapolations of PIOMAS data and warn about the potential of a seasonally ice-free Arctic ocean in just a few years. So does it make sense to extrapolate sea ice volume for prediction? In order to do a successful extrapolation several conditions need to be met. First, an appropriate function for the extrapolation should be chosen. This function needs to either be based on the underlying physics of the system or needs to be justified as appropriate for future projections beyond just fitting the historical data.

But what function should one choose? Since we don’t really have data on how the trajectory of the Arctic sea ice evolves under increased greenhouse forcing, model projections may provide a guide about the shape of appropriate function. Clearly, linear, quadratic or exponential functions do not properly reflect the flattening of the trajectory in the next few decades seen for example in the CCSM4 (Fig 3). The characteristic flattening of this trajectory, at first order, arises from the fact that there is an increasingly negative (damping) feedback as the sea ice thins described by Bitz and Roe (2004) and Armour et al. (2011). The thick ice along the northern coast of Greenland is unusually persistent because there are on-shore winds that cause the ice to drift and pile-up there. So extrapolations by fitting a function that resembles a sigmoid-shaped trajectory may make more sense, but even that, as shown in the figure, yields a much earlier prediction of an ice-free Arctic than can be expected from the CCSM4 ensemble.

Figure 3. CCSM4 AR4 ensemble and PIOMAS September mean arctic ice volume. Exponential and sigmoid (Gompertz) fits to PIOMAS data are shown. Note that the 1979-2011 September mean of the CCSM4 ensemble has about 30% higher sea ice volume than PIOMAS. To visualize the difficulty in choosing an appropriate extrapolation function based on PIOMAS data we shifted the CCSM4 time series forward by 20 years to roughly match the mean ice volume over the 1979-2011 fitting period.

But there is a second issue that may foil prediction by extrapolation: The period over which the function is fit must be sufficiently long to include adequate long-term natural variability in the climate system. The goodness of fit over the fitting period unfortunately may be misleading. Whether or not this is the case for sea ice extent or volume is an open question. The sea ice trajectory shows considerable natural variability at various time scales on top of the smoother forced response to changes in greenhouse gases. Periods of rapid decline are followed by slower periods of decline or increases. By fitting a smooth function to a sea ice time series (e.g. PIOMAS) one might easily be tempted to assume that the smooth fit represents the forced (e.g. greenhouse) component and the variation about the curve is due to natural variability. But natural variability can occur at time scales long enough to affect the fit. We have to remember that part of the observed trend is likely due to natural variability (Kay et al. 2011, Winton, 2011) and may therefore have little to do with the future evolution of the sea ice trajectory. This is visualized in figure 4 where ensemble members from the CCSM4 AR4 runs are fit with S-shaped (Gompertz) functions using the 1979-2011 period to estimate the parameters. The differences between the ensemble members, reflecting natural variability, yield vastly different extrapolated trajectories. Natural variability at these time scales (order of 30 years) may very well make prediction by extrapolation hopeless.

Figure 4. CCSM4 AR4 ensemble with sigmoid (Gompertz) fits. Light vertical lines represent fitting period for ensemble members (1979-2011).

In summary, we think that expressing concern about the future of the Arctic by highlighting only the earliest estimates of an ice-free Arctic is misdirected. Instead, serious effort should be devoted to making detailed seasonal-to-interannual (initial-value) predictions with careful evaluations of their skill and better estimates of the climate-forced projections and their uncertainties, both of which are of considerable value to society. Some effort should also target the formulation of applicable and answerable questions that can help focus modeling efforts. We believe that substantially skillful prediction can only be achieved with models, and therefore effort should be given to improving predictive modeling activities. The best role of observations in prediction is to improve, test, and initialize models.

But when will the Arctic be ice free then? The answer will have to come from fully coupled climate models. Only they can account for the non-linear behavior of the trajectory of the sea ice evolution and put longer term changes in the context of expected natural variability. The sea ice simulations in the CMIP5 models are currently being analyzed. This analysis will reveal new insights about model biases, their causes, and about the role of natural variability in long-term change.It is possible that this analysis will change the predicted timing of the “ice free summers” but large uncertainties will likely remain. Until then, we believe, we need to let science run
its course and let previous model-based predictions of somewhere between “2040 and 2100″ stand”


Bitz, C. M., and G. H. Roe (2004), A mechanism for the high rate of sea ice thinning in the Arctic Ocean, J Climate, 17(18), 3623-3632.
Boe, J. L., A. Hall, and X. Qu (2009), September sea-ice cover in the Arctic Ocean projected to vanish by 2100, Nature Geoscience, 2(5), 341-343.
Hibler, W. D. (1980), Modeling a Variable Thickness Sea Ice Cover, Monthly Weather Review, 108(12), 1943-1973.
Holland, M. M., C. M. Bitz, and B. Tremblay (2006), Future abrupt reductions in the summer Arctic sea ice, Geophys. Res. Lett, 33(23), 5.
Johnson, M., et al. (2012), Evaluation of Arctic sea ice thickness simulated by Arctic Ocean Model Intercomparison Project models, J. Geophys. Res., 117, C00D13.
Kay, J. E., M. M. Holland, and A. Jahn (2011), Inter-annual to multi-decadal Arctic sea ice extent trends in a warming world, Geophys. Res. Lett, 38.
Lindsay, R. W. (2010), New Unified Sea Ice Thickness Climate Data Record, Eos Trans. AGU, 91(44), 405-416.
Lindsay, R. W., J. Zhang, A. J. Schweiger, and M. A. Steele (2008), Seasonal predictions of ice extent in the Arctic Ocean, J.Geophys.Res., 113(C2), 11.
Lindsay, R. W., and J. Zhang (2006), Assimilation of ice concentration in an ice-ocean model, Journal of Atmospheric and Oceanic Technology, 23(5), 742-749.
Rothrock, D. A., Y. Yu, and G. A. Maykut (1999), Thinning of the Arctic sea-ice cover, Geophys. Res. Lett, 26(23), 3469-3472.
Schweiger, A. J., R. Lindsay, J. Zhang, M. Steele, H. Stern, and R. Kwok (2011), Uncertainty in modeled Arctic sea ice volume, J. Geophys. Res., 116, C00D06.
Tietsche, S., D. Notz, J. H. Jungclaus, and J. Marotzke (2011), Recovery mechanisms of Arctic summer sea ice, Geophys. Res. Lett, 38.
Thorndike, A. S., D. A. Rothrock, G. A. Maykut, and R. Colony (1975), Thickness Distribution of Sea Ice, J.Geophys.Res., 80(33), 4501-4513.
Wang, M. Y., and J. E. Overland (2009), A sea ice free summer Arctic within 30 years?, Geophys. Res. Lett, 36, 5.
Winton, M. (2000), A reformulated three-layer sea ice model, Journal of Atmospheric and Oceanic Technology, 17(4), 525-531.
Winton, M. (2011), Do Climate Models Underestimate the Sensitivity of Northern Hemisphere Sea Ice Cover?, J Climate, 24(15), 3924-3934.
Zhang, J., D. R. Thomas, D. A. Rothrock, R. W. Lindsay, Y. Yu, and R. Kwok (2003), Assimilation of ice motion observations and comparisons with submarine ice thickness data, J.Geophys.Res., 108(C6), 3170, DOI: 3110.1029/2001JC001041
Zhang, J., and D. A. Rothrock (2003), Modeling global sea ice with a thickness and enthalpy distribution model in generalized curvilinear coordinates, Monthly Weather Review, 131(5), 845-861.
Zhang, X. D., and J. E. Walsh (2006), Toward a seasonally ice-covered Arctic Ocean: Scenarios from the IPCC AR4 model simulations, J Climate, 19(9), 1730-1747.
Zhang, J., M. Steele, and A. Schweiger (2010), Arctic sea ice response to atmospheric
forcings with varying levels of anthropogenic warming and climate variability, Geophys.
Res. Lett, 37 (L20505)

302 Responses to “Arctic Sea Ice Volume: PIOMAS, Prediction, and the Perils of Extrapolation”

  1. 151
    Axel Schweiger says:

    @150 Peter
    The study indeed assumes that the all of the variability in the base periods is natural. Therefore the climate noise in the projections is exaggerated. The evolution of the trajectory comes from the superimposed temperature trend and the model sensitivity. As you can tell, the model quickly forgets the initial conditions once the artificial atmosphere is introduced. So the noticeable break in the surface temperature changes doesn’t last very long. Since the projected surface forcing changes come from a climate model(s) the underlying assumption is that the important ice-ocean feedbacks are captured in the superimposed forcing changes, so it really isn’t an independent test and not meant to be a substitute for a coupled model. This experiment simply shows that having a more realistic spatial distribution of sea ice doesn’t alter the results very much.


  2. 152
    Peter Ellis says:

    As you can tell, the model quickly forgets the initial conditions once the artificial atmosphere is introduced

    Yes, but that also involves “forgetting” half the total warming from 1948 through to the present! That is, it “forgets” the initial 2009 temperature and drops down to the temperatures you’re feeding it (plus the additional exogenously-added trend). So yes, if you “forget” that the Arctic has already warmed several degrees, the ice tends to remain.

    the noticeable break in the surface temperature changes doesn’t last very long.

    I disagree vehemently. In the B2 run, the SAT trend in the projection NEVER gets back up to the 2009 value, and only 4 individual years in the entire run are above the 2009 value.

  3. 153
    James Overland says:

    Two quick points
    Since ice response at the end of summer is the integral of meteorological forcing, getting the timing of individual weather events correct is not required.
    Using a range of summer climatological weather distributions is not too poor an approach for a probability outlook.

    Current climate models (CMIP3 & 5) seem to be slow for a variety of reasons. comparison with data, model resolution and lack of regional physics. It is not clear that they will solve the problem any time soon

  4. 154
    Jim Larsen says:

    129 Ray L asks, “if these scenarios are credible, then why have they not happened before?”

    For the Holocene, the warmth of today is NOT separate from the warmth 8kya. Instead, it is laid on top of. Put a fire under some water, and it doesn’t boil… does that indicate that placing a fire under water for a longer period won’t cause the water to boil?

    The previous ice ages are another matter, of course. Then again, they’re not nearly as constrained. Also, natural interglacials are slower than the current events and clathrate atmospheric CH4 emissions are limited by the capacity of ocean organisms to consume CH4, so exceeding that limit is more of a potential problem today. A big natural release over 1,000 years might result in ~0 atmospheric CH4 increase. Do the same today in 50 years, and CH4 could increase tremendously.

    The big question in my mind is whether the potential release is self-limiting. The gulf oil spill involved clathrates. They tried to cap the leak, but expansion caused freezing and clathrates gummed up the works. Will that happen naturally so leaks will self-seal?

    Now this is the worst captcha I’ve ever seen. The first half HAS NO LETTERS! Just a picture. Just how am I supposed to represent that??? Please please PLEASE dump your current provider and get a system that allows humans to post relatively easily.

  5. 155
    Paul Beckwith says:

    Clearly, the sea ice volume data plot is the single most important topic of discussion, yet in the article it is shown in Figure 1 with a poor vertical scale and amongst linear trend lines which mislead and make the curve appear to be linear and reach the zero point far out in the future. The data does appear also in Figure 3 and with an exponential fit although in this figure the data is somewhat concealed amongst a plethora of other curves.

    It is important that the readers see the data clearly displayed, for this I would refer them slide 24 of the presentation: ,one can clearly see that a linear trend line to the data makes no sense. In fact I asked my 9 year old where the curve is trending to zero, and he correctly responded 2015, as most people would conclude.

    It is important to note that the PIOMAS volume curve is for Pan-Arctic ice, the prefix indicating that it includes ice outside the Bering Strait into the Pacific. It is clear that this ice will melt every year, so the actual volume withing the Arctic proper is even less than the data indicates.

    The ambiguity over the definition of ice-free is not really important as far as the strong albedo feedbacks magnifying the warming of the region, so is kind of a red herring in the discussion.

    How can anybody have much confidence in the so called “published projections” for the ice free state between 2037 and 2100, given that these projections have been wrong every single time they have been made over the last decade or more; they missed the collapse in area in 2007 and they also missed the exponentially declining behavior over the last several decades.

    Invoking the natural variability explanation for making a prediction based on so called “simple extrapolations” is also a very dubious claim. Simple physics dictates that with less sea ice there is magnified warming of the Arctic due to powerful albedo feedback; this in turn reduces the equator to pole temperature gradient which slows the jet stream winds causing them to become more meridional; this combined with 4% more water vapor in the atmosphere (compared to 3 decades ago) is leading to much more extremes in weather. There is nothing “natural” about these extremes of weather over the last 2 years, or about the unprecedented ozone hole in the Arctic last year (troposphere warming from greenhouse gases caused stratospheric cooling to below threshold temperature for polar stratospheric cloud generation and ozone destruction). Neither is there anything natural about the large variation in the Arctic Oscillation (AO) from record positive to record negative levels). Ditto with the rapid increase in methane emissions from the Arctic region as flask measurements indicate, as well as satellite measurements. Both methane datasets show a very large increase in methane in 2011 versus 2010, this is also confirmed by Russian measurements on the East Siberian Arctic Shelf (ESAS) which saw methane plumes of 1 km in diameter when a year or two previously the plumes were a mere tens of meters in diameter.

    If you just consider the Arctic alone, then maybe you could argue on some anomalous years of low sea ice. However, when you look at all the “big picture” evidence of the global system it is clear that there is nothing “natural” about it, in fact it appears that the planet is in early stages of an abrupt change of climate from our “normal” system to one that is much warmer and tropical like. Over the ESAS the temperatures were 20 degrees Celcius higher than normal for much of Jan/Feb/Mar this year, and of course the March heat wave broke enormous numbers of records, not to mention the massive numbers of tornadoes spinning off the supercharged storm systems. Nothing normal about all this. Time to step away from the models and pay more attention to the observations…(more details in pdf link )

  6. 156
    Hank Roberts says:

    > captcha

    Click the little icon with the two circling arrows for a fresh choice.
    (Pictures are “Street View” addresses, generally, these days; it changes)

    This is a fast changing “arms race” — well funded spambot herders (Motto: “We will bury you! In Spam!”) versus websites. None of the responses are easy; I’m seeing more sites give two or three different challenges per post.
    I’m also seeing small websites simply choked to where the owners give up.

  7. 157
    John Nissen says:

    @Paul, #155,

    Excellent posting. All your points support AMEG’s assertion that we have a planetary emergency on our hands.

    But what do we do about it? Clearly the Earth System will not return to any kind of normality (hospitable for humans) without intervention. If we let the sea ice disappear completely and the methane rip, then we are sunk. So we have to take some measures to cool the Arctic.

    And we have to do it on a large scale, so it involves geoengineering – preferably using a number of techniques in combination. But we can take immediate measures to avoid the risk of inadvertent warming, e.g. from gas or oil spills. And we could even allow more sulphate aerosol into the atmosphere, as this has proven successful at global dimming – taking care about not to release “pollution” near centres of population where it could damage health. I’m sure there are other things to do if we put our minds to it. Necessity is the mother of invention.

    The evidence suggests we could already be at the point of no return. So we have to fight to save the situation with utmost determination. There is no time to lose.


  8. 158
    Dominik says:

    Concerning predictive functions: With something wobbling so much up and down as the volume curve, just putting your finger on the screen and drawing a freehand curve is not less precise than any fit function, much more economical though.
    Axel Schweiger wrote, that we had just a couple of warm springs, which caused the deviation from the GCM predictions, and this is one interesting point: Is this “couple o’ warm springs” really something coming and going like any cyclone, or is it a sign of a changing weather regime with stronger mixing and stronger heat transport? There are arguments for the latter, e.g. change in jet stream trajectory ( For the time being we cannot be sure, but this might be an effect escaping the GCMs so far.

  9. 159
    Ray Ladbury says:

    Paul Beckwith, I would also beware of invoking “simple physics” in making predictions about a complex system. Gavin has already pointed out that ceteris probably ain’t paribus, as there could be negative feedbacks due to clouds that diminish the positive albedo feedbacks.

  10. 160
    Paul Beckwith says:

    @Dominik, #158

    I agree completely that with the fluctuation in the volume curve one can eyeball the curve and do a decent fit, in fact my 9 year old son said it looked like the zero crossing was at 2015. Not necessary to get a room full of Ph.D.s to see what the trend is in this case.

    I disagree completely with the Axel Schweiger “couple of warm springs” explanation to describe the last few years. In fact in my presentation( )on slides 26 through 45 I discuss how the extreme weather is a pattern and not an anomaly, and how meteorologist Jeff Master is going ballistic about the last two years, as is ClimateProgress blogger Joseph Romm (quotes on slide 45). I am sure this is a pattern and not a simple excursion from the norm, as is James Hansen. Particularly damning is Hansen’s climate dice analysis showing the spatial distribution of heat events around the globe in standard deviation units (slide 42); the enormous increase in heat events exceeding 2 sigma and 3 sigma within the last decade show an undeniable pattern of increasing extremes.

    Clearly, these extremes are global and nature and there is every reason to conclude that they will increase in frequency and intensity as the sea-ice collapses further. The main question is when will these extremes hit the global food supply and cause shortages, just this week there are articles about how China’s rice and grain crops are being stressed by flooding and drought events. Remember that when the jets stayed in a stationary meridional blocking pattern for about 5 weeks or so over Asia a few summers back Pakistan was flooded out (being in the trough) and Russia was baked and burned (in the ridge), the grain crops were hammered there so much that there were no exports from them that year. The same meridional blocking pattern hit North America this March, keeping the East at record high temperatures and the West colder than normal such that it snowed in Northern California and also rained much more than normal. What more do we need to be sure?

    [Response: The problem with all of this handwaving is that you are equating coincidences in time (-ish) with causation. Where is the mechanistic analysis that says that it is the sea ice over the last couple of years (and not SST, or north-south gradients, or strat-trop connections or whatever) that has caused this? Where is the statistical analysis that says that you can confidently say that blocking variability has become greater in the last couple of years? The fact is that you are making claims of certainty where no such certainty exists. It is not inconceivable that sea ice extent changes affect jet stream volatility – but this needs to be quantified. By how much does it affect the variance? and is it conceivable that it is so large that it is confidently detectable in only a few seasons? Do some of the maths – and you’ll very likely find that only ridiculously large shifts would be confidently detectable in such a short time, and there is no evidence for such large changes. Note that your use of Hansen’s graph to support your claim doesn’t follow since his result arises from a shift in the mean even in the absence of any shift in the variance. I totally get that you are concerned, and that these connections may be happening, but you are not doing yourself any favours in trying to convince anyone else of that. Take a step back and start thinking about detectability and quantify what you are interested in – that, in the end, will be much more telling. – gavin]

  11. 161
    Paul Beckwith says:

    @Ray Ladbury, #159

    I do not buy the blanket statement that the climate system is all complex. There are “core” linkages that the physics clearly explains with absolute certainty and of course there are many “peripheral” connections where things get more complex and obscure. For example simple spectroscopy dictates that the CO2 molecule vibrates, stretches, and rotates creating quantized absorption lines that are Doppler broadened and pressure broadened and absorb the infrared radiation coming from the warmed planet. Snow and ice has a high albedo and when it is replaced by sea water or soil and tundra the albedo drops and there is warming, this is simple optics. Slide 8 of shows the spatial warming, the Arctic amplification of the warming is enormous and is due to this “core” albedo effect. Sure, there are some negative effects from clouds but they are clearly not preventing this large latitudinal amplification effect.

    I should qualify that I have a multidisciplinary background with an undergraduate degree in Engineering Physics and an M.Sc. in laser physics, an I am working towards a Ph.D. in abrupt climate change in a Geography department, however this has not stopped me from sitting in on many human geography and policy courses. I completed all the courses required towards a Ph. D. in physics, and I have audited many courses in Earth Sciences and mathematical physics.

    A huge problem is that far too many scientists (including climatologists) are way too specialized in niche areas of their field and refuse/hesitate to step outside their comfort zones to study the “big picture”, which is vital step to enlightenment in the field…

  12. 162

    #155–I’m sympathetic on several counts. But the March heat wave was not a global phenomenon; NCDC has March as the 16th warmest ever, and the coolest since 1999. (Still warm in the big picture, but far from remarkably so by 21st century standards.) Citing it in this context just weakens your case.

  13. 163
    Chris Dudley says:

    Gavin in #160,

    Detectability may require new tools though. While the mean shift argument works well for NH summer, in the spring we often speak of a phase shift such as an early spring or summer come early rather than a mean shift. The shift in the mean for spring is about the same as for summer but the variiance is much larger in the spring so the attribution argument that works in the summer does not work in the spring. I suppose shifting hardiness zones is one quantification but something that captures just how wild March was seems a little hard to find.

  14. 164
    Hank Roberts says:

    > John Nissen
    > … allow more sulphate aerosol … not to release “pollution”
    > near centres of population where it could damage health

    Ah, would you claim that acid rain and mercury “pollution” (your quotes) only affected humans in centres of population, not lakes and streams and soils downwind for hundreds of miles?

    Oh, wait. That industry argument failed 40 years ago when the science showed it was bogus.

    What else ya got?

  15. 165
    Randy says:

    @Paul, #155
    Do you have a reference for this statement “combined with 4% more water vapor in the atmosphere (compared to 3 decades ago) is leading to much more extremes in weather.

  16. 166
    wili says:

    @Paul #155–As to satellite measurements of Arctic methane release, have you seen the new AIRS NH map for March:

    Looks like a big increase from February:

    Especially over ESAS.

    Should that be happening this time of year? Shouldn’t increasing sun be oxidizing the methane? Am I missing something here?

  17. 167
    Ray Ladbury says:

    Paul Beckwith, The statements you are voicing are not based on evidence. They are opinions. They may be correct. There’s even a reasonable probability that they are so. Nonetheless, they do not change the fact that there is a whole helluva lot we don’t understand about what is going on in the Arctic at present. Very little is clear, and none of it is simple. That is not something from which to draw comfort.

  18. 168
    Ray Ladbury says:

    Jim Larsen
    Huh? Dude, are you suggesting that melting of ice and clathrates is not a thermally driven process?

  19. 169
    Hank Roberts says:

    > Am I missing something here?

    You’re pointing to one image deep down in their large file system.

    One thing worth trying: go to the top of that file system (with http, not ftp!) — it would be

    That’s their ‘front door’ — it’s often the case that one of the pages linked to a public front door invites questions about the site.

  20. 170
    wili says:

    @ Randy #165. I knew I had heard that 4% water vapor figure somewhere before, so I pulled a hank ‘-) and googled it:

    It’s not a published source from a scientific journal, but it is an interview with a major climate scientist, Kevin Trenberth.

    “For every one degree Fahrenheit increase in sea temperature, the water holding capacity for the atmosphere goes up by 4%. And since the 1970′s on average there’s about a 4% increase in water vapor over the Atlantic Ocean and when that gets caught into a storm, it invigorates the storm so the storm itself changes, and that can easily double the influence of that water vapor and so you can get up to an 8% increase, straight from the amount of water vapor that’s sort of hanging around in the atmosphere. This is reasonably well established.”

  21. 171
    wili says:

    hank, it’s not some random image “deep down in their large file system”

    It’s the most recent image they have of methane above the north hemisphere.

    And thanks for posting their ‘front door,’ but is there something in particular you wanted me to see there?

    Could I just ask the good and informed folks here, from what people know about methane, is this what we should expect to see–increasing amounts in the Arctic in March?

  22. 172
    Andrew Holder says:

    I have followed ice news closely over the last 3 years and I am worried about future ice loss. But can anyone explain how we have had previous ice free occurrences in the last 100 years or so. If I understand correctly then 1934 or 1953 were “ice free” or very low at least. The problem is that if this is true then public opinion is less likely to be too concerned with it happening again.

    Also, it appears by looking at the antarctic ice graphs that the antarctic is doing well and has if anything slightly increased over the last 30 years or so. Wouldn’t we expect this to be behave in similar way to the arctic?


    Andrew Holder

    [Response: What is your source for 1934+1953 being ‘ice free’? sounds remarkably implausible if you ask me. As for Antarctica – there are many differences, not least the heat content of the Southern Oceans, the isolation of the continent, mostly divergent sea ice flow, etc. And penguins. – gavin]

  23. 173
    Marco says:

    Andrew Holder, are you the same Andrew Holder who has had some comments at Wattsupwiththat? If so, it explains your confusion. When you go there, you are fed so often with misinformation, it is difficult to enter back into reality.

  24. 174

    Andrew, this claim is flat out false. I’ve seen the 1934 claim before, but never supported by anything other than fragmentary anecdotes–and actually, IIRC, “anecdotes” is a generous description; “a single vague reference” would be more like it.

    Quick Google searches:

    1) Japanese observations in the Sea of Okhotsk from 1934 (note that this area is relatively southerly, so if there’s ice there, we can be quite sure there is lots of ice elsewhere):

    2) Russian sea ice observations and activity in exploring the “Great Northern Sea Route” from 1933:

    3) Historical backgrounder on sea ice research in the 20th century:

    3) Declining sea ice *beginning* in 1953:

    4) Study of cyclicity in Arctic sea ice from 1953:

    5) Blog post giving a chart of sea ice standard anomalies from 1953:

    6) Summary and discussion of pre-satellite data in the scientific literature:

    I could keep going, but I think you get the point: there is no evidence whatever of ice-free periods in historical times, and a great deal of evidence showing the opposite.

  25. 175

    #172–“Wouldn’t we expect [antarctic sea ice] to be behave in similar way to the arctic?”

    Well, given that:

    1) the Antarctic ice is largely seasonal, whereas the Arctic ice has historically been semi-permanent (formerly having a considerable amount of ice more than 10 years old); that

    2) the Antarctic ice forms at the margins of a largely glaciated continent surrounded by a powerful circular ocean current, whereas the Arctic ice forms at the margins of a ocean basin largely surrounded by continental landmasses; and that

    3) the Antarctic (with the notable exception of the West Antarctic peninsula) shows low rates of warming, whereas the high Arctic is the most rapidly warming part of the planet–

    no, this observer, at least, really wouldn’t expect them to behave in a similar way at present.

  26. 176
    Andrew Holder says:

    Yes I am, i know it’s strange to some people but I like to read and digest information from all sources and then make up my own mind about things.I think it’s a sensible question to ask why antarctic ice is increasing when arctic ice is decreasing but I understand that might be a topic for another post as it will probably, as Gavin indicated, involve many different areas for discussion. As for previous years when arctic was “ice-free” i think one of these possible sources is from old pictures of submarines or ships being “photographed” at the North Pole, eg in 1958 although I understand that this has been open to debate. As in all these things, nothing is black and white – even in old photographs!

  27. 177
    Ray Ladbury says:

    Andrew Holder,
    As other posters have pretty much scuttled the Arctic portion of your concern, I will confine myself to the Antarctic. There are a lot of things that folks seem not to understand about the poles. The first and perhaps most important is that while they are warming, they are still bloody cold–especially in winter–and hence, ice will still freeze. In Antarctica, this means that cold and moister air from the surrounding oceans will blow over the interior and fall as snow, so increasing ice mass is to be expected. It is along the edge of the continent where we are seeing deteriorating ice conditions. Ice shelves are collapsing. That is not healthy.

  28. 178
    Dan H. says:

    Agree on all points. Two different regions.

  29. 179
    Jim Steele says:

    I am not sure why Gavin replies “[Response: What is your source for 1934+1953 being ‘ice free’? sounds remarkably implausible if you ask me.”

    Indeed, there is no way to truly compare ice coverage during the 1930’s to 40’s but the source of that speculation was pictures taken from submarines that surfaced at the north pole with considerable open waters. I don’t think there is enough data to say such conclusions are justified or to dismiss as “remarkably implausible” but the temperatures in the Arctic during that time were remarkably similar to this current period and the subject of several peer reviewed papers. For example:

    In “The Early Twentieth-Century Warming in the Arctic—A Possible Mechanism” BENGTSSON 2004 , they wrote “The largest warming occurred in the Arctic (60–90N) (Johannessen et al. 2004) averaged for the 1940s with some 1.78C (2.2C for the winter half of the year) relative to the 1910s. As can be seen from Fig. 1, it was a long-lasting event commencing in the early 1920s and reaching its maximum some 20 years later. The decades after were much colder, although not as cold as in the early years of the last century. It is interesting to note that the ongoing present warming has just reached the peak value of the 1940s, and this has underpinned some views that even the present Arctic warming is dominated by factors other than increasing greenhouse gases (Polyakov and Johnson 2000; Polyakov et al. 2002).

  30. 180

    #172 Andrew’s source? Would it be the Larsen taking 2 years to sail through the NW passage, instead of less than a week now a days??? Or is it some secret Nazi Arctic submarine navigation chart smuggled to Argentina after the war, the U-boats needed to surface often for air, and it was so ice free they had a regular sub charter schedule to Japan. By the way the same war in the 40’s during which the 3rd Reichs war machine froze dead on its tracks just short of Moscow??? No no, lets see, must be something more obvious… Please elaborate!

    But be warned, there is no such memory of such warm times by the people of the Arctic, sorry that there was no weather stations, but there were people here, currently entranced by a real current warming period.
    I suggest Spitzbergen records…

  31. 181
    tamino says:

    Re: #177 (Jim Steele)

    First, read this.

    Then go get this data and plot the temperature for the Arctic.

    By the way, that picture which is supposedly of the submarine U.S.S. Skate surfacing at the north pole in open water … as it turns out, it wasn’t taken at the north pole.

  32. 182
    Hank Roberts says:

    > Jim Steele

    The story from the primary source:

    “… A knot of sailors in the control room stared intently at an instrument inscribing patterns of parallel lines on a rolling paper tape. The pattern looked like an upside down mountain range.

    “Heavy ice, ten feet,” said one of the sailors.

    Suddenly the lines converged into a single narrow bar. “Clear water!” the sailor called out.

    Calvert turned toward the man in charge of the ice-detecting instrument. “How does it look?” The sailor flashed him the okay sign.

    “Bring her up slowly,” Calvert said. The three-thousand ton sub began drifting upward like a giant balloon. The diving officer called the depth as the Skate rose.

    Otherwise the room was deathly quiet. A wrong move or a miscalculation would endanger the mission or even the ship. Calvert continued to peer through the eyepiece. When the top of the periscope came within sixty feet of the surface, he spotted heavy ice to the side. He flipped the prism to look straight up, but saw nothing except the same blurred aquamarine. Sweat appeared on his forehead as he felt all eyes in the control room bear down upon him. If the sub rose too slowly, it could drift away from the opening. If it rose too quickly and struck ice, the collision could tear open the pressure hull and send the sub and all ninety men on board to the bottom.

    … The submarine’s black hull stood out in stark relief against the deep blue of the calm lake in which the ship now floated. Beyond the lake, stretching to the horizon in every direction, was the stark white of the permanent polar ice pack. The officer who had climbed to the bridge with Calvert called the skipper’s attention to the port side of the ship. There a full grown polar bear was climbing slowly out of the water and up onto the ice.

    The date was 11 August 1958 and the Skate had just become the first submarine to surface at the North Pole.”

    Lesson: cite the original source.

  33. 183
    Hank Roberts says:

    Aside to Jim — just to be very clear:

    No submarine ever surfaced at the North Pole in the 1930s/1940s. No diesel submarine could go anywhere near that far under the ice.

    Where did you find that mistaken claim? It’s a bad source and should be flagged as unreliable.

    A few limited ventures under the edge of the ice were made with diesel subs:

    Note mentions of the ice when the Skate surfaced– as it says there, very thick and variable; the quote mentions ice at 10 feet and 60 feet below the surface, for example.

    Current conditions: “The overhead ice canopy, with ice keels that can reach as deep as 200-feet, adds another layer of operational complexity that submarines do not routinely encounter. Additionally, salinity differences throughout the Arctic Ocean present challenges to even the most experienced sonar operators.”

  34. 184

    Jim Steele,

    Polyakov and Johnson 2000; Polyakov et al. 2002….

    Exactly. Back at the end of the last century it was thought possible that natural variability was a key driver of the current phase of Arctic sea ice loss.

    Now, a decade on, nobody serious buys that.

    Bengtsson 2004 figure 1 shows that the pre 2000 warming is greater than that of the 1920s – 1930s. A co-author of that paper Ola Johanessen in a paper of which Bengtsson was a co-author “Arctic climate change: observed and modelled temperature and sea-ice variability.” (Tellus 2004) shows that whilst the 1940s warming doesn’t appear in all simulations the recent warming does. Hence whilst the recent warming is a forced response, the 1940s warming was likely mainly internal variability of the climate. They also find that “the warming trend for the last 20 yr is more widespread and has a markedly different pattern from the earlier periods [1920s-30s] in both winter and summer.”

    They conclude that “anthropogenic forcing is the dominant cause of the recent pronounced warming in the Arctic.”

    Really this game of trying to pretend that the changes in the Arctic are natural, or commonplace in human history is very boring and unproductive.

    Patrick Lockerby nicely debunks a lot of this rubbish about past ice and the USS Skate in this post:

  35. 185
    Hank Roberts says:


    US submarines are being chartered for commercial operations under the ice.

    — petroleum companies? Who else?

    A Canadian blogger writes:

    “The United States, in particular, denies that the waters separating Canada’s Arctic Islands belong to our country. Because they want to ship through those narrow straits, and would like to drill for the oil and gas …, the US maintains the waters are international and open to anyone.

    Increasingly, the US is trying to find work for its multi-billion dollar fleet of strategic submarines. Four Ohio-class ballistic missile boats have been converted over to support special opeerations.

    … US Navy submarines routinely carry researchers involved in private projects sponsored by academics and corporations. It is probable that – if they aren’t doing it already – the American Navy will use some of their underultized submarines to explore beneath the Arctic ice for minerals and energy deposits.

    That would be the first step in a concerted effort to dispute our claim to the Arctic waters…..”

    There’s the data the climatologists need — being collected no doubt under nondisclosure proprietary programs.

    Stupid, stupid, stupid.

    Your tax dollars at work for corporate profit.

  36. 186
    Hank Roberts says:

    The same blogger on the same page points out that there’s an inexpensive alternative for operating under the ice now:

    “Germany, Sweden and China are all having good success with a new technology, called Air Independent Propulsion (AIP) for diesel-electric submarines. It eliminates the traditional weakness of the time-proven diesel submarine design – which requires the boat to either surface or use a “snorkel” to vent fumes and draw in fresh air when the diesel engine is employed to operate the sub or to charge its batteries.

    Diesel electric subs are quieter than their nuclear counterparts, because pumps are required to continually move water through the boat’s nuclear reactor to cool it. A diesel-electric sub simply runs on batteries. Solve the recharging problem, and you have an undetectable submarine for a fraction of the price of a nuclear boat.

    How good are they? The US Navy leased a Swedish boat, the Gotland, and its crew back in 2005 ( to try to determine if it could successfully fight this new technology.

    It wasn’t an idle gesture. The same year, a Chinese AIP submarine surfaced in the wake of the American aircraft carrier John F. Kennedy in the Sea of Japan. The crew of the Kennedy had no idea it was there until it was spotted by the pilot of a landing F-18 jet.

    Had the Chinese sub had hostile intent, the Navy knew, super-carrier would have been lost.

    The Swedish sub exercised with the US Navy off San Diego for 24 months ( While the results have never been released, sailors who were involved in the exercises were quoted as saying that the Americans were never able to hear the Gotland, despite operating the most sophisticated sonar systems in the world.

    The AIP subs can stay submerged and operating for three to five weeks, while traditional diesel electric like the Victoria-class boats in the Canadian Navy, have to come up to breath every 20 to 24 hours…..”

  37. 187

    #177–Jim, are you suggesting (in light of my links which show observers charting ice in the Arctic in 1934 and in 1953) that it’s even remotely plausible that it was ice-free and not one observer mentioned that fact?

    Ice retreat, possibly, though to present-day levels is most unlikely.

    Ice-free, no way.

    As to ‘submarine pictures,’ don’t even bother. Large leads can and do form at any time in the pack ice, and sub commanders consistently use them (if they can find them) in preference to busting through the ice with their conning towers. And as far as I know, all extent ‘sub pictures’ date from late in the 1950s, after the years in question, anyway.

  38. 188
    dhogaza says:

    Jim Steele:

    Indeed, there is no way to truly compare ice coverage during the 1930′s to 40′s but the source of that speculation was pictures taken from submarines that surfaced at the north pole with considerable open waters.

    What was the name of that submarine that surfaced at the North Pole in 1934?

    I’m having trouble remembering … please help me out …

    And while you’re at it, the name of the sub that surfaced there in 1953?

    Those are the two dates mentioned by Andrew.

    I don’t think there is enough data to say such conclusions are justified or to dismiss as “remarkably implausible” but the temperatures in the Arctic during that time were remarkably similar to this current period and the subject of several peer reviewed papers.

    Now, moving on to 1958 …

    1. The Skate never surfaced at the north pole, despite Watts’ claims to the contrary.

    2. Plenty of ice when she surfaced this time, in 1959

    3. Hey, look, scattering the ashes of Sir Hubert Wilkins! They’re not swimming! They’re walking on the missing sea ice!

    4. Of course, subs do search for leads in the ice, and surface in them at times, rather than bash through. The existence of these leads aren’t a sign of the arctic ocean being “ice free”.

  39. 189
    Susan Anderson says:

    Jim Steele @~177 provides a reference that asserts extreme warming from 1910 to 1940 and

    the ongoing present warming has just reached the peak value of the 1940s

    I thought this might be misleading so did a little armchair amateur search. On the whole, the conversation about melting has been about the years since 1979 when we have more complete and accurate measurements, but I don’t think one can support the above assertion unless you work hard to exclude any inconvenient data. Although recent acceleration takes a while to be incorporated in the records, even without it this is not correct. The graph I found (ACIA*) appears to be cut off at about 2003 which makes it slightly favor what is IMNHSO a false assertion, but even so it doesn’t look that way if one uses unbiased eyes.

    If you look only at single years and hide your eyes from the clumps of data, and ignore the last ten years, you can almost support that assertion. But it takes an effort to ignore the surrounding information.

    *An international project of the Arctic Council and the International Arctic Science Committee (IASC), to evaluate and synthesize knowledge on climate variability, climate change, and increased ultraviolet radiation and their consequences. The results of the assessment were released at the ACIA International Scientific Symposium held in Reykjavik, Iceland in November 2004.

  40. 190
    Susan Anderson says:

    As the publications cited were from the early oughts, it might also be appropriate to note that the Arctic warming picture has passed from a less noticeable trend supporting the strong theory supporting warming to obvious with a strong signal in the last 8-10 years.

    — (these dashes denote change of focus)

    Kevin McKinney@~174, thanks for all the heavy lifting on observations, useful for reality-based community in yet another knuckle-dragging skirmish. Every little thing seems to be used to stoke the fires of the hide your eyes contingent, but we can hope a thoughtful reader or two will take note of this information.

    About that 4% increase in water vapor, it’s been around for a while (Trenberth) but I’m wondering if there isn’t now a bit more? Hasn’t it grown?

    Chris Dudley@~163 voices the question we must all be asking – there must be some better ways to quantify how off the wall things are becoming.

    Of course, we all must realize that absent something we don’t all know about (or the methane shock troops being right, which the science does not appear to support; while faintly agreeing that increased methane can’t be good it appears the more knowledgeable sorts are saying the quantities are out of whack for going all shock-horror on it just yet, while other problems multiply and are bad enough without giving ourselves nightmares), the weather is going to return to something more like normal in the next couple of years.

    I don’t know how Dr. Hansen nailed it when he said that 2012 was going to be really bad, but it sure is looking that way.
    captcha: religious leceduc which I nominate “lord luv a duck”

  41. 191
    Hank Roberts says:

    PS for Jim Steele, there’s a correction in comments at that Navy page. I don’t vouch for the facts either way, but note this too:

    “Graham P Davis says: (October 30th, 2011)

    USS Skate did indeed surface at the North Pole but not until 17 March 1959. Ice conditions in August 1958 were too heavy at the Pole for the Skate to surface, as they were for the Nautilus some days earlier. The Skate did surface in several other leads and polynya that August, including one near Ice-station Alfa. The above picture may have been from one of those.

    When the Skate sailed for the Arctic the following year, the sail had been strengthened to allow it to break through thin ice. At the Pole, they eventually found a small, refrozen lead, or skylight, and managed to break through it. Later, many of the crew gathered for a service at which the ashes of Sir Hubert Wilkins were sprinkled in the wind. The temperature during this service was -26F (-32C).”

  42. 192
    Hank Roberts says:

    So, Jim Steele — tell us where you found the erroneous info about the submarines at the North Pole? No doubt they will getting corrections and the citation. I see the link to the quotes I posted above didn’t get in, they are from:
    Remember to read both the article and the first comment correcting the info.

  43. 193
    dhogaza says:

    Hank Roberts:

    USS Skate did indeed surface at the North Pole but not until 17 March 1959.

    Yes, my link in my post above shows a photo of the ash scattering ceremony referenced in your quote.

    Looks awfully cold and there’s lots of ice and no open water, just as your quote suggests.

  44. 194

    #188–Thanks, Susan, but the “lifting” wasn’t very heavy; maybe 15 minutes, most of which was writing the summaries. Should have taken 15’30”; then I wouldn’t have had 2 points labeled #3…

  45. 195
    Hank Roberts says:

    > Skate


    With just two links–to the Navy page and to the photograph of the event–this can be corrected. Jim, please, tell us you’ve told whoever misinformed you?

    Geez, I bet the Navy has scanned in those pen-and-ink tracings from their ice depth finder, which would give a profile of ice depth all along the cruises.

    Memo: avoid Google for searches if you want facts; they give you a result based on what you have looked for or gone to read in the past — distorted.

    This search engine says they don’t “personalize” or track your results, so you ought to see the same thing everyone else does (on a given day anyhow):

    “… This data set includes submarine data collected in the Arctic Ocean by U.S. Navy and Royal Navy submarines. U.S. Navy guidance has stated that previously classified, submarine-collected ice draft data may be declassified and released according to set guidelines. Those guidelines include restrictions stating that positions of the data must be rounded to the nearest 5 minutes of latitude and longitude, and date is to be rounded to the nearest third of a month. The guidelines also specify a region in which the data may be released. The Chief of Naval Operations has expanded the release area beyond the original “Gore Box” (so called because of Vice President Gore’s advocacy for releasing the data). See the map …”

    “… Kwok and Drew Rothrock of the University of Washington, Seattle, recently combined the high spatial coverage from satellites with a longer record from Cold War submarines to piece together a history of ice thickness that spans close to 50 years.

    Analysis of the new record shows that since a peak in 1980, sea ice thickness has declined 53 percent. “It’s an astonishing number,” Kwok said. The study, published online August 6 in Geophysical Research Letters, shows that the current thinning of Arctic sea ice has actually been going on for quite some time….”

    “Ice Draft from Upward-Looking Sonar
    101 data points, each a 50-km average. Profile data in archive. … basic measurement Hx,t,l comes from the upward-looking sonar and is the ice thickness … Wensnahan (2007), ‘The Accuracy of Sea-Ice Drafts Measured from U. S. Navy …”

    And a reminder that the best equipment the world has ever known for navigation under the ice can still be off by a bit, when checked:

    “… After the 180-mile sprint was complete, we found a surfaceable feature and punched through. The moment of truth had come. The GPS fix indicated that we were on the exact latitude line the quartermasters had calculated by the hand DR, but the heading error placed us 145 nautical miles due east of that position! That was tough to swallow. In hindsight, I was happy enough just being on the right chart. The Mk-19 Gyro was re-started and provided the heading reference …. Eighteen hours later, we were underway with three separate heading sources working well.

    We completed our transit of the North Pole while the embarked scientific team accomplished their own goals, dropping 77 under-ice conductivity-temperature-depth probes along our track for collecting data. With the excitement of the scientific mission behind us, the only obstacle remaining was the Bering Strait passage, which would entail traveling submerged 1,000 miles inside the 100-fathom curve with ice pack overhead….

    … Will we ever enjoy the same success we had with the Sturgeon class again, or are we retiring our one true under-ice capability for good?”

  46. 196
    Susan Anderson says:

    Hmm, the point in my overlong sentence was meant to be, that in the normal course of events, 2012 will become another year out of whack with the trend, just like 1998, unless something we don’t know about is under way.

    The normal thermostat for identifying the unusual is likely to be adjusted upward. In the midst of all this, the truth remains our only hope. The truth, and a lot of it. It is tempting and even possibly true to say that this is what the beginning of a tipping point might look like, but premature to insist.

    The stoking of fear has been a weapon of cultists since the beginning. It doesn’t work to join the forces of darkness. The truth is defenseless but unchangeable; one can hope it will prevail in the face of tawdry exploitation.

  47. 197
    Paul Beckwith says:

    @Gavin, #160

    I would rather “hand wave” and be correct rather than “mechanistic” or “statistical” and be wrong. Many scientists are like chess pieces on a chessboard, their knowledge and worldview is based on the given square that they occupy and the squares that they can legally move to.

    I would rather be the chess master that sees the pattern amongst all the pieces, consider the strategy and tactics that the whole board and the entirety of pieces dictates,and projects where the game is headed and what the other player Earth is liable to do,as opposed to being one of the pieces myself. Calling the player a “hand waver” because they are not a chess piece is just silly…

    I do not have time now to post a detailed defense of my previous postings with peer-reviewed support until early next week when I fire my next salvo of torpedoes at the erroneous hope that the sea-ice will be around like the models claim. I hope that everybody enjoys Earth Day, and contemplates a world this decade with no Arctic sea-ice.

    [Response: You (and indeed anyone else) is entitled to hold any unsubstantiated view you like. However, if you want to claim that opinion is scientific, there is a higher bar. And if you want to convince other scientists that you are correct, there is an even more work to do. It is not because people are prejudiced against new ideas that this is needed, but rather it is to distinguish strongly held opinions (of which there are many) from scientifically supported theories (of which there are few). If you reject the discipline that this forces on you as being somehow not relevant to your particular point, then you end up sounding like any number of homeopaths, astrologers and assorted cranks. That is not the way to win citations and influence scientists. – gavin]

  48. 198
    dhogaza says:


    With just two links–to the Navy page and to the photograph of the event–this can be corrected. Jim, please, tell us you’ve told whoever misinformed you?

    Well, WUWT has been pushing this meme for years, and denying any attempts to point out his misrepresentation.

    Is this Jim’s source, or just his source’s source? Not sure. But I’m quite sure that WUWT has been the main source of these lies.

  49. 199
    dhogaza says:

    And, of course, I doubt Jim Steele will be back. These folks are typically drive-byes, and are not interested in learning facts. They’re convinced they’ve learned all there is to know at sites like WUWT. Facts won’t interfere with that, especially if they don’t revist and read them …

  50. 200
    Jim Steele says:

    I see my reply hasn’t been post, so on the off chance it was my mistake and not another blow to freedom of speech I repost:

    Wow, that was a bountiful counter-attack for something that was not the point of my post. I never tried to argue the extent of the ice and indeed only spoke the the “source of the speculation” was the submarine photos. Indeed all your replies simply support what I said, there is not enough data to argue how much ice was present at that time, so I give llittle weight to CO2 advocates or skeptics in this regard. Please try to keep to the points and not create straw dogs to attack using my name. Again I wrote “Indeed, there is no way to truly compare ice coverage during the 1930′s to 40′s but the source of that speculation was pictures taken from submarines that surfaced at the north pole with considerable open waters. I don’t think there is enough data to say such conclusions are justified or to dismiss as “remarkably implausible” but the temperatures in the Arctic during that time were remarkably similar to this current period and the subject of several peer reviewed papers.”

    My criticism of Gavin reply was simply that the temperatures at the time suggest it is not ‘highly implausible’, but because of the observed warming that it was certainly within the realm of possibility. Only Chris Reynolds reponsded with

    “A co-author of that paper Ola Johanessen in a paper of which Bengtsson was a co-author “Arctic climate change: observed and modelled temperature and sea-ice variability.” (Tellus 2004) shows that whilst the 1940s warming doesn’t appear in all simulations the recent warming does.’

    I’d like to suggest to you Chris that you look at Johannessen’s Fig 1 more carefully. When the model was run with natural variability it captured the 30’s polar warming but not the late 20th century warming. After adding CO2 in Fig 1b, it was too warm but after adding some arbitrary amount of sulfates in 1c they reduced the extreme heat and come closer to the 20th century warming. I find it amazing that they then claim that only after adding greenhouses gases can they replicate recent climate. For those who have not stuck their head in the sand, please notice that the natural warming of the 1930’s and 40’s was eliminated. The real scientific conclusion would be that their models failed to capture the recent and the past warming correctly, and when they approximate one they lose the other. Therefore the model is unreliable and does not faithfully represent reality.

    The warming of the 1930’s-40’s was natural, and whatever contribution of recent warming in the Arctic by CO2 is only trivial in that context.