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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. 551
    Dan H. says:

    Maya,
    I would agree with Kaplan’s findings about dire climate warmings.

  2. 552
    CM says:

    re: Central England Temperature

    Some background and pointers I find helpful:
    http://rabett.blogspot.com/2010/07/this-is-where-eli-came-in.html

  3. 553
    Septic Matthew says:

    528, Barton Paul Levenson,

    That is amazing.

  4. 554
    Septic Matthew says:

    528, Barton Paul Levenson,

    I forgot to add that, as the US, EU, BRIC nations and everyone else changes their energy industries, you’ll be able to update the model runs and tell us whether the model says we are getting better or worse.

  5. 555
    Maya says:

    Dan, that’s nice, but the article says he blew it – used a study way too small, and didn’t even listen to what the people he was interviewing were trying to say.

    I know dire warning scare some people into not wanting to think about the issue at all, but I don’t think platitudes are useful.

  6. 556

    Did 536: it is utterly insane to give much weight to a single model.

    BPL: Dai used an ensemble of 22 models. Did you read his paper with any attention?

  7. 557

    HR 542: I want you to speak to people’s belief that the world can be fair

    BPL: Do you really believe the world is fair? Do you want to encourage a belief in fairy tales? The world is not fair, HR. The world is manifestly unfair. The Holocaust was not fair, nor the eruption of Pompeii, nor the GULAG.

    [Response: I think the main point is not that the world is unfair (which it clearly is), but rather you are trying to hook into people's aspirations that the world can become a little fairer - gavin]

  8. 558
    David B. Benson says:

    Dave Walker — Tamino, oveer on
    http://tamino.wordpress.com/
    did a correct statistical analysis of CET [He is a profeessional satistician.] All his old pages have been saved somewhere on Skeptical Science.

  9. 559
    SecularAnimist says:

    Gavin replied to BPL: “… hook into people’s aspirations that the world can become a little fairer …”

    Well, the problem is that not everyone aspires to a fairer world. In particular, some people aspire to a world in which fossil fuel corporations continue to rake in one billion dollars per day in profit through business-as-usual consumption of their products for decades to come, massively enriching a tiny, already ultra-rich minority at the cost of unimaginable, monstrous suffering and death for billions of people.

    But certainly, for those who DO aspire to a fairer world, the rapid and widespread proliferation of the very same renewable energy technologies that are needed to reduce GHG emissions (particularly low-cost small-scale off-grid PV) will also make electricity — and with it access to modern technologies including telecommunications — available to billions of people in the developing world who currently lack it and have no other prospect of getting it, thereby dramatically transforming their lives for the better.

  10. 560
    Hank Roberts says:

    Look again at the eco-equity web page, and at this recent study:
    http://www.people.hbs.edu/mnorton/norton%20ariely%20in%20press.pdf

  11. 561
    Ray Ladbury says:

    Dan H.@525, Oh ferchrissake! Are you just going to go from one metric to the next until you find some number you can cling to as a straw. Do you have any idea how pathetic that is? You aren’t even worth the bother.

  12. 562
    Ray Ladbury says:

    Dave Walker says, “I started my involvement in this thread by “declaring” an instinctive anti-establishment, increasingly curmudgeonly, approach to life and the universe – and I guess that’s what drives me.”

    Try caring about the truth before you take up nihilism.

  13. 563
    JiminMpls says:

    David Walker – I actually LOOKED at the graph you referenced and it clearly shows that the past two decades are significanlty warmer than at any other time in the past 300 years. Furthermore, the graph clearly shows that temps in England were markedly warmer in the 1940s than in the 1930s, which is quite the opposite of what occured in the continental USA.

  14. 564
    Septic Matthew says:

    544, Dave Walker: If the trend flatlined for the whole 25 years would that change your view?

    Obviously (?!) the models that in 2005 – 2010 made the most accurate prediction for 2025, as judged in 2025, will gain the most credibility, and the models that made the worst predictions will lose credibility. There are in fact disparate predictions. We can’t exactly bate our breaths in the meantime. I recommend grinding our teeth and making reasonable preparations for all outcomes in the meantime, including the transformations of the energy industries highlighted by SecularAnimist, me, and others.

    Perhaps unintentionally, your wording suggests that you already believe you know what the next 15 years will look like.

  15. 565
    Gilles says:

    “But the fact is that we have a pretty good idea (excellent in fact) of why temperatures change, and in particular why they are trending up over the last few decades. And given that understanding, and the accelerating nature of those drivers – principally CO2 emissions – people have concluded that there is a very strong risk of very large temperature and other climate changes in the future. That is what is “worrisome” – not how warm it was in Central England in March 1948. – gavin”

    Gavin : since you point out that the danger is in the acceleration, is there any sign of acceleration in the trend since 1990, and if yes, where ? Note that the radiative forcing has almost doubled since 1970 ! a basic test of the causality is that the response should clearly vary with the intensity of the excitation. Is it proven beyond any doubt ?

  16. 566
    jyyh says:

    c–p, this makes calculations of the sum of the frozen H2O on the MSL much more difficut.

  17. 567
    Dave Walker says:

    562 Ray

    That’s the point Ray. I do care about the truth. As I have mentioned in previous comments, the establishment, the consensus, call it what you will, has, on a number of notable occasions in the recent past, let us down badly.

    This results in increased cynacism and a jaundiced view of those proporting to tell us the truth. Please do not interpret this as me suggesting that the regular contributors to this site are in some way knowingly contributing to some global conspiracy. I believe you believe.

    I cant’t argue the science with you because I don’t have the knowledge, qualificatons and skills. However, that doesn’t stop me reading and drawing conclusions. Just like we do in other walks of life. I have disagreed with doctors and been right, lawyers and been right and football referees and been right! (I have also been wrong on a just a couple of occasions!).

    The CET graph offers laymen a relatively simple and uncomplicated representation of one set of information. I judge that the graph illustrates something entirely different to that which I am battered with on a daily basis by my politicians, the MSM and “the consensus” in the UK.

    The “trendy” stance is to accept that the English climate has changed beyond recognition in recent times. Every period of low rain fall, every hot day, every storm, flood or wierd weather event is discussed as further evidence of AGW.

    You and I know that is not the case – so why is it happening? Why are politicians (whom, I assume have advisors on these matters) dropping in comments everywhere relating every wierd weather event to AGW? Why are intelligent journalists and editors of national newspapers allowing these ridiculous links to be published and promoted without the normal jounalistic cynacism and questioning.

    We had ministers of state commenting on flooding in one of England’s northern counties earlier this year and pronouncing with 100% certainty that the flooding was evidence of AGW. At the same time, and without any sense of irony, they related the then, current, flood levels to previous record flood levels 100s of years ago.

    More topically, on the news last night was a report on the exceptional flooding in Queensland, Australia. The voice over related the floding to AGW – whilst showing pictures of a post in the ground, but inundated, that indicated the higher flood levels achieved in a couple of previous events 60 and 100 (I think) years ago.

    Maybe it is my nature for me to want everything to be OK. Maybe my increasing anti-establishment stance is skewing my ability to accept information – on an almost irrational basis.

    However,we often hear the term “healthy cynacism” and that is what, I think and hope, I am demonstrating.

  18. 568
    Slioch says:

    558 David Benson

    See here for Tamino’s old article on scepticalscience:

    http://www.skepticalscience.com/Open_Mind_Archive_Index.htmlstopies

  19. 569
    Didactylos says:

    BPL:

    Please try to actually read what I write. I’m sick to death of you misreading what I say. Dai used 22 models, and it is because these models disagree in so many respects that I can say with confidence that “it is utterly insane to give much weight to a single model”.

    Would you rely on one model when another model shows not just a slightly different result, but the opposite result? For me, that would cause me to interpret the results very cautiously.

    It’s what is generally called a “sanity check”. Try it.

  20. 570
    ghost says:

    “That’s the point Ray. I do care about the truth. As I have mentioned in previous comments, the establishment, the consensus, call it what you will, has, on a number of notable occasions in the recent past, let us down badly.”

    How many of your “letdowns” involved the work of thousands of serious scientists in hundreds of fields compiled over dozens of years? “Apple, meet Orange.”

    “This results in increased cynacism and a jaundiced view of those proporting to tell us the truth.”

    You could be correct about that, only not in the way you present it–things could be much more dire than your favored information feed suggests.

    “I cant’t argue the science with you because I don’t have the knowledge, qualificatons and skills. However, that doesn’t stop me reading and drawing conclusions. Just like we do in other walks of life. I have disagreed with doctors and been right, lawyers and been right and football referees and been right! (I have also been wrong on a just a couple of occasions!).”

    None of those is a scientific discipline, of which you admittedly are unqualified or unwilling to assess.

    “The “trendy” stance is to accept that the English climate has changed beyond recognition in recent times. Every period of low rain fall, every hot day, every storm, flood or wierd weather event is discussed as further evidence of AGW.
    You and I know that is not the case….”

    We do not know anything of the sort. We may not be able to say with certainty that an individual extreme weather event is related to AGW, but we certainly cannot rule it out. That actually is an important distinction.

    “More topically, on the news last night was a report on the exceptional flooding in Queensland, Australia. The voice over related the floding to AGW – whilst showing pictures of a post in the ground, but inundated, that indicated the higher flood levels achieved in a couple of previous events 60 and 100 (I think) years ago.”

    You’re pinning your belief on one data point? Demonstrate similar measurements scattered uniformly throughout the ‘Germany plus France-sized area’ of the flood, plus the length of time of respective flood coverages, and then we’ll talk.

    “Maybe it is my nature for me to want everything to be OK. Maybe my increasing anti-establishment stance is skewing my ability to accept information – on an almost irrational basis.”

    Well, we can agree on that one, but criticizing things you don’t know about seems to be a modern human trait. I think you have the “establishment” thing backwards, though, and that your view actually is the “establishment” view. The “establishment” view includes a firm policy, and has for decades-to-centuries, that human action cannot affect the environment, despite the long, broad, and deep science evidence to the contrary. What’s more “establishment” than the harmless joy of using fossil fuels in a widespread manner? [edit - OT]

  21. 571
    JiminMpls says:

    #566 Maybe my increasing anti-establishment stance is skewing my ability to accept information – on an almost irrational basis.

    If you replace ‘almost’ with ‘purely’, I’d say you nailed it.

  22. 572
    JCH says:

    Perhaps unintentionally, your wording suggests that you already believe you know what the next 15 years will look like. – SM to DW

    Reading blogs, there is a community out there that believes December temperatures mark the beginning of a prolonged cooling phase that will bring much lower global mean temperatures in the future. There’s even talk of an ice age.

    As for a prolonged pause, Tsonis and Swanson’s pause until 2020ish appears to include the notion that AGW never stops.

  23. 573
    FurryCatHerder says:

    ghost @ 569:

    That’s not at all what’s being said. The complaint is that if the present climate / weather is so badly skewed by AGW, why are there these events in the past that are worse? Or why are we having record breaking weather in the other direction?

    There is a completely irrational fixation on the “Global Warming” aspect of what’s going on and every time something like a “cold winter” happens it serves as further proof that “Global Warming” is simply the wrong name. At some point I hope the Powers That Be have the good sense to admit that “Climate Change” is the more accurate term. Not holding my breath, tho …

  24. 574
    Sou says:

    #566 Dave Walker said: “The voice over related the floding to AGW – whilst showing pictures of a post in the ground, but inundated, that indicated the higher flood levels achieved in a couple of previous events 60 and 100 (I think) years ago”

    If this was the only big flood for sixty years then you’d have a point. Instead now there are major floods happening not just every 100 years or every 60 years, but every year. With some localities getting 100 year floods two years in a row! Look at the list of major floods – 1958, 1974, a couple of big ones in the 1990s, then multiple major floods in 2007, 2008, 2009, 2010 and now the biggest of all in 2010-2011. Check out some of the reports:

    http://www.bom.gov.au/hydro/flood/qld/fld_reports/reports.shtml

    The increase in intensity of precipitation and amount of rain and geographic scope is all in line with what the Australian climate scientists have been telling us will happen as a consequence of global warming from our CO2 emissions. The north of Australia is getting wetter and the south is getting drier and hotter.

    The records keep being broken:
    http://www.bom.gov.au/announcements/media_releases/climate/change/20110105.shtml

  25. 575
    Ray Ladbury says:

    David Walker, Well, I suppose lumping all experts and authorities together is easier than actually thinking. Unfortunately, humans are social animals living in a highly complex, global society whose very survival is contingent upon having accurate and reliable information.

    If you were inclined to actually do some work and try to determine which experts are reliable and what information sources are lying through their teeth, then perhaps you could develop a more nuanced view of the human condition. However, given that you are willing to extrapolate from data for a tiny portion of a tiny island to the entire globe, I don’t hold out much hope that you are the sort of person who is actually willing to “do the math”.

  26. 576
    Ray Ladbury says:

    Gilles, regarding acceleration: In 1970, other forcings swamped the influence of greenhouse gasses. Since 1970, we have had a sustained warming trend — 40 years. Do you think natural variability has diminished or do you think that greenhouse forcing has gotten stronger?

    In any case, the trend is in line with expectations. That provides strong evidence that we know what is going on. But, hey, feel free to develop your own climate theory and run it up against those done by people who actually know what they are talking about.

  27. 577

    #566–Dave, the frustration with ‘pop attribution’ that you feel is, IMO, an inherent feature of the current situation, resulting from a combination of the statistical realities and human psychology. More specifically, the statistical reality is that we get, not so much qualitatively different events, as a shift in frequency and/or intensity of events. So, though the floods you mention may not be worse than all historical precedents, that doesn’t mean that their occurrence is irrelevant to climate change. What needs to be asked is, “Are these floods becoming more frequent on average?”, and “Are these floods becoming more intense on average?” And answering those questions may not be simple.

    That’s where you get to the psychology. For numerous good reasons, humans prefer certainty to uncertainty, so we want to know, and we want to know, if possible, now. So there is a tendency for us to attribute prematurely (as Gavin’s repeated cautions dramatize for us.) And you don’t need a license to do so, so all kinds of folks do this, including politicians, media folk, activists and all sorts of cranks. (For example, yesterday I saw a blog comment attributing the extremely warm weather currently being experienced in the vast Canadian territory of Nunavut to shifting of the magnetic pole!)

    Nor is it just one side or the other; while politician X may attribute a particular event to climate change, another may just as firmly and erroneously attribute it to, say, “natural cycles,” or human-caused degradation of some other sort. (A real-life example is the case of the Carteret Islands outmigration, which some attribute to climate change-caused sea level rise and others on reef degradation caused by poor fishing practices.) In general, my perception is that scientists are the most careful–which means conservative, which means they’ll miss some potentially valid attributions.

    None the less, we have some good reasons to link both flood and drought to climate change:

    For example, both thermodynamic
    arguments124 and climate model simulations125
    suggest that precipitation may become more intense
    but less frequent (i.e., longer dry spells) under GHG-induced
    global warming. This may increase flash
    floods and runoff, but diminish soil moisture and
    increase the risk of agricultural drought.

    (From Dai, 2010)

    So keep your skepticism, and question pop attribution all you want. I’d humbly suggest, though, that there’s a fine line between appropriate skepticism and knee-jerk rejection of orthodoxy. Experts in any field are not infallible, but on average they are going to be right much more often than the regular joe.

  28. 578

    #574–Thanks for the links, Sou–the summary report is certainly quite unequivocal about the long-term trends. I hadn’t realized that the BOM provides a nice time-series on Sea Surface Temperatures near Australia, and it’s nice to observe its congruence with the instrumental record for Oz.

    A question, though, about the other link–can we validly assume that the list is exhaustive? I see a note there to the effect there’s reports not available electronically, and if they tend to be older–rather than smaller-scale events–then we can’t draw conclusions about how frequent the flood events are. And I’d really like to know!

    I did some poking around on Google this morning and studying precipitation patterns seems to be a “messy” business, with complex patterns in space and time to process. And the focus seems to be mostly regional, probably just for that reason–but it’s not so easy to get a comprehensible “big picture,” despite all the data that’s out there. If this list were exhaustive, it would be nice; you could plot occurrences and easily calculate a frequency trend. It would be a nice little “citizen science” project.

  29. 579
    Kevin Stanley says:

    “Experts in any field are not infallible, but on average they are going to be right much more often than the regular joe.”

    Yes. I find it depressing and incredibly frustrating when people go beyond skepticism and start regarding expertise as something to be actively distrusted.

    Just because someone who has been studying the field for decades isn’t right about *everything*, that’s no reason to think they’re *wrong* about everything. And we would do well to remember that experts are BY A HUGE MARGIN more likely to be right about something in their field of expertise than is a layman (or a political pundit–I’m looking at you, Limbaugh).

  30. 580
    Sou says:

    #578, Kevin – I don’t know if the list is exhaustive or not, however it would seem so. I do know the flood in the 1950s and the flood in 1974 were big events. The following link shows floods in earlier times.

    http://www.bom.gov.au/hydro/flood/qld/fld_history/index.shtml

    Bear in mind that over time there have been flood mitigation works which means it is not so easy to make comparisons over time. In particular, following the January 1974 floods which badly affected Brisbane there was a large dam built (Wivenhoe Dam) so as to (hopefully) prevent a similar occurrence. AFAIK, if not for that, Brisbane would be currently subject to the same or worse event as in 1974. I would surmise that population density of affected areas at the time of floods would also have an impact on the reporting of historical (and current) flood events. (eg many people may not be aware of the major flooding in Western Australia this summer.)

    (As far as citizen science goes, I’ve got major bushfires on my list, plus health effects of prescribed burning – it won’t hurt to add floods :) )

  31. 581
    Chris G says:

    Re: #1, Gavin’s reply,
    I’ve learned that Gavin can be a bit caustic at times, and I understand how the repetition of strong beliefs based on a limited understanding can try one’s patience, but I think it would have been more instructive/constructive to use something like a dice analogy, rather than a good mocking, deserved or not.

    For instance, two, true, 6-sided dice will have a mean roll of 7 and a standard deviation of ~1.2. Let’s say that you encounter a pair of dice that are not true and have a mean roll of 7.5, but you don’t know that this is the case. The difference between the means is less that a standard deviation, and less than the variance you would expect from a set of rolls, but if you rolled them a thousand times, you could be nearly certain that they were not true. Applying basic stats, you could be highly confident that the mean of these dice is between 7.4 and 7.6, even though the variance on the set of rolls was greater than the difference between the means.

    BPL, your predictions scare the stuffing out of me. Not because of your work per se, but because your estimates happen to agree with my SWAG after looking at indices like fishery declines, rate of ocean acidification, peak oil estimates, population growth, etc. Convergence from separate lines of reasoning is a powerful thing. Course, that could be a case of a couple of nuts, or one nut and one non-nut, happening to agree with each other. You’ve put more effort into it than I have; so, I accept that I might be the nut. In any event, it baffles me when people show such a clear failure to comprehend that the well-being of society, economic and otherwise, is entirely dependent on the well-being of the environment in which they live, and their food is grown.

  32. 582
    Gilles says:

    Ray, actually I’m asking people (who are supposed to understand this kind of issue better than myself) to answer some questions I’m puzzled with.

    “Gilles, regarding acceleration: In 1970, other forcings swamped the influence of greenhouse gasses.”

    Which kind of “other forcings” are you talking of , and which variability are they suppose to be able to produce ? (max trend for instance)

    ” Since 1970, we have had a sustained warming trend — 40 years. Do you think natural variability has diminished or do you think that greenhouse forcing has gotten stronger?”

    I don’t think that the post-1970 trend is significantly higher than the 1900-1940 one, and it has not significantly increased since then. So the argument that something new must have happened is not obvious for me. Maybe the GHG have contributed, but why do you think that it is the only, and even the main contributor? computer models ?


    In any case, the trend is in line with expectations.

    a priori expectations? or a posteriori expectations ?

    other question : how can the trend be a robust prediction of all models if the asymptotic sensitivity is known only within a factor two ? I assume that the trend is something like the asymptotic sensitivity divided by a relaxation timescale, so if the trend is the same with various sensitivities, the relaxation timescale should scale like the sensitivity. But why? wouldn’t you expect other combinations of sensitivities and time scales producing different trends in models ? is the 0.15 °C/century a robust value, and why? especially if it is (strangely enough) not accelerating ?

  33. 583
    Dave Walker says:

    #575 Ray

    It is hard for me to debate with you Ray. I have no wish to try and undermine your personal expertise or your knowledge on this subject – I am in no position to do so.

    I would like to gently take issue with you on your assumption that anyone who has different view to you is therefore “not thinking”.

    Those of us on the outside (i.e. laymen) see and hear the constant and learned assertions with respect to AGW. Those of us that look and listen also see and hear the arguments from the contrarian side. These contrarians are not limited to just loonies and cranks. There are other “experts”, although they appear to be smaller in number, that argue, scientifically, their alternative view. Often, they will also go on to sugest reasons why the majority takes the stance that it does (career safety, funding, etc).

    As a layman, I hear many of the arguments and I am unable to judge who is right and who is wrong. I think you are suggesting that there are more experts supporting the case being made for AGW than not – therefore I should follow the majority.

    Here in the UK, our Met Office is coming under increasing criticism. You will be aware of the issues regarding forecasted BBQ summers and mild winters. The criticism of the Met office that I am reading currently is a serious attempt to argue that the Met Offices ability to get seasonal forecasts so wrong is the reason why there forecast on global warming should also not be trusted. I read, and this may be a myth, that the same supercomputer/model that did their seasonal forecasts (now stopped) is the same model that does the global warming predictions. The argument says, for whatever reason, the Met Office model has a “built -in” warming bias – evidenced by its regular, historical over estimation of the coming seasonal temperatures.

    Isn’t it entirely logical for a layman to judge the efficasy of 100 year forecasts from the Met Office, at least in part, on their ability to give us reasonably accurate 3 month forecasts? Apparently, even the BBC is considering dropping the Met Office.

    Whether it is politics, religion or science, I don’t think folowing the majority, or consensus view means that the majority is right. History is littered with examples of the opposite being the case.

    On the other hand though – I could be completely wrong and we are all going to fry!

    I do remember being wrong once though.

  34. 584
    wili says:

    Back to the titular topic of this thread–winter cold (or not):

    The NSIDC has now come out with it’s assessment of Arctic sea ice for December, and it’s a new record:

    http://nsidc.org/arcticseaicenews/

    “Arctic sea ice extent averaged over December 2010 was 12.00 million square kilometers (4.63 million square miles). This is the lowest December ice extent recorded in satellite observations from 1979 to 2010, 270,000 square kilometers (104,000 square miles) below the previous record low of 12.27 million square kilometers (4.74 million square miles) set in 2006 and 1.35 million square kilometers (521,000 square miles) below the 1979 to 2000 average.” (my emphasis)

  35. 585
    Maya says:

    Dave Walker: “Whether it is politics, religion or science, I don’t think folowing the majority, or consensus view means that the majority is right. History is littered with examples of the opposite being the case.”

    Carl Sagan: “The fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown.”

  36. 586
    Didactylos says:

    Dave Walker: You get the red-herring prize!

    Weather is NOT climate. Long range weather forecasting is just a really really hard form of weather forecasting, and has nothing to do with climate.

    The fact that the Met Office do slightly better than chance with their long-range forecasts is considered a success. Expectations for long range forecasts are really that low.

    Climate predictions, though – we have decades of successful predictions. Climate models have demonstrated more than just the basic level of skill, they have shown close agreement with observed temperatures.

    You, now: you cherry-pick those instances when the Met Office made a higher than reality estimate in their weather forecasts, and try to spin that into a “warm bias”. And that was you burning up your last shred of credibility.

    Bye bye now.

  37. 587
    wili says:

    There is also new research, apparently, on shifts in the ‘gulf stream.’

    http://www.redorbit.com/news/science/1973421/scientists_find_drastic_shift_in_atlantic_ocean_currents/index.html
    “Scientists Find Drastic Shift In Atlantic Ocean Currents

    Posted on: Tuesday, 4 January 2011, 13:35 CST

    Swiss researchers reported on Tuesday that they found evidence of a “drastic” shift since the 1970s in the north Atlantic Ocean currents that usually influence weather in the northern hemisphere.

    The team of biochemists and oceanographers from Switzerland, Canada and the U.S. detected changes in deep sea Atlantic corals that indicated the declining influence of the cold northern Labrador Current.

    They said that change “since the early 1970s is largely unique in the context of the last approximately 1,800 years,” and raised the prospect of a direct link with global warming.

    The Labrador Current interacts with the warmer Gulfstream from the south.

    They have a complex interaction with a climate pattern, the North Atlantic Oscillation, which has a dominant impact on weather in Europe and North America.

    Scientists have pointed to a disruption or shift in the oscillation as an explanation for moist or harsh winters in Europe in recent years.”

    Is this more legitimate than the fabricated news on this topic that was a subject of this site a few weeks back?

    ————————-

    Meanwhile, I have my own prediction to make. Posters on this site will largely continue to spend almost all their time interacting with trolls like DW while essentially ignoring actual ‘layman’ who look at the same range of statements as DW yet quickly somehow manage to understand that one side is non-science with no valid arguments to their name, largely funded by Exxon, the wealthiest corp in the world, and the Koch brothers (see recent New Yorker article on these jokers), while the other side has the vast bulk of scientific consensus on their side.
    The basics, are clear and completely well established, and easy to understand: CO2 is a GHG (established for well over a century); we are pumping ~30 billion tons of extra CO2 into the atmosphere; atmospheric levels of CO2 have increased dramatically; Global temperatures have increased appreciably. Anyone who can’t understand these or connect these dots should be ignored. They are either too stupid to be bothered with, or they are trolls (or both). For the finer points of exactly how strong of a GHG CO2 is, what paleo-record can tell us…I, for one, am happy to admit that I (and 99.999% of the rest of the population of the world) am unqualified to weigh in on and am also happy to watch as those who have committed their lives to understand these highly technical issues discuss them.

    Sorry about the cranky attitude, but I see otherwise thoughtful people here fall for almost every troll who comes along with no other purpose, as far as I can see, than to rile people up and distract people from the enormously important job of understanding what is really happening around us right now.

  38. 588

    Re: #583 “logical for a layman to judge the efficasy of 100 year forecasts from the Met Office, at least in part, on their ability to give us reasonably accurate 3 month forecasts…”

    Logical, maybe — but likely wrong. Ward and Brownlee made the excellent point in their book, “The Life and Death of Planet Earth” (prologue, pages 8 – 9), that “future climate prediction is actually easier — and probably more reliable — than the weather forecasts we use in our daily lives.”

    To understand why — read the book.

  39. 589
    Chris G says:

    #582,
    Well, for instance, in the 1970s there was more particulate pollution than there has been in more recent decades. Light colored particles in the air tend to cause a cooling effect. This was actually the basis for Stephen Schneider’s conclusion, subsequently retracted, that there would be a cooling trend.

    #588,
    By all means, read a good book, but you don’t have to in order to understand that predicting climate is a little like predicting the mean of a large number of dice roles (which can be done with tight confidence intervals) and predicting weather is a little like predicting what any one roll will be (based perhaps on their position and orientation just prior to being rolled).

  40. 590
    Maya says:

    wili, the very bottom of the article notes that “The scientists published their study recently in the Proceedings of the National Academy of Sciences (PNAS).” So, I don’t think it can help but be more legitimate than the fabricated news on this topic.

    As for trolls, I keep hoping that they’re really asking honest questions rather than trying to bait us. *sigh*

  41. 591
    Hank Roberts says:

    Gilles says: 6 Jan 2011 at 2:44 AM

    “… Note that the radiative forcing has almost doubled since 1970

    [Citation needed] — are you talking about the reduction in sulfate aerosols? But if so then you do understand what’s different now compared to the 1940s, though you claim later you don’t know what’s different. Try this:
    http://Fwww.mpimet.mpg.de/fileadmin/atmosphaere/acc/Marmer_etal_2007_JGR.pdf

    And Gilles also says: “Is it proven beyond any doubt ?”

    Gilles, you are confused about how science is done.
    One method that doesn’t work: repeating questions over and over.

  42. 592
    One Anonymous Bloke says:

    Wili 587 “I see otherwise thoughtful people here fall for almost every troll who comes along”
    Didactos 586: “Bye bye now”.

    The point’s been made before: it’s worth the team spending time answering Canutist memes, so that those of us who don’t know the science inside out have the resources to counter them (the memes) ourselves. I share Wili and Didactos’s frustration with it though: I doubt these…people are even being paid for the shilling they’re doing. The worst thing is that some of them will be genuinely confused, and will not understand the irritation they provoke.

  43. 593
    SecularAnimist says:

    ghost wrote: “We may not be able to say with certainty that an individual extreme weather event is related to AGW, but we certainly cannot rule it out.”

    I would say that no individual weather event, extreme or otherwise, is unrelated to anthropogenic global warming.

    We are now living in an anthropogenically-warmed world. NOTHING that is happening is unaffected by that. NO weather event, whether extreme or not, is unaffected by that.

    Today’s temperature hits a record high — anthropogenic warming is one of the causes and conditions of that weather event. Tomorrow’s temperature happens to match exactly the long-term average — anthropogenic warming is one of the causes and conditions of that weather event as well.

    If someone asks “did climate change cause this weather event”, the correct answer is:

    Climate does not “cause” weather. “Climate” and “weather” are not separate things such that one can be a “cause” and the other an “effect”. The words “climate” and “weather” refer to the same thing, just on different time scales.

    Anthropogenic global warming is a pervasive influence that inescapably affects ALL aspects of the Earth’s atmosphere, and this influence manifests itself in both the short-term events that we refer to as “weather”, and in the long-term patterns that we refer to as “climate”.

  44. 594

    583 Dave Walker 586 Didacto

    In the midst of many pointing to the latest weather and announcing that it proves something about climate, it is reasonable to be sorting out the difference.

    And you acknowledge a chance of being wrong.

    But you gave our Didacto a chance to strut. Didacto was only wrong once. That was when he thought he was wrong. I am not sure why he is so confident about ‘observed temperatures’ matching climate predictions. Maybe he forgot the part about climate predictions being calibrated based on observed temperatures.

    [Response: Of what value is a comment like this? Does it advance or help anything? As for the issue of being wrong, you are absolutely the last person with a right to voice opinions about others on this, given your history of wrong, off-topic proclamations on everything under the sun here.--Jim]

  45. 595
    Sir says:

    As a follow up to Wili in 584 concerning the NSIDC release on the low ice conditions in the Arctic, they went on to say:

    “The low ice conditions in December occurred in conjunction with above-average air temperatures in regions where ice would normally expand at this time of year. Air temperatures over eastern Siberia were 6 to 10 degrees Celsius (11 to 18 degrees Fahrenheit) above normal in December. Over the eastern Canadian Arctic Archipelago, Baffin Bay/Davis Strait and Hudson Bay, temperatures were at least 6 degrees Celsius (11 degrees Fahrenheit) higher than average. Southern Baffin Island had the largest anomalies, with temperatures over 10 degrees Celsius (18 degrees Fahrenheit) higher than normal. By sharp contrast, temperatures were lower than average (4 to 7 degrees Celsius, 7 to 13 degrees Fahrenheit) over the Alaska-Yukon border, north-central Eurasia, and Scandinavia.
    The warm temperatures in December came from two sources: unfrozen areas of the ocean continued to release heat to the atmosphere, and an unusual circulation pattern brought warm air into the Arctic from the south. Although the air temperatures were still below freezing on average, the additional ocean and atmospheric heat slowed ice growth.”

    http://nsidc.org/arcticseaicenews/index.html

    So, as we already know, cold Europe doesn’t necessarily mean cold world.

  46. 596
    SecularAnimist says:

    wili wrote: “I see otherwise thoughtful people here fall for almost every troll who comes along with no other purpose, as far as I can see, than to rile people up and distract people from the enormously important job of understanding what is really happening around us right now.”

    I have a hypothesis about denial.

    I don’t mean the deliberately dishonest, obstructionist denial perpetrated by the fossil fuel corporations through their phony “think tanks” and pseudoscientific frauds and cranks, that is disseminated by the phony “conservative” media to gullible dupes who endlessly and belligerently regurgitate zombie talking points on blogs anywhere.

    That is what it is: the funding and directing of the propaganda machine is well-documented; and the psychology of “true believers” who embrace that propaganda is well-understood.

    I mean “denial” in the psychological sense of rejecting, evading or suppressing knowledge that is simply too horrible to face.

    And my hypothesis is, that the reality of “what is really happening around us right now” is so horrifying and unthinkable to those of us who DO understand it, that some of us need to be “distracted” from it, so we retreat from dealing with it, into the far more comfortable space of engaging in endless, repetitive “debate” with trolls over basic scientific points that are, in fact, no longer subject to legitimate debate.

    We prefer to confidently lecture the trolls over and over again about the basic science, and take comfort in the feelings of understanding (and thus control) that scientific knowledge gives us, than to discuss the constantly emerging evidence that we are perhaps irrevocably committed to unimaginable suffering and destruction.

    Lecturing a WattsUpWithThat Ditto-Head gives a sense of strength and confidence. Discussing the ever-increasing evidence that we are hurtling faster than anyone imagined possible towards a worst-case scenario of global catastrophe gives a sense of powerlessness and fear. Better to deny and retreat into the comfort of schooling the trolls.

  47. 597
    Hank Roberts says:

    > climate predictions being calibrated based on observed temperatures.

    Citation needed.

    C’mon, Jim, you pick up the denier talking points really fast, you know that.

    If you looked them up rather than repeating them without citation, you’d know a lot more about the PR points and the people from whose heads they sprout.

    What you left out — is important. Paste your own words into Google and read some of what pops up in the first page. You want respect as a serious thinker. That’s one way to knock the rough parts off the ideas, check’em.

  48. 598
    Septic Matthew says:

    572, JCH: As for a prolonged pause, Tsonis and Swanson’s pause until 2020ish appears to include the notion that AGW never stops.

    Yes, and roughly consistent with Latif’s model as well. They forecast what is roughly a linear trend plus sinusoid with a much lower 2100 forecast mean temp than the GCM forecasts, if extrapolated that far. That pattern has been much disputed here at RC.

    Your comment about December starting a cooling trend is clever. However, we humans have recorded many Decembers and Junes in alternation these past thousands of years, but we have not yet recorded 2011-2020. So we can’t yet use our “knowledge” of 2011-2020 to tell us whether or when warming picks up again, or whether the apparent decline in ocean heat content recorded by the ARGOS system (2003-2008) is prophetic.

  49. 599

    #596–

    Lecturing a WattsUpWithThat Ditto-Head gives a sense of strength and confidence. Discussing the ever-increasing evidence that we are hurtling faster than anyone imagined possible towards a worst-case scenario of global catastrophe gives a sense of powerlessness and fear. Better to deny and retreat into the comfort of schooling the trolls.

    I think that’s perceptive, SA. We’re all human beings, and if you take the implications of this science seriously, the current reality’s a considerable stressor. (See Greg Craven as poster boy–and I say that pretty much admiringly.) As societal inaction continues, despair must be held at bay somehow. (Though I think the response is not so much a form of denial as a form of “reaction formation.”)

    It’s probably not a harmful defence mechanism as long as some balance is maintained–eg., one doesn’t fall into denial of whatever crumbs of good news actually do come along, or into an inability to accept that one’s ideas might be less correct or precise than one thinks (after all, “think” is the operative word, right?) These are understandable temptations, but probably not helpful.

    My two cents. . .

  50. 600
    Daniel Bailey says:

    Slioch’s link currently at 568 was broken.

    The correct link to the lost Open Mind Index is http://www.skepticalscience.com/Open_Mind_Archive_Index.html.

    Happy New Year to all!

    The Yooper


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