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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. 501

    Nice link, Maya–thanks!

    Following on from that link, you can reach a very meaty synthesis study on what the authors call “WWS.” (Renewables, basically.) Based on past discussions here, many readers will be interested. The takeaway is that the authors expect 100% renewable electrical generation to be not only technically but economically feasible by 2020, with the main barriers to achieving this goal being social and political. (Though they certainly recognize the technical and economic challenges.)

    The link to Part 2:

    http://www.stanford.edu/group/efmh/jacobson/Articles/I/WWSEnergyPolicyPtII.pdf

  2. 502
    jheath says:

    Gavin (Is that Dr Schmidt?)

    Thankyou for taking the trouble to respond to my questions. You are very kind. Looking at this (noting 1980 baselines in the references and the implications of that given the statements of Professor Jones re 1995 onwards) it is evident that the Governments in question are justified in taking a more prudent approach by allocating fewer resources to global warming issues given that the numbers are coming in below the previous policy assumptions, albeit within your predicted range. When added to the lack of rising sea levels in two of the countries, they are understandably interested in bringing power to their populations first and foremost in order to enhance their economies and their social welfare. I will not therefore advise them to revert to their previous more aggressive policy objectives on CO2.

    On the energy points perhaps you had best leave energy economics to me and I will leave climate science to you. I have yet to discover what problem smart grids are trying to solve, which customers want them, and how a cost benefit can be constructed for them that is not theoretical and academic. The more advanced power markets than those in North America have already achieved the extra gains from “negawatts” on top of the 1-2% per annum improvement in energy efficiency that has been going on since the 1940s at least. In addition negawatts are not too helpful for the many millions of people who still have inadequate power supplies. That is where natural gas has to come in as renewables – especially wind – are generally hopeless in terms of cost and reliability.

    [Response: Since you clearly had already made up your mind before coming here, I have to wonder what the point of asking us anything was. Still, doesn't mean you are correct. If you think that energy is used as efficiently as it can be in the US, you really need to look more closely. And similarly, if you think Phil Jones' statement means that it's not warming, you need to revisit you stats textbooks (look up signal vs noise). But thanks for stopping by. - gavin]

  3. 503
    Septic Matthew says:

    501, Kevin McKinney

    That’s a good recent review. Thanks.

  4. 504

    #503–De nada, Septic.

    Wonder if jheath (#502) saw that link, or if he’d bother clicking? Didn’t especially seem so. . . too bad. He might have found out something.

  5. 505
    Ray Ladbury says:

    jheath, I pity your clients having an adviser who will only tell them what they want to hear, regardless of how much it diverges from the truth.

  6. 506

    jheat 502,

    What part of “global warming will increase drought until we have at least one year where no country has a good harvest and we all die” do you not understand? My research, about to come out in J. Climate, estimates that will happen in 2052. Will your kids or grandkids still be alive then?

  7. 507
    Hank Roberts says:

    BPL, well, you may be right. If so you’ll be the first one to be correct of the many who have precisely predicted the end of history when everyone dies.

    I trust you will continue to act as though you may possibly be wrong, and plant trees and otherwise act as though you have faith life will go on.

    I mean, you know, just in case you’re wrong. As the others have all been.

    Congratulations, by the way. As far as I know, no previous end time predictions have been published in peer-reviewed journals.

    Perhaps a blog ring could be organized for the new planning.
    Here’s a shorter timeline:
    http://phytophactor.blogspot.com/2011/01/end-of-times-garden-planning-pre-and.html

  8. 508
    Hank Roberts says:

    (hat tip to Stoat for that end-of-times-gardening link)

  9. 509
    David B. Benson says:

    Hank Roberts @507 — In general agreement with Dr. Dai’s drought study:
    http://onlinelibrary.wiley.com/doi/10.1002/wcc.81/full

  10. 510
    Sou says:

    It’s been cold in Australia in 2010 according to the Bureau of Meteorology’s Annual Climate Statement for 2010, released today.

    http://www.bom.gov.au/announcements/media_releases/climate/change/20110105.shtml

    Colder than any year since, well, 2001! And the mean temperature was only +0.19 °C above the 1961 to 1990 average of 21.81 °C. We must be approaching that ice age :)

    “It has now been a record nine years since Australia experienced a below-average year and the past ten years (2001 to 2010) were the warmest decade on record for Australia.” (From the temperature chart, it’s unlikely we’ll get a ‘below average’ year any time soon, unless they move the base line up.)

    The decade has been the warmest on record. The temperature trend is up. The maps are worth looking at – wettest on record, driest on record, temperature trends.

    Despite the La Nina, “Australia recorded its 8th warmest year on record for minimum temperatures (with an anomaly of +0.59 °C), while maximum temperatures were below normal with an anomaly of −0.21 °C. “

  11. 511
    Brian Dodge says:

    “…a more prudent approach by allocating fewer resources to global warming issues given that the numbers are coming in below the previous policy assumptions, albeit within your predicted range.” jheath — 4 Jan 2011 @ 4:20 PM

    Your government clients who are changing their CLIMATE policies every time the WEATHER changes remind me of investors who sell every time their stock declines and buy every time the market goes up, and I expect they will be about as successful. How do you manage your portfolio – sell into a decline, and buy into a rise?

    [Response: Yes. And also, which 'numbers' does he think are coming in below previous assumptions?--eric]

  12. 512
    Hank Roberts says:

    > drought study
    Sure, and there are many others not in the peer reviewed journals.

    Catton’s work goes back decades. He pointed out early on that a world of regions each unable to supply itself with _something_ essential works fine as long as transportation and the economy distribute everything to everyone — that’s how we’ve been able to build well into overshoot conditions. And when that fails, comes the crash.

    http://www.greatchange.org/footnotes-overshoot-graphs.html
    http://www.amazon.com/Overshoot-Ecological-Basis-Revolutionary-Change/dp/0252009886

    He has a new book out too:
    http://www.amazon.com/Bottleneck-Humanitys-Impending-William-Catton/dp/1441522247/ref=sr_1_2?s=books&ie=UTF8&qid

    But nothing kills everybody — history is written by the survivors blessing fair providence that eliminated the competition and left them a world to expand into. It’s all a matter of perspective. Connie Willis got it:
    http://en.wikipedia.org/wiki/Doomsday_Book_%28novel%29

    Just sayin’, while you can go on for decades yet warning people they’re all gonna die — a few will survive and prove you wrong. From their perspective, it’ll be their world.

  13. 513
  14. 514
    One Anonymous Bloke says:

    If jheath really were a government adviser, that would explain a lot. Something has to drive that sloth and incompetence. Now I’m starting to wonder if it’s true after all.

  15. 515
    adelady says:

    Thanks Eric, I’ve been wondering about where these numbers might be published.

    I’m equally perplexed by the notion that European (I think that ws the implication about more sophisticated power systems) countries couldn’t do better in terms of efficiencies and reductions. Just because they’re now better than profligate USA, Canada, Australia type countries, does not mean they’ve exhausted the opportunities for further significant reductions.

  16. 516

    Chris R, there is no risk, integrated weather is climate.

    I suggest that the chaos caused by thinner ice is still active:

    http://www.weatheroffice.gc.ca/trends_table/pages/yxp_metric_e.html

    Pangnirtung is a large Arctic community on East Baffin Island, Further to its East across Baffin Bay: Greenland. It was +34 degrees above its mean temperature earlier today in Rain, +8 C . Imagine London or NY +34 C above and see if it would make some MSM news noise.

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

    Absolutely so, but this statement the effects of more energetic Arctic weather spawned
    by thinner or no sea ice is still not widely understood..

    Planetary waves are wild:

    http://www.weatheroffice.gc.ca/data/model_forecast/colour_images/12_054_G1_north@america@zoomout_I_4PAN_CLASSIC@012_000.jpg

    Northern Air masses are easily penetrated by Low pressure systems from the South. This means it can be crazily warm in one sector and strangely “new ice age” cold in another region.

    I am also interested in Australias weather, it looks like the current La-Nina may be short lived.
    Then again chaos is hard to project in any model….

  17. 517
    Septic Matthew says:

    506, Barton Paul Levenson: What part of “global warming will increase drought until we have at least one year where no country has a good harvest and we all die” do you not understand? My research, about to come out in J. Climate, estimates that will happen in 2052.

    That is certainly a clear and testable prediction. Surely there’s a confidence interval on that estimate?

    Congratulations on the publication.

  18. 518
    Rick Brown says:

    re Hank Robert’s #513 link to Sci Am article about dire predictions not working – this http://www.scientificamerican.com/article.cfm?id=why-dire-climate-warnings-boost or this http://www.nature.com/news/2011/110104/full/news.2011.701.html worked better for me.

  19. 519
    Didactylos says:

    jheath, Dai’s review of drought shows that many areas, including parts of the US, will experience moderate to severe drought in the next 50 years, and that will only get worse. So far as I am aware, BPL’s research only confirms this.

    If, as you claim, you advise governments, then it is absolutely critical that you don’t make blanket statements. Climate change is affecting different regions in different ways. It is a global problem, but apart from the simple necessity to reduce global emissions, solutions to climate change are going to be regional. Someone recommended nuclear power, for example. And, in general, that’s a good idea. But nuclear power isn’t needed in some countries, and is unsuitable for others. Some countries, meanwhile, cannot practically achieve 100% renewable energy without it.

    Sea level rise is a problem for the future. A real problem, but one that can be tackled now by changing planning laws and regulations. For some countries, it is no issue at all. For others, it is going to have serious implications. Don’t be fooled by the current sea level rise. Be aware that sea level is the problem that will come latest, and last longest.

    You are also aware, I trust, that the IPCC has already underestimated some of the effects of climate change?

    You are also aware that governments have never fully funded climate change action. They haven’t even put up a tiny fraction of the expected costs. So, if you want to reduce your personal estimates of the final bill by, say, 50% (unjustified, but whatever) then you still need to recommend that governments increase their spending and do a lot more to tackle climate change.

    Please stop pushing a one-size solution, and give a complicated subject the time it deserves.

  20. 520
    dhogaza says:

    y’all are missing the obvious point …

    jheath:

    albeit within your predicted range.

    In other words, scientists have predicted, and events support it, therefore we should ignore science …

  21. 521
    Didactylos says:

    [edit - We've made it plain that calling other commenters names is not acceptable. You've made your feelings abundantly clear, there is no need to repeat yourself over and again. I suggest that the whole topic be dropped until the actual paper is available. ]

  22. 522
    Didactylos says:

    I didn’t say he is a moron. Clearly he’s not stupid. I said that’s how he will be perceived from the unvarnished claims he makes.

    “there is no need to repeat yourself over and again.”

    Will you kindly tell him the same? That would solve the problem, wouldn’t it?

  23. 523
    CM says:

    jheath:

    > I advise Governments and senior administrators in three countries

    Neverland, Narnia, and Oz?

  24. 524
    Dave Walker says:

    I am a non scientist, non climatologist, non meteorologist, non mathematician – but I have been following the AGW debate with more than average interest. I am, by instinct, anti-establishment and

    I live in Oxfordshire in England and I have just been made aware of the CET graph on the Met Office site in the UK which, I understand has been running since the late 1600s.

    As I understand it, this data is accepted as being beyond reproach by all and is accepted as being a true and fair representation of events over the last 300 years or so.

    Having looked at the graph and applied my admittedly limited skills I conclude that nothing extraordinary or exceptional is happening – other than a long term, gradual and limited amount of overall “warming”. Any attempt, by eye (I don’t have the ability to download the data and create a mathematical straight line), to apply a straight line trend line over the period would, in my view, reveal nothing – other than this long term trend.

    Of course, England is not the whole of Europe, Europe is not the whole of the Northern Hemisphere and certainly not the whole of the planet. However, it is at least one record that has been kept consistently, over a long period, by a reputable organisation, and can be relied upon to at least give an accurate picture for England (unless someone can tell me otherwise?).

    I would observe that there were increases in the 10 year trend from about 1985 to 2000. This increase is similar in increase and length to the periods starting in 1810, 1835 and 1890. I would also observe that the trend has been down since it peaked in about 2002/3.

    Currently, the 10 year average is roughly the same as was the case in about 1945 and 1988 – and is about 0.5 degree higher than in 1830, 1870 and 1900.

    All this suggests that England has experienced nothing other than about 1.0 degree of warming, spread out, over the course of 300 years.

    The rising temperature line from about 1985 to 2000 seems to have been the main catalyst for concern but the line has turned down since then and, on the whole, everything appears “normal”.

    With all of the above and 10 year average temperature trend being now roughly the same as it was back in 1945, based upon this graph, one cannot conclude that there is any evidence of AGW affecting England. Yes, there has been long term, gradual and marginal warming but nothing exceptional or extraordinary.

    The main issue for me is whilst all of this normal, gradual warming has continued (until the last 10 years or so) the press and media has “front-paged” every exceptional weather event in the UK as further evidence of AGW. Hot summers, mild winters, periods of little rain, periods of heavy rain, no snow, lots of snow, etc are splashed across the news as “evidence” of AGW.

    However, the CET graph shows us that the sum of all this is – “normality”. It shows, on average, that little, or nothing, has happened to English temperatures over the course of 300 years or so (other than the long term warming trend – which may, or may not, have ceased for the time being).

    Can we agree that AGW appears not to be affecting the climate in England?

  25. 525
    Dan H. says:

    Some have recently questioned jheath’s statement that “numbers are coming in below previous policy assumptions.” Check the CRU values.
    http://www.climate4you.com/
    According to the global temperature plot, the 10-year average reached its highest point in July, 2007, and has decreased since. Since 2000, the temperature record has been essentially flat, with the overal trend not significantly different from zero (the actual trendline is slightly negative). This is the statement that Phil Jones made, and that jheath is apparently reiterating. Some people apparently which to deny that this trend has occurred recently, but the lack of warming has become a real sticky point throughout the climate community. Yes, this is all within the predicted range, but it contradicts those who think that the IPCC underestimated the effects.
    Those who are lambasting jheath for his decision must remember that economic security comes before environmentalism. Only after countries achieved significant wealth, were they able to clean up their surroundings (much of which helped generate the wealth). Increased prosperity will lead to improved environmental policies. No elected government official (who wishes to remain so) will put the needs of the environment above the needs of the people. Whether you agree or not, this is the case.

    [Response: Oh please. The idea that the environment is somehow something that is independent of people is just bogus. Ask people in china whether they are separate from the dirty air they are forced to breathe. Or people in Bangladesh whether they are separate from the arsenic in their groundwater, or the Inuit whether they are separate from the sea ice on which their culture depends. And someone in the Netherlands if they are independent of the dyke system, or Arizonans if they can live without the Colorado. Your list of arguments would make a Greek rhetorician proud, but they are nothing but sophistry. -gavin]

  26. 526

    HR 507,

    Yeah, yeah, Hank, cute. End of the world. Impossible, right?

    The planet will still be here.
    Life will still be here.
    Very likely some humans will survive.
    Human civilization WILL NOT.

    We are DESTROYING THE ECOSYSTEM WE NEED TO SURVIVE. My paper covers ONE of the big problems, the one I think will be most immediate. In addition to the growing drought, the following facts may interest you:

    * Phytoplankton, the base of the ocean food chain, is down 40% since 1950.

    * 90% of the big game fish are gone. Expect the price of tuna to go up. Remember you heard it here first.

    * We are already in the middle of the sixth great mass extinction on Earth. Last year it was Brazil’s golden frog. But frogs are in trouble all over the world. Canary in the coal mine.

    * If polar cap melting turns out to be non-linear, we could lose trillions of dollars worth of infrastructure in this century, and create several hundred million climate refugees nobody will want to help. Consider how the US feels about Mexicans. Or India about Pakistanis.

    * One billion people depend on glaciers for fresh water. Glaciers, you may have heard, are receding. India and Pakistan, both armed to the teeth including nukes, have ALREADY exchanged fire and had troops killed over who owns a glacier. Nuclear armed China also wants the Siachen glacier region. Think those three parties will sit down and negotiate reasonably about it?

    Open your eyes. We get off fossil fuels as fast as humanly possible–say in the next five to ten years–or human civilization WILL END IN THIS CENTURY. I have no doubts about it. Call me a fanatic if it makes you feel better.

    Could I be wrong? Of course I could. So could you. For which wrong guess are the consequences greater?

  27. 527

    HR 513: Why dire climate warnings boost skepticism

    BPL: Do you want us to lie? Hello? The truth is, the situation IS dire. Even if you don’t walk out of your house today and see earthquakes and fire, the simple fact is that we’re killing our life-support system, fast. If “dire warnings” are out, what do you recommend? Tepid warnings? Compromise? Give and take on both sides?

  28. 528

    SM 517,

    In 10,000 simulation runs, collapse was always reached between 2050 and 2055. The standard deviation on my estimate of 2052.34 was 0.66 years. 95% confidence limits would then be 1.32 years.

  29. 529

    DW 525,

    You need to Google “fallacy of composition.”

  30. 530
    Saugato Mukerji UOW says:

    Looking at the rising CO2 ppm there is no contest that the atmosphere is trapping more energy every year.

    The extreme weather events are primarily atmospheric energy events though there are significant exchanges of energy between the sea/land and the atmosphere.

    All major weather events including heavy rain, extreme hot dry spells, extreme cold snaps are a result of application of large amounts of energy in some parts of the atmosphere and exchange of energy between the regions of atmosphere and also associated earth and water surface.

    If we consider the weather to be something analogous to a pendulum where the amplitude of the oscillation is increased if we apply small amounts of external energy in each cycle. Then it is not hard to explain the increasing frequency and intensity of weather events. Imagine every year small amounts of additional energy is being applied, over what was applied in the previous year, from the trapped solar radiation in that year.

    If we look at the extreme weather in 2010 we can recollect unprecedented heavy floods, more and stronger storms, fires caused by dry hot spells, and more recently extreme cold spell in Europe and North America.

    [Response: While this might all seem very logical, there is no empirical evidence, nor theoretical basis, that supports this notion that all extremes have to increase with global temperature. Some extremes are predicted to increase (heat wave, droughts, precip intensity), some are predicted to decrease (extreme cold air outbreaks), and for many there is either no evidence or conflicting evidence for change in any direction (ice storms, hurricanes, tornadoes, etc.). We would all do well to bear this in mind when discussing 'extremes'. - gavin]

    Instead of looking for a trend of heating or cooling measuring the frequency and intensity of climate events is perhaps a better measure. In the long run though, it is logical to expect the global long term moving average of the surface temperatures to rise associated with the increase in atmospheric energy entrapment by rising GHG levels. This expected trend of temperature rise too appears to be happening.

    Given all this perhaps the data from a single location i.e. England over last 300 years seems to be less than sufficient to explain the whole global weather phenomenon in the climate change era.

    [Response: This is clearly true. - gavin]

  31. 531
    Dan H. says:

    Dave,
    I certainly agree with you. That graph is the longest running temperature profile available, and has shown a slight long-term temperature rise, but nothing extraordinary in recent years. The general shape of the graph is mimicked in other records, with general warming during the 1990s, 1930s, 1880s, etc., but with different amplitudes. While England certainly does not represent the entire world, the trends observed there are similar to what is happening worldwide.
    Yes, reports that recent weather events are examples of AGW are bordering on the ridiculous. It seems that we have a running joke of “blame it on global warming.” I believe Rowlings even used to explain some of the events in her books.
    I do not believe that England is unique in this aspect. Temperatures in the U.S. have been fairly average over the last few years, and although there exists a slight long-term increase, the trends over last 120 years or so match up quite well with England.

    [Response: The local variability will also be larger than the trends on short term scales - this is hardly news. Neither are people pretending that winter suddenly means that the globe is not warming. I have gotten used to increases in media attention to climate whenever the weather does something weird and our answers have not changed regardless of whether it's a 'warm' bit of weirdness, or a 'cool' bit of weirdness, or whether it's just weird: attribution is hard, and people claiming that individual events in themselves are either confirming or denying larger scale changes are going way out on a limb. Post hoc justifications for current weather made by trawling through the literature for papers finding small tendencies in one direction or another are almost pointless, and almost always confusing to the general public. But be very clear that there is a huge gulf between what the media says or how it spins such stories and what 'scientists say'. - gavin]

  32. 532
    Dave Walker says:

    BTL 529

    Done that – don’t get your point.

    I am not making arguments – I am commenting on “facts”. The graph is used to make the case for AGW and the Met Offices comments on the same page pick out landmark moments as evidence. For instance “2006 was the warmest year on record for min HadCET and mean HadCET”.

    Each point on the graph is a “fact”. The trend line is a “fact”. Trend lines show trends – “Fact”.

    Are you saying that I should ignore all of the facts and lsiten to rhetoric instead?

    BTW, for anyone interested, the graph is at: http://hadobs.metoffice.com/hadcet/

  33. 533

    Given all this perhaps the data from a single location i.e. England over last 300 years seems to be less than sufficient to explain the whole global weather phenomenon in the climate change era.

    [Response: This is clearly true. - gavin]

    And equally true of the latest squib from Easterbrook, which implicitly conflates records from a couple of different sources (US GISS data, Greenland ice core data) with GMT. It seems to be making the rounds at the moment, courtesy of (you guessed it) WUWT.

  34. 534
    Dave Walker says:

    BTL 529

    Is that it? Is that all you can come up with in response to what I thought was a reasonable and accurate summation of factual data produced by one reputable organisation relating to one area.

    What is the purpose of creating and publishing the graph if we are not to draw some conclusions from it?

    I didn’t extrapolate and say that therefore AGW was a crock. I didn’t say that AGW wasn’t real. I didn’t say that data for elsewhere in the world wouldn’t show a different picture.

    Based upon the graph alone, what conclusions would you draw?

    [Response: Why would you draw conclusions from a single graph when there millions of other bits of context available? This strikes me as a particularly silly line of questioning. - gavin]

  35. 535

    Dave Walker, (524, 525, 531) I think that the graph you point to utterly fails to support your comments in #524. There is no period of elevated temperatures comparable to that for the last three decades or so. And there is little evidence of a warming trend prior to 1880 or so, whereas warming has clearly dominated since (though there are several brief coolings, to be sure.) Is there a reason to think that the current cooling will be any more durable than previous such? I don’t see such a reason.

    On the other hand, the longer-term warming is likely to do so, for two reasons:

    1) Statistically, it is much more likely to be the result of ‘signal’ rather than ‘noise,’ simply by virtue of its length;
    2) In terms of causation, it is the expected result of a physical mechanism (climate change driven by greenhouse radiative forcing) for which a great deal of independent evidence exists.

    This much I can say, based upon eyeballing the graph. But it would help you, I think, to learn a bit more about the more formal statistical methods by which such questions are properly assessed. For that, I know of no better online resource than the “Open Mind” blog. It’s here:

    http://tamino.wordpress.com/

    If you do, you’ll find out that in the context of climate change most short-term trends, such as 10-year ones, fail to reach “statistical significance,” which essentially means that they are probably just due to random variation and have no longer-term significance whatever. That’s why Professor Jones, whom you quote, is not worrying unduly about the “lack of warming” during the 2000s. (Actually, global measures, unlike CET, do show warming during this span, but not at statistically significant levels.)

    He may, however–as the victim of some outrageous quote-mining based upon a certain leading question put to him in a BBC interview–worry about misinterpretations of this observation by those whose understanding of statistics is not very strong. There is no shortage of the latter, many of whom exhibit certitude inversely related to that understanding.

  36. 536
    Didactylos says:

    BPL said “My paper covers ONE of the big problems”

    This doesn’t make his paper less valuable. But it does limit the scope of what he can conclude from it.

    Yet his conclusions have nothing to do with that problem, and ignore all the other factors, pro and con.

    Interestingly, William M. Connolley has criticised Dai’s 2010 review quite strongly. Nothing that casts much doubt on the results, but he highlights the uncertainty that somehow doesn’t quite make it into some of the headline figures – such as the low agreement on even the sign of the change in modelled precipitation, runoff, etc from model to model.

    Now, I quite like Dai’s paper. What I understand of it, anyway. But William’s point is a good one; it is easy to read too much into some of the maps, and it is utterly insane to give much weight to a single model. If other models give wildly different results, then claiming that the results from just one model are absolutely certain makes no sense at all.

    I admit, I had assumed there was higher agreement among models. And there is high agreement if you confine yourself to statements about what sort of changes will happen, and don’t get too detailed about regional change or too hung up on magnitude.

    I was going to save all this for when BPL’s paper eventually appears, but it seems he’s using his unpublished results as sole support for his claims for the uncounted time. I’m rather tempted to recommend PZ Myers’ Pascal’s Wager, but I’m afraid it will distract from serious matters – such as saving future generations.

  37. 537
    Didactylos says:

    Dave Walker: What would you expect HadCET to show if there is no such thing as global warming?

    What would you expect HadCET to show if global warming is a reality?

    How would you expect this to differ from the global temperature record?

  38. 538
    Dave Walker says:

    KM 535

    1. You wrote “I think that the graph you point to utterly fails to support your comments in #524. There is no period of elevated temperatures comparable to that for the last three decades or so. And there is little evidence of a warming trend prior to 1880 or so, whereas warming has clearly dominated since (though there are several brief coolings, to be sure.) Is there a reason to think that the current cooling will be any more durable than previous such? I don’t see such a reason”.

    - My comments were meant to be factual and non argumentitive!

    The graph shows a long term, gradual increase including peaks and troughs along the way – Yes? No?

    The graph shows periods of relatively “rapid” increases at various times along the way. Yes? No?

    If the trend, over a long period is that of gradual warming then, of course, and given no other information, it is a statement of the obvious, that the more recent figures will be, on the whole, higher than those of 300 years ago – and all stops in between. Yes? No?

    “Will the recent cooling be any more durable than previous such?”

    Based upon the long term trend, one would expect the trend line to turn up again at some point – unless something has happened such that the warming cycle has ended and the trend is now for “cooler” times – and neither I, nor anyone else can pretend to “know” that – only time will tell.

    With respect to your comments about me alledgedly quoting Prefessor Jones – I think you are confusing me with someone else.

    2 With respect to Gavin’s comment “[Response: Why would you draw conclusions from a single graph when there millions of other bits of context available? This strikes me as a particularly silly line of questioning. - gavin]

    Gavin, the issue is about warming – which is about temperatures. The graph is about temperatures. The conclusion I drew was about temperatures – based upon the facts shown in the graph.

    I live in England, the graph is about my country. I trust the graph (given the source) to provide acurate data. I apply my limited intelligence to the graph and drew conclusions about what has happened to temperatures in my country over the last 300 years.

    Where did I go wrong?

    The graph appears to show a long term, gradual warming with peaks and troughs along the way. If this is correct then the graph suggests that England is not suffering any exceptional or worrisome phenomena – only a long term trend of warming.

    This doesn’t mean that other places aren’t being challenged by exceptional warming – it just means England isn’t. Doesn’t it?

    [Response: You are putting too much onto a single graph. This current decade is exceptional - even in the UK, as it is globally. Whether the that is "challenging" the UK certainly can't be seen in that graph - it would need to be assessed locally using all sorts of information about agriculture, coastal erosion, water resources, building codes, infrastructure etc. Whether this is "worrisome" is also not determinable from the graph alone - indeed if the only thing we had was temperature measurements, I doubt too many people would be worried. 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]

  39. 539
    Didactylos says:

    Dave Walker said: “The graph shows a long term, gradual increase including peaks and troughs along the way – Yes? No?”

    No.

    Don’t believe me?

    Try fitting a line to the period 1780 to 1880. Do the same for 1910 to 2010. You will find that the two periods have very different trends. There is virtually no trend in the earlier period. There is a strong warming trend in the later period.

    This is exactly what you would expect if global warming is reality.

    You would also expect the variability (the peaks and troughs, and the spiky outliers) to be much greater than the global temperature record. This is, after all, only a tiny, almost negligible part of the globe. And what do we see? Lots of ups and downs, it almost looks like a rollercoaster. The peaks and troughs don’t affect the long term trends, nor does the current trough mean anything more than any other trough.

  40. 540

    #538–Evidently, I was insufficiently clear. Let me take as point of departure this bit:

    The graph appears to show a long term, gradual warming with peaks and troughs along the way. If this is correct then the graph suggests that England is not suffering any exceptional or worrisome phenomena – only a long term trend of warming.

    Yes, the graph shows “a long term, gradual warming with peaks and troughs along the way.” However, I don’t think it’s as long as you are thinking.

    You’d characterized it as a 300-year trend, but my “Eyeball Mark I” analysis suggests a 120-year trend, with a particularly abrupt rise from ca. 1980. I also note very dramatically elevated temperatures–.5 C being pretty dramatic in this context–in the last decade. That last I would indeed characterize as “exceptional,” and given the larger context–what we know about GHG emissions, their effects on climate, and the probable results of said effects–I personally think it justifies worry quite well.

    Another .5 C in 30 years–the naive linear extrapolation–might not seem that significant at first blush, but such a shift can have very marked effects on the frequency of highly temperature-dependent events–such as, to offer a few quasi-random examples, health-threatening heatwaves, freeze days or the low-temperature days and nights necessary to set fruit for some commercial tree crops. And of course, there’d still be lots more warming after that, if nothing were done.

    Of course, I’m basically just quickly restating what Gavin already said in more detail in his response, but put me down as seconding the motion, so to speak.

  41. 541
    Dave Walker says:

    538 Gavin’s comments

    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.

    I accept that you differentiated yourself from the “establishment” by stating your concerns about the links that are often assumed between any weird weather event and AGW.

    The problem is that the establishment trots out his stuff all of the time. Whether it is flood or drought, heat or cold, it is stated that it is AGW that it is the cause.

    I instinctively react to such stuff and nonsense!

    [Response: This has nothing to do with the 'establishment' and every thing to do with how the media deals with complex issues. You are directing your ire towards completely the wrong target. The science 'establishment' is extremely conservative (small c) and does not collectively give misleading quotes to reporters, write op-eds touting their (proprietary) new forecasting system, make up headlines that scream 'scientists say' when in reality no scientist has ever said that. What you see is because the media loves sensation, conflict and man bites dog narratives far more than they love objective truth. No story is too complex to be reduced to a misleading headline in the Daily Mail. - gavin]

    The graph shows, as far as England is concerned, that there has been little change over a very long period. And yet, if you were an alien landed from Mars and read the newspapers or listened to the TV and radio news, you would believe that England has been, and is still, suffering huge climate change that is affecting our lives on a daily basis.

    [Response: A wise man once said 'never believe anything you read in a newspaper' - and that goes double for the UK press (with a couple of small exceptions). - gavin]

    When some idiot talks about exceptional flooding – they invariably mention AGW. When we have, in English terms, a relative drought (i.e. some areas of the country may be banned from using hose pipes to water their gardens)- its AGW – not a drier spell that is a result of normal weather variations!

    We will be fed pictures of a dried up stream – but no pictures 2 weeks later when everything is back to normal. I am shown pictures of flowers blooming exceptionally early in one spring (its AGW don’t you know) – the next year, spring arrives 3 weeks later and – nothing!

    [Response: Again - you are viewing science through the prism of the media. It is the lens that is distorted, not the science. - gavin]

    It is a constant stream of nonsense propoganda based upon no facts (as far as English weather is concerned) whatsoever.

    I therefore “know” that the poiticians and the MSM are either part of an “intellectual conspiracy” – or they are stupid – or they are just folowing like sheep. They may be be well meaning or maybe they are just afraid to look at data themselves and draw their own conclusions in case they suffer career wise for not swallowing the party line.

    [Response: This is less likely - most governments have big research staff and spend a lot of time digging into the details outside of the what is in the media. Governments across the world have all looked into the science of climate change and decided that this is a threat worth hedging against. This has very little to do with media reporting, and much more to do with the scientific consensus on the subject (as summarised by IPCC, Royal Society, National Academies etc.). - gavin]

    I liken the situation to WMDs in Iraq. Many “curmudgeons” like me doubted the whole proposition. Bush and Blair, FBI, CIA, MI5, MI6 – all trotting out an establishment “line” when, with the benefit of 20/20 hindsight we now know that all of the “expert” consensus was totally and utterly wrong!

    [Response: But there never was an 'expert' consensus - there was instead politicians determined on a course of action from the beginning and pulling in cherry picked and misleading 'expertise' to bolster their predetermined plan. This is nothing like the climate change situation at all - politicians have had to be dragged kicking and screaming into even acknowledging this is a problem. - gavin]

    I’m starting to rant now and that is not fair to you and achieves no purpose – but I am sure you get my drift.

    Thank you for allowing me on the site and for the time you gave me in your replies.

  42. 542
    Hank Roberts says:

    >> HR 513: Why dire climate warnings boost skepticism
    > BPL: Do you want us to lie?

    I want you to speak to people’s belief that the world can be fair and find allies among the people working to improve this who are smart enough to be doing it right.

    From the sidebar: http://www.ecoequity.org/
    From the eco-equity page: http://gdrights.org/
    where they say: “… despite an increasingly widespread sense that climate catastrophe can no longer be averted … radical action, on the necessary scale, is still a very much within the realm of possibility. (more…)

    Those who know the science are aware of the point you’re trying to make. Those working in the policy area who know where we’re headed are working on it, some of them in ways that may help.

    Your task is to accept that you’ve added one more tiny bit of documentation to an overwhelming mass of documentation, not discovered something unknown.

    Then notice who’s working on it.

    Here’s what to avoid — pushing the wrong way. Trying to scare people isn’t effective. It makes people dig in and deny the fear. Know evolutionary biology? It’s deeply engrained, it used to work. It continues to happen.
    Urging fear is like urging Irish Elk to grow bigger antlers, not useful.

    You know this stuff. But right now you’ve got your name on something coming out in a journal and you’re proud of it. But — you need to think about what leverage you have and which direction to push.

    “…. ‘People know intuitively where leverage points are. Time after time I’ve done an analysis of a company, and I’ve figured out a leverage point. Then I’ve gone to the company and discovered that everyone is pushing it in the wrong direction!’

    “… complex systems are, well, complex…. leverage points are not intuitive.”

    http://www.developerdotstar.com/mag/articles/places_intervene_system.html
    – Leverage Points: Places to Intervene in a System by Donella H. Meadows.
    http://www.sustainabilityinstitute.org/pubs/Leverage_Points.pdf

    You’ve discovered what most people who know where we’re headed already know, you may have a more precise detail about when we’ll get where we’re headed and precisely how, but — aside from your pride in accomplishment — it doesn’t matter that much how precise your answer is because what’s needed doesn’t change — all the people aware of limits and overshoot understand.

    Work with them.

  43. 543
    dhogaza says:

    Dave Walker and Dan H:

    While England certainly does not represent the entire world

    Being a small island with a maritime climate, it is utterly unrepresentative of the rest of the (terrestrial) world.

    However, as others point out, warming is being observed in England. Also England researchers have been world leaders in gathering and evaluating phenomenological changes. English gardeners, birders, game wardens, etc have been keeping records of things like first arrivals of migratory species, first blooming times, etc for a long time, in some cases with a kind of fanatical obsession. Records at some locals go back well over a century. and what does this observational data show? Spring’s about a month earlier than in the Victorian area.

    Change is a happenin’ …

  44. 544
    Dave Walker says:

    537 & 539 Didactylos

    I have just posted a reply to Gavin’s comments as a “sign off” – however – I will reply to your two comments before I go.

    537
    Answer 1. I would expect to see lots of ups and downs on an annual basis with a horizontal trend lineline.

    Answer 2. I believe the graph does show English warming.

    3. Based upon Answer 2, I would expect the rest of the globe to be warming similarly I guess.

    The evidence of warming seems to be pretty clear. The issue is surely how much, if any, is due to man? And whether there is a damn thing we can do about it. Are we being brillantly clever in working out ways in which we can control the cliamte of a planet – or are we being Canutes (apologies for this reference if the King Canute fable is not part of USA educatinal culture.

    539

    Sir – you cannot just pick and choose start and end points at random to suit an argument. We have a graph, with a 10 year trend on it – so that it what I am commenting upon. If we start picking and choosing then what is to stop me focusing on the last 10 years, or just the period since 1830 (i.e. less than 0.5 degree in nearly 200 years).

    Of course, short term trends are meaningless – unless, it appears, we are talking about the period from 1985 through to 2000 when I am expected to believe that the rise is due to AGW obviously.

    Let me ask you a question. If we were able to go forward 25 years and then look back at the last 25 years temperatures, what would the graph need to have done before you might accept that there may be an issue with the AGW theory?

    If the line carried on down for say 5 years and then flatlined at the zero anomoly – would that change your view?

    If the line flat lined for 5 years and then rose gently for the remainder – would that change anything?

    If the trend flatlined for the whole 25 years would that change your view?

  45. 545
    Hank Roberts says:

    For DaveW if he’s not actually disappearing.

    For other readers, later:

    Do you know how many years (annual data points) you need to determine whether there is a trend, for that particular data set? Do you know how to find out?
    The answer depends on how variable the data is. There’s no simple global answer and you can’t tell by looking at a picture. What source are you relying on to decide whether a trend can be discerned in the data?

    For those at high school level or above, Robert Grumbine teaches this well:
    http://www.google.com/search?q=grumbine+results+trends

  46. 546
    Didactylos says:

    Dave Walker: You are quite right: cherry picking is bad. For example, you seem to be giving far too much weight to the last little dip in the graph. Most smoothing algorithms won’t even give values that close to the end of the data!

    But I didn’t cherry-pick. I chose the first century and last century of the graph you presented. As you say, short trends are meaningless. For global climate, 30 years is enough to establish a climate trend. For such noisy data as the HadCET annual record, a longer period is safer. I chose a century. The exact period isn’t important. You will get the same basic result if you pick 50 years or 150 years, or move the interval a small amount either way. The idea is to judge whether the trend in the early part of the graph is the same as the trend in the latest part. Clearly it is not. (It is possible to rigorously show what period best shows the trend and distinguishes it from the noise. That’s beyond the scope of this little comment, though.)

    You ask me some questions about what will change my views. Well, firstly nothing in the HadCET record is ever going to do that, since we have far better, global records. England alone is susceptible to changes in the position of the jetstream, and other regional climate changes. Despite this, I do expect England to continue warming. Small troughs in the next 25 years are inevitable. 5 consecutive years below the baseline is very, very unlikely. 25 years below the baseline would need an explanation we do not currently have.

    Note that this explanation isn’t going to affect global warming theory, because it has nothing to do with the globe. If we saw the same pattern in the global record, of course….

    2010 is an outlier given the warming trend. The possibility of 2011 being lower than 2010 is again, very, very small. It is extremely likely that the mean of the next decade will be significantly higher than the mean of the previous decade.

    The problem with what you say is that in 5 years time, you can say “but what about the next 5 years?” and repeat every 5 years after that. At what point do you concede that the warming is going to continue?

    Please remember that while local temperatures are the only important factor for some aspects of climate change, for others such as sea level rise, global temperature is going to be decisive.

  47. 547
    Dan H. says:

    I tend to agree with Kevin that the graph shows a 120-yr increase, although I would not say that the rise from 1980-200 was any greater than some of the others. The increase appears to be ~0.6C/century over that time frame.
    Will the recent cooling be any more durable than previous? Hard to tell. The previous cooling trends appeared to each last roughly 20 years; 1865-1885 and 1945-1965 (eyeballing). Based on past history, you have another decade or so before the warming resumes.

  48. 548
    Hank Roberts says:

    > Dan H
    > I tend to agree with Kevin

    But, Dan, you’re a notorious outlier.

  49. 549
  50. 550
    Dan H. says:

    I like it that way Hank.
    Is it not ironic that I am actually siding with Kevin on this one.


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