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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. 201
    FurryCatHerder says:

    Rod B @ 187:

    Especially since I lived in New Orleans during worse.

    Katrina was caused by a failure of the Army Corps of Engineers, not high winds.

    That said, having lived in New Orleans for 20 years (more or less), I don’t remember all that many seasons where we did “hurricane watch” nearly as much as the ’05 season. In a typical year we taped the windows once, maybe. And we evacuated exactly once in 20 years.

    Something definitely changed — speaking from 42 years of looking at the hurricane seasons in New Orleans — and it didn’t change for the better. It also isn’t 100% gloom-and-doom.

  2. 202
    Rod B says:

    Lawrence Coleman, I can accept that there might be extreme weather situations from time to time. These might or might not be a direct result from climate change. Going from one extreme (drought) to the opposite rainfall extreme in the same localized region within one year seems very hard to attribute to a consistent level of climate change. Are you sure it’s not the Devil — the Tazmanian type or another ;-) ?

    Ray Ladbury says,

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

    What you say is possible and not hard to understand. However, to extend the logic to say, therefore, that Moscow heat wave was caused by climate change, that Australian drought was caused by climate change, that Australian washout was caused by climate change, that hurricane was caused by climate change, that European cold snap was caused by climate change, makes very little and probably no sense (to the 95% confidence level, as it were). Why is that hard for you to understand? [And I'm sure you wouldn't, but if you consider answering that you don't want to understand, remember you'll have to answer to Nick Gotts :-- )} .]

  3. 203
    Patrick 027 says:

    Re 148 Pekka Kostamo
    None of these [factors determining a particular weather event being discussed] is immune to change by global warming.

    Apparently it is presently impossible to model direct causation of a given event. In principle it will always be difficult to trace the chains of causation beyond the horizon of the butterfly effect.

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

    Yes and no.

    Is any single day truly ordinary? Well, let’s say it wouldn’t have made headlines; it would have fallen into some category of a little warmer or colder, cloudier or sunnier, dryer or wetter, etc, but not so much as to make a big deal about it.

    But that’s because we would only make big deals about rare events, so without climate change, at a given day and location, it’s usually going to be unlikely to be so dramatic.

    However, even with climate change, that single day and location was unlikely to have been so dramatic (until the time horizon approached when it was possible to make forecasts for it). Consider all the days in the years 2000 to 2010 when one of the strongest/biggest hurricanes ever recorded did not make landfall near New Orleans.

    The question mixes the climate change itself with the butterfly effects associated will all the little things that have added up to it (ie the climate change caused by emissions vs the weather caused by each little incident involved in those emissions; even if CO2 had no effect on climate, CO2 emissions would change the weather – but nobody would notice and few would care).

    Climate change could have made a Katrina more likely; by either making tropical cyclones more frequent (I’ve gotten the impression that’s not expected) or by making them stronger (that one may be true), and except for immediate radiative effects of CO2, etc, that would be through the set-up (the warmer oceans, etc., caused by the effects of CO2 over time).

  4. 204
    Septic Matthew says:

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

    As you and others have pointed out, the Arctic right now is unusually warm, so 2010 may yet end up as the “warmest year on record”:

    http://ocean.dmi.dk/arctic/meant80n.uk.php

    Even as England and Germany seem to be having unusually cold winters.

    Right now, parts of Greenland are considerably above average in temp, and others are considerably below average.

    I am hoping that GCMs will be accurate enough soon enough (and computers fast enough soon enough) that 3-month ahead and 6-month ahead predictions can be made for diverse localities (and eventually for all localities of sufficient size, perhaps 100km x100km) and compete head-to-head with Piers Corbyn’s (proprietary) forecasts.

    A long series of accurate 3-month or 6-month ahead predictions would go a long way toward increasing the respect with which people treat AGW, though technically they are neither necessary nor sufficient for the long-term forecasts to be reasonably accurate. They would add, in my opinion, to the aggregate forecasts listed by Barton Paul Levenson.

  5. 205
    Septic Matthew says:

    148, Pekka Kostamo: Apparently it is presently impossible to model direct causation of a given event. Still it can be stated with very high confidence that in an unwarmed climate, August 29th, 2005 in New Orleans would have been just an ordinary summer day.
    !?
    Yet, probability of a storm hitting a particular city on any given day has also changed due to global warming – or has it not?

    Those are difficult to decide, IMO. The worst storms to hit the US Gulf Coast did so in the first half of the 20th century; the damage to N.O. was due in part to regional deforestation and the construction of a long, straight ship channel into the center of the city; 2010 saw no hurricane hit the coast of the U.S; a forecast by Kerry Emanuel, linked here by mike predicted slightly lower total hurricane activity due to AGW, but increased frequency of big hurricanes “might” occur in some places.

  6. 206
    Bob says:

    Gavin 1999 : Greenhouse Effect Makes Winters Warm

  7. 207
    Pekka Kostamo says:

    I listed ten background factors that are known to influence the birth, evolution and track of hurricane. These are factors used by meteorologists trying to predict the storms. None of them is completely immune to change in global temperature. Walking backwards one level deeper leads to changes caused by warming in large scale circulation (ENSO, Hadley and Walker circulations, seasonal highs and lows, patterns of vegetation and many more) that still are less well understood or measured. Yet they are governed by physics. Understanding and modeling them is very much work-in-progress.

    Surely, in an unwarmed world there would have been a storm named “Katrina”. A different birthday and location, a different strength development and path taken over a two week life cycle, extremely unlikely to hit N.O.. Details are not knowable as neither observations nor models exist at required accuracy level.

    However, there was/is no guarantee against a similar hit or worse, earlier or later. This was bad, very bad, but not the worst. A category 5 storm landfall west of the city, and surely more than a few dozed shingles would have been ripped off the Superdome sheltering some 15000 refugees, eventually leading to a total collapse. These are kind of one day in 300 years’ probabilities. They demonstrate risks with extreme impact but very low (yet real) likelihood.

    These kinds of extreme weather events are not truly random. “Random” is just a convenient way of description and rough modeling. Surely better descriptions and models based on physics will be developed to link the global warming and extreme weather.

  8. 208
    calyptorhynchus says:

    162 BPL “The bad guys have won”

    I think we’ll see the leading denialist propgandists on trial before too long.

  9. 209
    Sou says:

    We’ve had what seems like a cold and wet start to summer here in south eastern Australia. Yet the ‘cold’ is only by comparison with prior years’ record-breaking heat. With regard to temperature, the average maximum temperatures for October, November and December were actually above the average from 1971 – 2000. October was 1C above the average, November was 1.4C above the average and so far, December has been 0.4C above the average (Melbourne regional office).

    With regard to rain (la Nina effect), records of rainfall intensity and total rainfall have been broken, as expected in a warming world. It’s good to have plenty of rain to fill up the reservoirs after the long hot record drought, unless you’re in agriculture and lose the first decent crops after the drought, or your livestock is drowned. And unless your home and business are flooded out, or the main road is washed away (as in my valley), or your town closes down (as one town in Western Australia has had to do).

  10. 210
    Edward Greisch says:

    162 “BPL: There is no way out. The bad guys have won. I’m still arguing simply and solely because I hate letting them have the last word.”
    “I told you so” would be sweet. But let’s try for something better. Hang in there. Suicide is not allowed.
    There is reason to believe, provided by you, that it won’t get bad enough for everybody to notice until it is too late.

    167 Bob (Sphaerica) said it well and so did 208 calyptorhynchus. It doesn’t have to get bad enough for everybody to notice. Let’s take the lessons learned from the anti-smoking campaign and the civil rights campaign and try to apply them faster. Let’s use the David Koch tea party movie at:
    http://climateprogress.org/2010/10/14/video-proof-david-koch-the-polluting-billionaire-pulls-the-strings-of-the-tea-party-extremists
    in letters to the editors of lots of newspapers. Let’s get the witch hunts to backfire. Keep on working and keep on keeping on. We will find a way.

    [Response: Yep.--Jim]

  11. 211
  12. 212
    PeteB says:

    tangentially related – Mike Lockwood has been saying some interesting things (probably completely mangled by the press)

    (I left out the stuff I think is rubbish and stuck to what Mike Lockwood said, although half way through the express bit it changes the quote attribution to Cooke)

    http://menmedia.co.uk/manchestereveningnews/news/s/1403388_is_this_the_dawn_of_a_new_ice_age

    “I am of the view that this cold snap, and cold winters, are more likely when solar activity is low, though we don’t know the exact fit,” says Professor Mike Lockwood, a solar physicist from the University of Reading. Prof Lockwood’s theory depends on the level of ultraviolent light coming from the sun. When it is high, it is absorbed by the stratosphere, which warms up, generating more high-altitude winds and leading to a stronger jet stream. The reverse is true when radiation levels are low.

    Prof Lockwood says this could have big knock-on effects. “For the last 20 or 30 years, the sun has been unusually active, and we have got used to that. This has has serious implications for how we organise our society. We have got used to ‘just in time’ retailing, for example, but as the current cold snap shows, snow and ice seriously hamper how quickly things can be transported.”

    None of this means that man-made global warming is not happening, Prof Lockwood stresses. “Overall the world is still heating up. Local variations are more likely when global warming is happening,” he says.

    This from the Express (Sorry reduced to quoting from the express)

    http://www.express.co.uk/posts/view/218537/Dawn-of-a-new-ice-age

    And 2010 is apparently just the beginning. According to Mike Lockwood, professor of space environment physics at the University of Reading, we can expect the cold weather to peak between 2025 to 2040. The problem for us is the impact that low solar activity has on the jet stream, the current of air that blasts across the Atlantic carrying all our warm weather with it.

    “Britain lies just outside the Arctic Circle and on the same latitude as Labrador. If it wasn’t for the jet stream and to a lesser extent the gulf stream – the warming of ocean water – our winter weather would be similar to that the Eskimos experience every year,” says Cooke.

    In simple terms sunspot activity keeps the jet stream going. Take them away and the warm air won’t reach us during the winter months. Instead freezing air from Siberia in the North rushes in to fill the vacuum.

  13. 213
    Anne van der Bom says:

    Matthew,
    22 December 2010 at 4:0 PM

    A long series of accurate 3-month or 6-month ahead predictions would go a long way toward increasing the respect with which people treat AGW, though technically they are neither necessary nor sufficient for the long-term forecasts to be reasonably accurate.

    That is weather prediction, not climate prediction. Read up a little on chaos theory (aka ‘the butterfly effect’) and you’ll see that it is impossible. No amount of computing power will change that.

    What you would see in reality is that these predictions would fail on a regular basis. Each missed prediction will be easily spun by the obfucationist community into: “you see, they can’t even accurately predict the climate 3-6 months ahead, let alone for a century”. Of course conveniently ignoring the fact that it was a weather prediction, not a climate prediction.

    Do us all a favour and remember: weather is not climate.

  14. 214

    \Bob says:
    22 December 2010 at 10:16 PM
    Gavin 1999 : Greenhouse Effect Makes Winters Warm\

    Gavin was absolutely right, its a habit of his;

    Note huge area across the Canadian Arctic and Greenland,

    http://www.esrl.noaa.gov/psd/map/images/fnl/sfctmpmer_07b.fnl.html

    for 7 days having average temperature anomalies greater than +18 C. In fact some places were +25 C above average at times. Is that a warm winter? Spanned world wide its a warmer as well. Unimaginable to walk about clear skies full moon +25 above average in 24 hour darkness. Northern Ellesmere was -2 C today… So Bob its a warm winter. Especially hen Hudson Bay ice melts!

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.13.html

    From the passage of a Low pressure system which went the wrong way.

    As far as I am concerned the \bad guys\ have managed to make a fool of themselves.

    http://www.nytimes.com/2010/12/22/science/earth/22carbon.html?_r=1&ref=globalwarming

    NY times in article on CO2 about Keeling

    Lindzen makes the case for contrarians as usual:

    “I am quite willing to state,” Dr. Lindzen said in a speech this year, “that unprecedented climate catastrophes are not on the horizon, though in several thousand years we may return to an ice age.”

    That was a funny statement, from it will get cold in \4 to 5 years\ to several thousand years,
    the prof is a comedian!

  15. 215
    Anne van der Bom says:

    Barton Paul Levenson
    21 December 2010 at 5:0 AM

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

    What a black-and-white way to say that.

    Have you been influenced by watching too much Hollywood movies that end in a sweeping victory for the good guys and a humiliating defeat for the bad guys? ;-)

    This episode in human history will not have a final victory, neither a crushing defeat. There will be grades of ‘defeat’ and ‘victory’. The more we push, the more we expose the false skeptics, the more we educate, the sooner will people start linking the visible changes to climate change and greenhouse gas emissions and the sooner will they be motivated to take action and accept that difficult choices will have to be made.

    Look at what has been done until now in this respect: many renewable energy solutions have matured over the past decennia. Their contribution to lower CO2 emissions until now has been negligible. But the fact that they are ready for large scale deployment is what is important. Imagine we were still be plodding along with 50 kW wind turbines and $ 30 per W solar panels? Let’s keep the momentum.

    You should think: “Even if our efforts only limit temperature change to 2.3° C instead of 3.5° C , then it’s worth it”

  16. 216
    Esop says:

    #206 (Bob):
    It still makes winters warmer, but not in the same places every year. Right now, the Arctic above 80degs latitude is on average 22F above normal, actually melting sea ice in locations, all while it is dark 24 hours a day. The side effect is that frigid air that should have stayed in the Arctic dumps onto lower latitudes, causing deadly cold snaps. Another good reason to swiftly reduce greenhouse emissions and thereby reduce disturbances to the circulation systems.

  17. 217
    Esop says:

    #212 (PeteB): Lockwood is always worth listening to, but it is worthwhile to note that the NAO was positive in both December 07 and January 08 when the solar activity was also very low. This very fact has also been used as an argument against the sea ice vs. NAO theory, since sea ice extent was the lowest in September 2007. One thing to keep in mind, though, is that 2010 extent has been below 2007 extent since mid-November and it is right now the lowest on record (by date) by far. We are actually losing sea ice at the moment, with Hudson Bay losing 200,000 km^2 over the last 10 days. Also note that the lowest sea ice extent in the period mid to late november was seen in 2006. Interestingly, that period was accompanied by an extremely negative NAO, something that strengthens the ice extent-NAO theory. In 2006, the NAO was negative until New Year, and flipped to strong positive in January. This negative in December to positive in January flip has been observed in close to 60% of the years since 1988.

  18. 218
    SecularAnimist says:

    Barton Paul Levenson: “The bad guys have won.”

    The important thing from the point of view of the “bad guys” is that each and every day that business-as-usual consumption of fossil fuels can be perpetuated, they “win” more than one billion dollars in profit.

  19. 219
    catman306 says:

    Global warming caused climate change will cause the weather, pretty much everywhere, to no longer be ‘mild’. Mild, seasonal weather is the opposite of climate change.

  20. 220
    Septic Matthew says:

    213, Anne van der Bom: That is weather prediction, not climate prediction. Read up a little on chaos theory (aka ‘the butterfly effect’) and you’ll see that it is impossible. No amount of computing power will change that.

    The butterfly effect refers to long-term modeling of chaotic systems, not short-term modeling. Accurate enough short-term forecasts of chaotic systems are possible (for example, models of heart beat are accurate for 1 or 2 cycles, but not beyond.) My first post (#40) on this thread agrees with what you wrote about the impossibility of accurate long-term forecasts from GCMs.

    The GCMs model many localized short-term processes at small scale. Their long-term forecasts (whose results are frequently posted here and elsewhere), are long-term simulations whose results are aggregated across space and time to produce results that are plotted versus time with the time axis marked in years. “Climate” is “weather aggregated over long times and the whole earth”; my claim was merely that a series of short-term forecasts that were accurate would go a long way toward making the long-term forecasts more credible, as the long-term forecasts based on GCMs gain their credibility from the fact that they model the actual physical processes generating the weather and climate. Such a claim is more credible if the models make accurate short-term forecasts.

    Also reread this quote from the main text: Rather, recent analysis suggest that the global mean temperature is marching towards higher values (see figure below), and Petoukhov and Semenov argue that the cold winter should be an expected consequence of a global warming. The use of the word “expected” maybe can’t be disambiguated, but it would surely be more credible a claim if someone last summer had predicted this winter using GCMs and the state of the world at that time. The biggest loss of Arctic Ice occurred 3+ years ago and was followed by a warm winter in England; I don’t think any model or group of people would have predicted that a subsequent regression of Arctic Ice cover to its 30-year trend line would have produced 3 consecutive colder-and-snowier winters than average. Yet, that’s what the authors claim that we ought to have expected — and it’s what I cautioned might be inherently unpredictable.

  21. 221
    Septic Matthew says:

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

    Are you asserting outrigght that changes in OLR (and increased heat retention) will have no effect on atmospheric circulation? Is that an established proposition in AGW research?

  22. 222
    Rod B says:

    Esop (216), what is your source for the 22F far Arctic increase?

  23. 223
    Nick Gotts says:

    \This episode in human history will not have a final victory, neither a crushing defeat.\ – Anne van der Bom

    We can’t know that – particularly with regard to the \crushing defeat\. Anthropogenic climate change could trigger the end of our civilisation and a huge loss of biodiversity – and possibly even human extinction. Most likely by leading to nuclear and/or biological warfare, as viable agricultural land becomes increasingly scarce. However, I do agree with your larger point: there is no reason to despair, and some to hope.

  24. 224
    Nick Gotts says:

    “A long series of accurate 3-month or 6-month ahead predictions would go a long way toward increasing the respect with which people treat AGW” – Septic Matthew

    No problem: I predict that in six months time it will be warmer than it is now in the northern hemisphere, and cooler than now in the southern hemisphere. In six months time, I predict that I will confidently be able to predict that in six months time it will be cooler than it is now (i.e., than it will be in six moths time!) in the northern hemisphere, and warmer than now (i.e., than it will be in six months time) in the southern hemisphere. In 12 months time…

    Seriously, this makes an important point about complex systems in general: you may be able to make accurate predictions at some spatial and temporal scales, even if you can’t make them at finer (or coarser) scales. So the fact that experts cannot make accurate regional six-month forecasts has absolutely no relevance to whether they can make accurate global, or even regional forecasts (of climate, not weather) at decadal timescales. None. At. All. So if accurate regional six month forecasts were available that should not, rationally, increase confidence in such decadal forecasts.

  25. 225

    Bob Sphaerica (167) and Anne van der Bom (215) say it exactly right. That’s the spirit we need to have. It’s good to be reminded with an uplifting message once in a while…

  26. 226
    Ray Ladbury says:

    Matthew says, “A long series of accurate 3-month or 6-month ahead predictions would go a long way toward increasing the respect with which people treat AGW…”

    Matthew, I’m going to assume that you still remember the distinction between climate and weather, and that this was some sort of momentary cerebral flatulence. If you have in fact forgotten, I’m sure there are many here who would be happy to remind you of the relative definitions. BTW, have you tried gingko?

  27. 227

    Climate scientist Richard B. Allen (Penn State): balanced reporting should tell that doubling of CO2 (to 560 ppm) may lead to 10-11 degrees C of global warming: http://bit.ly/CS1820

  28. 228
    FurryCatHerder says:

    Nick Gotts @ 196:

    I suspect it isn’t simply chronic denialism, but the name “Global Warming”.

    Surely “The Day After Tomorrow” was sensationalism, but the basic concept that a change in the thermohaline circulation could result in some amount of cooling, and likewise other changes in atmospheric and oceanic cooling could do likewise. By hanging their hats so firmly on “Global Warming”, any deviation in a cooler direction — like, we’ve now had “winter” three years in a row, where we’d not had “winter” for several years prior — is taken as disproof.

  29. 229
    FurryCatHerder says:

    Esop @ 216:

    Cherry picking. Right now the other end of the planet is cooler, but I don’t see anyone crowing about the negative anomaly over the Antarctic.

    Wonder why …

  30. 230
    Maya from the peanut gallery says:

    Was this the thread where folks were discussing extreme weather events and their frequency? If so, this article over on climateprogress has a lot of good links in it that you might want to peruse. If not, sorry for the OT.

    http://climateprogress.org/2010/12/23/the-year-of-living-dangerously-masters-weather-extremes-climate-change/

  31. 231
    Esop says:

    #221 (Rod B):
    Source is the Danish Meteorological Institute (DMI):
    http://ocean.dmi.dk/arctic/meant80n.uk.php

  32. 232
    Chris R says:

    #227 Maya,

    Thanks for posting that. I tend to spend a lot of my free time with my head buried in some specific and narrow line of learning. It’s like I’m crouching at the foot of a tree lost in all it’s detail and often forget the fact that I’m in a wood.

    Jeff Masters has come out and said what I’ve been thinking the last few months.

  33. 233

    Edward Greisch says:
    23 December 2010 at 2:49 AM

    162 “BPL: There is no way out. The bad guys have won. I’m still arguing simply and solely because I hate letting them have the last word.”
    “I told you so” would be sweet. But let’s try for something better. Hang in there. Suicide is not allowed.
    There is reason to believe, provided by you, that it won’t get bad enough for everybody to notice until it is too late.

    167 Bob (Sphaerica) said it well and so did 208 calyptorhynchus. It doesn’t have to get bad enough for everybody to notice. Let’s take the lessons learned from the anti-smoking campaign and the civil rights campaign and try to apply them faster. Let’s use the David Koch tea party movie at:
    http://climateprogress.org/2010/10/14/video-proof-david-koch-the-polluting-billionaire-pulls-the-strings-of-the-tea-party-extremists
    in letters to the editors of lots of newspapers. Let’s get the witch hunts to backfire. Keep on working and keep on keeping on. We will find a way.

    [Response: Yep.--Jim]

    I agree, but I will say again, unless or until we **prove** the ill will of the anti- machine, and hold some accountable in real ways, we will have to wait for Point of No Reurn, at which time it will be time to start digging tunnels, dragging our topsoil down into them and installing solar tubes and fresnel lenses to grow food and keep from turning albino.

    I believe there are people/groups out there starting to file class action lawsuits. I suggest very large numbers of us jump on board.

    Mann’s prosecutor buddy would be a perfect first case as he abused his office, as opposed to merely being a denialist.

  34. 234
    Rod B says:

    Esop (229): Other sources (GISS, et al) show about a 1-1/2 degreeC 2009 anomaly for the “upper” Arctic (65-90 latitude). Eyeballing your link’s graphs it is hard to see even a one degree C change from 1958 to 2010, in either the high summer or low winter temps in the 80-90 latitudes. (I couldn’t find the database that went into the daily graphs.) Others’ analyses of the DMI data show a 0.38 C/decade trend of average annual temps — a 1.2C increase since 1980 or 1.9C since 1960. 12 degrees F seems nowhere to be found.

    As an aside temperature stations seem to be very sparse in the 80-90 latitudes, though I don’t know the significance of that.

  35. 235

    #231–Well, England in 1940 had no smart money on them, either. Despair is not adaptive, and overconfidence in one’s own ability to “see all ends” may not always pay, either. Call it the “Churchill clause.”

    We’ll keep slugging.

    And Merry Christmas–or other winter festival of the heart–to all.

  36. 236
    Septic Matthew says:

    226, Ray Ladbury: Matthew, I’m going to assume that you still remember the distinction between climate and weather, and that this was some sort of momentary cerebral flatulence. If you have in fact forgotten, I’m sure there are many here who would be happy to remind you of the relative definitions. BTW, have you tried gingko?

    I also wrote that it was neither necessary nor sufficient, as Magellan’s circling the earth was neither necessary nor sufficient to persuade everyone else that the earth was round. Nevertheless, the mechanistic models purport to be accurate over short time scales and small regional scales, which is why their long-term forecasts )with model results averaged over space and time) are given some credibility.

    Let me quote again from the main text: 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.

    I wrote something like the first sentence in my first post in this thread: chaotic models (models of dissipative nonlinear systems) may be compatible with more extreme extremes of both ends. However, if Petoukhov and Semenov argue that cold weather should be an “expected” consequence of global warming, then I think that the “expectation” would actually be expected if it were backed by a series of accurate predictions.

    Especially, I might say, since for years we heard of the “fact” that warmer weathers were the consequence of global warming, and that children in Great Britain would grow up without ever experiencing snow.

    As to actually modeling extremes and doing statistical analyses on extremes, you should probably work with one of the extreme value distributions. And if you are going to do any inferences that depend on asymptotic approximations, then you should use one of the Fisher-Tippett asymptotic extreme value distributions. As you know, for samples of increasing size from a given distribution, and for time series of increasing duration, the sample extremes become more and more extreme even as the sample standard deviation converges to a fixed value. Consequently, the mere existence of greater extremes than previously measured extremes is no evidence for change. The excess has to be greater than expected based on the most accurately fitted extreme value distribution.

    Ray you are a good guy, but you are embarrassingly naive and superficial sometimes, and this is one of those times.

  37. 237

    gut gemacht to Potsdam scientists

    http://www.independent.co.uk/news/science/expect-more-extreme-winters-thanks-to-global-warming-say-scientists-2168418.html

    although if one or two from there reads this little message
    good day hey!

    I am more inclined to add Hudson – Baffin Bay “no ice” effect as
    a double whammy, an additional to Kara- Barents ice free model play.
    Planetary waves have been reshaped by the sea surface change.

    To prove this, as sea ice thickly covers these open sea areas, winter weather
    patterns will more or less return to ” normal”. They seem to show early signs of
    this.

  38. 238
    Edward Greisch says:

    231 Killian O’Brien: Please keep us informed of lawsuits to jump on board of.

  39. 239
    Alex Katarsis says:

    BPL. No way out??? Engineering is the way out. Social Engineering. Civil Engineering. And, ironically, faith, hope and charity. This group spends too much time with the theoretical. So easy to find the guilty, already? How about those who fail to see the possibilities of engineering?

  40. 240
    Mike M. says:

    The extreme low temperatures are breaking more than enough records to be significant and many of them are over 100 years old. That must have been global warming back then too huh?

    [Response: Records are broken all the time, and if you look at the year as a whole, far more warm records were broken than cold records. This is also true of the last ten years, where the ratio of warm records to cold records was higher than any other recent decade. - gavin]

  41. 241
    Ray Ladbury says:

    Mike M.,

    Yeah, things look pretty cold (relatively) as long as you don’t look at the Arctic, huh?

    Those blinders fit you OK?

  42. 242
    Ray Ladbury says:

    Alex Katarsis,
    Human population will crest at around 10 billion people (we hope) sometime in the latter half of this century, which will coincide with serious drought due to climate change. I am all for engineering. However, engineering demands a bound on the scale of the problem unless you want to over-engineer (and so overspend) the problem. At present we do not have a good way to bound the risks due to climate change. At the very least, the likely impacts of drought, sea-level rise, increased severe weather, etc. demand engineering projects on a pretty much unprecedented scale.

    The problem is that so far along engineering lines, we’ve accomplished precisely bupkis–not even a bound to the problem, let alone breaking ground on irrigation projects, floodwalls… I do not think you can have it both ways. Either you accept what the science is telling us and begin mitigation with all deliberate speed (damn the cost!) or you admit that you are willing to gamble the future of human civilization on a 20:1 longshot.

  43. 243
    Ray Ladbury says:

    So, Matthew, do you require Newtonian mechanics to be able to predict heads or tails on a single flip of a coin before you beleive it?

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

    As to extreme value statistics, I think that you are failing to comprehend that we simply don’t have enough data to really understand the extremes of the distribution–particularly given that the distribution is likely changing, so the past is likely not representative of the present–particularly in the extremes.

    Sorry, Matthew, I fail to see where my understanding the definitions of climate and weather makes me naive. Care to ‘splian that one?

  44. 244
    Lawrence Coleman says:

    Just wishing everyone at RC and all their contributers a Very Merry Xmas!!

  45. 245
    Anne van der Bom says:

    Matthew,
    23 December 2010 at 12:0 PM

    What you call a short term climate prediction (3-6 months) is actually an EXTREMELY LONG range weather forecast. With all the supercomputing power available to meteorologists today, they can’t predict much further than 2 weeks ahead.

    The fact that climate models model the regional short term artifacts does not imply they are able to predict each individual artifact. This is a chaotic system, and the climate models only replicate the weather PATTERNS, but they show no correlation whatsoever to the actual WEATHER that occurs in the real world.

    From a climate model run you can deduct that the occurrence of cold winters increases by, say, 50%, but you can never predict WHICH will be those cold winters. And from what I read, that’s what you are asking. And that’s simply impossible.

  46. 246
    SWDoughty says:

    An amateur observation from northern New England. References have been made to a cold winter phenomenon in ‘North America’. This likely excludes the northeastern quadrant, for last year and beginning this year we are getting an unusual series of retrograde storm patterns. The one just past brought in 40F weather from the northeast, where we should be in the 20s. These storms seem to be happening in conjunction with very large perturbations in the jet stream; very large troughs (with us on the east side) or very weak eddys. We are receiving very little, or relatively little northwesterly flow of cold air as a result, unlike central North America. Could this also be connected with the positive temperature anomaly in Baffin Bay, from where we seem to be getting some of this airflow? Temperatures in lower Labrador are sometimes higher than here. Has this regional phenomenon been studied?

  47. 247
    Esop says:

    #234 (Rod B): Approx 22F is the current (as in today and yesterday). Watch the red graph go straight up at approx. day 350. From the graph, the average temp right now is at right under 257K, while the normal temp (green graph)at this date is approx 245K.
    It is the spike in temperature over the past weeks that is interesting in this discussion (cold European winter), as the very high Arctic temps happens at the same time as the cold temps in Europe.
    Interesting to note is that the graph indicates that from day 150 to 250, the temp was actually below normal most of the time, but it seems to spike very high in fall/winter/spring.

  48. 248
    Esop says:

    #229 (Furry): Why would anyone be crowing about negative anomalies over regions of the Antarctic when the average global temperature is the highest on record (UAH near surface temp, last week)?
    BTW, why don’t “skeptics” quote the UAH temps anymore?
    Wonder why…
    This discussion is about the lack of Arctic sea ice and its influence on the current cold snap on the continents (something that was modelled back in 2004).
    In that very discussion, how is the current Arctic temperature anomaly an example of cherry picking?

  49. 249
    Septic Matthew says:

    243, Ray Ladbury: So, Matthew, do you require Newtonian mechanics to be able to predict heads or tails on a single flip of a coin before you beleive it?

    Are we now forecasting weather by flipping coins?

    Anyhow, I have to leave for a few days. If the thread is still alive, perhaps I’ll respond then. Meanwhile, you can review the Fisher-Tippett extreme value distributions, if you seriously want to make statistical inferences from observed extremes in large samples and long time series.

    I wish you all well for Christmas and the New Year. It doesn’t sound right in a contentious debate via electronic media, but so I do.

  50. 250
    dhogaza says:

    SWDoughty:

    An amateur observation from northern New England. References have been made to a cold winter phenomenon in ‘North America’. This likely excludes the northeastern quadrant, for last year and beginning this year we are getting an unusual series of retrograde storm patterns

    And the west coast, too, which has been on the receiving end of a series of “pineapple express” storms.

    Pineapples don’t grow where it’s cold, and those storms don’t bring cold weather. Currently Portland, Oregon is right on average, slightly warmer at night and slightly cooler during the day.


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