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Cold winter in a world of warming?

Filed under: — rasmus @ 14 December 2010

Last June, during the International Polar Year conference, James Overland suggested that there are more cold and snowy winters to come. He argued that the exceptionally cold snowy 2009-2010 winter in Europe had a connection with the loss of sea-ice in the Arctic. The cold winters were associated with a persistent ‘blocking event’, bringing in cold air over Europe from the north and the east.

Last year’s cold winter over northern Europe was also associated with an extreme situation associated with the North Atlantic Oscillation (NAO), with the second lowest value for the NAO-index on record (see figure below).

I admit, last winter felt quite cold, but still it wasn’t so cold when put into longer historical perspective. This is because I remember the most recent winters more vividly than those of my childhood – which would be considered to be really frosty by today’s standards. But such recollections can be very subjective, and more objective measurements show that the winters in Europe have in general become warmer in the long run, as explained in the German blog called ‘Wissenlogs’. If there were no trend, then such a low NAO-index as last year’s would normally be associated with even colder conditions over Europe than those observed during the previous winter.

NAO-index for December-March

NAO-index for December-March, which the winter 2009-2010 being associated with the second lowest value on record.

In a more recent press-release, Vladimir Petoukhov and Vladimir Semenov, argue that Global Warming could cool down winter temperatures over Europe, and a reduced sea-ice extent could increase the chance of getting cold winters. Also they propose that cold winters are associated with the atmospheric circulation (see schematic below), and their press-release was based on a paper in Journal of Geophysical Research (JGR), which may seem to have a serendipitous timing with the cold spell over Europe during the last weeks. However, the original manuscript was submitted in november 2009 (before the statement made by James Overland) and accepted in May 2010. One could regard the paper more as a ‘prediction’ rather than an ‘explanation’.

Schematic illustration of proposed effect. Courtesy of PIK.

Although Petoukhov and Semenov’s findings sound plausible, I don’t think they are as straight-forward as they initially seem in terms of their implications for this winter either. For one thing, it is impossible to prove that one single event is due to a change in the long-term, as we pointed out for the case of hurricanes (The 2010 hurricane season this year, by the way, was quite active).

I think it is important to keep in mind that the Petoukhov and Semenov study is based on a global atmosphere model that simulated a non-linear response to the loss of sea-ice in the Barents-Kara seas: initially warm winters, followed by cold, and then warm winters, as the sea-ice extent is gradually reduced.

NCEP/NCAR reanalysis: surface temperature anomaly wrt 1961-1990.

One interesting question is how the Barents-Kara sea-ice affects the winter temperatures over the northern continents. By removing the sea-ice, the atmosphere above feels a stronger heating from the ocean, resulting in anomalous warm conditions over the Barent-Kara seas. The local warming gives rise to altered temperature profiles (temperature gradients) along the vertical and horizontal dimensions.

Changes in the temperature profiles, in turn, affect the circulation, triggering a development of a local blocking structure when the sea-ice extent is reduced from 80% to 40%. But Petoukhov and Semenov also found that it brings a different response when the sea-ice is reduced from 100% to 80% or from 40% to1%, and hence a non-linear response. The most intriguing side to this study was the changing character of the atmospheric response to the sea-ice reduction: from a local cyclonic to anti-cyclonic, and back to cyclonic pattern again. These cyclonic and anti-cyclonic patterns bear some resemblance to the positive and negative NAO phases.

Sea-ice over Hudson Bay

They also show a different response in surface air temperature (SAT) during December, January, and February. From their Figure 2, it is not immediately obvious from that figure that a sea-ice reduction leads to lower SAT during January. This is, however, very much in line with similar analysis that I have carried out with colleagues and struggled to find a consistent response (albeit we looked at the summer season).

But Petoukhov and Semenov provide theoretical support for their observations, and argue that the non-linear response can be explained in terms of ‘convectional-frictional’ and ‘baro-clinic-frictional’ mechanisms. The former includes warming over the areas where sea-ice disappear, and changes in the vertical temperature gradients, stability, and hence friction, while the latter involves a change in the surface friction force associated with temperature changes over distances.

I think that the scientific community will need some time to confirm this link, and there are some
important caveats: For one thing, the spatial model resolution (the size between the boxes in the grid mesh, through which the models represent the world) has an influence on their ability to represent blocking frequency. Hazeleger et al. Has observed that “… different horizontal resolutions … confirm the resolution-dependence found in NWP [Numerical Weather Prediction]”. The atmospheric model used by Petoukhov and Semenov has a fairly coarse spatial resolution (2.8 degrees x2.8 degrees), and it is legitimate to question whether it can reproduce the
frequencies of blocking events realistically, and whether that has a bearing for the conclusions.

But also the fact that the sea-surface temperatures (SSTs) were fixed in these experiments may affect the conclusions. Balmaseda et al. found that the atmospheric response to changes in sea-ice conditions may depend on the background SSTs, at least for the summer months. They also compared results from a coupled ocean-atmosphere model with the results from an atmosphere model for which the SSTs were given. Their unexpected finding was that the atmospheric response in these two cases were very different.

In fact, global atmospheric and climate models are better at describing the large picture than more regional and local characteristics. There is a limit to what they are able to describe in terms of local regional details, and it it reasonable to ask whether the response to changes in regional sea-ice cover is beyond the limitation of the global model. If different models give different answers, then it is likely that the response is not robust.

Another interesting question is whether the sea-ice the is whole story. Not long ago, there were some suggestions of a link between low solar activity and cold winters (this correlation, however, is so weak that you would never notice without statistical analysis. Also see comment here). Do these factors affect the circulation patterns over the North Atlantic? The sunspots tend to vary on a time scale of 10-12 years, but the NAO-index suggests that few of the extreme low values were repeated over two subsequent years. In other words, the NAO doesn’t show the same persistence as the sunspots. It will be interesting to see if this winter will break with previous patterns – if it does, that could be interpreted as a support of Petoukhov and Semenov hypothesis.

It is nevertheless no contradiction between a global warming and cold winters in regions like Europe. Rather, recent analysis suggest that the global mean temperature is marching towards higher values (see figure below), and Petoukhov and Semenov argue that the cold winter should be an expected consequence of a global warming.

Global mean near-surface air temperature from NCEP/NCAR reanalysis. Reanalyses are often not regarded as reliable as more traditional analyses for long-term trends, but can nevertheless give some indication on where the last year lies in terms of the recent past.

618 Responses to “Cold winter in a world of warming?”

  1. 451
    Brian Dodge says:

    I can’t help but notice that Theon spoke out in January 2009, following Obama’s election in 2008, following Theon’s “recent” retirement from NASA in 1994, about James Hansen’s 1988 statements to Congress which he considered “embarrassing” to NASA.

    What took him so long? Politics, maybe?

    According to Tony Hake, Denver Weather Examiner, at the 2009 Heartland Conference Dr. Theon said that he would have liked to have fired Hansen during his tenure at NASA but was thwarted by Hansen’s powerful political friends, including former vice president Al Gore. Theon said, “I have publicly said I thought Jim Hansen should be fired. But, my opinion doesn’t count much, particularly when he is empowered by people like the current President of the United States.”

    While working at NASA, Theon thought Hansen should be fired, but put politics ahead of doing what he thought was right, then kept quiet about it until “people like the current President of the United States” got elected.

  2. 452
    Septic Matthew says:

    444, Didactylos: I said you fail to understand the difference between weather forecasting and climate modelling.

    243, Ray Ladbury: Each run of a climate model is a single event–a realization of a single outcome influenced by random processes as well as those trends that make up climate science. In any one of those outcomes, the random processes may dwarf the climate signal and wind up hiding the trend. However, the random processes are short-term processes. That is precisely why climate restricts itself to multi-decadal timescales for evaluating trends. What you are asking for is weather prediction on 6 month timescales. That would be great, but it would have nothing to do with climate.

    It would be useful if you could show, that is if the climate modelers could show, along the way that the random processes in RL’s quote had 0 mean across the spatial and temporal distributions. This assertion of mine is not a “failure to understand” the distinction between weather and climate; it is an assertion that there is a potential for the short-term predictions, when they become accurate enough, to increase confidence in the long-term forecasts. Given that the climate system is inherently chaotic, as just about everyone has agreed to, there is no good reason to believe that the long-term prediction, being the average of the space-time distributions of the chaotic process, is accurate.

    Barton Paul Levenson has accumulated a record of modeling successes. The most important modeling success will be the first accurate 30 year forecast. Right now the long-term forecasts made about 10 years ago are running high, and there is little evidence that the apparent bias will not grow with time. I think that modelers should look to the short-term spatio-temporal errors for hints of where the long-term forecasts could be improved. If by 2030 no 30 year forecast is less than 2C too high on average (which now looks possible), then no one will believe AGW even if it is true.

    I acknowledge that it’s possible for the long-term forecast to be accurate enough despite inaccuracies in the weather forecasts, as outlined by Ray Bradbury, but that has not yet been demonstrated. It takes a great deal of belief to believe it.

  3. 453
    Hank Roberts says:

    “ge0050” has made the round of climate blogs recently, posting (often off topic) disbelief-from-incredulity statements in whatever thread was open, usually ending up with a reasonable-sounding question easily answered by looking at the FAQs here, or at SkepticalScience, or with a bit more effort by pasting it into Google Scholar, or by reading Spencer Weart’s history.

    I think “geo0050” has played a full round of Talking Point Climate Blog Bingo.

  4. 454
    Charles says:

    ge0050@ 440:

    “So, I went looking for reports for scientists that met these criteria.”

    And you bring up an unsubstantiated quote from someone who has been retired for years and who doesn’t meet your own criteria? Gavin’s response to you was both appropriate and polite.

    Stop while you are ahead; you are fast making a complete fool of yourself.

  5. 455

    ge0050 (and others) may be interested in the Clear Code initiative; here’s a link to their post on the station drop out issue:

  6. 456
    JCH says:

    Just curious, but if ge0050 looks at ccc-gistemp, or reads Steven Mosher’s blog, will what he find meet his “criteria”?

  7. 457
    Cheng Chin Hsien says:

    Dear Dr Gavin,

    I just wrote down my understanding on the extremely cold winter. Understanding that you are quite busy, I will be very appreciate if you could read through and give some short comment. Thank you and Happy 2011!

    The Global Warming Driven Extremely Cold Winter: the Pull and the Push to North Wind

    Let’s start from Dr. Judah Cohen’s recent hypothesis. With the impact of global warming and more water vapor accumulated in atmosphere over the summer, the very wet air has to condense more water vapor in fall and winter. The Siberia, with mountains like Himalaya, Tianshan, Altai blocking the air flow, the heavily accumulated water vapor hence start turning into snow since fall season. The large quantity water vapor allows long lasting precipitation into snow in Siberia, and lowers down the local pressure there. A lower atmospheric pressure in Siberia hence pulls the cold north wind from Arctic. With the cold wind comes but blocked, to balance the energy, the Siberia’s getting colder with more snow accumulated. As the north wind come to Siberia, it has to go elsewhere like the Europe and even US east this winter. In fact, this logic applies not only in Siberia; it should apply to all regions in mid-latitude with enriched water vapor. The water vapor condensation is the process creating lower pressure – the pulling force to north wind. On the other hand, the pushing force however is not illustrated in Judah’s hypothesis.

    Other than Judah’s prediction, Dr. Vladimir Petoukhov also tried to link the observation of the decrease in Arctic ice extent to a stronger north wind. It is definitely an inspiring observation, although I am not very sure if my understanding is same as his hypothesis. The below is my description. Since the driving force of wind is mainly the water vapor condensation, the north wind will not be that strong if there is also strong condensation in Arctic. The decrease in Arctic ice extent is actually a decrease in heat insulation between the surface seawater and the cold Arctic atmosphere. As a result, with a lower Arctic ice extent in summer, usually there will be a faster recovery of ice-extent in late autumn and winter (although it is faster, it is still unable to reach the extent before global warming). The faster freezing of seawater into ice means a faster release of heat from the sea to the atmosphere. It therefore lowers down the need for water vapor to release its heat, i.e. lowers down the precipitation in Arctic. Since the heavy cold air is difficult to get rid of its water vapor, its air pressure remains high and therefore has to flow somewhere else – the lower latitude. This is the pushing force to north wind from the Arctic.

    If the logic here is correct, with the combination of the pull and the push, both driven by global warming, we can anticipate the winter north wind getting stronger in coming years. In other words, such freezing winter will become worse until the north wind is not that cold (yes global warming again).

    Last but not the least; I have a good suggestion to deal with this. The government or green companies should set up more on wind turbine at suitable locations. By utilizing the north wind for power generation, we will also weaken the strong north wind. In turn we save lives from suffering the extreme coldness, and save economic cost to deal with heavy snow, and also save the energy consumption for heating up the city. Oooops, isn’t it wonderful?

  8. 458
    john byatt says:

    David Karioly on the ABC news in Australia this evening

  9. 459

    From my vantage point I basically think we are overwhelmed by ignorance.
    Its bad, really bad, many blogs, “newspapers”. radio commentators talk about the new ice age… Standing in the Arctic when just the opposite is happening, is quite disturbing. I read even here some of the usual “points of confusion” dedicated to discourage a rational explanation because the critic is stubborn beyond a reasonable discourse to understand the very basic tenets of AGW, despite astounding evidence of otherwise:

    Hudson Bay is open by 500,000 square kilometers compared to a once upon a time
    average year.

    even compared to 1998:

    warmer 2005

    and warmest in NH 2007

    During La-Nina With Hudson strait is wide open!

    OK contrarians, is this the beginning of an ice age???? And or those arguably
    not so keen on understanding that weather is not a regional event, but a world wide
    phenomena. When Northern Europe gets cold, while the Canadian Arctic becomes very warm, is there a connection? Common sense dictates that some of the North Atlantic warm air flow was diverted to the low sun Arctic while the Arctic air mass was readily shared with Northern Europe. it is that simple. The process of which creates this in a steady way is of huge interest and was greater in size than 500,000 square Kilometers. Big enough?

    The subject of AGW is way more serious than an argument to have fun with, or a political cause to take a side with, its misunderstood by disinformation on a grand scale designed to replace reason with an agenda far away from it.

  10. 460
    Ray Ladbury says:

    Septic Matthew,
    Do you have a 401K or other retirement money in stocks? Is your decision to keep you money in the fund/stock contingent on the ability of analysts to predict the closing price of the stock on a date certain?

    Dude, You may contend that your demand is not predicated on your failure to understand the difference between climate and weather. You are wrong.

  11. 461
    Didactylos says:

    Oh, I see, Septic Matthew. It’s not that you know less about these things than climate scientists (and the average person who stays informed) but that you know more than the climate scientists.

    Do let us know when you publish your results.

    As for your fundamental misunderstanding that chaotic systems can’t display order at other scales – well, that’s just plain wrong. There are countless examples. Take the N Body Problem, for example. There is no way we can accurately work out the orbits of all the many bodies in the solar system. But for the bigger objects, our approximation is excellent. The calculation is trivial, even, for a first approximation.

    The same principle applies to fluid mechanics, and any number of other fields or natural processes. And in the case of fluid mechanics, the way we solve the problem is much the same as climate science.

    Oh, and absolutely nobody is under the delusion that models can’t be improved, so do please stop harping on about that.

  12. 462
    Didactylos says:

    Rod B: You accuse me of hyperbole.

    I did think long and hard, searching for other examples. I also admittedly limited my search to comparable endeavours: attempts to create an empirical data series.

    What else meets my description? What other data series has been scrutinised by government after government, been subject of report after report, and consists of half a dozen independent analyses from two completely independent data sources?

    I know what you’re thinking. The hockey stick! Yes, that has been subject to equally ludicrous over-examination, and has also come out well. But the hockey stick has quite large inherent uncertainties, unlike the modern global temperature record.

    What other scientific observations have been scrutinised like this? Perhaps some in medicine come close, particularly with respect to lung cancer. But I didn’t really count those as being comparable, since it is a problem of attribution not simple measurement.

    Can you think of anything comparable?

  13. 463
    Septic Matthew says:

    from the main text: In fact, global atmospheric and climate models are better at describing the large picture than more regional and local characteristics. There is a limit to what they are able to describe in terms of local regional details, and it it reasonable to ask whether the response to changes in regional sea-ice cover is beyond the limitation of the global model.

    It is reasonable to suggest, in paraphrase, that the response to changes in regional sea-ice cover will not always be beyond the limitation of the global model. Inferentially, from their comments, others here do not believe it is reasonable to ask whether the response to changes in sea ice cover is beyond the limitation of the global model — they already know it is and will be.

    460, Ray Ladbury: Do you have a 401K or other retirement money in stocks? Is your decision to keep you money in the fund/stock contingent on the ability of analysts to predict the closing price of the stock on a date certain?

    I allot my meager savings to mutual funds who have at least a 10 year history and did least poorly in the last 2 major financial panics. It is a poor analogy to predicting weather or climate because no physical principles are involved. My strategy would be analogous to backing the climate model that was least bad in 1997, 1998, and 1999. But in investing, the regional effects are key.

    From the main text: Rather, recent analysis suggest that the global mean temperature is marching towards higher values (see figure below), and Petoukhov and Semenov argue that the cold winter should be an expected consequence of a global warming.

    I also wrote that cold winters should be expected from global warming, using the analogy of the wind/ocean wave interface and phenomena of other nonlinear dissipative systems. What about cold summers, as currently experienced in Antarctica? Curry’s model predicted that global warming would produce increased snow accumulation in Antarctica, a regional effect; we should hope for a model that predicts with reasonable accuracy when Antarctica will experience unusually cool summers, analogous to the Petoukhov and Semenov expectation about the cold winter.

  14. 464
    Septic Matthew says:

    461, Didactylos: Oh, I see, Septic Matthew. It’s not that you know less about these things than climate scientists (and the average person who stays informed) but that you know more than the climate scientists.

    That’s a poor paraphrase of my text.

  15. 465
    Septic Matthew says:

    a small joke: 11 inches of rain, more or less, fell on San Diego this Christmas season, and comparable amounts fell elsewhere in CA. Heavy rainfall at Christmastime was called “el Ninyo” (forgive me, I do not have enya), after the Christ Child. El Ninyo was taken as the name in ENSO; alternating low rainfall years are called “la Ninya”. This is a strong “la Ninya” year by the multivariate ENSO index, but we had a strong “el Ninyo” anyway.

  16. 466
    Hank Roberts says:

    > anyway

    Consider the possibility that changes beget changes:

    “The weather pattern known as El Niño, which can bring heavy rains to Southern California, has doubled in intensity and warmth and shifted westward over several decades, according to scientists from the Jet Propulsion Laboratory and the National Oceanic and Atmospheric Administration.

    JPL oceanographer Tong Lee, an author of the paper, said …. “El Niño is the largest fluctuation of the climate system. It has worldwide impact on climate patterns, so any change in El Niño’s behavior might cause a change in its impact.”

    Lee suggested that the findings revealed “two competing effects. Shifting El Niño’s location could mean less rainfall” in Southern California, he said. Still, “since it is getting stronger, we may get more rainfall. How these two effects play out is something that needs to be investigated.” The study, he said, “documents the change of a major climate system, but I cannot tell you the impact.”

    Bill Patzert, a JPL climatologist who was not involved in the paper, said three decades were too short a time period to draw conclusions. But, he added, “This is another piece of evidence that the climate is shifting. It is clear that in the last century the planet has warmed by almost two degrees Fahrenheit. More than 80% of that is taken up by oceans. Oceans are the canary in the coal mine.”

    Patzert said the paper was observational rather than conclusive. “What will happen if this new type of El Niño becomes permanent? Will it give us wetter or dryer El Niños?” he said. “It is too early to tell. The one thing we know is that the future ain’t what it used to be. The planet is definitely warming, and El Niño has morphed into something different.”

    That was last August, of course. We don’t know enough more now to say much more; one data point, one season added to the record.

  17. 467
    Philip M. Cohen says:

    @364 shooshman, BS
    My research has in fact indicated however that the poles are growing.

    I’ve been following RC for about four years and I don’t recall any other poster who established his trolling credentials so quickly and definitively. I’m embarrassed to see how many people are using a sledgehammer to crush this tsetse fly, no doubt providing it with a lot of laughs.

    Open debate is one thing, sabotage is another. At @364, if not earlier, the response should have been something like ‘Your assertions are preposterous even for a denialist. You don’t even have the excuse of ignorantly parroting other denialists. You are a liar and a troll, and since you have no respect for this site or for rational debate, your comments will henceforth be removed immediately until you offer evidence for them.’ The usual denialists around here at least try to look reasonable. The blogosphere will of course produce a pile of accusations of censorship, but it claims that all climatologists except a favored dozen or so are lying money-grubbers, so one more piece of nonsense will make no difference. And you can always quote the BSer at the accusers.

  18. 468
    Septic Matthew says:

    466, Hank Roberts: Consider the possibility that changes beget changes:

    Good comment. What’s happened is that “El Niño” in this context no longer has anything to do with the Christ Child after whom it was named. It amused me because we had so much rain at Christmas time.

  19. 469
    JiminMpls says:

    Re: Inhofe/Theon and other fossilist conspirators…

    When is somebody going to hack into THEIR email server and make their corespondence public? Is it only former KGB operatives capable of such an act? How bout some of the Wikileaks supporters?

  20. 470
    Slioch says:

    One issue puzzles me concerning Petoukhov and Semenov’s findings and I haven’t been able to find any reference to it in the above article or comments, but my apologies if I have missed it. (I also appreciate that if I understood more of what they were saying there would probably be more things that puzzled me!)

    The puzzle is this: As I understand it, the suggestion is that open water in the Barents and Kara Sea areas allows anomalously high amounts of heat and water vapour to be released to the atmosphere above compared to ‘normal’ conditions when the seas are frozen. Addition of heat and water vapour both reduce the density of air and would therefore be expected (by me, at least) to produce an area of LOW pressure in the vicinity. How is it that it produces the opposite – an anticyclonic high pressure area?

    I also appreciate that the above relates to the medium position with respect to sea-ice and that the model suggest both more and less sea-ice than this would produce low-pressure cyclonic conditions. But that just deepens my puzzlement.

    I also note the caveats – ‘non-linear’ and ‘unexpected’ and so on. Perhaps I am hoping for a simple explanation where none exists.

  21. 471
    Didactylos says:

    JiminMpls: Think carefully about your ethical position before wandering down that road.

    Personally, I believe whistle-blowing to be not only a right, but a duty. I also consider stealing private information to be a crime. Clearly there is some conflict there, and a rather large gray area.

    This is why there usually exists legal protection for whistle-blowers. Unfortunately, such protection does not usually extend to the armed forces.

    Fishing expeditions are another thing again. Most jurisdictions do not allow trawling for information to use against someone or something. Doing it by means of hacking just adds another crime to an indefensible action.

    Remember also, that there have already been leaked denier documents. They show exactly what we expect to see: fossil fuel companies were aware of the reality of global warming long ago, and the denial industry is unadulterated astroturf. But the leaking of those documents have changed very few minds. Deniers *already* believe it’s all a conspiracy – reason and evidence do not impinge on their world-view.

  22. 472
    Septic Matthew says:

    Another relevant example is a tsunami: the first evidence from land that it is about to hit is when the water recedes from the coastline; the farther it recedes initially, the higher inland will be the resultant surge. Increased energy in the wave increases both extremes, the recedence from the shore and the surge inland.

    Cold winters in a warming climate are to be expected because increased troughs and peaks with increased total input are general phenomena of nonlinear dissipative systems. Most readers here already accept that AGW predicts more extreme floods and droughts, and the same may be true with respect to temperature as water: more extremes of hot and cold.

  23. 473
    JiminMpls says:

    #471 Didact – Of course you are right on all counts.

  24. 474
    Esop says:

    As I predicted a few weeks back, the weather here in Norway flipped from very cold to rain and well above 0C (32F) right at New Years. The long term forecast is back to rather cold again, though. Will be most interesting to see how it develops from around January 10th.
    The mild weather coincides with a cold period in the Barents Sea (Bjørnøya at 75 degs latitude). They have been way warm until now, and are getting warm again when lower latitudes are scheduled to cool down again in 3-4 days. These temperatures (75 degs vs 60degs latitude in northern Europe) have been in opposite phases since December 09, so there is a definite oscillation going on. A quick look at the 8 day forecast for this remote island in the Barents sea, and I know the temperature forecast for the next 8 days in central Scandinavia. Pretty fun. What is not so fun is that the circulation patterns will cause public support for climate action to continue dropping, ironically while thousands of square kilometers of Arctic sea ice is melting in early January.

    BTW: the new preview feature is great!

  25. 475
    John Pollack says:

    #470 Slioch I think you’re correct that the first order response of the atmosphere to a regional anomaly of warm water exposure would be to encourage low pressure in the area. However, the second-order effects invoked, an increase in convective and baroclinic friction, could be opposite, especially when other influences enter the balance. That’s why you need a coupled ocean-atmosphere model to begin to get a handle on it, and one model isn’t enough for a robust conclusion, as noted in the original discussion.

    Overall, I don’t think the situation so far this winter is a good match for the Petoukhov and Semenov scenario, anyway. For one thing, the ice cover in the Barents Sea region isn’t especially anomalous. Instead the big anomalies are over the Pacific and eastern Atlantic sectors:

    Possibly in response, a hemispheric pattern has evolved with anomalous blocking in the NAO sector, but also in the Pacific sector, shown by huge positive monthly anomalies at 500hPa:

    South of the blocking, there is a somewhat broken annulus of lowered heights at mid latitudes, bringing more storminess and cold air incursions further south that usual. The cold generally not that extreme by historical standards, since the arctic air it draws upon is not nearly as cold as it can get.

  26. 476
    Slioch says:

    re #475 Thanks John. Yes, it seems I’m looking for a simple mechanism where none exists.
    BTW Hansen, (posted 11th December and mainly referring to November in Europe) suggests it may be due to anomalous lack of ice cover over Hudson and Baffin Bays:

  27. 477
    Bill says:

    on Dec 31st 2010, we seem to be midway between record high and low on the Aqua ch5 :
    Just an observation…………………..

  28. 478
    Snapple says:

    Jim wrote:

    “Re: Inhofe/Theon and other fossilist conspirators…

    When is somebody going to hack into THEIR email server and make their corespondence public? Is it only former KGB operatives capable of such an act? How bout some of the Wikileaks supporters?”

    Forst of all, US denialists shamelessly quote Russian dubious Russian sources. It’s not a secret, so nobody writes about it. If it were a leaked “secret” that Inhofe, cuccinelli and others quote dubious sources, it would be a scandal.

    [edit – this is seriously OT]

  29. 479
    Septic Matthew says:

    Here are the NOAA 3-month mean forecasts through Sep 2011:

    Last updated today.

  30. 480
    Snapple says:

    [edit – OT]

  31. 481
  32. 482

    john byatt #481: the floods in Queensland are pretty bad but fortunately only hitting low population areas, so the number of people affected is in the thousands, not like in Pakistan where it was millions. Still, for people who’ve lost their homes and crops it’s pretty traumatic. Here in Brisbane, it’s just very wet, not a disaster.

    While this may well all be within limits of natural variability (despite various records being set), you’d expect the hydrological cycle to intensify with warming, so this sort of flooding should become more commonplace. Has anyone done a study of changes in incidence of floods and droughts related to climate change?

    Welcome back, my old friend, preview. Thanks, whoever got it working again.

  33. 483
    Chris R says:

    #479 Septic Matthew,

    On the owning page for the graphics you linked to it states:

    CAUTION: Seasonal climate anomalies shown here are not the official NCEP seasonal forecast outlooks. The NCEP seasonal forecast outlooks can be found at CPC website. Model based seasonal climate anomalies are one factor based on which NCEP seasonal forecast outlook is issued.

    The graphic you linked to is the 850mbar temperature forecast for ensemble 2. The 2m temperature is the one most relevant to people’s experience.

    The actual NCEP forecasts are here:

  34. 484
    Sou says:

    @ John Byatt #481 – The Daily Fail didn’t say if Capricornia is a newly created State in Australia or if it’s another country altogether. Has anyone told Prime Minister Gillard or Premier Bligh that we’ve lost our north eastern corner?

  35. 485
    Esop says:

    Seems that the new year has brought rather warm temperatures to England as well. Temperatures up to 10C in the 8 day forecast for London, that is way above normal (normal is less than 6C). If the mild temps last, I’m confident that the British MSM and the mayor of London are going to start quizzing Piers Corbyn et al. why the lack of sunspots and position of celestial bodies no longer turn Britain into a freezer, as this was predicted by these prophets to be persistent all winter.
    Looks like the MET office wasn’t that far off after all (although I would advise not to issue 3 month forecasts for the winter when the Arctic is in the current state of chaos). The Barents region is cold right now (-20C), but is forecast to warm drastically towards the end of the 8 day period with temps close to 0C, so that might mean that Arctic air will dump into Europe again pretty soon and could hit England and central Europe in about 2 weeks time.

  36. 486

    #482–Phillip, did you catch Dai 2010, which reviews studies of past (and future) drought extent?

    A PDF is available here:

  37. 487
    Dan H. says:


    The article does sum up long-term droughts fairly well. As you can see Phillip, recent droughts pale in comparison to the so-called mega-droughts experienced in previous centuries. Historically, it appears that recent precipitation is above average, but within natural variability. I have not seen a good documentation of recent flooding compared to historical accounts. Flooding can also be enhanced due to manmade changes in the landscape including, but not limited to, dams, dredging, drainage systems, and other developments which reduce the lands ability to absorb rainfall.

  38. 488
    Septic Matthew says:

    483, Chris R

    Thank you. The first of your 2 links is great, including hindcasts and skill assessments.

  39. 489
    Chris R says:

    #485 Esop,

    At the risk of turning RealClimate into RealWeather. ;)

    The AO is still negative:
    And forecast to remain so, possibly to go more negative. There’s a good relationship between low AO and cold weather in the UK caused by blocking; negative AO tends to mean the UK gets cold weather.

    #475 John Pollack,

    I don’t think that the issue is what sa-ice is doing now. It’s more what sea-ice was doing at the minima and the re-freeze season.

    Deser 2007 “The Transient Atmospheric Circulation Response to North Atlantic SST and Sea Ice Anomalies.” Finds that in response to sea-ice anomalies:

    Following the initial baroclinic stage of adjustment, the response becomes progressively more barotropic and increases in both spatial extent and magnitude. The equilibrium stage of adjustment is reached in 2–2.5 months, and is characterized by an equivalent barotropic structure that resembles the hemispheric NAO–NAM pattern, the model’s leading internal mode of circulation variability over the Northern Hemisphere. The maximum amplitude of the equilibrium response is approximately 2–3 times larger than that of the initial response. The equilibrium response is maintained primarily by nonlinear transient eddy fluxes of vorticity (and, to a lesser extent, heat), with diabatic heating making a limited contribution in the vicinity of the forcing.

    They find the the initial localised baroclinic response “reaches maximum amplitude in 5–10 days, and persists for 2–3 weeks.” But the major response is the barotropic one which reaching equilibrium after 2-2.5 months is able to carry the impact of sea ice anomalies over into the winter period. This is also shown by Francis 2009 “Winter Northern Hemisphere weather patterns remember summer Arctic sea-ice extent.” In that case using NCEP/NCAR reanalysis data.

    I am still trying to get to grips with the formation of the barotropic structure from the initial baroclinic. And the involvement of transient eddy fluxes in this.

  40. 490
    Septic Matthew says:

    Here are the NWS/NCEP T2m forecasts from NWS/NCEP made on Oct 13. It appears that the unusually cold N. European weather for December was indeed forecast.

    The claim in the main thread that cold winters ought to be expected seems especially pertinent if this cold N. European winter was indeed forecast (NWS/NCEP call it a forecast). The British Met forecast a warm winter in October — did they simply ignore the NWS/NCEP?

  41. 491
    Esop says:

    #489 (Chris R): True about the AO, but the NAO (which seems at least as important as the AO this winter) is forecast to go more positive in the coming weeks. Will be interesting to see.

    [Response: There is almost practical difference between the NAO and the AO in the Atlantic sector, so the forecast for one is as good as the forecast for the other. Not that this necessarily implies that the forecasts are particularly skillful. – gavin]

  42. 492
    dhogaza says:

    The Daily Fail didn’t say if Capricornia is a newly created State in Australia or if it’s another country altogether. Has anyone told Prime Minister Gillard or Premier Bligh that we’ve lost our north eastern corner?

    Capricornia and Ecotopia unite!

  43. 493
    Septic Matthew says:

    oops, correction to my 490; here are the forecasts from last October:

  44. 494
    jheath says:


    Can you help me please.

    I advise Governments and senior administrators in three countries on energy issues. How can I respond to their following persistent and increasing concerns?

    1. Global warming in the 2000s is well below what was predicted by the climate modellers and the IPCC despite the fact the CO2 levels are pretty much where they were predicted to be. This is evident in all the measures that I can find. Why should these Governments continue to take taxpayers’ or customers’ money to invest in unreliable wind power etc. when the correlation is now longer there between temperature and CO2 in the evidence?

    [Response: This question is based on a misconception. The trends in temperature are well within bounds of what was predicted. See this post from last year and imagine where the 2010 point comes in for the first figure. (We will update this in the near future). See also this post at Open Mind. – gavin]

    2. How can these Governments justify the higher energy costs and lower security of supply of wind power and solar when they could instead increase their use of natural gas which has become more abundantly available and increasingly economic? They are now much more reluctant to consider non-fossil options.

    [Response: This is not a climate science question. It is true that moving to natural gas from coal is undoubtedly beneicial in terms of CO2 emissions per unit of power generated. But in the long term, the only sustainable generation will be non-fossil. Security of supply can be enhanced by investments in smart grid technologies, extension of the grid to cover more regions, and better real-time forecasting of generation. The one missing issue in your question is that of efficiency – as Amory Lovin’s has often (and rightly) said, Nega-watts are much cheaper than Mega-watts. See also the McKenzie report. – gavin]

    What evidence can you give me to help move their positions? The cost of energy and the seciurity of supply is more important to them – unless better evidence is available. Each country (in 3 different continents – none in Europe) has experienced colder than expected weather in the last 4 months – which does not help.

  45. 495
    john byatt says:

    #492 “Capricornia and Ecotopia unite”

    Queensland has now regained control of the break-away province of Capricornia. The map has been exorcised from the Mail report after much ridicule and thigh slapping in the comments .

    now, about their Climate change reporting.

  46. 496
    Isotopolopolus says:


    Re: Flooding in Queensland’s inland basins.

    Maybe a change in nomenclature is in order. We could rename the “Bowan Basin” to the “Bowan Bathtab”

    >That way people will better understand the meaning of “Basin” with repect to hydrology.

  47. 497
    adelady says:

    @487 Dan H
    “other developments which reduce the lands ability to absorb rainfall.”

    At least for Queensland, the “other developments” affecting the land’s ability to absorb rainfall amount simply to lots of previous rainfall saturating the ground leaving no capacity to absorb any further moisture.

  48. 498
    David B. Benson says:

    jheath @494 — I strongly recommend considering nuclear power plants. There are many helpful threads on this and related topics on

    You may also find it useful to follow
    for some of the energy related topics and news.

  49. 499
    David B. Benson says:

    Philip Machanick @482 — Check the Munich Re and Swiss Re websites.

  50. 500
    Maya says:

    jheath, a short piece on the economics of wind-generated power: