Models Fail: Scandinavian Land Surface Air Temperature Anomalies

UPDATE: I’ve added a comment by Marcel Crok to the end of the post.

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The climate models being used by the IPCC for their upcoming 5th Assessment Report show little skill at being able to simulate a number of variables. We can now add Scandinavian land surface air temperature anomalies to the list.

Figure 1 compares the UKMO CRUTEM4-based land surface air temperature anomalies for Scandinavia, starting in January 1930, and the CMIP5-archived multi-model ensemble mean of the climate models prepared for the IPCC’s upcoming 5th Assessment Report (AR5). Both the data and the model outputs are available to the public through the KNMI Climate Explorer. The coordinates used were 55N-72N, 2E-30E. The climate model hindcasts are based on the historic forcings and RCP6.0 scenario. And both data and model outputs have been smoothed with 13-month running-average filters to reduce the monthly variations—what some would call weather noise. Also note that the linear trends were calculated from the monthly data and model outputs, not the smoothed versions. As shown, according to the models, if greenhouse gases were responsible for the warming of land surface air temperature anomalies in Scandinavia, they would have warmed at a rate that’s about 2 times faster than the rate observed. Or phrased another way, since 1930, Scandinavian land surface air temperatures warmed at rate that was half the rate simulated by the models. Not a very good showing on the parts of the models.

Figure 1Figure 1

But it gets worse.

Look closely at the surface temperature data in Figure 1. There’s a very obvious upward shift in the data in the late 1980s. It may be hard to see with the model output in Figure 1, so I’ve highlighted the 2-year period of January 1987 to December 1988 in Figure 2.

Figure 2Figure 2

From 1930 through 1986, Scandinavian land surface air temperatures cooled. (Note the large dip and rebound at the time of World War II.) Then there was a very strong warming surge in 1987 and 1988, which was followed by the period of 1989 to present when surface temperatures don’t appear to have warmed much at all. So let’s compare the models to the data for the periods before and after that upward shift.

Figure 3 compares the modeled and observed Scandinavian land surface temperature anomalies for the period of Jan 1930 to December 1986. Scandinavian surface temperatures cooled at a rate of -0.132 deg C per decade, but the models say they should have warmed at a rate of +0.058 deg C per decade. The models missed the mark by a rate of about 0.19 deg C per decade. Or, phrased another way, based on the linear trends, the models say Scandinavian temperatures should have warmed about 0.33 deg C from 1930 to 1986, but surface temperatures there actually cooled approximately 0.75 deg C.

Figure 3Figure 3

Then there’s the period of January 1989 to present. The climate model simulations indicate that Scandinavian land surface temperature anomalies should have warmed about 1.3 deg C over the past 23+ years (based on the linear trend) if manmade greenhouse gases were responsible for the warming. But, based on the linear trend of the observed temperatures, Scandinavian land surface air temperatures have not warmed.

Figure 4Figure 4

WHAT CAUSED THE SHIFT?

It’s probably a combination of a couple of natural factors. I did a quick search for papers that explained the shift but didn’t find anything conclusive. Scandinavian visitors may know of some and hopefully they’ll provide us with links.

The Arctic Oscillation appears to have had a strong influence around that time. The Arctic Oscillation Index is based on sea level pressures north of 20N. Wikipedia has a good overview here. Also see the NOAA webpage here, and the Arctic Oscillation Index data here. According to the annual Arctic Oscillation Index data, Figure 5, there was a significant spike in 1988 and 1989. The change in the Arctic Oscillation was most prevalent during the winter months, regardless of whether you define winter as December to February (Figure 6) or January to March (Figure 7).

Figure 5Figure 5

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Figure 6Figure 6

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Figure 7Figure 7

For the period of 1985 to 1995, the Arctic Oscillation Index correlates very well with Scandinavian land surface air temperatures. See Figure 8. (The correlation maps were created at the KNMI Climate Explorer.)

Figure 8Figure 8

(Note that I’ve also marked the coordinates used in the post for the data and model outputs.)

But using the full term of the Arctic Oscillation Index data, 1950 to present, the correlation between Scandinavian land surface temperature anomalies and the Arctic Oscillation is not as strong, Figure 9. That’s why I noted that it was probably influenced by a number of natural factors.

Figure 9Figure 9

Some of you may be concerned that the shift shows up in the Scandinavian surface temperatures from January 1987 to December 1988, while the spike appears in the Arctic Oscillation Index data in 1988 and 1989. Sorry, I had used monthly data for the surface temperatures and annual data for the Arctic Oscillation Index. With the Scandinavian surface temperature anomalies in annual form, Figure 10, the shift appears in 1988 and 1989.

Figure 10Figure 10

Regardless of the cause of the shift, the cooling of Scandinavian land surface temperatures before the shift, and the flat temperatures after it, were not captured by the climate models.

STANDARD BLURB ABOUT THE USE OF THE MODEL MEAN

We’ve published numerous posts that include model-data comparisons. If history repeats itself, proponents of manmade global warming will complain in comments that I’ve only presented the model mean in the above graphs and not the full ensemble. In an effort to suppress their need to complain once again, I’ve borrowed parts of the discussion from the post Blog Memo to John Hockenberry Regarding PBS Report “Climate of Doubt”.

The model mean provides the best representation of the manmade greenhouse gas-driven scenario—not the individual model runs, which contain noise created by the models. For this, I’ll provide two references:

The first is a comment made by Gavin Schmidt (climatologist and climate modeler at the NASA Goddard Institute for Space Studies—GISS). He is one of the contributors to the website RealClimate. The following quotes are from the thread of the RealClimate post Decadal predictions. At comment 49, dated 30 Sep 2009 at 6:18 AM, a blogger posed this question:

If a single simulation is not a good predictor of reality how can the average of many simulations, each of which is a poor predictor of reality, be a better predictor, or indeed claim to have any residual of reality?

Gavin Schmidt replied with a general discussion of models:

Any single realisation can be thought of as being made up of two components – a forced signal and a random realisation of the internal variability (‘noise’). By definition the random component will uncorrelated across different realisations and when you average together many examples you get the forced component (i.e. the ensemble mean).

To paraphrase Gavin Schmidt, we’re not interested in the random component (noise) inherent in the individual simulations; we’re interested in the forced component, which represents the modeler’s best guess of the effects of manmade greenhouse gases on the variable being simulated.

The quote by Gavin Schmidt is supported by a similar statement from the National Center for Atmospheric Research (NCAR). I’ve quoted the following in numerous blog posts and in my recently published ebook. Sometime over the past few months, NCAR elected to remove that educational webpage from its website. Luckily the Wayback Machine has a copy. NCAR wrote on that FAQ webpage that had been part of an introductory discussion about climate models (my boldface):

Averaging over a multi-member ensemble of model climate runs gives a measure of the average model response to the forcings imposed on the model. Unless you are interested in a particular ensemble member where the initial conditions make a difference in your work, averaging of several ensemble members will give you best representation of a scenario.

In summary, we are definitely not interested in the models’ internally created noise, and we are not interested in the results of individual responses of ensemble members to initial conditions. So, in the graphs, we exclude the visual noise of the individual ensemble members and present only the model mean, because the model mean is the best representation of how the models are programmed and tuned to respond to manmade greenhouse gases.

CLOSING

The list of model-data posts that show models performing poorly grows and grows. We can add Scandinavian land surface temperatures to the list of variables the CMIP5 climate models show no skill at simulating. The others include:

Alaska Land Surface Air Temperatures

Daily Maximum and Minimum Temperatures and the Diurnal Temperature Range

Hemispheric Sea Ice Area

Global Precipitation

Satellite-Era Sea Surface Temperatures

Global Surface Temperatures (Land+Ocean) Since 1880

And we recently illustrated and discussed in the post Meehl et al (2013) Are Also Looking for Trenberth’s Missing Heat that the climate models used in that study show no evidence that they are capable of simulating how warm water is transported from the tropics to the mid-latitudes at the surface of the Pacific Ocean, so why should we believe they can simulate warm water being transported to depths below 700 meters without warming the waters above 700 meters?

Many thanks to Harold Ambler for prompting this post. Harold is the proprietor of the blog TalkingAboutTheWeather and the author of Don’t Sell Your Coat.

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UPDATE:

Marcel Crok writes:

Jos de Laat (of KNMI) and I (a science writer) just have a paper out on the European temperature shift of 1987/1988. The title is A Late 20th Century European Climate Shift: Fingerprint of Regional Brightening? and can be downloaded (freely) at http://www.scirp.org/journal/acs/

An introduction is at my blog http://www.staatvanhetklimaat.nl/2013/06/29/a-late-20th-century-european-climate-shift-fingerprint-of-regional-brightening/

We link it to the NAO and to the transition from dimming to brightening.

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Thanks, Marcel.

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39 thoughts on “Models Fail: Scandinavian Land Surface Air Temperature Anomalies

  1. In Esper’s 2012 “Variability and extremes of northern Scandinavian summer temperatures over the past two millennia. Global and Planetary Change 88–89 (2012) 1–9″ Both tree rings and instrumental data showed no summer warming that exceeded 1940s.

  2. How is it that the pro-crowd never find these relationships, particularly the ones being paid with more powerful processors, recognition and salaries?

    Where’s Lew when you need to find an example of conspiracy ideation?

  3. There was a large intrusion of warm water that lasted until the 1960s. According to Drinkwater (2006) During the 1920s and 1930s, there was a dramatic warming of the northern North Atlantic Ocean. Warmer-thannormal sea temperatures, reduced sea ice conditions and enhanced Atlantic inflow in northern regions continued through to the 1950s and 1960s, with the timing of the decline to colder temperatures varying with location. Ecosystem changes associated with the warm period included a general northward movement of fish. Boreal species of fish such as cod, haddock and herring expanded farther north while colder-water species such as capelin and polar cod retreated northward. The maximum recorded movement involved cod, which spread approximately 1200 km northward along West Greenland. The warming in the 1920s and
    1930s is considered to constitute the most significant regime shift experienced in the North Atlantic in the 20th century.

    When the North Atlantic Oscillation (NAO) is positive, it enhances the northward flow of warm water but the Icelandic Low intensifies and expands the subpolar gyre, blocking the warm water from entering the Norwegian Sea. So the positive NAO warms Europe mostly in the winter as the stronger winds blowing across the ocean bring milder winters. When the NAO shifts to a negative phase Europe cools as the westerly winds decline and the Icelandic Low shrinks, but the shrinking Low allows warm waters to invade deeper into Arctic waters and the Norwegian Sea. If memory serves any recent warming of northern Scandinavia is mostly a summertime phenomenon as winds blow across these intruding warm waters.

    Robson (2012) wrote “In the mid-1990s, the subpolar gyre of the North Atlantic underwent a remarkable rapid warming, with sea surface temperatures increasing by around 18C in just 2 yr. This rapid warming followed a prolonged positive phase of the North Atlantic Oscillation (NAO) but also coincided with an unusually negative NAO index in the winter of 1995/96. By comparing ocean analyses and carefully designed model experiments, it is shown that this rapid warming can be understood as a delayed response to the prolonged positive phase of the NAO and not simply an instantaneous response to the negative NAO index of 1995/96.”

    The Drinkwater, K. (2006) The regime shift of the 1920s and 1930s in the North Atlantic. Progress in Oceanography vol. 68, p.134–151.

    Robson, J., et al. (2012) Causes of the Rapid Warming of the North Atlantic Ocean in the Mid-1990s. Journal of Climate, vol. 25, p. 4116_4136.

  4. I suggest that for Scandinavia the late 80′s were the crossover point when the high solar activity of cycles 21 and 22 finally succumbed to the slightly lower (but still high in historical terms) cycle 23 and as per my previous contentions the level of solar activity has an effect on the polar vortices and through them the Arctic Oscillation.

    The state of the AO then feeds into the NAO with the results noted by jim Steele.

    At base it is all a matter of jet stream tracks and latitudinal climate zone positioning which I aver are significantly affected by the level of solar activity via means that I have described previously.

    Scandinavia is ideally placed as a bell weather for climate changes due to its position downwind of the Atlantic Ocean and the flow of warm water into the Arctic Ocean.

  5. Talking of climate shifts, it looks like we will be having one over the coming week over a fairly large area of the NH. lt looks like the Polar jet will be pushing northwards right across from North America over the Atlantic and most of Europe. At its biggest extent over western europe the jet could up move up to a 1000 miles or more northwards over the coming week. So we can expect sudden warming over here in europe over the coming week, plus the hot weather extending further across America.

  6. “Scandinavia is ideally placed as a bell weather for climate changes”

    If so, it’s getting colder.

  7. taxed says: “So we can expect sudden warming over here in europe over the coming week, plus the hot weather extending further across America.”

    I’m looking forward to some warm weather.

  8. Bob Tisdale says: l’m looking forward to warm weather.
    Here in the UK we are in need of some warm summer weather, after the last six summers we have had. This sudden push of the jet stream to the north has got my notice because its such a change to the sort of pattern we have had to suffer during the summers since 2007. With the jet pushing so far to the north it will allow a blocking high to settle over europe. What will be of interest is to see how much effect this will have on warming up the waters around western europe, which are rather cold at the moment. Because l think its changes to the jet stream which have a large impact on the ocean and its currents. This blocking high setting over europe will help to see if am right or not.

  9. Love your “Figure 4.” UN-DENIABLE.

    Thank you for sharing more of your fine research and hard work, Bob Tisdale. You are a science gem.

    Hope that warmer weather you’re hoping for happens soon in your neck of the woods.

  10. So if I understood it right, is that Marcel Crok would argue that the cooling trend beteen 1930 and 1986, like in the Netherlands,must be due to solar dimming caused by aerosols.

  11. I am sorry Anthony but all these graphs etc., leave me cold (not meant to be a pun), parts of Scandinavia are in the Arctic Circle, and the lands of the midnight sun. I reckon they would enjoy some more heat. Some northern Scottish islands are the same, the Hebrides etc., they get 22 hours of daylight in the summer and nothing in the winter. How can you compare this to the rest of the world. One little thing I noticed locally is on the Northern Tablelands of NSW where I live at 3,500 ft absl, and the coastal area of Coff’s Harbour 185 km to the east of us is where the sunlight disappears earlier than where we live. Because the mountain ranges blocks the sun setting in the west. Coff’s is unusual as the mountain or foothills come down almost to the sea. A very pretty area and great fishing, but some years ago almost ran out of fresh water. Then they flooded. C’est la vie.

  12. Try 45-60 N 0-200 E: no warming since 1989 -1990 (take Pinatubo into account)
    That’s a big piece of land.

  13. John Bills: We don’t need to worry about the effects of Mount Pinatubo for that chunk o’ real estate. The data (CRUTEM4) trend is only 0.09 deg C/decade since 1988, while the models say it should’ve warmed at a rate of 0.48 deg C/decade. In other words, the models over predicted the rate of warming by a factor of 5.

    Nice find. Thanks for the idea for another model-fail post. I’ll use the coordinates of 45N-60N and 0-160E and call it the mid-latitudes of Europe and Asia. I may play with the coordinates a little bit to see if we can expand them.

  14. We’re finally experiencing triple digit Fahrenheit temps at lower elevations here in northwest USA – the first time in 2 years. Of course the media is making a big deal about it, but my garden tomatoes will be ripening in mid July instead of end of August.

  15. noaaprogrammers, gud on you, tomatoes are hard to grow in my garden because of the low temps at night, they flower but do not set fruit. Yet down in Tamworth on the warmer plains they do well. Greenhouse would be an answer. You’ll find your tomatoes will go on producing longer too. Nothing like the taste of a free range tommy. Grow some nice lettuce and cucumbers too.

  16. Multi-model ensemble mean? Wasn’t there a post/thread about how that’s meaningless?

  17. Perhaps missing the obvious? See on the Sea Ice page “Arctic Sea Ice Extent With Anomaly”. You will note the sea north of Scandinavia is more free of ice than historically. Strangely, the drop in arctic ice extent began right about the same time as the arctic ice extent began to drop. What melts ice? Warmer water. What heats air? Warmer water.

  18. Beeing a Norwegian I remember the “waring” that took place late 1980s.
    It did take place mainly in the winters with several of them milder and wetter Than “normal” Like still green grass in Oslo in January and now snow to see. In the years before the Winter Olympics in Lillehammer the media was very worried that there would be now snow when the games started. Actually it was lots of snow and freezing cold!

  19. I am not in a position to comment on the WHY, but I do consider that the late 1980s climate shift may be real and not just a figment of data homogenisation.

    I lived in Norway in the late 1980s./early 1990s and I recall people telling me how mild the winters were and how much less snow was being experienced compared to just 3 to 15 years earlier.

    Norway runs very efficiently and even very small roads (at least in and around the city areas) are cleared with snow ploughs coming around at about 5am clearing the snow. The snow was collected and dumped in the Fjord. When I was there, for the main part, it was not necessary to collect the snow and dump it in the Fjord, since there was less of it and it could usually be just left at the side of the road (obviously not in teh main city side walks).

    When I was there, for the winter, I fitted studded (metal spikes) tyres. Some years later, the government banned these, at least from city areas. It was compulsory that winter tyres were fitted, but these were just smaller width with different compound and different tread patterns, not spikes. I guess that that change also indicates that the winter conditions were less harsh, with less snow and ice being experienced, so that the government no longer considered that the added safety of spiked tyres were worth the additional damage they inflicted to the road when snow and ice thinned, as slight changes to conditions were experienced during the winter months.

    Happy times!

  20. Jon says:

    July 2, 2013 at 10:43 pm
    /////////////////
    Picture perfect weather, and brilliant games.

    The Norwegian team really did the country proud.

  21. Hoser says:

    July 2, 2013 at 8:37 pm
    //////////////////
    We are not discussing whether it is warming, or not warming, but rather why the models do such a lousy job and replicating, and predicting the local climate. But then again, it s well known that models are lousy on regional basis.

    This is particularly unfortunate since climate is not global but regional, and for the main part, the effects of climate change are sustained regionally, not globally. No country can know whether future climate change will be, or will not be a problem for them, or will be beneficial, or not beneficial for the country until such time as models can accurately deal with matters on a local/regional basis.

    Personlly, I am all for scrapping models and I consider that our understanding of climate and climate change in general is being held back by models, and the reliance (I would say over reliance) upon them. There are unlikely to be signficant advances in climate science until such time as they are scrapped.

  22. Regional, not global quanta of temperature change.

    Acute, not chronic temperature changes.

    What part of global warming due to worldwide, continuous CO2, man-made CO2 emissions do we see here?

  23. “When I was there, for the winter, I fitted studded (metal spikes) tyres. Some years later, the government banned these, at least from city areas. It was compulsory that winter tyres were fitted, but these were just smaller width with different compound and different tread patterns, not spikes. I guess that that change also indicates that the winter conditions were less harsh, with less snow and ice being experienced, so that the government no longer considered that the added safety of spiked tyres were worth the additional damage they inflicted to the road when snow and ice thinned, as slight changes to conditions were experienced during the winter months.”

    The reason could also be the use of salt on the roads. The salt and the studded tires erode the surface/roads much more than roads with snow and ice and studded tires?

  24. Taxed is looking forward to the blocking high to bring warmer weather. Well so am I Taxed but this means less wind power and then the UK goes into meltdown with no available power.
    If we had an energy policy here in the UK I would not mind so much but our politicians have sat on the energy fence for so long they have cleft bums.

  25. Scandinavian winter tyres are still nobbled/spiked, but now the nobbles/spikes are made from a rubber compond/composite rather than metal. Plus not sure about the rest of Scandinavia, but in Sweden it’s mostly grit that gets put on the roads rather than salt. That’s not to say that salt isn’t used, but it is mostly grit as-in very fine gravel, rather than coursely ground rock salt. The idea is to provide more grip (a grippy surface) rather than to try and melt the ice using salt…… given the amount of ice that we are talking about that would be a rather herculean task, that would be both doomed and destined to fail…..

  26. Chris Schoneveld says, July 2, 2013 at 5:57 pm:

    “So if I understood it right, is that Marcel Crok would argue that the cooling trend beteen 1930 and 1986, like in the Netherlands,must be due to solar dimming caused by aerosols.”

    European temperatures are dictated by the sea surface temperatures of the nearby sector of the North Atlantic Ocean:

    The shift in SSTs around 1987-90 is very real and most likely tropical in origin (ENSO->AMO). But the AO/NAO apparently ‘opened the door’ to aid the tropical heat in its northward flow …

    Regarding this, there’s an interesting relationship between the winter AO and the NH tropical-polar temperature gradient:

  27. Sorry, forgot to mention: The red ‘gradient’ curve in the AO vs. temp grad figure above is inverted, that is, it’s polar (90-45N) anomalies minus tropical (30N-0) anomalies.

  28. For me this was an interesting debate back in the early 2000s.
    This was one of them based on an earlier Jones et Al. Before they started correcting the data to make Me wrong on Norway and the Arctic? .
    For Southern Norway (60N-65N 5E-15E) we have the following
    # These are the actual spatially averaged temperature anomalies. Based on Jones et al ground stations only(2006).
    1929 -0.410000
    1930 1.315000
    1931 -0.705000
    1932 0.755000
    1933 1.180000
    1934 1.635000
    1935 0.265000
    1936 0.830000
    1937 0.450000
    1938 1.080000
    1939 0.420000
    1940 -1.010000
    1941 -1.055000
    1942 -1.155000
    1943 1.050000
    1944 0.315000
    1945 0.560000
    1946 0.525000
    1947 -0.025000
    1948 0.570000
    1949 1.205000
    1950 0.460000
    1951 -0.145000
    1952 -0.660000
    1953 1.190000
    1954 0.130000
    1955 -0.375000
    1956 -0.650000
    1957 0.040000
    1958 -0.375000
    1959 0.895000
    1960 0.160000
    1961 0.920000
    1962 -0.375000
    1963 -0.150000
    1964 0.195000
    1965 -0.365000
    1966 -0.795000
    1967 0.275000
    1968 -0.200000
    1969 -0.110000
    1970 -0.455000
    1971 0.230000
    1972 0.565000
    1973 0.280000
    1974 0.915000
    1975 0.870000
    1976 -0.165000
    1977 -0.450000
    1978 -0.560000
    1979 -0.950000
    1980 -0.330000
    1981 -0.750000
    1982 0.080000
    1983 0.275000
    1984 0.280000
    1985 -0.995000
    1986 -0.445000
    1987 -0.690000
    1988 0.510000
    1989 1.050000
    1990 1.315000
    1991 0.240000
    1992 0.415000
    1993 -0.250000
    1994 -0.180000
    1995 0.040000
    1996 -0.325000
    1997 0.635000
    1998 0.400000
    1999 0.940000
    2000 1.100000
    2001 0.080000
    2002 1.045000
    2003 1.155000
    2004 0.780000
    2005 0.930000
    The warmest years are :
    1934 1.635000
    1930 1.315000
    1990 1.315000
    1949 1.205000
    1953 1.190000
    1933 1.180000
    2003 1.155000
    2000 1.100000
    1938 1.080000
    1943 1.050000
    1989 1.050000
    2002 1.045000

  29. Jim Ryan says at July 2, 2013 at 7:19 pm , “Multi-model ensemble mean? Wasn’t there a post/thread about how that’s meaningless?”

    It is meaningless, as rgbatduke wrote at length in a recent thread, as far as telling us anything about the real world. It is, however, not meaningless as to the workings of the climate models themselves.

    Apparently, you did not read the following part of Bob Tisdale’s Post (which I’ve quoted in part for your convenience):

    STANDARD BLURB ABOUT THE USE OF THE MODEL MEAN

    *** … when you average together many examples you get the forced component (i.e. the ensemble mean).

    To paraphrase Gavin Schmidt, we’re not interested in the random component (noise) inherent in the individual simulations; we’re interested in the forced component, ***
    The quote by Gavin Schmidt is supported by a similar statement from the National Center for Atmospheric Research (NCAR). ***

    … we exclude the visual noise of the individual ensemble members and present only the model mean, because the model mean is the best representation of how the models are programmed … .”

  30. Taxed is looking forward to the blocking high to bring warmer weather. Well so am I Taxed but this means less wind power and then the UK goes into meltdown with no available power.

    This is actually a very good point. Let’s keep an eye on the power grid in the Uk over the next 2 weeks. Going to be funny.

  31. It would add much to the relevance of your analysis, if you included errors bars on your trend estimates. But very consistently you fail to do so, as in always, leaving one to wonder why…

  32. The error bars for the multi model ensemble mean should for every year be outside the individual model highest and lowest? The error bars will be all over the graphs?
    If IPCC can’t pick the single correct model and validate it why do they think that an average of the many individual incorrect models are correct?
    This is scientific crazy and tells a good story about the scientific level in IPCC?

  33. Bob’s approach in looking at climate data regionally, region by region, is a good one, and restores the original and possibly more meaningful definition of climate, i.e. being associated with a particular geographic region. Long term trends seem to be more clearly in evidence in such regional data.

    BTW its curious how the financial crash of 2007-2008 took place as the climate started to cool. The two might not be unrelated. Taking the edge off economic growth by reducing shopping from bad weather may have been all it took for the debt time-bomb to go off.

  34. Almost all representations are made with smoothing series of monthly temperature anomalies over a time filter of 5,12, 13 or more months.
    What about trying to run averages of every month over a multi-year window? It may make more sense to average all January readings (and then February, etc) over the past 6 or 12 years then to aggregate one single reading with preceding and following months.
    More explanations and graphs can be seen at http://db.tt/DHBzSHJd
    With his charting experience Bob may make more refined representations.

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