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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. 151
    Patrick 027 says:

    Re 136 Eric Swanson From a conceptual point of view, saying that the Icelandic Low caused the storms to pass over Iceland is a bit of circular logic to me. In other words, it’s like saying that the atmospheric mass flows pushed the storms toward Iceland, which resulted in lower than average pressure as shown on weather maps, which caused the storms to be pulled toward Iceland. I think this is an incorrect point of view, the cause of the flow being higher pressure elsewhere, which is the result of the overall energy flow thru the atmosphere, especially the seasonal difference between the tropics and the polar regions in winter.

    I think I taylored my comment more to the general parts of your statement regarding the atmosphere not being in tension, etc. What can appear as circular logic may also be a case of positive feedback – I don’t know if that applies to the climatological Icelandic low. However, I’ve gotten the impression that it can be the case for storm track variability (it can be the case that the average flow affects propagation of waves so as to shape the wave energy and momentum transport to reinforce variations in the average flow), which in this case could involve variations in the Icelandic Low (?) – I’ll look at the link. I don’t see how it makes more sense to say that the higher pressures elsewhere are the cause any more than it makes sense to say that the Icelandic Low is the cause; for one thing, highs would not exist without lows (of course you can have well-defined low pressure systems without such highs but rather with a general higher pressure outside the systems, etc.); also, the storms will get moved around by the flow but also propagate through it – although, at least for the strengthening stage, there must be a critical level where the structure doesn’t propagate relative to the flow itself, but so far as I know that only applies to the direction along the storm track; anyway, below that level the air is actually flowing through the system from (for a zonally-aligned storm track) east to west, relative to the system, while above that level it is from west to east; there needn’t be a pressure gradient at the critical level; one could imagine a storm track with an easterly jet at the surface and a westerly jet aloft with a critical level where the average pressure gradient vanishes. The flow at the critical level requires motion of systems, but perhaps (?) one could say the systems don’t move because the flow at the critical level is pushing them along, but because stengthenning (via baroclinic instability) requires counterpropagating Rossby waves, which requires the systems are propagating relative to the flow in opposing directions at different vertical levels, so there must happen to be a level where the flow moves with the system (and where that level is will depend, among other things, on the wavelength of the system. Hence, different systems with different wavelengths can propagate past each other – setting aside nonlinear interactions). On the other hand, if you set this up and then add some additional barotropic flow, it would be added to the critical level and this would push things along… But to debate this seems unnecessarily complicated.

    Ultimately, it’s the cycle of warm air pushing toward the poles which cools and then returns as cold air masses which present the cold weather events we know and love (to talk about). Here’s a link to a paper by Hurrell (2009), which discusses his view of the NAO.

    The NAO index is not a cause, it’s a result of the flows and gives a simple metric which may quantify the intensity of the repeated patterns which have been found thru statistical analysis.

    I agree, but the NAO index can be thought of as a measure of the state of some mode of internal variability which may be called the NAO, and as a whole it can be a cause, and an effect, and can also be a link in a longer chain of cause and effect, of course.

  2. 152
    Patrick 027 says:

    … important to what directs storm track activity, I understand that the advection of the warm surface anomalies by the storm track systems will tend to cause propagation of the cyclones poleward (for zonally-oriented basic state) (likewise the anticyclones will tend to propagate equatorward with the advection of the cold anomalies). And then there’s occlusion/seclusion. I still don’t really understand the process by which the systems become untilted (become more barotropic).

  3. 153
    Lawrence Coleman says:

    Are all you Climate change sceptics out there watching events all over the planet!. We in eastern Aussie are enduring record rainfall, California and up the whole western seaboard down to Colombia are having a taste of what we have been putting up with over the past year. Although every time it showers here we get about 2 inches!… Look at Europe cloaked in snow and ice. If you remember last year was asia’s turn to smash rainfall record after record..does Manila ring a bell?
    There is definately more water vapour in the air and that coupled with a more pronounced tropospheric temperature gradient spells..well look around.
    We are seeing the beginning of the undeniable and unmistakable pan global effects of Climate change. I still find it quite incredible that those people I speak to on CC still dismiss it as a regular occurence and just the effect of the la doesn’t seem to register that the global increase in CO2 driven water vapour must go somewhere. Unless the people in the street take this issue seriously I can not for the life of me see a way out. Copenhagan-Cancun are just talk fests with no concrete and urgent action planned for now, or in the pipeline. Just looked at the 7-14 day forcast for us in SE Queensland..guess what! lots more rain until the well into the new year.

  4. 154
    Edward Greisch says:

    101 Patrick 027: Yes, Alfven, a Swede, was inspired by the Northern Lights. He saw our aurora often. But Auroras happens at higher altitude than climate and weather, as far as I know. I don’t know anything about the core of the Earth.

  5. 155
    Gilles says:

    Ray : “Gilles,
    I am talking about the science of climate change (WG I), not its consequences (WG II and III). ”

    Do you mean that a science can be “well established” without any accurate prediction ? I think that it deserves to be discussed, on a purely epistemological point of view. What kind of climate science would have been called by you being “not very well established” ?
    And besides this, do you mean that although “well established” in your sense, it is not yet capable of doing any accurate prediction concerning the all-day life of people in the world ?

  6. 156
    Gilles says:

    Lawrence #153 : do you think that you firmly demonstrated that you aren’t doing some kind of cherry picking ?

  7. 157
    Gilles says:

    The Russian heat wave was a 3.6 standard deviation event, implying by use of Poisson statistics that we haven’t had such an event in at least the last 1000 years with 95% confidence.”

    But this very fact shows that it IS STILL an exceptional event, even if most of the warming is anthropogenic, so you cannot demonstrate anything on its origin. Only if this kind of event would become usual, could you infer that something has really changed. But this is obviously not yet the case.

  8. 158
    Lawrence Coleman says:

    Re 156: Gilles. Ok! Gilles you got me..haha! tell you what…go to as many counties meterological bureaus as you can and see how many climatic records have been broken from the last 5 years whether it’s extreme temps or rainfall or duration etc. Then compare that to 1950′s to 2005 and then from where their respective record keeping began. You will no doubt notice a quite striking trend..then get back to me.

  9. 159
    Ray Ladbury says:

    Did you bother to read the rest of my posts on the matter? If you had, I am puzzled why you bothered to repeat exactly what I already said.

  10. 160
    Ray Ladbury says:

    Gilles, I realize you are not a native English speaker, but your #155 strains credulity as to how you could get that. Are you drinking tonight? You simply are not making sense.

    Climate science has quite a good record of prediction. I can point you to references if you are unaware of them.

    Climate science is like any other science. There are aspects that are well established, aspects that are cutting edge and aspects where we still do not know how to proceed. None of the basic elements required to explain current warming fall into the latter two categories. Ferchrissake, dude, there are volumes of predictions of climate science. Read the frigging literature!

  11. 161
    pete best says:

    Re #153 – Here in the UK with the present cold snap (lots of snow to be fair) the media have been having a field day interviewing people about how this will effect their xmas. Millions of people travelling aborad or home to relatives and family to see them all laden with presents etc. I as yet see little if any evidence of anyone taking ACC seriously. Its just not sinking in amongst the masses that travel, goods and services equates to ACC.

  12. 162

    LC 153: Unless the people in the street take this issue seriously I can not for the life of me see a way out.

    BPL: There is no way out. The bad guys have won. I’m still arguing simply and solely because I hate letting them have the last word.

  13. 163
    Ray Ladbury says:

    Wayne Davidson,
    I agree, and I must have really failed in communicating my point. I will try again: When you have a single freak event or a few such events, even one where probability is determined by an underlying probability distribution, Poisson statistics apply. Poisson stats don’t really start droping rapidly until the event total is 3 or so even for very low mean expectation values.

    The decreasing ice volume is almost certainly evidence for climate change, as is increasing drought, the temperature trend, increased extremen weather … And of course, the simultaneous warming of the troposphere and cooling of the stratosphere is diagnostic for a greenhouse mechanism. These trends are all climate. Any single event is weather. A trend of multiple “single events” taken together may be climate. I hope that is clearer.

  14. 164

    Gilles 155: Do you mean that a science can be “well established” without any accurate prediction ?

    BPL: Read and learn, petit:

    Seventeen successful predictions is not “without any accurate prediction.”

  15. 165
    Grabski says:

    Giles The Russian heat wave was a 3.6 standard deviation event, implying by use of Poisson statistics that we haven’t had such an event in at least the last 1000 years with 95% confidence.”


    Unless this sort of event does occur regularly, just that we haven’t recorded it. There are not data points for most 1,000 year periods in the 6,000,000 year history of Earth, so how can you state what the probability is?

  16. 166
    tamino says:

    This summer’s heat wave in Russia is a *vastly* more unusual event (statistically speaking) than the cold December in Europe. No contest — early December in Europe is highly unusual, the Russian heat wave was total freakazoid. Also, some of the claims going around how extreme the current European cold wave is (apparently originating with Thomas Globig, a TV weatherman) are just plain wrong.

    But July heat in Russia doesn’t follow the normal distribution, so it’s not valid to treat it as such. I estimate it as only a 1-in-260-years event given present average temperature for that region (see this). But present average temperature is considerably higher than it used to be. If not for the last century’s warming, the heat wave would indeed have been a 1-in-1000-years (or even more rare) event.

    In fact that’s rather the point: global warming makes such rare events not so rare after all. And as temperatures continue to rise, such events will happen even more frequently.

  17. 167

    162 (BPL),

    The bad guys have won.

    You’re far too pessimistic. Things should be done ASAP, but humanity doesn’t completely lose if we fail for the moment. In ten years CO2 levels will be about 20 ppm higher, and global warming effects will be even more pronounced. The “it hasn’t cooled since X” argument will be moot, and I think even the most intense deniers will be embarrassed to continue to use it. Similarly, all of the UHI and “CRU can’t be trusted” and other issues will be dead and buried. Decades of unequivocal and continuous tropospheric warming, measured by satellites, will be enough.

    Of course they’ll still argue other things, but their position is going to weaken incrementally. It’s going to be, sadly, a war of attrition rather than intelligence (does that surprise you?), but in the end they will lose a war of attrition. It means a senseless price will be paid, but it doesn’t mean humanity will lose.

    So… I think the worst case is that after ten years of inaction, increasing warmth, and worst of all enough Russian heat wave style events — everything from a summer of dramatically reduced ice in the arctic to a frighteningly large forest fire in the Amazon to one really nasty hurricane season to dangerous, more frequent, and more costly droughts — things that affect everyday people (particularly the if-it-doesn’t-hurt-me-personally-it’s-no-big-deal Americans) — will cause people to sit up and take notice.

    By then it will be far, far more expensive to mitigate CO2, will hurt the economy far worse than was ever necessary, and will go hand in hand with other (unnecessarily incurred) expenses needed to mitigate the damage that another 20 ppm will do.

    But it will get done. I can’t believe that it will go so far as to destroy civilization.

    It will, unfortunately, go so far as to transform civilization, and to create a new wave of suffering (sadly, possibly, the modern day equivalent of the Black Plague). A transformed civilization will have new “haves” and “have-nots”, new priorities, and new limitations and goals. The world and lifestyle that we have enjoyed will simply not be bequeathed to our children.

    It remains to be seen, however, whether or not a transformed civilization will be worse or better than what we have today, and I actually hold out hope that — excluding the senseless suffering of those that will be most grievously hit by climate change — a new perspective and new priorities could actually mean a better, healthier and happier lifestyle for generations after ours, one where they’ll look back on how we lived in the twentieth and early twenty first centuries and wonder what the hell we were thinking.

  18. 168
    Anne van der Bom says:


    Do you mean that a science can be “well established” without any accurate prediction ?

    Are biologists able to predict how an elephant will look like in 10000 years? Does that refute the theory of evolution through natural selection?

    Please define ‘accurate’. I get the impression that somehow you will set the bar always a tad higher than the current state-of-the-art in climate science and that your definition of ‘accurate’ is a moving target.

  19. 169
    Maya from the peanut gallery says:

    Grabski, such things leave marks, and we’re getting better at reading the paleoclimate record. Start here:

    It even has a link to data and code. That focuses on more “recent” data, the last couple of millennia or so. There’s also some good stuff here: that goes back further (at least, they have entries on the fossil record) along with free software and tools.

    If you go up to the upper right hand corner of this page and put in “paleoclimate data” and click the radio button for Google Custom Search, you come up with 532 hits. Have fun. :)

  20. 170

    #16 Norman Page

    Net primary production is already indicated dropping due to droughts and fires

    and FACE experiments indicate that anything that does not fix nitrogen drops proteins

    Do you have evidence for your wishful thinking?

    Economics: Balancing Economies
    October Leading Edge: The Cuccinelli ‘Witch Hunt”

    Fee & Dividend: Our best chanceLearn the IssueSign the Petition
    A Climate Minute: Natural CycleGreenhouse EffectClimate Science HistoryArctic Ice Melt

  21. 171
    Michael G says:

    The large-scale convection in the Earth’s atmosphere traces out three hemispheric convection cells: the Hadley cell between the equator and about 30 degree latitude, the Ferrel cell at mid-latitudes and the polar cell over the pole. Would one expect this cellular structure to undergo spontaneous reconstructions as global mean temperatures are raised by about 4 degree C or so over the next century?

    Anyone who has studied fluid cellular structures in the lab will have seen spontaneous reconstructions in fluids as parameters, such as viscosity (via temperature) are changed. Is there any evidence that such phenomena will not occur in the coming decades in the global system? Do climate models predict such reconstructions? At what temperature rise might one expect the jet stream to no longer be a stable structure?

  22. 172
    Chris O'Dell says:

    Anybody seen this recent article by the daily telegraph?

    They are talking about statistical correlations between solar output and climate in europe, according to the \Man who beats the weather experts.\ Would love to see some feedback on this.

  23. 173
    Esop says:

    #172 (Chris): I was about to post about the distinguished Mr.Corbyn as well….
    Would be interesting to hear this forecasting oracle’s comments on why the temperature in the lower troposphere is now the warmest in the posted UAH record, and why large regions of the Arctic are warmer than continental Europe.
    We are seeing Arctic sea ice melting on December 21st, the shortest day of the year. That can’t be a good sign?
    Pretty telling that the MSM does not mention these fun facts whatsoever.

  24. 174
    Brian Dodge says:

    “…can you tell us the “well established ” consequences of the CC on the local temperatures felt by average people living in average countries…” Gilles — 20 December 2010 @ 1:49 AM

    Average people can’t feel the average AGW change in local temperatures any more than they can feel the excess calories from that extra donut every morning. The consequence they notice is that they are shoveling a lot more snow this winter in Wales, which Lord Monckton assures them is due to “global cooling”. Some suddenly drop dead of a heart attack, which is attributed to too much snow shoveling in too cold weather, and the role of too many donuts, and more frequent weather extremes from too much atmospheric CO2 remains unnoticed.

  25. 175
    Maya from the peanut gallery says:

    Chris, they don’t really say much that can be rebutted. Sure, there could be a mini ice age. The distribution of heat in the atmosphere could spontaneously redistribute itself and melt Greenland by next Tuesday, too, but I don’t really see that happening, either. I think the next ice age has been cancelled.

  26. 176

    Grabski 165,

    The Earth is over 4.5 billion years old.

  27. 177
    Esop says:

    #174 (Brian): Wasn’t Lord Monckton down in Cancun recently, claiming that he had predicted that 2010 would be the hottest year on record? Now he is back in England claiming global cooling? I wish these honest and inquiring skeptics could make up their minds and decide once and for all whether we are cooling or warming (all natural, of course). It is so easy to get confused by their ever changing claims.

  28. 178
    Jimbo says:

    Gavin, you were one of the authors of the 1999 paper. Does the 2010 paper better represent AGW theory in relation to warming in the northern hemisphere?
    June 4, 1999
    “Warm Winters Result From Greenhouse Effect, Columbia Scientists Find, Using NASA Model”
    Nov. 17, 2010
    “Global Warming Could Cool Down Northern Temperatures in Winter”

    [Response: What is your point? Are all scientists supposed to think the same things for all time in agreement with all other scientists? Once one effect is identified are scientists supposed to stop thinking or not look at other issues? Or do you think that scientists should be in charge of all media headlines so that there is never any confusion for people that don't actually read the papers? Perhaps you would care to examine the mechanisms proposed in both papers and see whether they are contradictory or complementary? Or which one (or both) actually appear to explain the observational record?
    - gavin]

  29. 179
    Chris R says:

    #171 Michael G,

    Interesting question.

    Purely speculating here. But put aside for a moment the absolute global temperature increase. Consider instead the reduction of sea-ice and it’s impact upon the Arctic atmosphere and pole-equator temperature and geopotential gradient.

    I’ve been idly wondering – given that there are fixed constants – the geography of the Northern Hemisphere being the most important. To what degree is atmospheric circulation free to change? Or do we indeed already see all the variation that’s possible in the historic record of temperature and pressure (weather)? I suspect that this is the case.

    The model study discussed in the lead article finds a non linear response with different regimes (which I’ve named A B C) from 100%-A-80%-B-40%-C-1%. With more blocking activity, resembling the negative phase of the NAO in regime B.

    Can a shift to a predominantly very negative phase of the AO in winter for a prolonged period be considered a change in winter climate? i.e. Climate Change. We’ve seen similar instances already, such as 1963 – an instance of an extreme negative phase of the NAO/AO. But if the atypical conditions of winters like 1963/4 and 2009/10 (Overland’s Warm Arctic – Cold Continents pattern) persisted for many winters, or at least became far more prevalent. Could we call this climate change? I think “yes” – climate is the statistics of weather over a sufficiently long period (World Met Organisation say 30 years) – change the statistics by the exception becoming the regular and you have changed the climate, IF that state persists. If it’s a substantial change, and here in the UK a decade or two predominantly of winters like we’re having would be substantial, the change needn’t persist for 30 years to be considered a shift in climate.

    However crucially, the changed climate wouldn’t be something we’ve never seen before on occasions and experienced as weather.

    As for how often we’ll see the Warm Arctic Cold Continents pattern, we’ll have to be patient and see what happens. Two years together could still be a blip.

  30. 180
    Chris R says:

    #172 Chris O’Dell
    Interesting stuff about Piers Corbyn on his wikipedia page:

    He won’t divulge his method because he makes his living off it. So given his equivocal success rate (about chance from what I’ve seen of his forecasts as reported in the press) it’s hard to say if he’s got something.
    Stoat is unimpressed:

    As for the Little Ice Age, it’s all related to the predictions of a series of low solar output from this cycle (24). See ACRIM for some context:
    Seems too early for this little ice-age to be starting if it’s due to solar factors.

    Furthermore as Esop points out, the solar explanation doesn’t seem to explain the current conditions throughout the Northern Hemisphere. The observations need to be explained by any available theory, and IMHO Overland is on the ball.

  31. 181
    Patrick 027 says:

    Re my 151 – third paragraph was copied, erroneously not deleted.

  32. 182
    flxible says:

    Some Christmas humour, “The good Lord” from Cancun [audio clip], where he was booted from a meeting … entertaining bafflegab.

  33. 183
    Brian Dodge says:

    Monckton’s written testimoney (oops – Freudian slip – i meant testimony) before the US House Subcommittee on Energy and BTW Monckton also states that “SPPI no longer uses any terrestrial-temperature datasets, because they have proven unreliable.” in contrast to Norman who believes “Because of the thermal inertia of the oceans and the absence of the UHI effect the Hadley CRU SST data are the best for discussion purposes.” Wonder if that has anything to do with Monckton’s newly discovered “prediction”?

  34. 184
    Brian Dodge says:

    @ Michael G — 21 December 2010 @ 1:08 PM and Chris R — 21 December 2010 @ 5:50 PM

    Regarding rearrangement of the circulation cells. I grew up in Florida on the beach, and there is a diurnal shift from onshore to offshore winds from afternoon to nighttime, when the sea temperature stays warmer than the land after sunset. I’ve wondered whether in the fall as the sun moves below the horizon of an Arctic Ocean with mostly open water if the polar cell would reverse to updrafts over the pole and offshore winds along the coast. Freezing from the coastline in and wind driven upwelling/surface currents would tend to keep the surface water warmer, saltier and open. Downwelling instead of upwelling over the circumpolar land masses would change the coupling to Ferrel cells from the current mode, (and may have some impact on temperate zone weather patterns &;>)

  35. 185
    Brian Dodge says:

    My 181 cut and paste got mangled – It should be

    Monckton’s written testimoney (oops – Freudian slip – i meant testimony) before the US House Subcommittee on Energy and Environment on March 25 2009 – – said that there had been 7 years of cooling at 3.5 Degree F per century. and that “This century we may warm the world by half a Fahrenheit degree, if that.”
    In – Monckton states
    “The El Nino of 2010 has now ended, and temperatures have fallen back to the long-run trend-line. ”
    Presumably his testimony before Congress is less likely to be mendacious than PR statements made to reporters, or perhaps he made his prediction after talking to Spencer about UAH data at Cancun in December.

    BTW Monckton also states that “SPPI no longer uses any terrestrial-temperature datasets, because they have proven unreliable.” in contrast to Norman who believes “Because of the thermal inertia of the oceans and the absence of the UHI effect the Hadley CRU SST data are the best for discussion purposes.” Wonder if that has anything to do with Monckton’s newly discovered “prediction”?

  36. 186
    Patrick 027 says:

    Re 171 Michael G – I think, if the Earth spun fast enough, you could get more such cells. Regarding AGW, I don’t think anyone expects a profound restructuring of these cells, but rather shifts in size and location and strength. However, these cells are zonal, or zonal-time averages (zonal average = average around a line of latitude; ie averaged over longitude at a given latitude and vertical level) and additional circulation changes could occur that wouldn’t be described by those circulation alone. I think at any one time you may see the Hadley cell, but the Ferrel cell is weak compared to the circulations found at any one time and place in the midlatitudes – which actually drive the Ferrel cell.

    (the Ferrel cell is a thermally-indirect circulation, meaning warmer air sinks and colder air rises, and kinetic energy is converted to available potential energy (APE). The source of that kinetic energy is storm-track activity, which converts the APE of the temperature gradient into kinetic energy – via conversion of a ‘basic-state’ APE into eddy APE (The APE of the temperature anomalies) which is then converted to eddy kinetic energy, some of which is then converted to basic-state kinetic energy. Meanwhile differential heating is producing basic-state APE (and some eddy APE) while viscosity converts kinetic energy to a higher-entropy heat.)

    PS Rather simple models can produce multiple equilibria in the circulation pattern for the same external forcing – in particular the quasistationary wave pattern of the Northern Hemisphere.

  37. 187
    David B. Benson says:

    Patrick 027 @185 — Consider the number of cells on Jupiter and Saturn.

  38. 188
    Rod B says:

    Pekka Kostamo says,

    it can be stated with very high confidence that in an unwarmed climate, August 29th, 2005 in New Orleans would have been just an ordinary summer day.

    How in hell can it be so stated???

  39. 189
    Rod B says:

    Lawrence Coleman (153), yet just about a year and a half ago these pages were rife with blaming severe Australian drought on global warming. Which is it? Both?

  40. 190
    flxible says:

    Try that funny Monkton clip again … yes, a preview would be nice.

  41. 191
    Lawrence Coleman says:

    188. RodB Our climate’s bazaar allright. That’s why I prefer to use the term climate change over global warming..coz there’s always annoying little people who say but we have had the coldest winter for eons blah blah. Actually two nights ago we had the coldest december night on record due to the rain and then a day of clear skies which dropped our nighttime min to 11C..the mean for dec is about 17C. Many farmers out west are packing up and moving to the cities because after having year after relentless year of severe drought and relying on bank overdrafts they are suddenly swamped by massive flooding and no sooner does the flood waters recede and they have mopped up then another drenching happens and they are back to square one again.

  42. 192
    Brian Dodge says:

    Lawrence Coleman — 21 December 2010 @ 1:37 AM cites multiple record rainfall events as “…the beginning of the undeniable and unmistakable pan global effects of Climate change. ”
    Rod B — 21 December 2010 @ 9:29 PM notes that “…these pages were rife with blaming severe Australian drought on global warming.” and asks “Which is it? Both?”


    Evidently Rod B has forgotten the predictions from 1997-2000, noted by the IPCC in 2001 –

    “In global simulations for future climate, the percentage increase in extreme (high) rainfall is greater than the percentage increase in mean rainfall (Kharin and Zwiers, 2000). The return period of extreme precipitation events is shortened almost everywhere (Zwiers and Kharin, 1998). ”
    “a global climate model with increased CO2 was analysed to show large increases in frequency of low summer precipitation, the probability of dry soil, and the occurrence of long dry spells (Gregory et al., 1997). The latter was ascribed to the reduction of rainfall events in the model rather than to decreases in mean precipitation.”

    “In short, changes in extremes and in the frequency of exceeding impacts thresholds are a vital feature of vulnerability to climate change that is likely to increase rapidly in importance because the frequency and magnitude of such events will increase as global mean temperature rises.”

  43. 193
    Patrick 027 says:

    Re 186 David B. Benson – in my internet searches about atmospheric circulation, I’ve come across a few really good review articles that would be helpful here, one of which does discuss number of storm tracks/jet streams as a function of planetary spin. Of course if the Earth spun at the same rate but were significantly bigger, that would have a similar effect. PS – I wonder what this means for paleoclimates in deepest time (Earth spun faster; tidal deceleration).

    The great depth of gas giant atmopsheres (with significant internal heat sources relative to solar heating, at least for Jupiter so far as I know) may make some things not readily analagous to Earth’s atmosphere; I wondered about possible similarities to Earth’s outer core.

  44. 194
    Patrick 027 says:

    … but of course, the atmospheres are not good electrical conductors…

  45. 195
    Ray Ladbury says:

    The thing you apparently fail to understand is that in science, truth is something you discover over time. The precise effects of climate change on weather are still at the bleeding edge of the science. The reality that the climate is changing was realized 100 years ago and the basic science has not changed appreciably.

    Indeed, it is quite possible that aspects of climate change could result in both warming of winter in some regions and cooling of winter in others. Why is that hard for you to understand?

  46. 196
    Ray Ladbury says:

    Rod B., Climate change predicts both increasing drought and increasing extreme weather events, including rainfall events resulting in flood. The two are not exclusive. All that has to happen is that you get all your rainfall at once. The ground saturates and you get flooding rather than a recharge of groundwater. Greater urbanization (impermeable surface) worsens the effect.

  47. 197
    Nick Gotts says:

    “Indeed, it is quite possible that aspects of climate change could result in both warming of winter in some regions and cooling of winter in others. Why is that hard for you [Jimbo]to understand?” – Ray Ladbury

    I can answer that one: it’s because, like any denialist, he doesn’t want to understand it.

  48. 198
    Radge Havers says:

    Apropos of being OT (and since the history thread looks to be closed) Charles David Keeling:
    A Scientist, His Work and a Climate Reckoning
    at the NYT.

  49. 199
    Chris R says:

    Rod B,

    Re “Both”

    The droughts are related to the Indian Ocean Dipole;
    Ummenhoffer 2009, What causes southeast Australia’s droughts?

    The periods of rain and their assoc intensity by other processes (I’m not sure which exactly).

    But I’m sure you can appreciate how two different processes operating at different times can have opposing impacts, while both are affected by AGW.

  50. 200
    Chris R says:

    Re Jimbo,

    It’s quite clear to anyone who actually reads the articles he cited that there are 2 parallel mechanisms that do not contradict each other, the impact of GHGs on OLR and changes in atmospheric circulation.

    Is every branch of science plagued with people who repeatedly put forward arguments without having even a vague notion of the sources they cite?

    Or is this just a climate science thing?

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