Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Warm Start to This Year

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The global December 2006 to February 2007 land surface temperature was the warmest on record according to NOAA.

But Melbourne’s The Age newspaper was wrong to suggest this means the planet is “hotter than ever”!

There is some dispute as to whether the planet was warmer than it is now during the medieval warm period (from about the 9th to 14th Century when Greenland was colonised by the Vikings). But I think it is generally agreed that the earth was warmer during the last interglacial warm period which was about 125,000 years ago.

Nevertheless, the warm start to this year does not bode well for the two Russian climate change skeptics who have bet US$10,000 that the earth is going to cool soon. But this year (2007) won’t count. Their bet depends on the period 2012 to 2017 being warmer than the period 1998 to 2003.

temp anomaly dec06-feb07.JPG
Map from NOAA via Luke, added as an update to this blog post on 19th March 2007

Reader Interactions

Comments

  1. Gavin says

    Jennifer: You may have noticed in my post today on Ian’s sea level thread another reference to Luke’s link in my Canberra stormed discussion on the current very warm waters around Bass Strait. This I believe continues to help pelt us from far above.

    See NOAA “Current Operational Coral Bleaching HotSpots for the year 2007” and zoom in on Bass Straight.

    http://www.osdpd.noaa.gov/PSB/EPS/SST/climohot.html

  3. Luke says

    South America, southern Africa and a few parts of Australia, notably the Murray Darling Basin, were warmer than average too. But we are coming out of El Nino. I predicted it of course – see archives.

  4. Jennifer says

    Luke, thanks for the map and could you please provide the URL/some background as a comment?

    Ian, some of your questions perhaps answered with the map added as an update this morning. and sea temperatures were not warmest, details at that NOAA link in the original post.

  5. Schiller Thurkettle says

    Looks like the people in the northern hemisphere are benefiting disproportionately. Coincidence or conspiracy? You decide.

  8. Davey Gam Esq. says

    Pursuing, with dogged determination, my claim for seismic/volcanic activity as a climate factor, those readers actually interested in ideas may care to look at http://www.iris.edu for a map of seismic activity, and the Smithsonian site on global volcanism. Fascinatin’ what? Polly put the kettle on. Look at the Antarctic peninsula.

  9. Ian Mott says

    Just as I thought. Most of the North American “warmer weather” was in the Yukon and Nunavit. Does anyone here actually understand what a 2 degrees warmer temperature anomaly actually feels like in the northern Yukon, in %&$@# January???

    It usually means the difference between minus 20C and minus 22C. I bet the locals are really worried about the fact the snow is only 12 metres deep.

    And it is time we really got stuck into these people who still flog the old Mercators Projection in world mapping. The very good reason why it went out of date long ago was because it seriously distorted the area of high latitude northern hemisphere locations.

    So when we look at this map we all say gee whiz that is an awful lot of warming but in reality it is a gross exaggeration. At that latitude the area of warming is overstated by 100%. Five degrees of Latitude is twice the distance of five degrees of Longitude.

    So when the actual areas involved are considered, we get the temperate and tropical world in a balance of slightly cooler and slightly warmer with a northern winter that is slightly warmer and a southern summer that is slightly cooler.

    Plus ca change, plus c’est le meme chose.

  10. gavin says

    Ian: with a little stretch of our imagination most of us can guess there is a lot less ice round the Arctic edges

  11. Ian Mott says

    Enclose today’s weather for Yellow Knife, NT.
    http://www.weathercity.com/ca/nt/yellowknife/

    I wonder what it was in January?

    Guess we won’t be seeing much glacial melt water for a few months yet, eh?

    Note the absence of any designated time for sunrise. It could be any week now.

    And while you’re at it check out some of the other places like Jakobshavn, Greenland, at
    http://www.weathercity.com/gl/jakobshavn/

    And Yakutsk, Siberia, at
    http://www.weathercity.com/ru/jakutsk/
    Temperature -17C and still no sign of sunrise. That permafrost is still looking pretty solid too, I don’t think the locals are expecting any methane burps just yet either.

    I guess the absence of any sun at all sort of puts the whole scare story about altered Arctic albedo in proper pespective, don’t you think?

  12. Luke says

    Ian desperately pleads a case for a record warming not being a record warming. Actually it was “sooo teeensy weensy” it may have been a cooling if you think about it for a very long time. And hell it was not even in the right spot for Ian. Memo to God “God pls think more carefully about the next place for a record warming so your cherub Ian is happier”.

    Why not just say “cool” a record warming across a fair swag of the northern hemisphere – how interesting. Let’s see how the year progresses.

  14. Ian Mott says

    The curious thing about the NOAA map is to look at each point and determine the extent to which any warming has actually had on melting ice sheets and how that feeds into this single number called the global mean temperature.

    Remember, this map represents 25% of all the records that go into compiling this global mean temp. We can say with absolute certainty that;

    1 None of the high anomaly warming points have contributed to melting ice sheets or melting permafrost because they have all taken place in northern hemisphere mid winter and have involved temperatures that are still well below freezing.

    2 None of the cooler anomaly points have contributed to any abnormal melting of ice sheets or permafrost because they are, by definition, cooler than the norm, especially in the southern summer.

    3 The remainder of the planet in the temperate and tropical zones is clearly in a balance of warming and cooling that is very much within the normal range.

    Conclusion

    While it may be the case that the December to February data may amount to a warmer change in the data that makes up 25% of global mean temperature, the net impact on ice sheets of this supposed warming is zero.

    It is a warming on paper only and it is entirely within the historical norms.

    Indeed, as ice melt at the poles only takes place in the three months of each hemispheric summer, we must conclude that ice melt for the southern half of the annual equation is less than the norm.

    Watch this space for June, July and August data.

  18. Paul Biggs says

    I saw this from Doug Hoyt:

    Ren G. Y., Z. Y. Chu, Z. H. Chen, Y. Y. Ren (2007), Implications of temporal change in urban heat island intensity observed at Beijing and Wuhan stations, Geophys. Res. Lett., 34, L05711, doi:10.1029/ 2006GL027927.

    Zhou L. et al. (2004), Evidence for a significant urbanization effect on
    climate in China, PNAS, 101, 9540-9544.

    Using Ren et al and the HadCRUT3 temperature data, we have:

    HadCRUT3 temperature trend for 1960-2006 = 0.238 C/decade
    UHI = 0.155 to 0.190 C/decade
    HadCRU3 corrected for UHI = 0.048 to 0.083 C/decade, for eastern China.

    Similarly, using Buntgen et al for central Europe for 1942-2006, we have:

    HadCRUT3 trend = 0.113 C/decade
    UHI = 0.113 C/decade
    HadCRUT3 corrected for UHI = 0.00 C/decade

    It would appear that if UHI effects were properly corrected for, then the net global warming in the 20th century would be much less than 0.7 C, perhaps around 0.2 to 0.3 C.

    These studies and other similar ones raise lots of doubts about the validity of the present temperature reconstructions.

    Comment by Douglas Hoyt — March 17, 2007

  19. Paul Biggs says

    We’re off to an above average start in the UK for 2007 temperatures. This week however, we’re getting a cold blast from the Arctic that is bringing low temperatures and snow.

  20. rojo says

    Interesting discussion on radio national about ice cores and methane on the science show radio national. Sat Mar 17.
    http://www.abc.net.au/rn/scienceshow/

    basically says that methane in the permafrost soils will be taken up by microbes and converted to CO2 and shouldn’t add too much to feedback.
    The Prof. is not to optimistic about greenlands ice sheets though

    skip in about 20 mins for the interview.

  21. gavin says

    Paul; 22.7 C here downunder at bed time, no A/C either.

    Be assured too people behind all that data at NOAA are no fools and will have accounted for something as simple as major UHI everywhere.

    nite all

  23. Paul Biggs says

    Roger Pielke Sr will tell you about warm bias in surface temperature – not just UHIE – if it’s ‘simple’ why hasn’t it been properly corrected for?

  24. SJT says

    It’s not simple, and they’ve been putting a lot of work into understanding it. So far, it’s been overstated. I think the glaciers are proof of that.

    China has just undergone a massive change in technology and economic growth, there is no evidence that this effect would apply to other countries.

  26. Ian Mott says

    So, Luke, SJT and Gavin simply go into denial mode to avoid a conclusion that is staring them in the face.

    So which part was the “utter nonsense” fellas? The actual temperatures in the North West Territory? Greenland? Siberia? Or the fact that this warming was limited to reduced extreme cold temperatures?

    Or are we now denying that this set of temp records make up 25% of the compilation of the annual mean temperature?

    Perhaps you guys would like to explain how higher than average sub-freezing mid-winter temperatures actually melt ice sheets.

    And as for Gavin’s little chestnut about there being a lot less ice around the arctic edges is complete bollocks because the places with the high anomalies are all still well below freezing.

    It has not dawned on these clowns that there are no degrees of freezing. It is either freezing or it is not freezing. Unlike spring or autumn weather, arctic cold weather is all freezing. The anomalies are only relevant once the temperature nears or exceeds the melting point of ice.

    And the line from Luke about the NOAA guys being so clever that they are bound to have taken out the Urban Heat Island (UHI) effect just about says it all. “Trust me, I’m an expert”, yeah, right Lukey.

    So why didn’t Jones provide his data to substantiate his claim to have removed the UHI?
    And how can NOAA have taken it all out when we know that UHI is not the only distortion. UHI does not include changes from landuse change. The discussion to date on UHI has all assumed that rural location means an absence of UHI type distortion which Luke knows perfectly well is bollocks.

  27. gavin says

    Yeah Ian, I worked with a few clowns and met others who insist on communication via the Khyber Pass. In case other readers thought I came down in the last shower let’s chat about “degrees of frozen” for a mo.

    About 40 yrs ago a fellow factory worker presented me with a big fish still “deep frozen” at -40C, and then he deliberately dropped it on to the concrete roadway, warmed by the morning sun near the works canteen. Guess what; the whole thing instantly shattered like a fine crystal glass into a million pieces. By lunchtime all that was left was the horrible fishy stench, a potent reminder to the squeamish diners. We made paste.

    The moral of that story is I was about to go inside with my minder in the ship load of “couta” and work on their thermometers. We each carried a stopwatch and locked the warehouse freezer doors from the inside. I knew from this and other experience there was no chance of me making up with teams destined for Antarctica despite the frequent invitations from veterans who ran the selection. That’s all about carrying blubber.

    Back to NOAA: Any idiot glancing at Luke’s map tendered above (curtesy Jen) can see the “majority” of the earth’s surface temperature is above the “norm”. Why some here want to go fishing for – “anomalies” instead of discussing the implication of say the “minium” + deviation defies any ordinary logic.

  28. Ian Mott says

    Gavin, you have tried on some shockers here but that was a good one. I would have thought a map of temperature anomalies might be a good place to “go fishing for anomalies”, as you put it.

    And as for your fish anecdote. When you have evidence of the equivalent of an ice sheet being dropped on a hot cement pavement do come and talk about it here.

    And as for the NOAA map, that is just the point, any idiot glancing at that data placed on a mercators projection map of the world, as in this case, will gain the false impression that “the majority of the Earth’s surface temperature is above the norm”.

    But when the data is placed in proper spatial proportions there is no such impression. On a mercator projection the top of Greenland looks almost as wide as the width of Australia when in fact, it is only 1000km wide, the distance from Sydney to Broken Hill.

    Or are you, Luke and SJT now even claiming that there is no such narrowing of meridians near the poles? If that is the case then you have certainly identified yourself in the category of “any idiot”.

  29. Sid Reynolds says

    I posted on a previous thread, another NOAA report released this month which stated tha the US had recorded its av. Feb. 07 temp at 32.9 F which was 1.8F cooler then the 1901/2000 average. This made it the 34th coldest Feb. for 113 years up to the present.

    Further, Anchorage has its harbour frozen solid still, which is most unusual for late March. They have not had a day above freezing since Feb. 3rd. which puts them close to an all time record. (Previous record, 1956 with 41 days below freezing).

    Here in Australia, the BoM has just quietly released their climate review for the summer Qr. just ended which says that Aust. has experienced a relativly cool summer, with many areas experiencing below av. min and max temps. This is after their much trumpeted forecast last Nov. that because of ‘global warming’ Aust. could expect an extremely hot summer.

    I can’t see how’Any idiot glancing at Luke’s map’ could see that the majority of the earth’s surface temp. was above normal. Even with the distortion of Mercator’s Projection!

  30. Luke says

    Look at em’ go. But but but but – “look here’s an issue” – “oh but what about this” – you guys are rabid and frothing at the mouth aren’t you.
    Soooo desperate to hold back the tide as the realisation sinks it that “jeepers this might be happening after all”.

    I’m not making much out of all this post – you are. Just anothe rpoint on the long graph gentlemen (and others).

    I reckon Ian is right – there’s sooo much UHI – that everywhere is UHI – so therefore UHI is the norm so it’s a representative sample of “reality”.

    Is anyone except Ian bleating on about melting?

    Sid throws some handpicked cherries – ROTFL.

    And Ian your good friend in tree clearing Sir William would tell you – the trend is your friend. And the trend my friend is up up up .. .. hahahahhahah LMAO.

    Supported by more than just surface temperature data. Ian have you ever thought of not being such a tosser and only swinging at balls you can hit?

    Keep it up guys – I’m kacking myself at your antics.

    “But but but but but” hehehahahahehehaha oh it hurts.

    “reduced extreme cold temperatures” – it’s on the noticeboard and they’ve all gathered to read.

  31. Ian Mott says

    All Luke can come up with is substance 0.5, invective 9.5, defamation 7.5 and avoidance 9.5, just another day of climate cretinism.

    It is all getting pretty obvious, guys. It must be a change of strategy from getting a drubbing every time you venture into the world of fact. And best stick to posting links Luke, keep clear of facts, and be really careful of maths, it will always be your undoing. Ideas never have to add up do they?

    These damned right wingers keep adding things up. We give them all the “education” they need and the bastards keep checking the figures. They got no damned gratitude, have they Luke?

  32. gavin says

    I was waiting to see if anyone else would state the obvious re UHI, that these unfortunate truths too are also part of the general global warming.

    Why not put a few in for good measure? since Ian here for one has no idea how to reverse any of them.

  33. SJT says

    Sid

    it had one of the coldest Feb for a while, after the hottest start to winter on record. My hottest on record trumps your one of the coldest.

  34. Luke says

    Wot an opinionated blowhard you are Mott. If you believe you know anything keep on dreaming. So far you’ve no come up with a single factoid of relevance. I’m actually surprised.

    But is an education what brown scum you guys are and how low you’ll sink.

  35. Ian Mott says

    Gavin, urban heat island (UHI) effects and landuse effects may well be part of a general warming but if they are exaggerating the impact of CO2 emissions then we need to know about it before we put the whole carbon economy on a Prozac vacation.

    Hhmmn, as I thought, Luke at the end of his tether, sacred cows in the bog of deception. An intelligent man would change his views to fit the facts but the mediocre just lash out.

    Best buy a black dog, Walter Mitty, a small one that won’t bite back.

  36. Luke says

    On the contrary I cannot believe how much you’re bucking the trend of up up up. Rabid is the word. You’ll have to come round eventually. So insteasd of worrying about belching cows in methane emitting bogs you’ll be mending fences.

  38. Paul Biggs says

    “Fuelling further fears of global warming, US scientists yesterday announced that the northern winter just ended was the warmest on record.”
    http://www.theaustralian.news.com.au/story/0,20867,21396464-30417,00.html

    These stories are triumphs of climate prediction, in that they claim records for a season that had not yet finished. Indeed, as I write on the afternoon of March 19th (UTC), the northern winter has yet to reach its conclusion.
    Although people very often regard winter as stretching from 1st December through until the end of February (as is explicit in the LA Times quote above), strictly that season lasts from the winter solstice (about December 20-22) until the vernal equinox (about March 19-21). The distinction I am drawing here is not simply pedantic, as explained below.

    The winter solstice is defined by the instant when the Sun reaches its southernmost point in the sky (‘solstice’ is derived from the Latin ‘sol stetit’, meaning ‘the Sun stands still’). The equinox (which is not actually when there is equal day and night length, as its Latin derivation implies) occurs when the Sun crosses the celestial equator (but note that modern astronomers define the equinox instant slightly differently, in terms of the mean solar longitude rather than its latitude).

    This year the equinox occurs at approximately seven minutes past midnight on March 21st (UTC), the date being that the Catholic Church defined in 1582 to be the (ecclesiastical) equinox for Easter calculations in perpetuity. In fact the astronomically-defined equinox will not fall on that date again until the year 2102.

    The above information should draw some attention, even from those who are not religiously-inclined in any way. The point is that the equinox is now occurring progressively earlier in the year. Taking a wider timebase, in the present segment of the overall leap year cycle of 400 years the latest that the equinox has occurred was just after 7pm on 21st March in 1903, and the earliest is just before 2pm on 19th March in 2096. That is, the equinox shifts over a range of about 53 hours. Thus when you hear someone claim that Spring is now coming earlier, you can confirm that indeed it is, as defined by astronomical science.

    The dates above are given on the calendar that is the global standard, which I prefer to refer to as being the Western Calendar. It is most often referenced as being the Gregorian Calendar (i.e. the calendar promulgated by the bull of Pope Gregory XIII in 1582), but this is technically incorrect in that the Gregorian Calendar is a luni-solar calendar defining ‘years’ in cycles of 12 and 13 lunar months for use in defining the dates of Easter, rather than the purely-solar calendar that we use for secular affairs.

    And that’s the whole point. Our everyday calendar derives from a scheme for fixing Easter, rather than following the cycle of the seasons. It follows that any comparison of climate records for particular dates, months or periods like December-February is founded on a false assumption: that, seasonally-speaking, all Decembers (say) are comparable. In terms of their distance from any of the solstices or the equinoxes, the months jump around by more than a couple of days.

    In terms of the viability of the foundations of such climate comparisons, it gets worse. Currently the northern winter (winter solstice to vernal equinox) lasts for about 88.8 days. The percipient reader will have noticed that to be rather less than a quarter of the year. On the other hand the northern summer (summer solstice to autumnal equinox) lasts for 93.7 days, rather more than a quarter of the year. These different durations are due to the fact that the Earth passes perihelion in its orbit around 4th January (on the Western Calendar) and aphelion around July 4th. At perihelion our planet is closest to the Sun, and is moving the fastest it ever does (about 30.3 km/sec) whereas at aphelion it has slowed to about 29.3 km/sec. This causes the seasons to have contrasting lengths.

    This situation does not remain forever, though. The date of perihelion shifts later by about one day every 60 years on the Western Calendar. This means that the duration of the northern winter will reach a minimum when perihelion is mid-way between the winter solstice and the vernal equinox in about 1800 years’ time. Over many millennia the precession of perihelion compared to the solstices and equinoxes causes all of the seasons to cycle through extrema of duration. Currently the northern winter is shorter but warmer than the equivalent southern season, whereas in 11,000 years’ time it will be the other way around.

    My mention of perihelion and how it shifts on the Western Calendar reminds me of a paper by David J. Thomson that was published in the 7th April 1995 issue of Science. Analysing all temperature records available from soon after the thermometer was invented (1659) he found that the cyclicity of such records was, until the past half-century or so, the anomalistic year (that is, the time between perihelion passages) rather than the mean tropical year (the long-term average time between solstices and equinoxes).

    The latter has always been assumed to be seasonal/temperature cycle, and indeed that assumption was implicit in my discussion above, meaning that Thomson’s result was surprising. The breaking of that cycle (anomalistic year) and picking up of the other (mean tropical year) since about 1940 was discussed in terms of being caused by anthropogenic climate change. However, I would suggest an alternative hypothesis: that the Earth’s climate cycle latched onto the anomalistic year due to the proximity of perihelion to the winter solstice (they were aligned about 700 years ago) and that the precession that has subsequently caused their widening separation (December 21st to January 4th) eventually caused a cessation in that cyclicity. So far as I am aware, the significance of Thomson’s work and the various possible explanations have never been properly investigated.

    A calendar note: since the anomalistic year lasts for about 365.256 days, if it were used as the basis of a calendar there would be a leap year every four years plus an extra day (a 367-day year) once per century.

    To return to the main aim of this essay: it is misleading to compare climate records in terms of months on the Western calendar (e.g. December-February). Due to the influence of (the shifting) perihelion, it may even be misleading to compare climate records for seasons defined astronomically (e.g. winter from the winter solstice to the vernal equinox). For example, over the present two centuries the date ‘1st January’ oscillates by more than two days when compared to the solstices and the equinoxes; and every sixty years it moves more than a full day away from the time of perihelion passage.

    Although such factors may not in themselves explain the observed temperature trends, they should at least be considered and acknowledged. It is possible to compare apples and oranges (apples are either green or red, whereas oranges are orange), but you must be careful.

    Duncan Steel
    Canberra, Australia
    nacnud@grapevine.com.au

  39. SJT says

    Paul

    If that is how they measure it, then that’s how they measure it. That’s how they compare their winter from year to year. All you are doing is shifting the goal posts. They are comparing apples to apples each year. If you feel they should be comparing oranges to oranges, fair enough, but the apples appear to be getting hotter.

  40. Luke says

    Paul – two days in 2 centuries – so what?

    Triumph of climate prediction? Not really – just another data point in the series.

  42. Ian Mott says

    Unlike the three stooges (Luke, SJT and Gavin) I see no cause to sneer at Duncan’s post. In fact, this issue needs much closer examination. In particular the fact that;

    “Currently the northern winter (winter solstice to vernal equinox) lasts for about 88.8 days. The percipient reader will have noticed that to be rather less than a quarter of the year. On the other hand the northern summer (summer solstice to autumnal equinox) lasts for 93.7 days, rather more than a quarter of the year. These different durations are due to the fact that the Earth passes perihelion in its orbit around 4th January (on the Western Calendar) and aphelion around July 4th. At perihelion our planet is closest to the Sun, and is moving the fastest it ever does (about 30.3 km/sec) whereas at aphelion it has slowed to about 29.3 km/sec. This causes the seasons to have contrasting lengths”.

    So we have an orbital influence on Earthly climate. But it is interesting to contrast the responses of Luke and SJT above with their ready acceptance of orbital change in relation to Mars and Pluto on a previous post. http://www.jennifermarohasy.com/blog/archives/001947.html#comments

    As SimonC put it;

    “Simply put – Mars shows large fluctuations in temperature due to its eccentric orbit and dust storms coupled with little atmosphere and a lack of seas or oceans to moderate temperature”.

    So the question then comes down to, how significant is this Earth orbital change?

    We know that the current temperature of the Earth is 173K plus about 14C to equal 187K. And there are loudly stated fears that CO2 could increase this temperature by 3C/K by year 2100. This 3 degrees warming cannot be expressed in percentage terms in relation to the 14C. It must be expressed in terms of changes in degrees Kelvin and that makes the feared change 3/187 or a 1.6% change in temperature.

    The claimed 0.6 degrees warming over the past century is 0.6/187 or 0.32 of 1% change.

    So how does the orbital change compare?

    If a normal calendar summer is 91.25 days but the current orbital summer is 93.7 days then the polar exposure to ice melting solar energy is 2.45/91.25 or 2.685% longer than the long term mean.

    It also means the polar exposure to an ice forming absence of solar energy is also 2.685% shorter than the long term mean. And this produces a net flux of 5.37% of that mean.

    And if it takes 11,000 years to reverse this effect then this cycle is likely to have cobtributed 11,000/5.37% each year ir 110/5.37% each century or about 0.15 of a degree of warming over the past century.

    I would welcome more detailed calculations and any corrections that need to be made.

    But given that UHI effects are considered by some to account for half the recorded warming over the past century leaving an actual warming of 0.3C over the past century, then orbital change is likely to have contributed 0.15C or half the change.

    It is also worth noting that this orbital effect is manifest in the winter and summer. Spring and autumn, being the transitional phases between the two warm and cold extremes, remain fairly constant. And this means the actual impact of this orbital effect will be more pronounced at the solstice points. Most of the extra days in summer will be in mid-summer and most of the missing winter days will be mid-winter days. And this would suggest that the warming will be greater than the simple mathematical proportion and the lack of cooling in winter will also be greater than the simple mathematical proportions.

    One thing we can say is that this hypothesis is entirely consistent with a sequence of record warm winter minimum temperatures as reported recently.

    This needs a great deal more detailed examination, don’t you think?

  43. SJT says

    Ian

    every year they adjust the time, as needed, by few seconds, to ensure the seasons aren’t drifting.

    http://news.bbc.co.uk/2/hi/science/nature/4562194.stm

    “Scientists are delaying the start of the New Year by adding the first “leap second” in seven years.

    The Paris Observatory said an extra second would be added to clocks worldwide at the stroke of midnight on 31 December.

    Leap seconds are required every so often to keep our clocks in sync with solar time used by astronomers.

    “Enjoy New Year’s Eve a second longer,” said the researchers at the US National Institute of Standards and Technology.

    Tidal friction

    The International Earth Rotation and Reference Systems Service, based at the Paris Observatory, tells the world every six months whether to add or subtract a second from atomic clocks, the standard for everyday timekeeping.

    A leap second is added to Co-ordinated Universal Time (UTC) to keep it in step with solar time – based on the Earth’s rotation on itself – to within a second. ”

  44. Ian Mott says

    Upon reflection there are a few corrections needed to my above post. The current temperature of the earth is 273k +14c which equals 287K, not 187k as mentioned above. And in the calculation of temperature change I neglected point out that a change of 5.37% in temperature is 287K x 0.0537 or 15.4C.

    When this is spread over 11,000 years we get a mean change each century of 0.14C. It is still much the same significance as the previous calculation but this time it is properly obtained.

    SJT the minor adjustments to the atomic clock have nothing to do with this topic. Lift your game and think about it.

  46. SJT says

    Ian

    they have known about the Milankovich cycles for years. Apparently, long before you did.

  47. Luke says

    Good grief – (a) 14 deg av temp for polar regions (b) Arctic is warming proportionately more it seems (c) Antarctic isn’t moving as much showing non-linearities like meteorology have an effect – so therefore who says autumn and spring are equal (d) who says it’s 11,000 years (e) no attribution for the role of CO2 in that warming and why not (f) is the rate of orbital change linear as our solar output hasn’t changed much recently

  48. Ian Mott says

    Luke, you should recognise 14C as the global mean temp. Obviously the mean Arctic temp is a lot lower and obviously the difference between the calculated percentage change of 15.4C and the actual long term range of variation as per the Vostok ice cores of about 12C is due to circulation of oceans and air.

    Duncan said it was 11,000 years I took that on face value until demonstrated otherwise. Do you have a better number?

    And SJT, most of us knew about the cycles but I had not had the information to be able to get right into the basic numbers until Duncan’s post. But if you knew about them, then how come you gave us that silly post about atomic clock adjustment?

    I would have thought that it was pretty obvious that this was a rough ballpark examination that was once removed from thinking aloud. I also made a point of inviting any additional information to improve our understanding of the issue.

    Paul, can Duncan expand on any of this for us? The chances of constructive input from the stooges seems pretty slim.

  49. Sid Reynolds says

    I have always thought that precession would have some bearing on temp. changes in the polar regions. The earth’s precession orbit, or wobble, occurs over a 26k year period I believe.
    Does anyone know the distance of the rotation of true north and south over this period?
    If in fact it is several hundred kilometers, this could contribute to one side of arctic and antarctic regions getting warmer while the other side gets cooler. Gradually of course.

  52. Ian Mott says

    That is a link to solar iradiance, Gavin, nothing on Duncan.

    Good question, Sid, can anyone fill us in? Rotational impacts at the poles are clearly present but where do they fit into the whole picture?

  54. Mark A. York says

    “Gavin, urban heat island (UHI) effects and landuse effects may well be part of a general warming but if they are exaggerating the impact of CO2 emissions then we need to know about it before we put the whole carbon economy on a Prozac vacation.”

    Tee hee! Still holding fast to “Jurassic” warming! yeah it’s the asphalt. Feel that tremor? There’s a problem on the Tyrannosaur paddock. Clever girl!