Historical climatology in Greenland

Indeed, the dampened late 20th century winter warming over a substantial part of Greenland, particularly the western and southern regions emphasized by the network of stations analyzed by Vinther et al, is known (see e.g. this NOAA page) to be associated with a trend toward the positive phase of the Arctic Oscillation (‘AO’) pattern. Whether or not this latter trend can, in turn, be related to anthropogenic climate change is not yet agreed upon, but a plausible argument for this has indeed been made in the peer-reviewed literature. Nonetheless, even if the substantial recent trend in the AO pattern is simply a product of natural multidecadal variability in North Atlantic climate, it underscores the fact that western and southern Greenland is an extremely poor place to look, from a signal vs. noise point of view, for the large-scale polar amplification signature of anthropogenic surface warming. This is a fairly basic point.

What would a rational data-model comparison look like? Since the data show southern Greenland temperatures over the last 150 years, it would be most useful to look at model simulations for exactly that period, run with the best guesses for CO2, solar and volcanic forcing etc. Fortunately, over 20 model groups have deposited these simulations in a public database at PCMDI – and anyone who is actually interested in seeing what the models produce can have access (you need to register, but it’s just a formality).

What do they show? Interestingly enough, the models do not predict large trends in the vicinity of Southern Greenland over the last 100 or so years (the figure shows the ensemble mean results just from the GISS model, but others are similar). Mainly this is because these areas are relatively close to both open water and the ice sheet and that keeps temperatures pretty stable. Like a glass of water with ice cubes, any extra energy tends to go into melting rather than temperature changes. And in this region, changes in the AO pattern discussed above also appear to play some role. (It should also be noted that the trends in this region are not larger than the standard deviation, and so any one realisation is likely to have a lot of variability, as is seen in the observations).

But if the models don’t show much change over the last 100 years, surely the predictions for the future indicate that this area will be hit hard? Again, no. Southern Greenland turns out to have one of the slowest rates of warming of any land area in any of the scenarios (the figure is the mean over all models for the SRES A1B scenario). To some extent, this is again due to the factors mentioned above, but additionally, the models predict that the North Atlantic as a whole will not warm as fast as the rest of globe (due to both the deep mixed layers in this region which have a large thermal inertia and a mild slowdown in the ocean heat transports). This is of course some positive news for the Greenland ice sheet, but the warming there is already substantial enough to cause significant net melting.

All this to demonstrate that when people use vague generalisations – ‘models’ predict this, ‘scientists’ say that – when there are specific data that could be used instead (which model? what period? which scientist?), be wary – they are usually trying to pull a fast one.

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48 comments on this post.
  1. Alexander Ac:

    Pat Michaels, Steven Singer, Richard Linzen, Lubos Motl, Bjorn Lomborg…who else? How long? Are these people the “true fighters” in the age, when climatology is becoming (or actually is for 2O years of AGW evidence cumulating) the dogma, in worse religion and worst case politics? Of coarse, it is not. There is no religion in climatology. There is no “dogma” (in the sense “critics” want to see it), there is no “politics” in it (somtimes yes, but unfortunately from the opossing site) there is no “conspiracy” in it…
    They are right just in one thing: The “alarmistic” statments (however meant with good intention) make no profit.
    They are unfortunately fueling the accusations of bringing “religion” into science.
    Hm, just not good times are ahead, when politics (and money) overheads science…
    I wish realclimate a will to continue, it is unfortunatelly needed…

  2. Lynn Vincentnathan:

    I’ve only been following news articles on the science (which admittedly go over the top to make sales, attract readers), but my sense from them is that as more scientific studies are done year after year, the scientists are somewhat surprised to find that it’s worse than they had thought, for instance the rapidity of the Greenland ice sheet melting.

    Is that just alarmist reporting, or does it reflect some trend in scientific studies.

    And were the models earlier (say 10 years ago) predicting the current speed at which the Greenland ice sheets are melting?

  3. Jeffrey Davis:

    Almost tangential question: if heating is not randomly distributed and (in fact) some areas warm more than others, will there be other areas that will experience a net cooling? And, if yes, do certain models zero on a specific areas?

  4. Charles Muller:

    You write :
    “the models predict that the North Atlantic as a whole will not warm as fast as the rest of globe”

    I believed that North Atlantic region was on the contrary sensitive to forcings and their feedbacks (a way to explain for example that OM and LIA were not truly global, but rather centered around Atlantic basin). Is it a wrong assumption? Or response to GHG forcing differs from response to solar/volcano forcings in paleoclimates?

  5. llewelly:

    if heating is not randomly distributed and (in fact) some areas warm more than others, will there be other areas that will experience a net cooling? And, if yes, do certain models zero on a specific areas?

    I’m not sure I’m understanding you, but if you click-to-enlarge the figure depicting the mean warming over all the models for the SRES A1B, you will see a patch of 0C warming near the S tip of Greenland, and another large patch of 0 warming between NZ and Antarctica.

  6. llewelly:

    To correct my previous comment, I meant 0C < warming < 1C, not 0 warming.

  7. Bill Durbin:

    Despite many recent news reports, suggesting that global climate change is finally becoming accepted fact, I read this morning an article recounting how the producer of “An Inconvenient Truth” is warehousing 55,000 CD’s, which he offered to provide free to the National Science Teachers Association for showing to their students, only to have the offer rejected, because they were afraid to jeopardize funding they hoped to receive from Exxon Mobile, et al..

  8. Chip Knappenberger:

    Hi Guys,

    Since there is a lot of discourse these days on context, perhaps you all could have included a link to our World Climate Report story so that your readers could read our complete article. That way your readers could come to their own opinions as to our coverage of the Vinther et al. findings.

    Also, for those interested, on page 41 of the Arctic Climate Impact Assessment Synthesis Report, is found a description of their Key Finding #2 which includes the statement “Climate models indicate that the local warming over Greenland is likely to be one to three times the global average.”


    -Chip Knappenberger
    To some degree, supported by the fossil fuels industry since 1992

    [Response: My oversight. Apologies. -gavin]

  9. joel Hammer:

    Let me get this straight.

    You are saying that if the temperature in Southern Greenland was going up like crazy, the “warmers” would say it can’t be due to global warming because their models show Southern Greenland won’t get very warm due to AGW. It must be due to some natural variability. Right?

    Or, would the “warmers” just tweak their models a bit to show Southern Greenland getting warmer and then announce an impending castrophe.

    So, now we know that Greenland is cooling and the ocean has recently cooled.

    Well, as my best professor used to say, “Facts are always friendly.”

    [Response: The model simulations are available in public archives. All we would ask is that people actually reference them before they claim that models are inconsistent with data. I don’t think that’s too much to ask. You can discuss hypotheticals all you want but the long term trends in the models are consistent with the changes in the data. If they weren’t there might be something interesting to discuss (as with the MSU data prior to their recent correction), but there isn’t. -gavin]

  10. Doug Watts:

    In response to #6: I would be interested to see if the National Science Teachers Association has offered a detailed explanation for why the scientific information in the film does not meet scientific muster. If not, then this would seem as odd as rejecting a film about biological evolution. If anyone here is aware of serious errors of science within the film, I would like to know what they are. Thanks. P.S. I think the authors/moderators of this site are doing a tremendous public service. Thank you for your efforts.

  11. Brant D:

    #7: While I wholly support the science presented in An Inconvenient Truth, I still have to admit it has some strong political overtones not regarding the science or science policy directly. I think it is reasonable to argue that such political topics are not appropriate for school settings, particularly in science classes. If these teachers are hesitant to show the movie for those reasons, and not because they question the scientific value, I can understand their position. It’s unfortunate, though.

    And as this is my first post here, I have to agree that this site rocks.

  12. Robert A. Rohde:

    Since you are on the topic of expanding the historical data record, I wonder if you could offer some background on the Global Historical Climatology Network (GHCN) and the strange apparent pattern of station distribution in time. If the GHCN’s collection is treated as a more or less complete accounting of the available instrumental temperature record, then the number of stations rose steadily during the first half of the twentieth century, surged in the 1940s-1970s, and then sharply declined afterward. (See center figure: http://data.giss.nasa.gov/gistemp/station_data/)

    Though not shown on that plot, the number of records that have been added to the GHCN database for 2000-2005 are roughly equivalent to the number of station records available from the 1920s. This seems a little screwy. With the proliferation of digital technology and the ease of communications and transportation, I’d have expected the number of stations to greatly increase not fall off. So what gives?

    Is the GHCN less complete for the recent few decades for some reason? Or perhaps in the age of satellites and weather models people are unwilling to fund lowly weather stations?

  13. Charles Muller:

    Another point :
    “This is of course some positive news for the Greenland ice sheet, but the warming there is already substantial enough to cause significant net melting.”

    You’re right in this statement for current models, without “non linear surprise” during the 21st century. If fact, a look at IPCC 2007 (chapter 10) simulations for Greenland/Antarctic mass balance in 2081-2100 is instructive. With a large margin error, it does not exclude a negative contribution to sea-level from melting/growing ice in South and North Poles. So, I suggest more skeptics should read IPCC reports. But many alarmists too!

  14. Eli Rabett:

    A small suggestion, how about closing off the link to World Climate Report until they open up comments. Kind of put it out there that if they want links they have to accept comments. Their choice.

  15. Steve Bloom:

    Re #13: Excellent point, Eli.

  16. adam f:

    Hi Gavin,

    Any comment on this study:

    Greenland warming of 1920-1930 and 1995-2005
    Petr Chylek and others

    I notice in comments on a Real Climate post that Chylek et al were claiming in March 2004 there was a cooling of Greenland. They’ve now backed down on that but are instead saying that the 1920-1930 warming was similar to last 10 years.

    [Response: Check out the GISTEMP site and see for yourself. As a function of the NAO trend through to about 1996 there was a significant cooling pattern over Greenland (look at annual mean trends from 1950 to 1996 for maximum effect), but the longer you average over the less that is seen (though since there is still a positive NAO trend it is still a factor). So 1900-2005 doesn’t show it for instance. Short time periods are always more variable. – gavin]

  17. David Donovan:

    Re 8,9

    Greenland is a big place and the figures clearly show big differences in warming between the south, interior, and the north.

    In your mad rush to proclaim “the models are wrong” you seem to be tripping over yourselves by resorting to inappropriate generalities.

  18. Jean-Luc P:

    Quoting :
    One persistent abuser of this technique is Pat Michaels, and in a recent piece he was unable to resist claiming that the century-scale trends (~0.8 C from 1891-1900 to 1991-2000 in the annual mean) seen in this extended Southern Greenland data apparently invalidate the notion of polar amplification as predicted by the ‘models’.

    -> How to debate about polar amplification watching at only Greenland, as it seems that it is a special case. If you look the same trend in Siberia, Northern Canada or Sea at 80th parallel, all of them show a strong amplification and push the average of North pole temperature increasing.
    Greenland as an high altitude inlandsis seems to be very special compared to these regions, and probably has more inertia towards meting, as the center isolated from sea influence and accumulate ice form increasing precipitations.I don’t really remenber what models predict in Greenland, but it doesn’t confuse me if the response is not temporally and geographically the same as other regions.

  19. wacki:

    A small suggestion, how about closing off the link to World Climate Report until they open up comments. Kind of put it out there that if they want links they have to accept comments. Their choice.

    Why? Information is on our side. I link to crappy sources of news all the time. How are people going to compare good info to bad info if you are forcing the people to hunt for the fraudulent info?

  20. Eli Rabett:

    Wacki, information is on our side ONLY if it is seen. Most people who read World Climate Report do not read Real Climate. That, among other reasons, is why blogs such as Climate Audit are censored. In information warfare you use what tools you have.

  21. Hank Roberts:

    Agreeing with the good Dr. Rabett. PR advertising sites never footnote or allow questions — that includes the “science advocacy” PR sites.

    Imagine if health warnings for tobacco advertising weren’t printed along with the tobacco ads, but only in another section of the newspaper under ‘Science’.

  22. Doug Watts:

    Re #21. Well said, Mr. Roberts. A cardinal rule of actual science is that discussion and information exchange is welcomed and fostered. Without this you end up with dogma. As a layman, I applaud the scientists here for being willing to discuss and defend their data, methods and conclusions. Cheers.

  23. Karen Street:

    Re question 2, there has been a change in the estimates of the rate of ice melt in the last year. These were formally presented in February, though Hansen referred to them in his speech last December.

    The 2001 IPCC report described large uncertainties in ice sheet stability; the 2007 report may describe fewer.

    Sea level rise this century was expected to be primarily from warming oceans, but glacier and ice sheet melt may pass warming mid-century. (Note: I don’t contribute to IPCC! this is just my understanding from what I have been reading.)

  24. lars:

    and then there is this……

    Cold set to snap city record

    Environment Canada says such low temperatures unusual for this time of year

    The arctic deep freeze trapping Calgary is on track to break a 110-year-old weather record today, but the bitter cold is expected to ease in the coming days.

    With a forecast low of -31C today, Calgary could break the -27C record set on this day in 1896.

    But factoring in the wind chill, it will feel even colder to people who have to brave the elements, said Environment Canada meteorologist Ross Macdonald.


  25. wacki:

    Eli Rabbet,

    Wacki, information is on our side ONLY if it is seen.

    Ugh… I wish I had your e-mail for a variety of reasons. The most pressing of which is that I’m wondering if we are even talking about the same link. The only link to world climate report I see is the one embedded within the “Historical climatology in Greenland” article that we are currently commenting on. Is that the link you want removed?

    If that is the link currently under scrutiny then how can people possibly click on that link without seeing Gavin’s article? That really doesn’t make a whole lot of sense. If that is the link we are talking about then your only worries are:

    1) Whether or not the random visitor can understand Gavin’s writing style.
    2) If people will put forth the effort to get past that annoying application barrier to see the model data and see the data with their own eyes.

    Gavin’s goal should be to make the pursuit of truth as easy and simple as possible for the average person. If the average reader is forced to spend an inordinate amount of effort either looking for or understanding the data then this blog quickly boils down to little more than a opinion blog. Those types of blogs are only good for either rallying the die-hard loyalists that are already on Gavin’s side of the debate or converting the very rare and very disciplined person that has too much time on their hands.

  26. cbone:

    “In information warfare you use what tools you have. ”

    Oh, I thought this was a science site. In Science, the theory that withstands scruitny wins. Censorship of scrutiny isn’t the same as withstanding it.

  27. lars:

    max global population 500 million

    Gaia scientist Lovelock predicts planetary wipeout

  28. Dan:

    re: 24. The fact is that local daily temperature records (high and low) are often set everyday at various places across the world. That is weather (short term). The issue is climate change (long term). Unfortunately some denialists or those trying to confuse the public intentionally tend to try to disprove climate change by looking at today’s temperature and tomorrow’s weather forecast!

  29. James:

    Re #24: Remember the last couple of summers, when lots of places were setting records for high temperatures? Remember also that (IIRC) one of the predictions of climate models is that warming is likely to result in more extremes of weather? Sounds like that prediction is right on the money :-)

  30. Eli Rabett:

    Micheals and Knappenberger do not have an site open for comments and it has not been open for some time (if it ever was). They are linked to a network of denialist sites and a lot of people get their information from World Climate Report. Knappenberger freely posts at climate sites across the net. Nothing wrong with that, but if he wants his site linked into the discussion he should allow comments on his site so that HIS readers can participate in open discourse. Refusing to link to a site which discourages discourse is quite different from censoring Knappenberger’s posts here.

  31. Ike Solem:

    It’s worth reading the realclimate article on polar amplification at http://www.realclimate.org/index.php?p=234 from Jan 2006 by Cecilia Bitz – yet another example of the great work realclimate is doing.

    Given that the main factor seems to be the retreat of ice/snow cover, then it’s disingenous to claim, as Michaels does, that one can ‘debunk’ polar amplification by looking at Greenland. Rather predictable behavior from the author of “The Satanic Gases”.

    The decrease in Arctic sea ice and the melting permafrost in the Siberian and Canadian tundra point to those regions as far more important sources of data for a comparison to the model results. Plants and animals are responding far more rapidly to these changes then are the ingrained opinions of the climate denialists (all scientists are ‘skeptics’ – it’s something of a prerequisite).

    A record cold snap doesn’t mean much other than that the weather is erratic. Less snow/ice cover can lead to colder winter temps; the Dry Valleys of Antarctic are among the coldest places on Earth. A single measurement thrown out (as in #24) means very little. More chaotic weather is expected as the climate system continues to accumulate energy, as well.

    Re#2 Yes, ten years ago the dynamics of glaciers were not as well understood as they are today. The notion of relatively rapid melting of the Greenland ice sheet was once openly ridiculed by some people, but not any more. This was a case of field data leading to new models. For example, see http://www.sciencemag.org/cgi/content/abstract/311/5763/986.

  32. Lynn Vincentnathan:

    #31, thanks, Ike, for your response to #2. It just makes one wonder what science doesn’t know well right now about global warming & all its ramifications, that will become better known in the future. I do hope science finds out global warming is not as bad as it seems now, but it might find out it’s still worse, beyond the bad things science is now able to predict.

  33. Jason Hornosty:

    As a point of irony.. Chip Knappenberger posted on behalf of World Climate Report asking that the article discussed be linked to so it can be read in context. He then goes on to give a one line quote from the Arctic Climate Impact Assessment Synthesis Report. Of course, he fails to provide a link.

    Arctic Climate Impact Assessment Synthesis Report

  34. Paul Biggs:

    Re;#7 – Why would anyone want to show a one-sided propaganda film from a politician, presented as scientific fact, to their students?

    Gore is chiarman of Generation Investment Management – so he stands to profit from the policies he advocates as a politician:


    The firm was created in 2004 by six founding Partners:

    Hon. Al Gore is Chairman;

    David Blood, the former CEO of Goldman Sachs Asset Management, is Managing Partner;

    Mark Ferguson, previously co-Head of Pan-European Research at Goldman Sachs Asset Management and a Global Equities Portfolio Manager, is Chief Investment Officer;

    Peter Harris, previously head of International Operations for Goldman Sachs Asset Management, is Chief Operating Officer;

    Peter S. Knight, formerly Managing Director Met West Financial, lawyer, Chief of Staff for Senator Al Gore (D-TN) from 1977-1989, and Campaign Manager for President Clinton’s successful re-election in 1996, is President of Generation U.S.; and

    Colin le Duc, previously Director of Research for SAM Sustainable Asset Management in Zurich and strategy consultant for Arthur D. Little in London, is Head of Research.

    Our Chairman, former Vice President Al Gore, has assembled Generation’s Advisory Board which consists of global leaders and thinkers from capital markets, industry, sustainability, economics, and geopolitical fields. The Advisory Board plays an important part in establishing our long term thematic research agenda into global sustainability issues, such as poverty, climate change, ecosystem services, biodiversity, pandemics, demographics, migration, public policy and responsible lobbying.

  35. Glen Fergus:

    #12: “Is the GHCN less complete for the recent few decades for some reason? Or perhaps in the age of satellites and weather models people are unwilling to fund lowly weather stations?”

    Partly the latter Rob, in this country at least (Australia). As well as reduced total numbers of stations, I notice a marked data quality decrease after about 1970, at least for daily rainfall data (my main interest). Stations that operated continuously for decades without a miss suddenly start to lose weekends, holidays, the odd complete month*.

    Traditionally, many manual surface stations were operated by dedicated volunteers, or by extraneous regional goverment employees (often postmasters). Seems the former have lost interest and the latter have all been outsourced. And in developing countries, the loss of the local colonial expat often seems to spell the death knell of many a regional record.

    [* In response, our state government found it worthwhile funding development of an elaborate interpolation-based patching algorithm, now run monthly nation-wide, to provide the gapless data required by modellers.]

  36. Barton Paul Levenson:

    Re “Gore is chiarman of Generation Investment Management – so he stands to profit from the policies he advocates as a politician:”

    Ad hominem arguments are a logical fallacy.

  37. Grant:

    Re: #34

    Re;#7 – Why would anyone want to show a one-sided propaganda film from a politician, presented as scientific fact, to their students?

    Because it’s true!

  38. guthrie:

    Hang on a minute- it was reported on this website that they harvested barley in greenland this year. NOw, by itself, you can take this to suggest that it is only currently as warm as the period the Vikings arrived there.
    So the question is, where was the barley grown? If it was grown in this not-warming-very-fast southern bit of Greenland, that suggests we’ve got lots of painful warming to do. If it was grown in the warming up nicely sides of Greenland, that would suggest that things have not got so much changing to do.
    MAybe I’ll try and look into it tommorrow.

  39. wacki:

    Eli Rabbett,

    …. if he wants his site linked into the discussion he should allow comments on his site so that HIS readers can participate in open discourse. Refusing to link to a site which discourages discourse is quite different from censoring Knappenberger’s posts here….

    Eli, think about this. Gavin isn’t putting a link to World Climate Report on the sidebar. Gavin is linking to an article that is in error and then critiquing that very same article. Yet you think Gavin should close the link? To me that sounds incredibly silly. If we don’t let other people see the proof with their own eyes then why on earth should they believe us?

    Let me describe to you a journey I had a while back. Hopefully this will make things clearer. Although I’ve always been a supporter of alternative energy I used to be a climate change skeptic. I read lots of material on a wide variety of websites. The only reason I trust Gavin’s writings at all is because I am able to check his facts. The same goes with Tim Lambert, Robert Rapier, and even yourself. Over time I’ve checked enough facts to become very impressed with Gavin’s accuracy (as well as yours) and appalled at the gigantor blunders of Pat Michaels and friends. If it wasn’t for this process I would probably still be a skeptic as to the severity of the CO2 driven climate situation.

    This is a process that occurred in my free time. And that means the time allotted for self education is limited. Providing direct links to those blunders allows me to take that journey with not only far more confidence (I’m not required to guess if I have the right article/source) but with far less effort and at a much faster pace. Playing the refuse-to-link wars is not going to force the professional climate change deniers to change their behavior. He can easily ignore it. If you remove the link it will only make it far more difficult for people like me to believe Gavin. I’m simply not going to spend a lot of time googling and hoping I can find the article Gavin is critiquing. And unless I can see the blunder with my own eyes I’m not going to tell other people how Pat Michaels or somebody else screwed up. Even if I know that person has screwed up 1,000 times before I’m not going to publicly criticize this mistake unless I see it with my own eyes. And if somebody is a newcomer to this site you can be damn sure they are going to be far less likely to believe Gavin as they will probably suspect Gavin’s hiding something. I know I would.

    What do you think is easier to accomplish – altering the behavior of a professional lobbyist/denier that has a history of fighting dirty or educating somebody that’s on the fence? I honestly don’t think you have a chance in hell in getting someone to drastically alter their behavior, especially not a paid lobbyist. Refusing to link to them is like cutting off your leg to cure athletes foot. The treatment is worse than the disease. As long as Gavin makes the learning process as painless and as easy as possible the truth will get out. If Gavin want to encourage them to open up the discussion he should add a sentence/footnote about this at the end of each article of theirs he critiques. He should make it painfully obvious that they have a history of refusing open discussion. He does not need to assign motives for this behavior, just show that they are doing it despite frequent requests to change. To me, the only mistake Gavin made was not putting the link up in the first place.

  40. Hank Roberts:

    Remember you can provide a link without increasing the Google searchrank of the destination site.

    To do this, for sites you don’t “recommend” but want to comment on — just leave off the http://

    Without that, it’s not a clickable hotlink; the reader can still paste it into their browser navigation box where it will be recognized.

  41. Doug Watts:

    Gore is chairman of Generation Investment Management – so he stands to profit from the policies he advocates as a politician: http://www.generationim.com/about/team.html — Paul Biggs.
    I like to fish and swim. By your logic, this discredits my statements about the value of clean rivers and preventing water pollution because I stand to directly benefit from the actions I advocate.

  42. SkyHunter:

    RE: #34

    It is true that as a politician, Al Gore has been advocating environmental responsibiity his entire career. However, he formed Generation Investment Management three years after he was out of politics.

    The fact that he has formed an investment company to provide capital for sustainability should come as no surprize to anyone. It is only natural that he continue to pursue his passion in the private sector. I find his efforts, as well as his movie, to be inspirational.

    What would you suggest he do as a private citizen to advocate his beliefs?

    What are you doing to advocate yours?

  43. Sidny Crosby:

    Some of you ‘believers’ are amazing. A skeptical approach to all future forecasts is crucial for a true scientific approach.

    Imagine us still believing in a flat earth just because the church has already proved that that’s the case.

    The point is we don’t know what is going to happen to the climate, we can guess and speculate. Let’s say there are good evidence and al loot that point towards a warmer climate. Do we know what that actually will be like?

  44. SkyHunter:


    It is my opinion that the scientists here are take a careful and skeptical approach. It is the nature of scientists to be skeptical.

    Here is a good place to start looking at what a warmer world would be like.


  45. Leif G Liland:

    The Greenland records show we have reached the spring of the 3500 years long climateyear, no need for CO2 to explain the varmer climate.
    More on http://virakkraft.com/climateyear.doc

  46. Barton Paul Levenson:

    Re “The Greenland records show we have reached the spring of the 3500 years long climateyear, no need for CO2 to explain the varmer climate.”

    Interesting that a 3500-year-long cycle would show such a sharp rise over just the past 30 or 40 years. How does it do that, exactly?

  47. Neal J. King:

    43, Sidny Crosby:

    Imagine refusing to believe in a spherical earth because Rush Limbaugh has refused to accept it.

  48. Leif G Liland:

    re 46.
    Like I said, the total cycle consists of several others. I an attempt to find these and in lack of a proper tool I played a little with excel, result found on http://virakkraft.com/GISP2.xls
    The first curve is the ice core data, the second a simulated curve besed on the assumption that the most siginificant cycles are 20000, 3500, 3000, 875, 437 and 150 years. The third show these cycles individually. The forth is also a part of the core data showing a 1 deg C increase in 40 years, so what we see today is nothing new. I find it quite interesting that the first and second curve are almost identical between 5000 to 3000 years ago. They are not identical over the rest of the span but that should not come as a surprise, I would be more surprised if all the cycles followed a clean sinus-curve over 10000 years, and there is at least one more cycle, the sun-spot cycle of about 11 years that is not included here. But back to your question: At some point several or all the curves may rise at the same time, producing a much more steeper curve than the individual ones. Also note that the amplitude of the single curves is max +/-1 but the resulting is +3/-2.